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Organic Vegetable Production - New York Cooperative Extension


Organic Vegetable Production - New York Cooperative Extension

Organic Vegetable Production - New York Cooperative Extension

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  • 1. Fair Use of this PDF file of Organic Vegetable Production, NRAES-165 Proceedings from NYS Agricultural Experiment Station, January 14–16, 2003 Published by NRAES, March 2004This PDF file is for viewing only. If a paper copy is needed, we encourage you to purchase acopy as described below.Be aware that practices, recommendations, and economic data may have changed sincethis book was published.Text can be copied. The book, authors, and NRAES should be acknowledged. Here is a sampleacknowledgement:----From Organic Vegetable Production, NRAES-165, published by NRAES (2004).----No use of the PDF should diminish the marketability of the printed version. This PDF shouldnot be used to make copies of the book for sale or distribution.If you have questions about fair use of this PDF, contact NRAES. Purchasing the BookYou can purchase printed copies on NRAES’ secure web site,, or by calling (607)255-7654. Quantity discounts are available.NRAESPO Box 4557Ithaca, NY 14852-4557Phone: (607) 255-7654Fax: (607) 254-8770Email: nraes@cornell.eduWeb: www.nraes.orgMore information on NRAES is included at the end of this PDF.
  • 2. AcknowledgmentsPartial FundingThe Organic Vegetable Production workshop was partially funded by the Northeast Region SustainableAgriculture Research and Education (SARE) program, which is administered by the Cooperative StateResearch Education and Extension Service and the USDA.About the Workshop and ProceedingsThe workshop was coordinated by Abby Seaman, Area Extension Educator, New York State IntegratedPest Management Program, Cornell Cooperative Extension. The proceedings was edited by Abby Sea-man.These meetings were intended for commercial vegetable growers who are currently growing organicallyor want to learn more about organic practices, as well as beginners contemplating organic vegetableproduction. University and farmer speakers covered the basics of soil and nutrient management, weedmanagement, and insect and disease management.Thanks to SpeakersThe workshop coordinator and NRAES would like to thank the speakers for their diligence in submit-ting their papers for these proceedings.DisclaimerTo simplify information, trade names have been used in this publication. No endorsement of namedproducts is intended, nor is criticism implied of similar products that are not mentioned.Proceedings ProductionJeffrey S. Popow, NRAES managing editor, designed the proceedings and managed the proceedingsproject.About NRAESSee the inside back cover for information about NRAES, including contact information and a list ofNRAES member universities.
  • 3. Cooperative Extension NRAES–165 Organic Vegetable Production Proceedings from a Three-Day Series of Meetings Jordan Hall Auditorium New York State Agricultural Experiment Station Geneva, New York January 14–16, 2003 Natural Resource, Agriculture, and Engineering Service (NRAES) Cooperative Extension PO Box 4557 Ithaca, New York 14852-4557
  • 4. NRAES–165 March 2004 © 2004 by NRAES (Natural Resource, Agriculture, and Engineering Service). All rights reserved. Inquiries invited. ISBN-13: 978-0-935817-96-6Requests to reprint parts of this book should be sent to NRAES. In your request, please state whichparts of the book you would like to reprint and describe how you intend to use the reprinted material.Contact NRAES if you have any questions. Natural Resource, Agriculture, and Engineering Service (NRAES) Cooperative Extension PO Box 4557 Ithaca, New York 14852-4557 Phone: (607) 255-7654 Fax: (607) 254-8770 E-mail: Web site: www.nraes.orgii
  • 5. ContentsAbout the Speakers................................................................................................................... viSoil and Nutrient ManagementSoil Life..................................................................................................................................... 3 Janice Thies Department of Crop and Soil Sciences Cornell UniversityInterpreting Soil Test Results and Estimating Nutrient Availability.......................................... 6 John Howell UMass Extension University of MassachusettsTillage Practices for Maintaining Soil Quality........................................................................ 16 Harold van Es Department of Crop and Soil Sciences Cornell UniversityCompost and Cover Crops for Organic Vegetable Growers.................................................... 21 Brian Caldwell Northeast Organic Farming Association of New YorkSoil and Nutrient Management Practices on Upingill Farm.................................................... 24 Cliff Hatch Upingill Farm Gill, MassachusettsSoil and Nutrient Management Practices on Roxbury Farm................................................... 34 Jean-Paul Courtens Roxbury Farm Kinderhook, New YorkFertility Management at Roxbury Farm.................................................................................. 45 Jean-Paul Courtens Roxbury Farm Kinderhook, New York iii
  • 6. ContentsWeed ManagementUnderstanding Weed Biology.................................................................................................. 59 Charles L. Mohler Crop and Soil Sciences Cornell UniversityWeed Management on Organic Vegetable Farms.................................................................... 76 Vern Grubinger University of Vermont ExtensionHow to Get 99% Weed Control without Chemicals................................................................ 83 Brian Caldwell Northeast Organic Farming Association of New YorkMulching for Weed Control and Organic Matter..................................................................... 87 Paul Arnold Pleasant Valley Farm Argyle, New YorkBio-Extensive Approach to Market Gardening..................................................................... 100 . Anne and Eric Nordell Beech Grove Farm Beech Grove, PennsylvaniaA Few Long Furrows on Horsedrawn Tillage....................................................................... 105 . Eric and Anne Nordell Beech Grove Farm Beech Grove, Pennsylvaniaiv
  • 7. ContentsInsect and Disease ManagementImpacts of Soil Quality on Disease and Insect Resistance in Plants..................................... 113 Anusuya Rangarajan Dept. of Horticulture Cornell UniversityDisease Management Strategies: Cultural Practices.............................................................. 120 Helene R. Dillard Department of Plant Pathology New York State Agricultural Experiment Station; Geneva, New York Cornell Cooperative ExtensionCultural Practices for Disease Management.......................................................................... 123 Curtis Petzoldt Integrated Pest Management Program New York State Agricultural Experiment Station; Geneva, New YorkIdentifying and Encouraging Beneficial Insects.................................................................... 128 Michael P. Hoffmann NYS IPM Program and Department of Entomology Cornell UniversityInsect Management:Managing Beneficial Habitats, Using Organic Insecticides.................................................. 136 Ruth Hazzard Dept. of Entomology University of Massachusetts ExtensionPest Management on Applefield Farm................................................................................... 142 Steve Mong Applefield Farm Stow, MassachusettsPest Management from a Farmer’s Perspective.................................................................... 152 . David Marchant River Berry Farm Fairfax, Vermont v
  • 8. About the SpeakersPaul Arnold and Sandy Arnold have been farming at David Marchant and Jane Sorensen operate River BerryPleasant Valley Farm for 12 years and raise about 8 acres of Farm alongside the LaMoille River in the Champlain Basinorganic fruits and vegetables on their 60 acres in Washington of Vermont. They grow approximately 40 acres of certifiedCounty, New York, with two children. Their living is made organic vegetables, 4 acres of IPM managed strawberries,by selling all of their produce at 4 area farmers’ markets. and 15 acres of grain. The vegetables are marketed out of state through the Deep Root Organic Cooperative, and lo-Brian Caldwell is the education director for NOFA-NY. cally through stores and farmers markets.He is also an experienced grower of organic vegetables andfruit at Hemlock Grove Farm in West Danby, New York. Chuck Mohler is a senior research associate in the depart- ment of Crop and Soil Sciences. Most of his work hasJean-Paul Courtens, the founding farmer of Roxbury Farm, focused on the effects of tillage, cultivation, and crop residuewas born and raised in the Netherlands, where he studied on the population dynamics of annual weeds. He is a co-biodynamic agriculture. Roxbury Farm grows vegetables, author of the book Ecological Management of Agriculturalherbs, melons, and strawberries using biodynamic practices Weeds.on 148 acres in Kinderhook, New York for a CSA of 650families in four communities. Steve Mong, his wife Kirsten, and brother Ray have operated Applefield Farm for 20 years. It is a 25-acre farm with 20,000Helene Dillard has conducted basic and applied research square feet in greenhouses, which are used for bedding plant,on the biology, ecology, and management of fungal and hanging basket, annual, and perennial production. Steve hasbacterial pathogens of vegetables at the New York State been an active cooperator in University of MassachusettsAgricultural Experiment Station in Geneva, New York since pest management trials.1984. She has been the director of Cornell CooperativeExtension, a primary outreach unit of Cornell University, Anne and Eric Nordell grow vegetables, herbs, andsince 2002. strawberries on 6.5 acres in Trout Run, Pennsylvania. They have developed an elegant whole farm approach to nutrientVern Grubinger is the director of the Center for Sustainable and weed management. Their produce is marketed throughAgriculture at the University of Vermont. He has extensive grocery stores, restaurants, and farmers’ markets.experience in many aspects of organic and sustainable veg-etable and small fruit production. He is the author of the book Curt Petzoldt is the Assistant Director and Vegetable Coor-Sustainable Vegetable Production from Startup to Market. dinator at the New York State IPM Program. For the past ten years he has conducted multidisciplinary trials comparingCliff Hatch has over 20 years of experience in organic the environmental and economic attributes of conventional,production. He grows a variety of vegetables, strawberries, IPM, and organic production systems at the research farmand grains at Upingill Farm in Gill, Massachusetts. and on growers’ farms.Ruth Hazzard is team leader for the Vegetable Program Anu Rangarajan is an associate professor in the Departmentand also coordinates the Integrated Crop and Pest Manage- of Horticulture at Cornell and statewide specialist for Freshment Project for vegetables. Her research has focused on Market Vegetable Production. Her research program focusesinsect and disease management in brassicas, sweet corn, on specialty crop variety trials, and developing productiontomato, and peppers. Currently she is involved with studies systems that minimize chemical fertilizer and pesticideon biointensive insect management in brassicas, cucurbits, inputs and maximize crop nutritive value.and sweet corn. Janice Thies is an associate professor of soil biology whoMike Hoffmann is the director of the New York State IPM joined the Cornell faculty in 2000. Janice’s research programProgram and a professor in the Department of Entomology focuses on three main areas: soil microbial population genet-in Ithaca. His research and extension program focuses on ics, the influence of management practices on soil microbialalternative insect management strategies. community structure, and the development of biofertilisers and biopesticides for use in low-input agriculture.John Howell recently retired as Extension VegetableSpecialist at the University of Massachusetts. His areas Harold van Es joined the Cornell faculty in 1988. Hisof special interest include vegetable production systems, research, extension, and teaching programs address thenutrient and soil management, greenhouse tomato produc- management of soil and water resources for sustainabletion, trickle irrigation and fertigation, and water garden agricultural production and environmental protection. Heconstruction and maintenance. is a co-author of the book Building Soils for Better
  • 9. This page is from Organic Vegetable Production, NRAES-165. To purchase the book,visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Soil and NutrientManagement
  • 10. This page is from Organic Vegetable Production, NRAES-165. To purchase the book,visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.
  • 11. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Soil Life Janice Thies Associate Professor Department of Crop and Soil Sciences Cornell UniversityThe diverse and numerous creatures living in the soil Soil arthropodsprovide a variety of benefits to crops and but also havepotential detriments. The benefits include the decom-position of organic matter, nutrient cycling and release, There are four major groups of soil arthropods. Preda-nitrogen fixation and mycorrhizal relationships, disease tors such as ants, ground beetles, and spiders help con-suppression, and soil structure improvement. Potential trol crop pests. Another group including dung beetles,detriments include immobilization of nutrients and the mites, and sow bugs shred organic matter. Fungal feed-ability to cause plant and animal disease. ers such as springtails and turtle mites release nutrients tied up in fungal biomass. And herbivores such as mole crickets and symphylans can cause crop damage bySoil food web feeding on roots. Functional roles of arthropods include shredding of organic matter which stimulates microbial activity, mixing microbes with organic matter, miner-The complex network interactions that occur between alizing plant nutrients, increasing aggregation of soil,organisms in the soil is sometimes described as the burrowing, which increases soil channels, preying onsoil food web. Plants are the foundation of the soil other arthropods, and feeding on web, capturing energy from the sun throughphotosynthesis and providing the organic matter thatother organisms work on. Decomposers such as bac- Earthwormsteria and fungi work on the material produced by theplants releasing nutrients in a form that is usable byplants. Small arthropods, nematodes, protozoa, and Earthworms are another important group soil or-earthworms shred and consume the organic matter ganisms, considered by some to be soil ecosystemproduced by the plants, making it more available to the engineers. They move tremendous amounts of soilbacteria and fungi, and also consume the bacteria and through their guts as they burrow. In the process, theyfungi themselves, releasing plant-available nutrients. stimulate microbial activity, mix and aggregate soil,Larger arthropods and small mammals then consume increase soil infiltration rate and water holding capac-the smaller creatures releasing more nutrients. ity, create channels for plant roots, and bury and shred plant residues.Soil and Nutrient Management 3
  • 12. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Nematodes mycorrhizae, such as many ectomycorrhizae, are good saprophytes, and function independent of plants. The ectomycorrhizae associate primarily with trees.Soil nematodes are very small (300-500 µm), ubiq- These associations consist of a sheath surroundinguitous and abundant in soils. They depend on water the root and limited intercellular penetration betweenfilms on soil particles to swim and survive. They have cells in the root cortex. The endomycorrhizae associ-a range of feeding strategies including plant parasites, ate primarily with crop plants. In this symbiosis, thebacterial and fungal feeders, predators, or omnivores. fungi penetrate the root cortex to form an intimateThe different types of nematodes can be distinguished relationship with host cortical cells. In both symbio-by their mouthparts. Plant parasitic nematodes have ses the integrity of the plant cell membrane remainsa characteristic stylet with a basal bulb, to penetrate intact and is the site of nutrient exchange with theroots. Bacterial feeders have a wide mouth opening fungus. In general, mycorrhizae improve the nutrientto gather in bacteria. To evaluate the health of a soil, status of the plants (especially for phosphorus), andsome researchers examine the ratio of different types may protect plants from exposure to salt, desiccation,of nematodes. Their functional roles in soils are to feed toxins or pathogens. The plant provides energy to theon bacteria, fungi, and protozoa and in turn release mycorrhizae in the form of carbon compounds. Theplant available-nutrients, feed on other soil organic external fungal hyphae explore more soil volume thanmatter, affecting soil structure and carbon utilization, the root itself, especially for phosphorus. This elementor parasitize plants and animals. is quickly depleted within a zone of 1 mm of the root, and does not move any further in soil. For nitrogen, the depletion zone is 10 mm from the root. The hyphaeProtozoa extend this depletion zone for phosphorous. These fungi increase soil stabilization. Tillage, monoculture, fungicides, and long fallows can deplete mycorrhizalThree types of protozoa can be found in soil: ciliated, populations.flagellated or amoeboid. They are animal cells (whichhave no cell walls, just the cell membrane), and aretherefore susceptible to and good indicators of the Bacteriapresence of environmental toxins. In animals, certaintypes of protozoa can cause disease. In soils, theirprincipal functional role is as primary consumers of Bacteria form the base of the soil food web. Theybacteria. In this way, they regulate bacterial popula- degrade a broad range of organic materials, and sometions, increase the turnover of soil microbial biomass produce antibiotics. Bacteria are the most numerousand organic matter, maintain plant available nitrogen, organisms in soil and represent the highest diversityand decrease establishment of plant pathogens. They of species in soil. Their functional roles include nu-are also food for nematodes and fungi. trient cycling and immobilization and formation of humus. There are bacterial pathogens as well, which may produce allelopathic compounds that are toxic toFungi plants. Because of the diversity of food sources used, rapid reproduction and small size, bacteria are very responsive to changing soil environments and criti-Fungi have diverse roles in soil. They produce diges- cal players in both organic matter decomposition andtive enzymes and function as primary decomposers. nutrient cycling.They can be saprophytes, predators of nematodes,parasites of other fungi or plant pathogens. The pro- Bacteria can also form symbiotic relationships withduction of hyphae by saprophytic fungi can be exten- plants. The primary example of this is the Rhizobiumsive, and forming a dense web in soil, and helping to symbiosis responsible for nitrogen fixation in the rootsimprove soil aggregation. Fungi are the organisms of legumes. Legumes lacking the symbiotic relation-with greatest biomass in soil. Symbiotic fungi such ship show signs of nitrogen deficiency when grown inas mycorrhizae form associations with plant roots that low nitrogen soils, while nearby plants inoculated withenhance the survival of both plant and fungi. Some the appropriate Rhizobium species do not.4 Organic Vegetable Production
  • 13. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Figure 1The soil food web(Source: Soil Biology Primer. 2000. Soil Conservation Society, USDA Natural Resources Conservation Service)The rhizosphere (root surface) is a “hotbed” of activ- growing in sterilized soil produce less biomass thanity for bacteria, actinomycetes, and fungi. Plant roots plants growing in soil where bacteria are present, whichexude or secrete carbohydrates that serve as food in turn produce less biomass than plants growing insources for a number of beneficial and pathogenic soil where bacteria, fungi and higher order consumersorganisms. Roots that are colonized by beneficial or- are present. Regular additions of organic matter fromganisms are less likely to be attacked by pathogens due diverse sources and avoidance of tillage practicesto competition for nutrients, production of antibiotics, and chemical applications that are detrimental to soiland/or parasitism of the pathogens by the beneficial organisms will help maintain a diverse and strong soilorganisms. food web on your farm.A strong food web is needed for optimal nutrientcycling and release. Research has shown that plantsSoil and Nutrient Management 5
  • 14. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Interpreting Soil Test Results and Estimating Nutrient Availability John Howell Extension Vegetable Specialist (retired) UMass Extension University of MassachusettsSoil quality is of major importance to crop health and pore space is filled about equally with water and air.productivity. Soil management practices should striveto protect soil from erosion, maintain or increase or- Mineral soil particles are grouped according to size.ganic matter, provide an environment which promotes Beginning with the smallest, they are classified asa diverse microbial population and create and maintain clays, silts, sands and gravel. Soils consist of mixturesgood soil tilth. A nutrient management program should: of various size particles. Texture is the proportional1) supply sufficient nutrients to achieve the optimum amount of each of these groups. Note that the wordyield that is realistic for the site; 2) avoid excess ap- loam does not refer to a specific group of particles,plication of nutrients which can degrade water quality but is used to describe mixtures of sand, silt and clay.or which create imbalances causing lower yield and/or Soil texture is determined solely by the sizes of thequality; and; 3) maintain desired soil pH, to ensure that mineral particles and has nothing to do with organicall nutrients are readily available to the crop. matter Weathering can change the size of these par- ticles, but only over thousands or millions of years. For all practical purposes, the texture of the soil doesPhysical properties of soil not change. Soil texture has a major effect on the physical andSoil texture chemical characteristics of soil. Sandy soils have rather large particles and large pore spaces (macropores).Soils are composed of solid particles with spaces be- Clay soils have very tiny particles with very small poretween them. The soil particles consist of tiny bits of spaces (micropores), but because there are many timesminerals and organic matter The areas between them more pore spaces, clay soils have greater total poreare called pore space and are filled with air and water. space than sandy soils. Water adheres to soil particles.An agricultural soil should consist of about one-half The force of this can pull water through a soil, evensoil particles and one-half pore space by volume. against gravity. This is called capillary action, and actsIdeally, organic matter will account for 5 to 8% of in the same way water is lifted in a straw or narrowthe weight of soil particles. Moisture content varies tube. In this case, water is lifted farther in a narrowconsiderably with factors such as soil drainage and tube than in a wide one. Capillary action is greater inthe amount and frequency of rain or irrigation. For micro pores than in macro pores. However, if a soil ismost agricultural crops, conditions are best when the compacted, all water movement including capillary6 Organic Vegetable Production
  • 15. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.movement is limited. Clay soils absorb and retain more soils. Tillage at proper levels of soil moisture causeswater than sandy soils, but are typically poorly drained granulation. Excessive tillage in an effort to prepare aand not well aerated. Sands are well drained as a rule, fine seed bed, especially when soils are dry, destroysbut retain little water. Loams combine some of the soil aggregates. It is very easy to overwork a soil withmoisture retention characteristics of the clays with the a rototiller. Pounding from rain or irrigation wateraeration of the sands and are widely considered the best droplets can also destroy soil aggregates. Soils shouldagricultural soils. Sandy soils are coarse-textured and be managed to create and maintain soil aggregates asare often referred to as “light” because they are easy much as possible. Mulches are an excellent way toto work. Clay soils are fine-textured and their particles protect aggregates from splashing water.will bond tightly together when they dry out after beingwet. These soils can become very hard and difficult to Biological activities are important to the granulationwork and are often called “heavy.” The terms “heavy” process. Earthworms pass soil through their digestiveand “light” do not refer to weight; sands actually weigh systems, adding viscous juices which bind particlesmore per unit volume than clays. together. Snails and other organisms leave a trail of slime behind them which acts as a glue. OrganicSoil structure matter is an important factor in the formation of soil aggregates and it adds greatly to their stability. SoilStructure is another term used to describe physical organic matter, particularly if it is well decomposedattributes of soils. While texture refers to the sizes (humus) is a binding agent which holds clay particlesof mineral particles, structure is the overall arrange- together. It is believed that this is due to chemicalment or aggregation of soil particles. Terms such as unions between humus and clay particles. The endloose, hard-packed, granular and cloddy are among result is that soil organic matter plays a major rolethose used to describe structure. Soil structure can be in granulation. By increasing the stability of soil ag-modified by activities such as tillage, moisture level, gregates, the soil becomes easier to work and doesn’tfreezing and thawing, root growth, earthworms and compact as easily.other soil inhabiting animals, and driving or walkingon the surface. Organic matter not only improves the structure of fine-textured soils, but it is equally beneficial forVery sandy soils nearly always have a loose structure coarse textured soils. Coarse soils have a high pro-and don’t become hard-packed or cloddy. Fine-textured portion of macropores, facilitating gas exchange andsoils can become hard-packed. This condition inter- water movement. However, due to a low proportionferes with root growth, inhibits movement of water into of micropores, these soils are not moisture retentive.(infiltration) and through (percolation) the soil. The This makes frequent irrigation a necessity duringmicro pores in fine textured soils can easily be filled dry periods. Organic matter substantially increaseswith too much water to the exclusion of air, limiting the proportion of micropores, greatly improving thethe exchange of oxygen and carbon dioxide. The mac- water holding capacity of a coarse-textured soil. It isropores of coarse-textured soils facilitate infiltration estimated that for each per cent of soil organic matter,and percolation of water and the exchange of gases, moisture holding capacity is increased by as much asbut they retain little water for crop use. By loosening 16,000 gallons per acre in the root zone.and aggregating a fine textured soil, we can improvewater infiltration, percolation, and gas exchange,and still maintain the ability to retain water for plant Chemical properties of soilgrowth. An aggregated soil consists of granules thatresemble crumbs. A granule consists of many clay orsilt particles clumped together. A well granulated soil Information about a soil’s chemical properties can behas micropores within the granules and macropores provided by a soil test. The soil test report indicatesbetween them and is both moisture retentive and well the levels of the nutrient elements that are availableaerated. for crop nutrition. It also provides information about soil pH, buffer pH, cation exchange capacity, baseNatural activities such as freezing and thawing and saturation and organic matter. If this sounds a bit in-the movement of roots contribute to granulation of timidating, the following discussion should be helpful.Soil and Nutrient Management 7
  • 16. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Essential elements these soils. Clearly, you cannot expect to achieve the benefits of other amendments when pH is suboptimum.There are thirteen mineral elements known to be essen-tial for plant growth. All of these nutrients are absorbed Cation exchange capacityfrom the soil. Six of these are called major or macroelements because the plant uses them in comparatively “Ions” are atoms or groups of atoms (molecules)large amounts. They are nitrogen (N), phosphorus (P), which have an electrical charge. “Anions” have apotassium (K), calcium (Ca), magnesium (Mg) and negative (-) charge and “cations” have a positive (+)sulfur (S). Sometimes Ca, Mg and S are referred to as charge. Plants take up nutrients from the soil eithersecondary elements because they are used in somewhat as cations or anions. Many of the nutrient elementssmaller amounts than N, P and K. The other seven are are cations (pronounced cat-eye-ons). These includecalled minor, micro or trace elements. These are ev- Ca++, Mg++, K+, Fe+++, Mn++, Zn++, Cu++ and ammo-ery bit as important as major elements, but are used in nium (NH4+) which is a form of N. Other cations ofvery small amounts. These elements include iron (Fe), importance are H+ and Al+++ (aluminum). Anions ofManganese (Mn), zinc (Zn), boron (B), copper (Cu), importance include nitrate (NO3-), a highly leachablemolybdenum (Mo) and chlorine (Cl). Nickel (Ni) is form of nitrogen.accepted by many scientists as the 14th nutrient elementderived from soils. The level of crop production can Cations are attracted to negatively charged surfaces ofbe no greater than that allowed by the most limiting small clay and organic (humus) particles called col-of the essential elements. loids. This attraction is called adsorption. Generally, cations are held tightly enough on adsorption sites toIn addition to mineral elements, carbon (C), hydrogen restrict their loss through leaching. These cations can(H) and oxygen (O) are essential elements. Plants take move from the adsorption sites on colloids into thethese elements from air and water. Although these ele- soil water solution and vise versa. In the soil solution,ments are not applied as fertilizer materials, our soil they are available for root uptake, but are also subjectmanagement practices affect their availability. to leaching (see Figure 3). Cation exchange capacity (CEC) is a measure of the number of adsorption sitesSoil pH in a soil and is an important indicator of the soil’s ability to retain and supply cations for plant use. CECOne of the most important aspects of nutrient man- is reported as milli-equivalents per 100 grams of soilagement is maintaining proper soil pH. Soil pH is a (meq/100 g). The CEC of agricultural soils rangesmeasure of soil acidity. A pH of 7.0 is neutral. If the pH from below 5 in sandy soils with little organic mat-is below 7.0, the soil is acid, but if it is above this level ter to over 20 in certain clay soils and those high init is alkaline. Most soils in the Northeast are naturally organic matter. A soil with a low CEC has little abilityacid and need to be limed periodically to neutralize to store nutrients and is susceptible to cation nutrientexcess acidity. Soil pH is important because it affects loss through leaching.the availability of nutrient elements for plant uptake.Availability of macro-elements and molybdenum (Mo) Cation exchange capacity is related to soil restricted in acid soils. Under alkaline conditions, Of the mineral particles, clay is the only group whichwith the exception of Mo, the availability of microele- makes a significant contribution to CEC. However,ments is reduced. Under acid conditions, Ca and Mg there are several types of clays, and they vary con-are frequently low and there may be toxic levels of siderably in their CEC. Crops are grown on a wideiron, aluminum and manganese. Most crops, do best range of soil types, including many that are sandywhen the soil pH is in the range of 6.0 to 6.8. At this and low in clay. In many areas of the Northeast, thepH, the availability of macro and micro elements is types of clay present have a low CEC. In much of themaximized, and accumulation of toxic elements is region’s soils, organic matter is the primary contribu-minimized. Although most soils in the Northeast are tor to CEC. This fact is true even of soils with lowable to supply sufficient amounts of microelements, organic matter. Not only does organic matter improvegrowers may find deficiencies in some of the sandy the physical properties of soil, it also plays a vital rolesoils. A soil pH of 6.0 to 6.2 is more appropriate for in soil chemistry by increasing CEC.8 Organic Vegetable Production
  • 17. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Base saturation recognizable characteristics for a while. This is the dead fraction of the SOM. It is also called the activeThe cations Ca++, Mg++, K+ and H+ normally account for fraction because it supports microbial activity. Soonernearly all cations adsorbed on soil particles, although or later the dead organic matter decays due to microbialtrace elements that are cations are also present in activity and cannot be recognized for what it was andminute quantities. Ca++, Mg++, and K+ are base cations eventually becomes humus. This is very dead organicthat raise soil pH and H+ and Al+++ are acidic cations matter. It is also called inactive organic matter becausethat lower soil pH. If all of the adsorbed cations are it will no longer support microbial activity. In addition,bases and none are acidic, there would be a 100% base animals eat plants or other animals and pass some ofsaturation, and the soil pH would be about 7 (neutral) their food through their bodies as manure which is richor above. In acid soils there are acid cations pres- in nutrients and organic matter.ent and the percent base saturation is less than 100.Besides having sufficient quantities of Ca, Mg and Organic matter consists of numerous compoundsK, they should be in balance with each other because which vary greatly in their ease of excess of one of these can suppress the uptake of Sugars, starches and proteins are rapidly decomposedanother. As a general rule a Ca:Mg:K ratio of about by microbes while lignin, fats and waxes are resistant20:4:1 is desirable. When expressed as percent base to this process. Fresh organic residues consist mostlysaturation, desired levels are: Ca 65-80%; Mg 5-15%; of easily decomposed compounds which break downand K 2-5%. rapidly under favorable conditions. The result is a rapid reduction of the volume of SOM. The resistant materi-Soil organic matter als remain and form the dark colored material called humus. Humus continues to decompose, but at a veryAs already noted, soil organic matter (SOM) improves slow rate. Carbon dating has shown some humus tomoisture holding capacity of sandy soils, aeration be thousands of years old. Humus forms the colloidsof clay soils and helps overall structure of any soil. which contribute to increased cation exchange capacitySoil organic matter is the chief contributor to cation and good soil capacity in many soils and is an importantfactor in all soils. The break down or decomposition of Soil organic matter is broken down by microbes asSOM releases nutrients which can be used by plants. they consume it for food. Any factor that affects soilOrganic matter is also food for organisms that are es- microbial activity also affects SOM break down. Insential for a healthy soil environment. the microbe, respiration combines most of the carbon from SOM with oxygen to form carbon dioxide gas.By definition, organic matter contains carbon. Carbon For this process to continue, there must be an exchangeis a source of energy for microorganisms (microbes) of oxygen and carbon dioxide between the atmospherein the soil. These are microscopic plants and animals and the soil pore spaces. Gas exchange can be restrictedsuch as bacteria and fungi. Some of these are patho- if the soil is compacted or saturated with excess water.gens which cause plant disease, but in a healthy, This slows the rate of SOM decomposition. Whilewell managed soil the vast majority are beneficial. excess water inhibits decomposition, a certain amountOrganic matter provides food for a diverse popula- is necessary to support microbes. Therefore, condi-tion of microbes in the soil and this helps prevent tions of moisture stress can be expected to slow theany one type of organism, such as a plant pathogen, decomposition of SOM.from dominating. Soil microbes are also influenced by soil pH and tem-Soil organic matter is continuously being produced perature. This is especially true of bacteria. Under acidand broken down by living plants and animals. Dr. conditions, bacterial activity in breaking down organicFred Magdoff of the University of Vermont coined an matter is greatly reduced. Soil fungi responsible forappropriate phrase: There are three kinds of SOM; the break down of SOM are generally less affected byliving, the dead and the very dead. The living fraction low pH. In most cases, however, bacteria are respon-of the SOM is made up of living plants and animals, sible for most of the decomposition of SOM, and asincluding microbes, that are found in the soil. When a rule this process is markedly slowed if soil pH levelthey die, stalks, leaves and other plant parts retain drops below 6.0. The optimum soil temperatures forSoil and Nutrient Management 9
  • 18. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.bacterial activity are in the 70 to 100° F range, but there are required intervals between application ofactivity occurs as low as 40° F, although at greatly manure and harvest of edible crops. Check with anreduced rates. accredited certifying agency.A moist, warm, well aerated soil with a pH betweensix and seven provides ideal conditions for decompo- Soil testingsition of SOM. These are the conditions that promoteoptimum growth of most crops. Productive farmingpractices can be quite destructive to SOM! This may Sampling a fieldseem frustrating if you are trying to build SOM, butdecomposition is a beneficial process. It provides To collect a soil sample, use a soil probe, soil auger,energy for a diverse group of soil microbes, releases or garden shovel to collect samples from throughoutnutrients for plant growth and produces humus. The the field. Use a “V” or “W” pattern to ensure that thechallenge is to continuously replace what is lost and, sample is representative of the field. Areas of the fieldif practical, increase SOM. that appear to be a different soil type, have been man- aged differently, or where you have observed poorAdding to soil organic matter growth, should be sampled separately.Compost is an excellent source of organic matter that Scrape away surface litter from the sites you choose,nearly all farmers can make. Most growers don’t have and then collect a core or slice of soil to the plowenough raw materials to satisfy their needs. Some are depth—usually about 6-8 inches. Collect cores frombringing in additional materials such as municipal 10-15 different sites and place them in a plastic bucket.yard wastes to compost on site. Others are purchasing Mix these samples well, and then take about one pintcompost from the increasing number of commercial of soil from this mixture to send to the lab. It is best tocomposters. Regardless of the source, compost should air dry this sample before you send it to the finished before use. Finished compost has no recog-nizable bits of matter and will not heat up after turning. The report you receive from the lab should indicate soilCompost should be tested for nutrient content. Most nutrient levels of most of the macronutrients and somesoil testing laboratories can test compost. Finished of the micronutrients, pH, and organic matter. Somecompost should have a low ammonium content, high labs also include cation exchange capacity, buffer pHnitrate level and a pH near neutral. Repeated use of a or exchangeable acidity, and/or base saturation.compost high in a particular element may cause a nu-trient imbalance and result in excess levels of certain Adjusting pHelements. This can easily be avoided by soil testing ona regular basis (at least every three years). Lime is used to correct the pH of acid soils. The amount of lime needed depends on several factors, includingAnimal manure is an excellent source of nutrients and current and desired pH, soil texture and soil organicorganic matter. About half of the nitrogen in fresh dairy matter. Soil testing laboratories measure soil pH, whichmanure and 75% of the nitrogen in poultry manure is is actually a measure of the concentration of H+ in thein the form of ammonia. Ammonia is subject to loss soil solution. This is called active acidity. There is alsothrough volatilization if not incorporated immediately H+ adsorbed onto soil colloids. This is called reserve (orafter spreading. In the soil, ammonia is converted to exchange) acidity and this is related to cation exchangenitrate and is available for plant use. However, since capacity (CEC). When lime is added to the soil, reac-nitrate is subject to leaching, large applications should tions occur which result in H+ being replaced by Ca++generally be avoided. There are times when readily and/or Mg++. At the same pH, a soil with a high reserveavailable nitrogen is needed, but fresh manure should acidity (loams, clays, high humus) may require 3 to 4be applied with caution. Many people prefer to com- times as much lime as one with a low reserve aciditypost manure before field application. This stabilizes the (sands, gravels). The soil testing laboratory uses anitrogen. Manure can be mixed with other materials procedure to determine the lime requirement of a soilfor composting. There are strict certification re- based on its reserve acidity. A buffer pH test is the mostquirements for composts that contain manure and common method used to determine lime requirement,10 Organic Vegetable Production
  • 19. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.but some laboratories use other procedures. years can lead to an imbalance between Ca and Mg. Because dolomitic lime is the most readily availableThe speed with which lime reacts in the soil is depen- liming material in some areas, many growers havedent on particle size and distribution in the soil. To used it continuously. As a result, many fields are lowdetermine fineness, lime particles are passed through in Ca and very high in Mg. Choose liming materialssieves of various mesh sizes. A 10 mesh sieve has 10 to achieve and maintain appropriate base saturationopenings per linear inch, or 100 openings per square levels. Shop around for and insist on the appropriateinch (10 X 10) and a 100 mesh sieve has 10,000 material, even if you must pay for increased haulingopenings per square inch (100 X 100). Lime particles costs. Gypsum may be used to increase Ca if calcitethat pass through a 100 mesh sieve are fine and react is not available, but it does not affect soil pH and israpidly—within a few weeks. Coarser material in the expensive.20 to 30 mesh range will react over a longer periodsuch as one to two years or more. Agricultural ground The neutralizing power of lime is determined by itslimestone contains both coarse and fine particles. calcium carbonate equivalence (CCE), also referred toAbout half of a typical ground limestone consists of as Effective Neutralizing Value (ENV). Recommen-particles fine enough to react within a few weeks or dations are based on an assumption that lime is puremonths, but to be certain you should obtain a physical calcium carbonate which has a CCE (ENV) of 100%.analysis from your supplier. If lime has a lower CCE (ENV), more than the recom- mended amount is needed, but if it is higher, as withSuper fine or pulverized lime is sometimes used for a some dolomitic limes, less is required. To determinequick fix because all of the particles are fine enough the amount of lime to apply, divide the recommendedto react rapidly. Hydrated lime, “quick lime” are fast amount by the per cent calcium carbonate equivalenceacting, but are not approved for use in organic systems of the lime to be used and multiply by 100. For ex-because they are highly caustic. ample, if the lime recommendation is 2 tons per acre and the lime has a CCE of 72%, apply 2.7 tons per acreFor the most rapid results, lime should be thoroughly according to the following calculation:mixed with the soil. Plowing turns lime under to theplow depth, but does not mix it with the soil. Harrow- recommended amount X 100% = amounting can do a good job of mixing, but generally only CCE neededincorporates lime to a depth of two to three inches. Asplit application can be use in which half the lime is ORplowed under, and the remainder is applied after plow-ing and harrowed in. A rototiller is effective for soil 2 tons/A X 100% = 2.7 tons/Aincorporation. Weather permitting, it is best to apply 72%lime when the soil is somewhat dry. If lime is spreadon damp soils, it tends to cake and will not mix as Wood ashes can also be used to raise soil pH. Thewell with soil particles. If the soil pH is already at a calcium carbonate equivalence of wood ashes variesreasonable level and rapid results are not needed, lime considerably, typically ranging from 30 to 50%. Theymay be recommended to maintain current levels. In are chemically similar to quick lime and supply K asthis case plowing or simple harrowing are sufficient well as Ca and Mg. CAUTION: Do not over-applyfor incorporation. wood ashes. Wood ashes spread in a concentrated area cause the soil pH to become extremely high, inhibitingBesides raising soil pH, lime is the most economical plant growth.source of Ca and Mg for crop nutrition. Select limingmaterials based on Ca and Mg content with the aim of On some soils, it may be necessary to lower the pH.keeping these nutrients in balance. If the Mg level is Elemental sulfur can be used for this purpose. Likelow, a lime high in Mg (dolomite) should be used. If Mg limestone, particle size and thoroughness of mixingis high and Ca is low, a lime high in calcium (calcite) affect the speed of reaction. It typically requires sixis preferable. “High Mag” lime contains about 5% Mg months to a year to lower pH to the desirable range.and 35% Ca by weight. Use this if both Ca and Mg are The ability of sulfur to lower pH varies among soils.needed. Continual use of one type of lime over several Sulfur must be oxidized to be acidifying. This processSoil and Nutrient Management 11
  • 20. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use carried out by certain bacteria. If they are not pres- calcium and magnesium at high pH. Added fertilizerent in the soil, this reaction, and hence, acidification phosphorus is fixed with other elements and is onlywill not occur. very slowly made available. Since this is a chemical reaction, it is faster in warmer soils than in cooler soils. Banding P with a material such as bone meal, ratherNutrient management than broadcasting, is a more efficient way to apply this nutrient if needed. Manure is a good source of easily available P.Macronutrients PotassiumNitrogen Potassium is the third of the “primary elements.” CropsNitrogen is often the most limiting nutrient. Deficiency deficient in K can suffer considerable loss in yield orsymptoms include yellow plants and stunted, weak quality without showing obvious symptoms. This isgrowth. The majority of crops absorb most of their often called hidden hunger. In severe cases, leaf edgesnitrogen in the nitrate (NO3-) form, but they can ab- may be scorched. Plants absorb potassium in the ionsorb some ammonium (NH4+). Unfortunately, nitrate- form K+. Potassium can be leached from sandy ornitrogen is very soluble and is easily leached. In most gravelly soils of low CEC and be fixed and unavail-soils, a considerable amount of nitrogen is tied up in able in some matter (crop residues, soil organic matter, mi-crobes, etc.) not immediately available to plants. This Calciumnitrogen must be released by microbes as they consumeorganic matter. This process is called mineralization Calcium is absorbed by roots in the ion form Ca++.These microbes are most active when the soil is warm, Deficiency symptoms include young leaves that aremoisture and aeration are optimum and pH is 6.0 or stunted, distorted and spotted and necrotic at the leafabove. Cool conditions, dry or waterlogged soils, low edge. Blossom-end rot is seen in tomatoes and otherpH or compaction will slow the conversion of nitrogen fruiting crops. Although calcium may be present into available forms. Under favorable conditions, we can high levels in the soil, dry conditions will limit itsusually expect from 20 to 40 lbs. of nitrogen per acre uptake by plants and cause deficiency symptoms.for each per cent soil organic matter. High levels of sodium, K, Mg, and ammonium may also cause deficiency by interfering with Ca uptake.Nitrogen uptake varies from as little as 50 lb./A forsnap beans to 200 lb/A or more for field corn. Soil Magnesiumorganic matter can provide some and in some cases allof a crop’s need for nitrogen. The rest can be provided Magnesium is absorbed in the Mg++ form. Deficienciesby adding an organic fertilizer. Manure can supply appear on older leaves as regions between leaf veinsa substantial amount of readily available nitrogen. which become yellow and sometimes a reddish colorFor safety reasons and to meet certification require- progressing to brown. Deficiency is most commonments, a minimum time interval is required between on acid, highly leached soils or those that are high inapplication of non-composted manure and harvest of potassium or calcium.edible crops. SulfurPhosphorus Sulfur is cycled through soil in a very complex fashion,Phosphorus, like nitrogen, can be found in organic and similar to nitrogen. In the northeast, significant quanti-inorganic portions of the soil. P deficiency appears as a ties of sulfur are supplied by air pollution. Deficiencypurpling of leaf tissue. P is found in three forms in soil; symptoms, while rare, first appear as a yellowing oftwo of which are unavailable to plants. The unavail- the younger leaves (as compared to older leaves withable forms include P in organic matter and phosphorus nitrogen). Sulfur deficiency is more likely in acid,fixed or bound to iron and aluminum at low pH, and sandy soils, low in organic matter.12 Organic Vegetable Production
  • 21. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Micronutrients (lb/A). This is not usually very helpful to a grower, but the report also has a rating of low, medium, highMicronutrients are not often deficient. Deficiencies (optimum) and very high (excessive). These ratings areare more likely in soils with high pH or sandy soils useful in determining the need for nutrient applications.with low organic matter. Some of the more commonelemental deficiencies are mentioned below. Generally, it is best to have nutrient levels in the high/optimum range. This means that for most crops,Iron deficiency there is an adequate supply of nutrients. If a nutri- ent is in the medium range, it is likely to limit cropIron deficiency appears as a white or yellow area production, but not severely. In such cases, crops canbetween the veins of youngest leaves. It is most com- be expected to respond to application of the nutrientmonly seen on soils with higher pH and can often be some extent. If a nutrient level is in the low range it isworsened by liming. Excess P can tie up some iron likely that it will limit production to a greater well. In this situation, increasing the level of the nutrient element will probably benefit the crop significantly.Manganese deficiency Conversely, if a nutrient is in the very high/excessive range, it may interfere with the availability of certainManganese deficiency can result in yellowing of the other nutrients which are otherwise in adequate sup-interveinal areas of young leaves (as compared to older ply. Excess levels of nitrogen and phosphorous alsoleaves for magnesium). It is most common on soils create potential hazards to water quality, and in thewith pH above 6.8. case of nitrate-nitrogen in drinking water, can have serious health effects.Zinc deficiency One of the goals of a soil management program shouldZinc deficiency often shows as small, abnormally be to maintain nutrient levels in the high/ optimumshaped leaves and stunted plants. As with iron, excess range. If a nutrient is in or is approaching the veryP can tie up zinc. high/excessive range, it should not applied until the level drops back into the high/optimum range. ThisBoron deficiency is challenging for organic growers, because many amendments such as compost contain a number ofBoron deficiency may result in browned, distorted, different nutrients. If a material is used, it may supplybrittle plants. Fruit may be affected by cracks, necrotic some needed nutrients, but may also increase the levelspots, and internal breakdown. Stems of cruciferous of nutrients already in excess. Also, many materialscrops may be hollow. It may occur on alkaline, highly are slow to release nutrients and may continue to doleached, or low organic matter soils. Caution: some so after levels are in the very high/excess range. Thecrops are sensitive to high levels of boron; don’t ap- best way to avoid excess nutrient levels is to test theply more than two lb per acre. Solubor or boraxo are soil regularly and be aware that many materials willapproved sources for organic agriculture. continue to increase soil nutrient levels for some period of years after application.Determining what nutrients to addand how much Pre-sidedress soil nitrate testThe only way to know the nutrient needs of a soil is by The pre-sidedress soil nitrate test (PSNT) was origi-testing. Guess work is dangerous. There are numerous nally developed to improve nitrogen management inexamples of fields with serious nutrient imbalances field corn on farms with a significant amount of ma-and excesses where they were not monitored by soil nure usage. It has been adapted for use in vegetabletesting. Most soil test reports indicate nutrient levels crops to predict the need for applying supplementalin terms of parts per million (ppm) or pounds per acre nitrogen during the growing season. Regular soil testsSoil and Nutrient Management 13
  • 22. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.performed in the fall, winter or spring do not provide an Organic fertilizers often improve soil organic matteraccurate indication of nitrogen levels in the soil during and generally have a positive impact on soil tilth.the growing season. The PSNT can also be a useful tool They are easy on earthworms and microbial popula-for organic growers to monitor nitrogen levels during tions. However it is possible to achieve excess levelsthe summer, when this nutrient is normally at its high- of some nutrients if some amendments are applied atest levels. This allows the grower to adjust applications high rates over a period of time. This can be avoidedof nitrogen containing amendments, such as compost by monitoring levels by regular soil avoid excesses of deficiencies. A nitrate-nitrogenlevel of 30 ppm measured in early summer is believedto be adequate for most crops. Levels above 50 ppm Referencesare considered excessive.To sample for the PSNT, collect 15 to 20 subsamples Brady, Nyle C. 1974. The Nature and Properties offrom the top 12 inches of soil about one week before Soils. 8th edition. MacMillan Publishing Co. Newthe pumpkin vines begin to run. Mix the subsamples York.and retain about one cup full for the test. Soil samplesshould be spread on a nonporous surface to air dry Garrison, Steven, ed. 1999. Commercial Vegetablesoon after sampling. Follow the general directions for Production Recommendations for Delaware, Mary-collecting soil samples described on page 10 in this land, New Jersey, Pennsylvania and Virginia. Coopera-chapter. When the soil is dry, send your sample to a tive Extension Systems of Delaware, Maryland, Newsoil testing lab for a nitrate-nitrogen test. Jersey, Pennsylvania and Virginia Heckman, Joseph. 2002. Personal communication.Organic fertilizers Howell, John C., ed. 2002. 2002-2003 New England Vegetable Management Guide. Cooperative ExtensionNutrients need to be added to fields to replace those Systems of New England.which have been removed by harvesting. If a soil islow in a nutrient(s), extra effort is needed to achieve Howell, John C. 1998. Soil Basics I, II and III. Univer-suitable levels for optimum production. Organic sity of Massachusetts Extension Fact Sheets: VegSFfertilizers include animal manures, compost, green 1, 2 and 3-98manures, and other natural materials. Many of theseare slow to become available to plants, but contribute Magdoff, Fred. 1992. Building Soils for Better Crops:to soil fertility in the long run. Some are available Organic Matter Management. University of Nebraskamore rapidly and are useful to correct a problem or to Press. certain nutrients while fertility is built up withother amendments. Some common organic fertilizers Sachs, Paul D. 1993. Edaphos: Dynamics of a Naturalare listed in Table 1 along with typical nutrient values Soil System. Edaphic Press. Newbury, Vt.and relative availability. The list of allowed inputssometimes changes, so it is important to consult with Pohl, Susan, ed. 1994. Vegetable Production Hand-an accredited organic certifying agency to determine book. Cornell Cooperative Extension.what fertilizer materials are currently allowed.14 Organic Vegetable Production
  • 23. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Table 1 Organic Fertilizers. Check with certifying agent on current status. Material N (%) P2O5 (%) K2O (%) Relative Availability Alfalfa pellets 3 0.5 3 slow Dried blood 13 2 0.5 med/rapid Bone meal (raw) 2-6 15-27 0 slow/med Bone meal (steamed) .5-4 18-34 0 slow/med Cocoa shells 1-2 1 2-3 slow Compost (unfortified) 1-3 .5-1 1-2 slow Compost (fortified blends) 3-5 3-4 3-5 slow/med Cottonseed meal 6 2 2 slow/med Fish emulsion 4-5 1-2 1-2 rapid Bat guano 6 9 2 med Manure (fresh) dairy .5 .2 .5 med/rapid horse .6 .2 .5 med sheep 1 .3 1 med/rapid poultry 1-3 1-2 .5-2 med/rapid Pumace (fresh apple) 6-7 1-2 .2 slow Soybean meal 6-7 1-2 2 slow/med Tankage (dry) 6-7 10-14 0 med Wood ashes 0 1-2 3-7 rapid Colloidal phosphate 0 18-25 0 slow; about 3% available Granite dust 0 0 3-5 very slow Greensand 0 0 4-9 very slow Rock phosphate 0 20-32 0 slow; about 2% available Sodium (Chilian) nitrate 16 0 0 rapid Sul-Po-Mag 0 0 22 rapid; also contains Mg and S Epsom salts 0 0 0 10% Mg-rapid Nutrient content varies with origin and handling; availability depends on fineness of grind.Soil and Nutrient Management 15
  • 24. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Tillage Practices for Maintaining Soil Quality Harold van Es Department of Crop and Soil Sciences Cornell UniversityHealthy soil is the foundation of sustainable crop through denitrification, and well drained soil can loseproduction. It is the result of a combination of factors. nitrogen through leaching. In the past decades, agri-While this presentation will focus mostly on how till- culture has too much focused on the chemical aspectsage affects soil health I first want to briefly go over the of soils and insufficient attention has been given to the“bigger picture” of soil health. physical and biological (especially) functions.A key concept for managing soil health is recognizing The key management approaches that can positivelythe interaction between the biological, chemical, and influence soil health are organic matter additions,physical aspects of soil. Biologically healthy soil has reduced tillage, and compaction prevention. Addinglow pest populations, or the ability to suppress pests, organic matter to the soil increases biological activityand is fully functional with respect to nutrient cycling and diversity, which in turn releases plant-availableand producing plant growth promoting compounds. nutrients and holds them in the soil, increases soil ag-From the chemical perspective, healthy soil has ad- gregation, pore structure, and tilth, produces humusequate levels of available nutrients, but not so high and other plant growth promoting substances, andthat there will be a lot of leaching; an optimal pH for reduces soilborne diseases and parasitic nematodesthe planned crop rotation; and low levels of toxic or (Fig. 1). At least one long term cropping experimentdisruptive substances such as heavy metals, aluminum, has shown a yield increases related to increasing or-or salts. The physical characteristics of healthy soil ganic matter levels, especially in dry years when higherinclude good tilth, water infiltration, aeration, and organic matter levels can improve water retention.water retention. Now we’ll move on to tillage. One question we canThe biological, chemical and physical properties mu- ask ourselves is why we till in the first place. The plow,tually influence each other, and if we ignore one, the which was invented in the England in the mid-1700s,other will be affected. For example, aggregation of soil revolutionized agriculture. It provided unprecedentedparticles is influenced by the types of cations (e.g. Ca, control of weeds, allowed for a more stable foodMg, K) and amount of organic matter present in the supply, and was a critical tool in the development ofsoil. The types of organisms present can be influenced virgin lands in North America. Plowing the soil incor-by compaction and availability of food sources, and porates residue from the previous crop, weeds, andsoil drainage influences the amount of nitrogen avail- amendments. It’s the first step in seedbed preparation,able to plants because saturated soil can lose nitrogen increases the conversion of organic matter to plant-16 Organic Vegetable Production
  • 25. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Add organic Increased biological activity matter (& diversity) Reduced Decomposition soil-borne diseases, Aggregation parasitic nematodes increased Nutrients Pore structure Humus and other released improved growth Harmful promoting substances Improved tilth substances detoxified and water storage HEALTHY PLANTSFigure 1available nutrients, and reduces compaction, at least oxidized the soil organic matter and released nutrientstemporarily. So, the first experience with the plow was for his crops. In time, however, he mined the soil ofvery positive, mainly because the destructive qualities its nutrients and food source for soil organisms. Indidn’t manifest themselves until after several decades. the long run this is not sustainable, and we have seen similar problems with modern farming methods. OneIn that respect, it is interesting to study the contribu- interesting lesson learned from Tull’s work is thattions of the eighteenth-century English agriculturalist short-term research does not always provide the rightJethro Tull. Tull made an everlasting contribution to picture.the worlds by inventing the seed drill, as he recognizedthat good seed placement improved germination and There are also other negative aspects of plowing. Itplant population over the conventional broadcast uses a large amount of energy, and repeated plowingseeding (of small grains). Now, we recognize that the destroys soil aggregates, which increases compactionmechanical seeder is an essential agricultural tool, and the potential for crusting, resulting in low waterespecially for conservation farming because no-till infiltration, increased erosion, and the development ofplanters allow us to place seeds with very minimal a zone of low microbial activity near the soil surface.tillage. Tull, however, also appears to have done an Intensive soil tillage exposes the soil to the elementsunintentional disservice to the land. He believed that and causes temperature and heat extremes near theplant roots absorbed nutrients as tiny soil particles surface, creating an environment that is uninhabit-(rather than as ions as was established in the following able for soil organisms. In that respect, we need tocentury). He therefore tilled his soils over and again start changing our somewhat romantic image of cleanto pulverize it. Sure enough, he was able to feed his tillage, which we often associate with goodness andcrops for many years without the use of manure or tradition. What could be better than a beautiful, aro-other forms of fertilizer. But what was he doing? He matic freshly-plowed field? In fact, we are actuallySoil and Nutrient Management 17
  • 26. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.doing something very unnatural, because soil is not do not have the large pores that readily drain and allownaturally exposed to the elements and we are creating air into it. When the soil dries, compacted soils morean ecologically unfavorable soil environment. A field readily experience drought stress, which is actuallycovered with residues may not have the aesthetics of a caused by hard soil not allowing for root penetration.plowed field, but it is a lot more ecologically compat- So crops growing on compacted soil are “happy” onlyible. Farm ugly, as they say. when the moisture conditions are “average.” During prolonged dry or wet periods, however, the plantsAnother factor associated with increased soil degrada- quickly become stressed and have decreased yield ortion is driving heavy farm equipment on a field. The quality. A well-structured soil will not show droughtweight of heavy equipment is concentrated in a small or aeration problems unless the conditions are veryarea underneath the tires, and can certainly increase extreme.soil compaction, especially if the soil is wet. The levelof compaction is greater and extends deeper into wet So how do we improve soil health? First, we have tosoil than into dry soil, reminding us of the importance recognize that some soils have become “addicted”of staying off fields when the soil is wet. to tillage. Depletion of organic matter over time has resulted in soils that are so compacted that multipleThe notions of water availability and compaction are passes are needed to break up clods to create a goodbrought together in the concept of the “optimum water seedbed. The relief is only temporary, however, asrange.” Highly compacted soil has a smaller optimum these soils usually settle back down and form crustswater range than a well-structured soil (Fig. 2). During after the first good rain, inhibiting seedling emergencewet periods, compacted soils experience prolonged and root growth. What can we do to remediate suchwater saturation and aeration problems, because they soils or prevent them from occurring in the first place?Figure 218 Organic Vegetable Production
  • 27. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Building Healthy Soils ing no-till, strip till, ridge till, and zone till. The cooler soils associated with no-till can be a challenge in the Northeast. Strip, zone, and ridge till are adaptationsIn general, the following practices will help build soils: of no-till that can overcome some of the cool soil problems. The narrow tilled zone warms up faster1. Organic Matter Management due to the removal of a small amount of residue, and is loosened and aerated, creating more favorable• Add organic matter to the soil regularly. conditions for germination and growth. My research program has shown that no till is most successful when• Use different types of organic materials. used with crop rotations rather than in monoculture. Also, we found that using ridges or beds, which force• Use different sources of organic materials controlled traffic, are very attractive for our climate conditions, especially on medium and fine-textured• Reduce organic matter losses soils. No-tillage is generally very successful on sandy and gravelly soils, which have less compaction prob-• Keep soil surface covered with living vegetation lems and are more drought sensitive. as much as possible We have learned that a good no-till seeder is a criti-2. Improved tillage cal piece of equipment, because it allows for good seed placement under a range of conditions. Many• Minimize tillage intensity times, farmers perform intensive tillage just to create a seedbed, while fine tilth is only needed in the soil• Optimize timing immediately surrounding the seed. With a no-till or zone-till planter, tillage options are much more flexible.• Maximize surface cover If serious cover cropping is part of the management of the farm, a no-till drill is essential. There should3. Minimize soil compaction be no tillage prior to cover crop seeding, because that mostly negates its benefits. Recent studies conducted• No traffic on wet soils (by far most important) in Michigan suggest that even when cover crops or manure are used in a rotation, soil organic matter levels• Minimize soil loading by reducing equipment don’t increase when a moldboard plow is used for till- weight and spreading the load with multiple axles age. Tillage practices such as no-till, zone-till, strip-till, and large tires and ridge-till do result in an increase in organic matter, even when cover crops are not used. In other words,• Use controlled traffic lanes, and take advantage of the less the soil is disturbed, exposing organic matter ridges and beds to the air, the less organic matter is oxidized and lost to the atmosphere.Reducing tillage results in many changes in the soilincluding higher carbon (organic matter) levels, bet- Mulching is another practice that can benefit soil healthter structure, better water availability, more biological by providing cover for the surface of the soil and pro-activity, and reduced erosion. viding a source of organic matter. The use of mulches enhances water availability by improving infiltrationOther changes to keep in mind are that soils may also into the soil and reducing evaporation from the soil.stay cool later in the spring, nutrients may become Mulching provides weed control by shading the soilstratified (higher levels near the surface) because they surface and inhibiting weed germination, reducesare not being mixed into the soil profile, and the pH splashing of soil and disease inoculum onto leaves andof the surface soil will change more rapidly after ap- fruit, and reduces infestations of certain insects (i.e.plications of lime because the lime is not being mixed Colorado potato beetle) on plants grown in a mulchwith a larger amount of soil. system. Also, the temperature and moisture modera- tion from a covered soil promotes biological activity.There is a range of options for reduced tillage, includ-Soil and Nutrient Management 19
  • 28. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.While bringing cut mulch into a field is feasible on soil types, and the climate. What works for one growera small scale, a different approach is needed for us- in one part of the state may not work for another growering mulch on a larger scale. Steve Groff, an innova- in another part of the state. Choose a system that is mosttive farmer in southern Pennsylvania has adapted a efficient in terms of energy use and passes across thetechnique for planting into standing mulch that was field, can handle organic matter additions in the formsdeveloped by USDA researchers. Steve uses a no-till available to you, and is appropriate for your manage-seeder or transplanter to establish a crop into the mulch ment style and operation. Be aware that a there is oftenfrom a killed rye/vetch cover crop that was planted a yield reduction that lasts 2-3 years when changing toin the fall of the previous growing season. The cover minimal tillage systems on unhealthy, degraded soils.crop is killed either with herbicides or by a piece of Start small and develop a system that works for youequipment that rolls down and crimps the cover crop before using it on your entire farm.just as it starts to flower. You can learn more about thistechnique from Steve’s web site: <http://www.cedar A good resource for learning more about soil>. is: Building Soils for Better Crops by Fred Magdoff and Harold van Es. It’s available from the SustainableWhat type of tillage makes the most sense on any par- Agriculture Network, <>.ticular farm? It depends…on the type of operation, the20 Organic Vegetable Production
  • 29. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Compost and Cover Crops for Organic Vegetable Growers Brian Caldwell Farm Education Coordinator Northeast Organic Farming Association of New YorkApplying compost and growing cover crops are ex- you know what levels of nutrients you are applying tocellent practices for growers to use to enhance soil your fields. Otherwise, have a sample of your compostfertility. They improve the soil’s nutrient, physical, or manure analyzed at a lab.and biological status. A few years (perhaps 3-5) of heavy, but diminishing compost applications will bring soil nutrient levelsImproving soil with compost up into the “high” range, even under heavy cropping. Crops remove far fewer nutrients than will have been applied. A ton of compost may contain 10 to 60 orIf one starts with a depleted soil, the first thing to do is more pounds of nitrogen, of which around half will beto correct the pH with lime if necessary, and then add in available form. It may also carry similar amountscompost to boost overall nutrient levels and biologi- of phosphorous and potassium, along with calcium,cal activity. This initial boost of compost is generally magnesium, sulfur, and trace minerals. An applicationput on at a high rate of 10 tons per acre or more. of ten tons per acre of compost with a 1-1-1 analysis,Uncomposted manure can be used in a similar way, then, may add something like 200-200-200 pounds ofobserving the time to harvest restrictions required by NPK. An average vegetable crop harvest might removeorganic certifiers. on the order of only 80-20-100 pounds from the field. So, 120-180-100 pounds per acre may have been ap-Composts made from different feed stocks can have plied in excess of what the crop harvest removed.widely different analyses. Chicken manure has veryhigh relative phosphorous levels, since chickens are Since P and K are mostly held by the soil, it is easy tofed large amounts of grain, which is relatively high see how they can build up to high levels after a fewin P. Therefore, compost made with large amounts of years of heavy compost applications. Nitrogen is a dif-chicken manure is also relatively high in P. Poultry ferent story. It is easily lost to air or groundwater andmanure composts generally have higher nitrogen- builds up more slowly. So even after the heavy nutrientphosphorous-potassium (N-P-K) percentages than applications of these first few years, nitrogen will stillcomposts made from other feedstocks, some as high as be needed each year for most crops. P and K will be5-5-5. Conversely, composts made mostly with plant in ample supply. The soil fertility strategy can shift atmatter may have an analysis below 1-1-1. If you pur- this time, so the N comes mostly from legume greenchase compost, get an analysis from your supplier so manure crops, and compost is used far less frequently.Soil and Nutrient Management 21
  • 30. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Legumes for nitrogen Crop rotationTilling under heavy stands of legume green manure During and after the first years of organic management,crops such as clovers or hairy vetch, can add over 100 a good crop rotation needs to be put in place. Thelbs./A of nitrogen to the soil. The nitrogen content of rotation is the key organic practice that allows pests,a legume cover crop is roughly proportional to its dry including weeds, to be controlled and soil fertility to beweight content. This, in turn, depends in part on how properly managed. Successful organic farmers realizemuch growing time the cover crop has had. In some the importance of their crop rotations.cases, red clover may occupy a field for a whole year,but heavy crops of some cool-season legume crops, The crop rotation can be seen as an organized succes-notably hairy vetch and field peas, can be grown before sion of crops grown over the seasons on a given field. Itor after partial-season vegetable crops like lettuce, varies from farm to farm, depending on markets, soils,spinach, herbs, brassicas, onions, carrots, etc. and many other factors. Good crop rotations, however, include a fairly wide variety of crops. In addition toAnother way of squeezing in a legume green manure vegetable crops for sale, an effective rotation furtheris to underseed it into a standing vegetable crop at includes green manure and cover crops, and possiblythe final cultivation. For instance, red clover can be even grains and sod crops.dribbled between rows of fall brassicas about a monthafter transplanting. By the time of harvest, the red clo- Vegetable crops tend to reduce soil quality, since theirver will form a low mat over most of the field. It will culture usually requires bare ground over much of thehave competed little with the crop, unless conditions season, repeated trips across the field, and they leavebecame very dry. In that case, extra irrigation will have little residue. Sod crops, on the other hand, cover thebeen necessary. By the following May, a good stand soil completely and provide heavy biomass whenof clover will put on enough growth to supply the N turned under. Over the years, a sod will raise soilneeded by the next crop. quality to its maximum potential. Cover crops and grain crops fall between these two extremes, in terms of effects on soil quality.Cover crops and green manures Sample simplified vegetable rotations: 1. Intensive:  Veg/cover crop  →  veg  →  veg/coverLegume cover crops include clovers, alfalfa, field peas, crop  →  (repeat)  →hairy vetch, field fava beans, sweet clover, soybeans, 2. Extensive:  Veg/small grain  →  small grain/cowpeas, etc. The clovers and alfalfa are perennial sod hay  →  hay (legume and grass sod)  →  veg/covercrops, while the others are grown as annuals in different crop  →  (repeat)  →parts of the season. Mixes of legumes and grasses oftengive the best overall results. Tried and true examples In the first example, a vegetable crop is grown everyare rye and hairy vetch; oats, triticale, and field peas; year, while in the second, there are two vegetable cropsand timothy and alfalfa or clover. in every four years. Since vegetable crops are generally worth far more than grain, hay, or cover crops, the firstTwo outstanding references on cover crops are the rotation would seem to be more remunerative than theNortheast Cover Crop Handbook, by Marianne Sarran- second. However, pest and weed problems are almosttonio (1994), and Managing Cover Crops Profitably, guaranteed to be worse in rotation 1, requiring far moreby the Sustainable Agriculture Network, 2nd ed. (1998). effort and expense. So rotation 2, in fact, may make the grower more money. Anne and Eric Nordell of Beech Grove, PA have taken this extensive vegetable rotation idea to a very high level. From a soil fertility standpoint, rotation 2 is also easier to manage. The cover crop used in rotation 1 will often be cereal rye, since rye can be planted late in the sea-22 Organic Vegetable Production
  • 31. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.son, allowing for late vegetable harvest. Since rye is will be significant. Adding excessive nutrients is alsonot a legume, it supplies no extra nitrogen to the field. wasteful. In other words, it is not a good sustainableNitrogen must be added the following year for good practice.yields, so most growers put on additional compost.As we will see below, on a continuing basis this will Oddly enough, even when soil P is in the “high” range,result in excess applications of P and K (and perhaps it is possible that some crops on some soils can be P-other minerals as well). Soil nutrients will gradually deficient under cool conditions. The crops will growbut continually build up in rotation 1. Also, the soil out of that deficient state when the soil warms. Myphysical condition will be degraded by “lack of rest” suggestion would be to use row covers and other meansfrom constant vegetable production. This will further to warm the plants and the soil if you want really earlyincrease the need for compost. crops, and soil P will not be a problem.Rotation 2, however, allows for improvement of soil Potassium is another issue. It can also leach into thequality with a sod crop, and plenty of nitrogen from groundwater, but is not considered a problem pollut-the sod plowdown. Other nutrients can be held at stable ant like phosphorous. However, very high K levelslevels. In fact, if need be, P and K can be removed may interfere with plant uptake of other cations likefrom this system by harvesting hay off the field. Little calcium or magnesium. The science gets fuzzy in thiscompost needs to be added into this rotation to maintain area, but soil organisms may also not be getting whatoverall nutrient levels and soil fertility. they need under very high K conditions. If your soil tests show continually increasing K levels, that alsoOrganic matter levels can be high in either rotation 1 raises a warning flag.or 2. But rotation 1 will require continual additions ofcompost to keep them high. Over 20 years or more ofproduction, P and K levels will become very high in Contaminantsrotation 1, but will remain fairly stable in rotation 2 ifhay is removed from the field. Another aspect of yearly applications of compost thatOther rotations can be designed that combine or alter needs scrutiny is that of contaminants in the compost.various aspects of these samples, and may incorporate Sewage sludge composts are not allowed for organicmany of the wide variety of cover crops for nitrogen production, in part because of heavy metal contamina-fixation and weed, insect, or disease control. tion. But this can be a problem in other composts as well. Some dairy and sheep farms use copper sulfate foot baths to reduce foot rot diseases. Compost fromPhosphorous and potassium these farms has shown high copper levels. Non-organic broiler chicken operations routinely feed arsenic-based coccidiosis control compounds as well. Yearly appli-Are very high P and K levels a problem? Let’s start cations of such contaminated composts could lead towith phosphorous. Fifty years ago, soil phosphorous undesirable soil levels of these heavy metals. Be surelevels were typically low enough to reduce yields un- to review analyses of the compost you use for heavyless extra P was applied, so farmers said, “the more P, metal content.the merrier!” But after years of P applications, manyagricultural soils now have high or very high P levels.Compost, especially poultry compost, is extra high In conclusionin P, so this attitude no longer applies. When soil Plevels get very high, small amounts of P will leachinto groundwater and, in the long run, degrade lakes To sum up, I suggest that poor fields can benefit fromand ponds. This is not good stewardship, even though heavy compost or manure applications for a few years.the overall phosphorous pollution contribution from Once soil nutrient levels and biological activity areorganic vegetable farms is small. Soil high in organic increased to high levels, a diverse rotation includingmatter is less “nutrient leaky” than those whose OM is vegetables, sod and cover crops has many benefits andlow. But eventually levels can build so high that losses avoids nutrient overloading problems.Soil and Nutrient Management 23
  • 32. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Soil and Nutrient Management Practices on Upingill Farm Transcript of a presentation by: Cliff Hatch Upingill Farm Gill, MassachusettsI don’t have very many slides today; usually I bring too of this lake effect snow which becomes lake effectmany. Also this is the first time I have ever been asked rain in the summertime and then we also get hurricaneto talk on this subject. I think 90 percent of my talks season that blows up from the coast. So, unless you areare always on strawberries and they generally center on exceptionally well drained land in the Connecticutaround weed control, so it is kind of nice to have to Valley, at least for me anyway, since I am not on thethink of something else to talk to you folks about. We really well drained stuff, I generally have too muchwill sort of plod through the pictures and I think by water in my environment.comparison to what I picked up out of Jean-Paul’s andwhat else has gone on here today, my talk will be very Also, the soils I am working primarily are silt loams,anecdotal on this subject. at least all of our level land where we do most of our crop production. Our biggest single crop is strawber-In general, I would have to say that much of our farm ries. It wasn’t what I had intended when I first wentis branded as certified organic, but I have never con- for my first career which was a chef. I decided thatsidered myself an “organic farmer.” I consider myself my farm was going to have three main enterprises allmuch more a traditionalist in the sense that the part integrated in a really nice way. We were going to growof the world that I come from, I come from a family wheat, raise my bees and I was going to have smallof farmers that have always been farmers. It just has livestock, basically sheep. I was never going to havenever gone out of our family. What has happened in anything more than sheep and chickens. I spent mymy life is largely just a large part of chance. teenage years chasing my father’s cattle around the county and I never wanted to see another cow on myThe land I farm is very typical of New England. You farm. As you will see as you go through this all of thiswill see from most of these photos that it is almost has changed because really the way you were raisedlike we are in the middle of a rain forest the way the and what is in your genes I guess probably just tendsforest has crept back in around the edges of the field. to keep coming back to you.Because so few people keep animals anymore, all themarginal land has just gone back to woods. All of the This is a typical soil, typical field of ours with ourland that we farm is probably class-I and class-II soil. biggest crop. We basically keep about five acres of strawberries in production and we have two typesAs it just happens to us, most of the land that we farm of production on the farm. We have our strawberrydue to our climate being in New England we get all production and we have our vegetable production. In24 Organic Vegetable Production
  • 33. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use sense for years I have been trying to get out of that we grow that we intercrop with all the rye thatvegetable production because of the low capital input we grow for mulching the berries and stuff like is almost where every farmer starts in our neck of We make sure that the bees are standing right on thethe woods—with organic vegetable production. There hillside at the a lot of heavy price competition from people whohaven’t been in business and don’t really know what We grow a lot of vine crops as you can see. Our big-it is costing them to be in business. gest vine crop is not so much squashes, which are for our own stand in the fall, we grow a pretty good sizeAfter a few years in the vegetable business one day melon crop. Primarily musk melons, but we are alsoI went to my cousin’s strawberry operation to pick growing watermelons, regular cantaloupes and somestrawberries and I went from being a leek farmer to a other exotic melons because now that our brand namestrawberry farmer in about twenty minutes of picking is established with our melons in these markets we canstrawberries in his field and seeing hundreds of people offer a whole line of things and the melons kind of arecoming to pick his strawberries for him and do his work paying the payroll for the summer labor that we needfor him I decided that that lonely work I was doing out in our the middle of all that mud in November with thoseleeks was for the birds. It just wasn’t making it for me. We have a lot of things happening on the farm at thisI was in physical therapy for my back. Lots of stuff point. One of the reasons we got into bees was that wejust wasn’t happening right. had no land and bees don’t really respect the boundar- ies that everyone else has so the bees basically wouldWe started with the berries big time in the early 90s do a fly over and bring back a crop for us.and I really think the demographics in the strawberryyou-pick is only going to get better as the population When we first moved into the county my wife and Iages. You can see from these first few slides, after I go were both working in the city and we decided that wethrough my introduction of my farming, I am going had to change our lifestyle and for raising our go into some of our strawberry cultural practices. We were living between Boston and Providence. II don’t have a lot of vegetable slides because since I worked in Providence, she worked in Boston and wealways do strawberry talks, I have lots of strawberry split between the two and we saw each other kind ofslides, but I do have some of our vegetable stuff. when we put the children in one another’s arms. We decided to leave that and come back to the small farmOur vegetable stuff is primarily field type things that that she had grown up on. It wasn’t a farm when shewe do now for our farm stand to decorate it in the fall. grew up on it, it was just a hobby farm where theyThe bees have stuck with our operation. They are a raised some horses. We started out with that and startedreal integral part of it. Partly because honey and bees renting little pieces of land around the town and thenhave such a good image. What we are endeavoring finally we got well enough established that peopleis to get out of the certified organic trap that we are would trust us with a little bit bigger piece of land. Ibasically in as not being a big grower, we still need come from a farming family and basically I ended upthird party certification because a lot of our produce selling farms in that town and using them as a landgets shipped to Vermont. There are some co-ops up swap arrangement to eventually buy a bigger farm.there, but basically once our own retail business at ourown farm is going well enough we hopefully can drop So, what we will go over when we get into the soilthat oversight thing and just do things that we want to fertility management thing is what is happening asdo. Having the bees on the farm and as a honey sales we start with the resource management of that farmperson it just acts as a really good all over thing with trying to incorporate traditional stuff with that. Whatthe public. It has good image. Not only that, I end up we started farming for was a better way to raise ourusing some cover crops that probably some people children. That was our primary mission with our farm.tend to avoid. That is kind of how the cattle have come into the pic- ture. Part of me rediscovering that cows weren’t soWe grow a lot of buckwheat because it gets us through bad, but also that I don’t like feeding my children dairythe summer dearth on nectar in our cover cropping product that we found in the store. I don’t believe thatprogram. Also, it makes use of the clover and stuff a homogenized milk product is at all healthy for youSoil and Nutrient Management 25
  • 34. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use well as the other stuff, plus I have always wanted for me, but this is sort of like the old share croppingto make cheese. situation. I will give you space to raise your chickens if you feed or help to sell them. She manages the frontMy grandfather was an international grand champion of the farm during the you-pick time. It has also beenbreeder of Ayshire cattle from 1930 to 1950. When good for my daughter. It has been one of her big proj-I went out shopping for cattle, I naturally explored ects. Believe it or not raising chickens can land you awhether or not I could get some stock that would trace $30,000 scholarship. She won a total scholarship to goback to the time when my parents and my heritage to college with. One of the kickers when we were atruled the roost in that breed. We had our first Ayshire this luncheon that they had, the chairman of the searchcalf just this past year. My little son that came along committee comes up to her and says, “Oh, you’re therather late in life glommed right on to it. Of course women who raises her own chickens.” She has beenthe calf is growing a lot faster than him and he can not involved with Vicki doing this throughout. Vicki andhandle it now, but that’s all right. There you can see I had always done the eviscerating and slaughteringthe start of our Ayshire herd with the other calf that and she does kind of the day to day management of thewas born this year. birds. She finally got to really get her hands into the operation with us, too. But, it is all part of what I thinkYou can see where our farm is situated. Those are the our farm is really about which is basically creating ahives right between the cows up on the hillside. Our good way to raise our children.ultimate plan for this farm is that we will have hornedcattle grazing on the hillside to sell that cheese at the I still use conventional tillage. It is part of my tradi-farm stand. My plan is that ultimately we will keep tional attitude. It is kind of the only thing I know. It isdoing vine crops, vegetable crops and potato crops also what I have and what I started out with. I try to befor a fall farm stand along with raspberries that we are good about it in terms of field passes, etc. We generallygetting into and then the cheese is basically my winter try to do our plowing and our harrowing in one passoperation as I am growing older. I find as I am getting by using a clod-buster following the plow so that wein to my 50s that the field work that I used to do out don’t go back and re-harrow. We use pretty much thein the sun just isn’t the greatest anymore. Hopefully, I same method whether it is melons or potatoes, the onlyam going to turn that over to people who are younger difference in the next shot is we prepare raised bedsthan myself and think it is a lot of fun. for most of our stuff because our soils tend to be very heavy and we have more than adequate rain fall. This isThis year we started putting in a food processing an alluvial deposit. There is a 20-foot drop between thisplant in the farm to sell more value added berries and deposit and its drainage basin. Our biggest problem inother value added products to make my cheese in and terms of structural fertility is generally too much waterto handle the milk and stuff. That will keep me busy and not enough air and soil life created from that. So,during the winter. I have always had to shift gears most of our stuff we put into some sort of raised bed.throughout my career. It is no different now. Now I am We do all of our melons into raised beds.going back to constantly try and remember all that stuffthat my parents used to talk about with the cattle and We have traditionally used plastic mulch on melonsthey’re gone. I don’t have them to ask the questions of. and a lot of our vine crops. What we are going to now is doing a living mulch, but what we have beenThe other thing that we are doing is raising pastured experimenting with is putting down our plastic in thepoultry. It is always nice on a hot day in the summer fall. Putting down compost or manure in the fall andtime to start slaughtering chickens. All of these things then laying the plastic right on top of that. We wouldwork in. Our compost piles are basically fancy manure have already previously drilled in rye. The rye comespiles. They will range in everything from potatoes to up within the lanes in the spring and all we do insteadsome feed corn that may have gotten moldy with a large of having to add mulch at that point is basically rollcomponent of cattle manure and bedding all just put in the rye down. It has worked out to be a nice system.a heap until it is has been steaming for awhile and once We are also taking it to the point which we are goingthe action has quieted down it becomes safe to put on to try this year in our field where we do not take up thethe fields. The pastured poultry has been a project to get plastic and we are going to try making it go anotherother people involved on the farm. This woman works cycle because the rye was interseeded with clover and26 Organic Vegetable Production
  • 35. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.that clover is now what is coming up between the lanes ment. I don’t know if you are familiar with “re-miner-in that plastic. alize the earth” or not. Over on the side there is a pile of stuff with which we are involved in an experimentOur basic method is if we have to correct any nutrient with some researchers at U-Mass and some people forlevels at this point we probably would have done it The Publication for Remineralizing the Earth. Whatthrough a broadcast application. Generally, we find their thought was is that soils that have been farmedwith most of our soils that we almost always need to a long time had been depleted of a lot of their tracehave an addition of potassium and our cheapest and minerals. There are several big quarrying operationsmost convenient thing to apply for that is Sul-po-mag. in our valley and a grant writer got the idea that weWe are able to get that for about $225 per ton. It goes should take some of these mineral wastes from theseon nice. It does a good job for potassium sulfate and we gravel operations and see what would be the affectgenerally put that on with our clover covers, etc. The of adding these minerals to the soils. There were twostrawberries in their establishment have a relatively types of stuff available. This was trap rock dust fromlow nitrogen requirement, which is kind of a nice thing the crushing of stones that they use primarily as schistfor our key crop. whose key ingredient is calcium. We have that stuff available to us and then we have the float from a gravelAlso, as it ends up for us, in most research on strawber- operation where when they are washing gravel thereries you can’t make them phosphorous deficient. Most will be all of these minerals that they want to wash outof our soils always test phosphorous deficient. Even and then that becomes a waste product and they haveon soils where we have gotten our organic matter ap- all this cloudy stuff with minerals at the constructionproaching five percent we have started to have some pit for you to go pick up for free. People were usinggood indications of available phosphorous already that in the area also.there. Our silty loam soils, the way it is explainedto me, that the phosphorous is there it is just hidden These researchers asked me if I would help them out.between the particles and it is not available. So, we We used this in various ways and it actually did workare generally on phosphorous deficient soil which is very well against Botrytis in strawberries. But as farthe other reason why the berries are a good thing in as raising the brix level of the fruit by applying this toour estimation with our soil. So, basically a broadcast the soil, no it will never happen. We applied it to grainapplication and then we make these ridges. If this was crops instead of our cover crops. We did not get anygoing to be a potato field, our potato planter does pretty results. The hypothesis was disproved. It is an inter-much the same thing. We try to keep everything on the esting thing in terms of soil fertility. If you do have asame system so that it can all be managed accordingly. quarry in your area that does crush rock and you can get it, what is nice about it is that most of our soilsAfter we have created the ridges, we primarily use also kind of have a little bit too much magnesium inWilson cultivators. We also use these for bed forma- them. The Lee lime that they get in the Berkshires istion as well, but we use basically the same system a high magnesium lime and that is generally what isfor hilling our potatoes or cultivating between things, available in our area. Actually as a source for calciumetc. It is our main piece of cultivating equipment. On without excess magnesium, different rock powders likeour soils what works for us is keeping everything up this from various quarries do come in handy. This oneon these ridges. The only place where we do not do had high calcium and would help buffer the soil’s pHthis in on the hillside slope that you are going to see but it did not add the excess a little bit. This piece of land is Hartland silt loam.We grow potatoes on this land. This particular piece The other thing in terms of approaching our fertility,of land fell prey to a practice of previous farmers of especially with the strawberries and the other cashalways putting lime on their manure when they were crops we rotate with strawberries is leeks. I can’tspreading manure on their fields. The pH in this field look at just my fertility as a single issue. I will not putwas running like 7.5-8.0 which is kind of high for most any animal manures and especially my own compostof the crops that we like to grow. stuff on this land where I am going to grow berries or leeks. We rely primarily on plant cover crops and thenA sideline that we were doing on this land that I don’t the additions of things like Sul-po-mag or black rockthink is worth doing is we got involved in an experi- phosphate and pure minerals like that.Soil and Nutrient Management 27
  • 36. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.We have also gone to making all of our own straw Alfalfa, orchard grass with a lot of quack grass by thebecause anytime we have bought straw it is almost like time we got it.going out and paying for somebody else’s problems.We have introduced a lot of really nice German chamo- The 14 acre field is two types of soil. There is a Rayn-mile with New York State wheat straw into our fields ham silt loam which is at the lowest parts of it and it hasat different times. You just create a lot of nightmares a Hartland silt loam in the upper part and the Hartlandwith that. Basically, 60 lbs of nitrogen per acre for the ranges out into some Merrimac at the extreme headlandtotal vegetative year of this crop. That is not hard to of the field. The Merrimac is a really fine soil for do-make at all. We are planting at usually about 14,000 ing organic production on because it is one of those– 28,000 plants per acre. We do a delayed planting to extremely sandy soils. The Hartland silt loam is realhelp aid with our weed control in these and the crop nice on this and it is the upper part there and that isjust ahead of this was the rye cover crop. We almost were we are putting all the berries. Our first year withalways precede our strawberries with sudan grass the this field to get it started we did that center strip whichseason before that. After that land is seeded with su- you see plowed up the center of it. The upper half ofdan grass we will go through seasons of clover on the that was the first place that we planted before it is replanted to leeks. We will generally That piece of land had been in continuous silage cornfollow leeks and strawberries back and forth. This is for about 15 years. The organic matter tested out inone of the few things that I don’t think does anything that field at five percent organic matter content. Thebad to my strawberries. If I can get sweet corn, we are farmer that I bought it from was a traditional guy withcurrently going in to having sweet corn at our farm a lot of cattle and huge equipment to really put downstand. If we can get sweet corn to be weed free we will a lot of manure. Our first year growing rye on that –probably grow that ahead of strawberries also because the rye at the end of May, early June was up to aboutas a relative of corn, etc. it would not vector anything eight foot high and the stalks were so thick on it thatbad to our berries. the equipment could not handle the stuff.The addition of the rye straw is probably the single big- The fertility on the field was incredible from thisgest source of organic matter. We are putting down an management, but the weed problems in it were alsoincredible amount of straw. We are putting out at least unbelievable in terms of everything that had beensix tons to the acre every single year. The plants are put on it. Every kind of broadleaf chemical had beenthere for at least two to three years besides everything used on the land and an entirely new family of weedselse that we have plowed into the land. The production is always waiting for you each year. The years thatof our rye straw is a major undertaking every year. We we have been bringing this farm out of that kind ofare probably putting in at least 10-15 acres into the production to make it fit for growing strawberries hasbarn of rye straw every year. As one of our biggest been a long hard climb.crops and work activity, what we do is plant the ryein late August, September, October all the way up to This slide shows that whole center strip – those berriesNovember if we can and we basically interseed most are now out of production and plowed under. We wouldof our rye, almost all of it with red clover. After we have disked them over as soon as we were finishedmow the rye in the spring we do not go back and have harvesting them in July. This is basically August/to do any tillage. The clover will come on. Hairy vetch September when we are getting ready to sow our rye.does not recover from the mowing – it never seems You can see on the right hand part of the middle fieldto come back. I don’t know why, it just doesn’t. To just below that black section, that is one of the fieldsme is seems like it should, the red clover will always that we cut rye off of and it is basically all clover forcome back. the summer period before we plow it under again and plant rye on it. Just ahead of that you see two whiteThe farm has two major resources, the one 14 acre strips going back and that is part of our buckwheat. Iflat field that you see going in the center field of the like to plant buckwheat. When I am first getting onto aphoto and there is another 10 acre field that we are piece of land I generally plant buckwheat on it just tocontour farming which is where I am standing taking assess what the land can do. If there is any part wherethis photo from. I am standing in the middle of the buckwheat doesn’t grow there probably is some kindalfalfa field that was there when we bought the farm. of a serious problem. The headlands in this field would28 Organic Vegetable Production
  • 37. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.not grow buckwheat. There had been so much traffic There is also a strip of pumpkins in this contour also.for years of harvesting the silage and the plowing pat-terns of the field that the entire headlands at the further Now this backs up to part of our strawberry rotationend of that piece would not grow buckwheat because you can see the buckwheat growing. As soon as weof the soil compaction and also because there was a disked off those strawberries I usually put buckwheatslope at the end that was bringing too much water on as a smother crop for weeds during the summer.into that part of the field. Between diverting it and There are still some berries in there that we are prob-growing various crops on it and going over it lightly ably going to try taking to a third year fruiting in thatwe are now growing on that part of the field. There back piece and this is the group of berries that we justwere a couple acres at the headland of that field that planted this year. That land before the berries wereweren’t productive because of water and compaction planted had buckwheat on it for two years with ryeand serious problems with that. covers in the meantime. Last year it had a crop of sudan grass with cowpeas and other things on it thatOver on the left you see a strip that went through our we plowed down. The rye was on it right before wemicro-cropping pattern which was to grow buckwheat planted it and that is the other reason for our delayedto assess what it would do. I can generally get three planting because we will take the rye off and then docrops of buckwheat into a piece of land in a single our planting.year, if I can, out of a single sowing before I plant ryeon it for the winter. Rye or winter barley, either one. Generally, what we have been using with the demise ofI will put on winter barley if it is quick enough. We Agway is they had a lot of fertilizers that they boughthave to get it planted before the first of October. We when they wanted to get into the organic produc-can’t really get a good stand of barley in our latitude tion business and I did a pretty sizable purchase of aif we put it on later than that. Anything later than that chicken fertilizer that they had put together. It includeshas to be rye. everything from manure to chickens, body parts and everything that they manufactured to sell to organicThe winter barley is a great feed for cattle, for pigs, farms. With their bankruptcy there was a big stock ofsheep and any kind of waterfowl love it and most fowl this at the local fertilizer plant that I bought up. Welove it also. There are a few dietary things you have to have bought that and used it for top dressing in thingswatch because it is very abrasive to the gut. You either like our renovated strawberries, this was 6-6-6. In ourhave to soak it or grind it or something, but it is a mar- renovation of strawberries if our nitrogen levels arevelous feed and it is pretty easy to grow. It threshes out low we go out and buy it in some form like that.nice. There again a straw from that I generally will sellto someone else after we thresh out the straw because We have not had good luck on berries doing things likeit will be too weedy for putting back on our land. What using alfalfa meal and soy. We have done that in yearswe like to grow is basically rye hay. We thresh out virtu- when all of a sudden there was a problem. I am notally none of the rye. We harvest it in early June when sure exactly what was going on in those fields whereit is just headed up and once it is mowed it is dead and we used a feed ingredient as a fertilizer, but I neverthen the clover can come on in the field. had such problems with a crop as I had when I used that and I can’t explain why. The plants were anemicThe center brown spot, where those stripes of white are and it came on suddenly. Tissue samples showedgrowing is where we took out the planting of straw- nothing. We had no nutrient imbalances of the majorberries and we will probably put you-pick peas in this things, anyway, but they just weren’t thriving. It isstrip next year because when we are up there picking possible it could have a seasonal thing. It was kindberries people will get a hold of that. of a cold, wet season. But, it was the only thing I had done differently from anything that I had ever doneThe other thing on this farm is on this slope that you with berries before. We had other berry plantings onare looking at that we have planted, the upper part is the farm that were doing fine but the field were westill in alfalfa that will get plowed down next year and put our combination of soy meal and Sul-po-mag,we will put field corn for grain on the top of the hill. because they were the only things that would matchThere is a strip of sweet corn and then there are strips organic certification that the local fertilizer mill couldof sorghum and then there is buckwheat at the bottom. put together for the planting and because they had runSoil and Nutrient Management 29
  • 38. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.out of what they had that was NOFA approved and so a way of keeping weeds down and putting stuff rightthey made that up for us. We applied that and used that back in to the the fertilizer. Broadcast, did our hilling and usualthings and then halfway through the season, basically You can see a crop of sudan grass and above that youwhen it was time for them to run and vegetate they can see the corn. Next year where that sudan grass andjust stopped. There were no nematode problems, there corn are will be re-seeded into rye and red clover overweren’t any of those other things that there should the winter and then where the alfalfa is at the top willhave been and that was the only thing I changed in be plowed down next year and field corn will go in upmy management. This is back in the days when we there. This is another shot of the same thing except, Iused to raise several acres of leeks. The same soil, don’t know how evident it is to you, but the key thingsthis is our key crop that we like to integrate with our we have had to do on this farm is the drainage. Theberries if we are going to grow another cash crop on drainage ditches that were in it are all filled in. It is ourthe land with them and work in as a rotation this is biggest thing. Soil that is holding too much water hasmy preferred thing with that. no life in it. That strip of buckwheat is for a new plant- ing of raspberries next year. We broke the sod on thatWe irrigate on our land primarily for frost control hillside two years ago, put it to rye and the followingwhere we very seldom have to put down water for year it was in a summer crop of buckwheat and nextwater sake. It is usually not necessary. We have had year it will be civilized enough and the sod broken outone or two seasons where I have watered crops for fear that we can put raspberries in there.of losing it to drought. Generally, if we are wateringwe are either evaporative cooling which we will do I am happy to take a question at this point of anyoneon potatoes a lot, especially in the summer. Potatoes has to be cooled down in the afternoon. They don’tlike hot days they like to go in to the night cool. Wewill water at midday on strawberries for evaporative Questions and answerscooling and then this past year we got to spend manysleepless nights watering all night long to keep thingsfrom freezing. That is winter barley in the foreground Q:  I find that rye can be a problem to handle. Howof the photograph. This is probably just immediately do you manage it for the least problems?after setting plants and we are watering them in oncethey have been set in the raised beds on there. The only A:  Likewise with you I have had rye in all kinds ofplace we really do not do that creation of the ridge is forms. The worse problem with combined rye is thaton that contour. it has too much rye seed still in it. Most growers will not reset the concaves and get the grain out of it. ItThis farm as you can see from this wet area that is is a pretty small seed so you end up with tons of ryerunning right through the center of the field were there seed and rye since it doesn’t winter kill like oats oris a lot of hazel wood growing etc. In terms of what something like that is nasty stuff to have as mulch ifit points out to there, saturated soils like that in a low it is really rye are virtually used as grazing land. There reallyis nothing you can do with them in tillage. They are The other problem with rye if you use combined ryebetter off as a resource just left. Even grazing them is that they don’t thresh it until late July or the extreme banks is a problem. Then the strip go- It takes a really long time for the seed to get to theing up the hill, the lower part of that strip we used for point where they can combine it. Generally, you havevine crops and then each edge of the contour on it, a lot of other weeds in the field. Unless they are usingbasically on the left edge we are raising raspberries, a really good herbicide management plan on it mostwe have a perennial crop that does not require any rye straw will be infested with weeds and more rye.tillage. Because it is a small part of the field it would My experience lately has been, like with this field thatbe difficult to be turning a tractor in and around. We has had so much high fertility and grows such rankplan to do pastured poultry also on that section, put- rye that my machinery can’t handle, I cut it fairlyting the poultry in amongst the raspberries on that as early. You cut it as early as you can when you have30 Organic Vegetable Production
  • 39. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.the weather in your side. At our latitude basically A:  A couple of things about it. Number one the ryefrom May 30th on if there is enough crop in the field is cheap. Rye is going to run you about $9 to $12 forto make a crop for you as far as what you want, cut 50-100 weight, depending on how you are buying itthe stuff. The earlier you cut it the less weed seed you and it is untreated seed they do not put any work into it.are going to have. As soon as it heads up. If the headhas formed it will not regrow. You can wait until the Compared to other species, most other species of cerealcuticle on the leaf dries down if you want a stalk on grains they have developed have very low amounts ofit, but the other thing you have to worry about is if straw and very high amounts of grain. Most of the ryeyou let it get too high. we plant as cover crop is still primitive in that respect and has a massive amount of straw compared to theIf you take rye that is grown to eight foot and on re- amount of grain in it. The barely that you saw in thatally good land rye will get up to eight foot high with other shot, if we get a couple of tons of straw off anno problem, by the time that goes through a hay baler, acre we would be doing really good where as we canunless you have got a chopper, you go to shake the stuff probably get six tons off any acre of rye easily. Becauseout you are going to have strands like this that you are it is just that much more product in straw compared totrying to put down around stuff. It will be a very poor the grain species. Most of the wheat that you see grow-mulch. It won’t keep any of your weeds out either. I ing out in this part of the world, I guess it is actuallyused to mow it myself with a disk. I have a disk mower. called Geneva, which is the principle soft wheat grownNow I pay the farmer next door, who since the local in much of the northeast now. The stuff doesn’t evenstraw dealer went out of business the dairy farmer next get to two feet high and it has these huge seed headsdoor had taken to growing rye and selling it. As he is on it. It is a very highly bred plant. It is bred for graincutting his rye I have him cut it with a disc-bine. He it is not bred for producing straw.has a flail conditioner after his mower which pulver-izes the stock so it dries better. We have a chopper that Plus the rye will also germinate. No matter how latechops it. We put all of our rye through a bale chopper. you are in your management you can put that stuff onWe have a trailer with a chopper mounted on the front. in the middle of November and it can make a catch.We load the trailer with about 40-50 bales and the It is a really remarkable plant. The other thing thatchopper is out in front and we just throw whole bales we do with it is the rye was planted on this contourinto it and it chops it up. The rye hay is no problem. and you can see that it is gone now. We have our ryeThat is one advantage that combining has is the extra down on our berries. We put these guys out on it, toobetween having gone through a combine and then go- and they were making a remarkable amount of milking through a baler you could generally hand shake it on it. It is really incredible how much milk they makeout and it is not bad. The rye hay is really nice if you on a bin of rye.have a chopper to do it. We flail condition it. The otherthing you can do to make it easier to handle is let it Q:  Do you have any problems with pests?get rained on a few times. Don’t worry about it, let thestuff get rained on it will help break the cuticle down A:  We have a lot of problems in our organic berrieson it. Just rake it again, dry it out again and then bale with strawberry rootworm, it is our biggest pest.the stuff. Your baler will probably handle it a lot bet-ter, too. Because it is so waxy, most balers, unless they For tarnished plant bugs I can tell you what not to do.have straw tuckers, the baler can’t handle the stuff. It We do scouting and we put in a lot of traps for captur-goes through too fast and it is a weird adjustment you ing them. Don’t leave rye standing or any weediness orhave to make on a hay baler to handle that stuff, but aging plant near them. I’ll relate the worst experiencemost people who bale straw have special bale retarders we had with tarnished plant bugs this past year. I leftin their balers to handle a waxy cuticle. I know that a strip of rye standing near a stretch of strawberries,is kind of an essay answer to what you thought was hopefully to act as a windbreak and create a nice littlesimple question. microclimate to boost those berries along because they were a late variety and I wanted them quicker. We neverQ:  Why do you use rye if it’s so tricky to manage? had such an infiltration of tarnished plant bugs as we did in a patch of strawberries with a wintered overSoil and Nutrient Management 31
  • 40. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.crop like that left standing beside them. It just was an they have been around the longest and growers haveenormous pest gatherer. bought them the most.Q:  Are you sure it was the rye? I am always kind of a “contrarian” and I always was buying more exotic ones and pricier ones and I neverA:  Well it could have been chance because also there is had such good luck as when I bent back to gettinga strip of rye between them and a hay field and the hay something like Honeyoyes which are a good Newfield also could act as basically a reservoir for tarnished York State development. They are the most productiveplant bugs, the hay field had alfalfa and other species strawberry I grow or that I think anybody can grow.that tarnished plant bugs like and I have tried putting They are a good sturdy plant. They are not good whenreservoirs of alfalfa near strawberries but tarnished they get over ripe, but they have amazing production.plant bugs just love that little white blossom they will They’re a good plant maker because in strawberriesalways come over and get some. for organic production the key thing that you are going to want to do is be on a nice light friable soil that youJust as well we have to watch for tarnished plant bugs can do a lot of hoeing.whenever we are using row covers because the rowcover will boost their populations also. They like be- Unlike most other things, to get strawberries estab-ing under that row cover it helps them out just like it lished in a weed free way, if you want to get a couplehelps the berries out. They are a major problem. Cold years production on them. They are really devilishis your best asset against them. Early fruit doesn’t get on weeds. Strawberries don’t mind other plants theybothered by them as much as all of your late varieties. have no bad will against any other plant. They thinkJewels, Late Glows and all those things and there is that growing in the edge of the woods in a bunch ofvery few effective organically approved pesticides that weeds is just where they belong. They appreciate thewill be effective on tarnished plant bug. shade that they get from other plants. The only way being able to counter their whole thing for organicWe do not have any problems with root weevil. The production is to increase their planting density so thatstrawberry rootworms we can’t really live with. I have they are shading one another and keeping each othertried various management strategies and I thought I had cool because that is what they really like. They likefigured it out, but this past year I got another infesta- nice cool roots. I don’t know how people get them totion after having gotten rid of them for awhile. I look survive in plastic. I have never seen strawberries thatat that as a syndrome. Usually we get a strawberry I thought looked happy growing in that stuff. Nicerootworm problem whenever I damage some roots on well drained soil that can be cool like a north slope.some strawberries and in this case I hit them kind of If you have a nicely drained north slope and you havehard with some cultivators when we were renovating. eradicated the perennial weeds in it to some degreeIt was a dry time and it was just this one section I did something like Honeyoye.not feel like resetting the irrigation to irrigate this onelittle patch and those stressed plants got a patch of Honeyoye is a really nice berry, but in strawberries it isstrawberry root worms in them who have proceeded going to depend a lot on your marketing and how youto try to take over more than I think that they have any are selling them as far as what will go well. Honeyoyeright to have. is a good all over berry. Cavendish works really good for you-pick operation, but it does have some whiteQ:  What varieties of strawberries do you use? fruit problems. The only ones I would probably tend to avoid for organic operations are anything that isA:  This is supposed to be soil fertility and it turned sensitive to leaf spot. You probably should avoid theseinto another strawberry lecture. What varieties of because even the copper based fungicides which are thestrawberries, for what? only thing you really have in an organic management program to fight leaf spot with are extremely toxic toThe way you can always tell the ones that are good strawberries. They just don’t like copper. If you havefor production are they are usually the ones that are bad leaf spot on a plant and you’re not able to controlthe lowest price in the nurseryman’s catalog because that fungus, if leaf spot gets onto the calyx it makes32 Organic Vegetable Production
  • 41. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.very unattractive fruit; nobody buys it. They don’tcare how organic it is. They’ll hop over that fruit withthe damaged calyx, won’t sell in anybody’s marketcompared to something with a nice looking calyx. Soa Midway would be one to avoid in that respect.In conclusionI have arranged this one as the last slide as far as thecows out grazing on the cover crop. It is incrediblewith them. I had always been told by my father thatrye would make the milk stink and not to graze yourcattle on it. You couldn’t keep them off of this stuff.They would wait at the gate and would much ratherbe out there shuffling through the snow than eatingsomething else and the milk didn’t stink and the butterwas extremely yellow.Soil and Nutrient Management 33
  • 42. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Soil and Nutrient Management Practices on Roxbury Farm Transcript of a presentation by: Jean-Paul Courtens Roxbury Farm Kinderhook, New YorkI caution you that everything you heard today you will What I like to point out in the first slide is the analysishear again in a different way. So hang in there, there on one of the tables of our own compost made fromwill be some repeats, but hopefully some practical dairy manure. The same table is also in your handouts.application on what you already heard by the other As you can see here compost is a much drier productspeakers. I noticed some different approaches on fertil- than animal manure, and you can compare the numbersity management here and there. For example, Harold as far as nitrogen, phosphorus, and potassium. Sincedifferentiates three qualities in determining soil fertil- the compost is made from cow manure, they are rela-ity. I distinguish one more, and I make the case for a tively comparable. The numbers go up a little bit whenfourth quality, which is called structural fertility. I see made into compost. The number that is considerablythis as a quality that in itself needs to be recognized. higher in compost than in manure is the organic and the dry matter, which I think is fascinating. I always won-Let me walk you through these four different qualities dered about how the dry matter can contain so muchone by one. I will start with chemical fertility. more than organic matter, but I just have to believe the analysis. What you have to realize with the nitrogen in the compost, is that it all consists of nitrates, whileChemical fertility the eleven pounds of nitrogen in the solid cow manure is half ammonia and half nitrates. I also have some numbers here of pigs, chickens and horses.I realize we mostly concentrate on vegetables, but Ilike to mention that when maintaining the chemical The other thing I wanted to point out is that the poultryfertility of our land, the hayfields are usually much manure analysis shows high phosphorus levels. Whenmore self-sufficient than the vegetable fields. I think you look at the needs and fertility requirements forthis is an important thing to notice. vegetables’ development, its needs for phosphorus are kind of low, so we don’t really need poultry manureBut first let us look at the composition of different and in general we could be quite happy with compostfertilizers. I gave you a handout (pages 45–56 in this made from cow manure coming from animals that haveproceedings). By the way, there is no way that I will be not been fed grains. High phosphorus manure comesable to cover this handout in one hour, which is about from the very high grain diet animals consume. So, youeight pages printed in a very small font type. will see phosphorus numbers go down for an animal34 Organic Vegetable Production
  • 43. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.that is being fed less grain and lives mostly on a diet it. Again, there is a huge cost involved in it. I happenedof grass and hay. to be in a situation, about ten years ago, where some- one came to me with just such question. It involved a corporation that wanted to have an organic farm asPhysical fertility part of the business. They invited me to consult with them and said, “We want to grow vegetables here.” My initial response was, “No, you’re not. This landI was in the interesting situation that I had to look has too many obstacles.” And they said, “Oh, yes, wefor a new piece of land. This is interesting from the are.” I did not realize the amount of resources that thisperspective of assessing land for its physical fertility. particular corporation had to make it work. And theyI had to put myself in the shoes of a new farmer. What made it work. So, it is not that it can’t work, but nobodydo you do when you look for land? The first thing I in here at least, has the resources to do it.did was obtaining a soil map from the soil and waterconservation service. It shows you where all the good When it comes to the physical fertility of the piece ofland is in your county, in my case Columbia County. land, you can’t make too many changes. I like to relateThose soil maps showed that a lot of good land, all the to the physical qualifications of a piece of land like theclass-I and class-II soils, are located in Kinderhook. genetic code we inherit. Assume that you found a goodWhat are class-I and class-II soils? It tells you how piece of land. It is flat and has other positive qualitiesthey behave, but it does not always mean that they are for growing vegetables; you still have to determinesuitable for vegetables. Some of these class-I soils are what kind of land it is. Is it a sand, silt, or loam soil? Iactually flood plains and frequent flooding does not go tried to compare those soils to a riding or a work horse.well with growing vegetables. The riding horse is going to be the sandy soil, you get there quick. It is a means of transportation. They pro-One of the most important aspects of a physical qual- vide you with early season vegetables. The workhorsesity of a soil to be suitable for vegetables is that it has are the silt loams. They give some real production allto have a high carrying capacity. In other words the through the summer. It has a much larger window ofability to drive your tractors on them. When one inch getting through a drought.of rain or more doesn’t prevent you a day or two laterto get back on there. With a clay soil you are not be So, in short, if you want to grow vegetables, try to getable to do that. You have a very narrow window to get the best soils you can get your hands on in your par-on there with your tractors – it can drive you crazy. ticular area. In Massachusetts, the best is a Hadley siltAnother aspect is good drainage and is related to the loam; in Columbia County, it is an Unadilla or Occumfirst. You also have to have good access to irrigation silt loam. I have no idea what the good soils are in thiswater, and a good deep A-horizon or what we generally area, but good land is the best place to start. We foundcall the topsoil. These things are all physical qualities. a good piece of land.These are all things that are very hard to change, andthe list goes on. Structural fertilityWhen you determine the physical qualities of a pieceof land, you should accept those as they are, withoutthe notion that you are going to change it. If you have a When you talk about structural fertility, you definelot of rocks in your soil, you have the option of buying how all of the different soil particles are connected anda rock picker. It is going to take a lot of time, a lot of organized in relation to each other. When you want tomoney and many resources to get these rocks out of evaluate the structure, you imagine a circle and draw athe field. In the end it is a lot cheaper to buy a piece of line through the middle; one half of it contains the poresland that does not contain any rocks to begin with. If in your soil filled with water and air with the otheryou already have a piece of land that you might have half containing the mineral component. That image isinherited, you come to realize there is a cost involved true for good vegetable land. It may not look like thatin making it suitable. If the slope exceeds, say, two for grasslands or for croplands, but especially whenpercent you could bring a bulldozer in. You could level growing potatoes and onions you aim for a relativelySoil and Nutrient Management 35
  • 44. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.fluffy soil. You can achieve that with equipment, but the plowing which has to happen in the Fall. Givenit is much better if you can accomplish that with other our winters and slopes, exposed soil over the wintermeans. A good structure means it has a good ability causes too much erosion. Harold showed a slide offor roots to penetrate, therefore a good ability to hold how we were taught to plow back in Holland. Thewater and to drain water. Now again, all of this has furrows were supposed to be nice and straight, andalready been said before today. I feel like much of shiny. There was this whole idea about this shiny fur-what I prepared to say today is a repeat, and I will try row that rested over the winter and after that it wasto move into the more practical applications of every- beautifully broken up by the frost Only later did I learnthing we are doing at our farm. One thing that I might that it was about the worst plowing job one can do.add and I haven’t heard anyone mention today, is that The Nordell’s showed me the benefits of turning thewhen you have a clay soil, and I do not recommend soil only slightly without completely turning it over.this for vegetables, you can improve it by altering When you make the choice to expose the ground andits chemical component to give it a better structure. loosen it up before the winter it is amazing how thatWhen, for example, the clay contains low amounts can change its structure. One trick that a lot of peopleof calcium, it will start losing its natural structure, it may not know about is that you can cause the samebecomes unstable. effect over the summer. Over the summer when the soil has become extremely dried up, you can put yourWhen we talk about tillage, I mean when you are overhead irrigation on and drench the soil. This willworking your soil, a rule of thumb is to take a lump of fracture the soil as well.your soil in your hand and drop it down from four feethigh. The natural breaking points of your soil allow This slide is an example of some good soil. This was athis lump to be broken up in smaller pieces. This is a crop of rye being spaded in, and this is what you wantguideline how hard you should work your soil. Soil to be looking for when it comes to a good structuralshould have a composition that is build up of natural fertility. The decision to take a field out of vegetableaggregates. Soil aggregates are relatively small, since crop production is based on what I see. I do not haveyou can hardly see them, but they make up the natural any tools available for me to know how the fungi actu-composition of your soil and are created by root ac- ally hold the soil together, but you can see it. You cantivity, microorganism, and earth worm activity since see in this slide that there have to be a good amount ofthey break up the soil, and through digestion glue soil mycorrhizae and other microorganism that hold the soilparticles of different sizes together. You can disturb this together. At the moment the soil becomes blocky andnatural formed aggregate through the use of a tillage has straight edges, I know it needs a period of rest. Itool to create a seed bed when this is done in a violent need to take it out of production. I have been workingmanner. A rotovator is such a violent tool. What can it too hard. Soil should never feel hard on your hands.happen is that these tiny aggregates, which we have It should be soft. It doesn’t matter if it is clay soil orseen some beautiful pictures of today, are falling apart. silt loam soil while it is very hard to create structureThe consequence is that after a heavy rain storm the on a sandy soil. It is extremely difficult. It just doesn’tsand, the silt or the clay separate with the smallest have much to it. After incorporating a lot of organicparticle floating to the surface, which causes crusting. matter on a gravely soil it will still feel hard. When itThis will have a detrimental effect on the quality of a comes to the better quality soil, the silt loam and theseed bed. Root activity is a very important tool for soil clay, they can really feel soft to your hands.improvement. I will talk more about that later. Biody-namic preparation 500 is another. Repeatedly, research Aeration incorporation, and seedbedshows that where the Biodynamic preparations have preparationbeen used the soil shows increased microbial activ-ity, and rooting depth of the plants. The homeopathic Aeration is important both for the breakdown of themedicine that we use on our land has a real impact on organic matter to release nitrogen, but also to createits structural fertility. more pore space in your soil. Proper incorporation of organic material is a very important thing if thisFrost tillage is a common used tool in Holland in re- involves large amounts of organic matter. If you can’tgard to light clay soils. I am not highly recommending incorporate it properly, it can’t properly break down.the use of it in this country because of the timing of It has to be distributed into the soil. We need a quick36 Organic Vegetable Production
  • 45. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.breakdown in the process of creating a seed or plant of sod and I wondered how I would get a quick breakbed. The moldboard plow has no use on our farm any- down. Moldboard plowing was one option. The chiselmore – (showing a slide of land being plowed). This plow wasn’t. I chose to spade the sod in the springis an old slide, since it has been rusting away on our for vegetable crop production that year. It worked. Itlot for it hasn’t been used for a long time. The reason proved to result in a very quick breakdown of organicwhy, is when I noticed that the kale or corn stalks matter by distributing the organic material.that were plowed under were still there buried in theground at the end of the season. Nothing happened to Here is an example (showing a slide of a spadingthem. You want to plow under, say, a tremendous crop machine), of what the soil looks like when you spadeof Sorghum Sudan or anything comparable. What are in sod. Extremely effective, mainly because of theyou doing? You might be creating silage down there. secondary tillage action following the spades. This isIs that the point? It really doesn’t do a lot of good. The not a machine that pushes the spades straight in themoldboard plow makes a beautiful seedbed though, ground, which is preferable. This is a rotating spadingbecause it doesn’t take much but a pass of a disk and plow. It moves very slowly. It is not at all like a rotova-we are ready to seed. The plow makes the land look tor. It picks up big clumps of soil with organic matternice and clean. It buries all this organic matter. and it inverses it into the soil. You can set it anywhere between six and twelve inches deep. You can go rela-After this, we went into a stage where we used the tively shallow with it. But the tool, the power harrowchisel plow. The chisel plow is a wonderful tool and that goes behind will push all the bigger clumps deeperwe still use it a lot. It is a fast working tool. I like down. So, if you don’t go over it again with a harrowanything that can work up an acre of ground in 20 and bring the clumps back up again, those clumps willminutes or less. This width of the chisel shown here stay deeper down and not interfere with seeding. If youis about seven feet. The problem with this tool is that wait long enough they will be decomposed by the timeit leaves a lot of the plant matter relatively close to the you seed. A problem when plant matter stays relativelysurface (Harold would say this is a great thing), well, close to the surface is that it will not decompose, sincefor vegetable growers it might be a problem if you decomposition needs moisture.don’t have the right seeders. It will demand severalnext passes of discs and harrows to create the right (Showing a slide of incorporating full grown Sorghumconditions. I am trying to stay away from the disk Sudan) We also wanted to see how much we could docompletely because it has a tendency to cut the soil. with it. This is a full grown crop of Sorghum Sudan.It can cut the aggregates in pieces, while the s-tines I wouldn’t recommend it. It is just one of these thingshave a tendency to find the natural breaking points. that we wanted to know what we could do with it.They rather hammer the soil all the time. This is the Under normal circumstances you would flail mowprocess of creating a seedbed. this Sorghum Sudan crop and then spade it in because, especially when the ground is a little on the wet side,The problem with this system is that you need to make it will wrap itself around the axle of the spading plow.many passes on your field, going back and forth, back It has also proven to be a good tool as far as lookingand forth. First you go over it with a chisel plow, then at the whole farm system. We grow thirty acres ofwith a disk, then with a Perfecta and then finally with vegetables but can still look at it on a bed-by-bed case.something that makes a seed bed to make it nice and As soon as the beds of squash are done harvesting welevel. That is four passes. You have aerated the soil all can spade it in and by the next day come in and plantright but you compacted it again by needing to create a crop of lettuce. You can see here (showing a slide ofa seedbed. This felt very silly to me. So, a couple of a mulched crop of summer squash), with technology,years ago we purchased a spading machine, although this is what it was before – this is not a trick picture.I was forced to, out of the practical situation we found We went over it exactly one pass.ourselves. The lease on our land had been terminated.I had to produce the following year and needed to find Question:  How many horsepower do you need tocertifiable organic land. All the good land I found was run the spader?in corn, and given the herbicides used, I could notgrow vegetables on that land. The only land I found 72 horse power for a two-meter spader. This is a heavythat would work was in sod. I had to get rid of a lot machine. The nice thing about the Italian models isSoil and Nutrient Management 37
  • 46. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.that you can do some real deep tillage with a much the handout at home when you have the energy.smaller model tractor. For example, comparable to achisel plow in order to cover the width of your tractor The important part in fertility management for usyou need a much more powerful with four-wheel drive is based on cows, or on other large hoofed animals.compared to the same width with a spader. Maybe a little bit too much emphasis has been put by biodynamic agriculture on cows. They definitelyQuestion: How is the rotating spading plow dif- have a role but other large hoofed animals can makeferent from a rotovator? They look like they work similar contributions. I actually like sheep, especiallythe same. integrated with vegetables. I like them a lot better than cows, since cows are incredibly heavy. I have tried it.Looks are very deceptive – I have to go back to the I have had my cows graze some cover crops but I willslide where you saw the rye. We dug the rye back up never do it again. The ground is so soft in the veg-after it was spaded in. The integrity of the soil was etables they sink right in there. Sheep are much lighter.still intact. When you talk about any particular fertil-ity program on a farm it is really about preserving The point of keeping large animals is that we needintegrity. A rototiller or a disk invades integrity much their manure and turn it into compost. I would neverstronger than this particular spading plow. All of the consider applying fresh manure. Manure is an unfin-things that you see moving around move relatively ished product. It is half way there. It is great though.slow. They take big chunks of dirt in the front and It is the first step in the process of decomposing plantthrow it backwards. matter. I feel that the cow adds a lot of qualities to the plant matter. The inside of the cow is like a plant within(Showing a slide of a bed former) We need to make an animal. The inside of the stomach is filled withone more pass to make a seed bed for carrots and salad microorganisms that break down plant matter. Whenmix with a bed former. We have a system where our it comes out it is a very volatile product, because it istractor wheels are spaced at 72 inches apart, which not completely finished or stable. You have to be veryallows for a 54 inch raised bed top in between the careful with it and if you do not treat it right you willtires. This raised bed former was made in Ohio for lose many of its positive qualities.tomatoes. They have a whole culture of plum tomatoesin Indiana and Ohio and they grow them on raised In this particular case (showing a slide of a manurebeds. It works very well for creating a fine seedbed. pile) you see that the material is being brought to a pileThe tool is based on S-tines, staying away from disks and then we mix it with horse bedding. Most of theas much as I can. S-tines will not pulverize my soil as cow manure that we are getting is on the wet side somuch as the pan behind it will. It unfortunately kind we have to make it dry again with horse bedding. Theof smears over the ground and every time you smear particular person I am working with at Earth Works,ground you are rubbing these aggregates apart. One Bob Walker, has all kinds of materials that he makesthing you could do if you take the soil and rub it in into compost. He uses cranberry pulp and any otherbetween your hands you can see a discoloration there organic material he can get his hands on. He needs toof the soil. That is how you can see where the particles figure out the correct carbon nitrogen ratio when heare coming apart where the soil was one particular has those materials in front of him. He looks at whatcolor before, you rub it between your fingers, and he’s got, determines what will make the correct C/Nsuddenly you can see all these other colors on your ratio, and then he mixes them all.hand. That is because the sand, the silt, and the clayare becoming separated from the organic matter. This He uses a Sandburger turner (showing a slide of theis what you do with tillage equipment. Sandburger turner) from Austria and its inverts the pile. Whatever is on the outside goes to the inside, whatever is on the inside goes to the outside. After it has goneBiological fertility through the turner it has become a much more homog- enous product than before. We add the biodynamic preparations to our piles. The way you can look at aA lot has been said about this already today. I will go compost pile is to think of having another animal oninto the practical applications of it. I will let you read the farm. It is not a true analogy or true metaphor but38 Organic Vegetable Production
  • 47. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.just an attitude type of thing. It is like an animal since Also, this table shows that growing vegetables isit has all the qualities of an animal like body warmth, detrimental in maintaining organic mater levels. Atmoisture, organs (by adding the biodynamic prepara- least two or three percent of the organic matter is be-tions), and a skin (by covering it with the covers). I ing burned up all the time through cultivation. Notobviously actually take this very literally, but I do not only the nitrogen but also the organic matter is beingask you to do that. The Valerian preparation should mineralized. So, if you grow onions year after yearfunction as the skin. We find that it is not sufficient you could see that you are in a rapid declining stateenough especially in our climate where thundershow- here. Maintaining organic matter is done somewhat ifers can bring down two inches in one hour. The skin you put a field for one year in clover. It is much bet-we are providing is a cover made out of a polyester ter than doing nothing, but all you replace is about atype product that sheds the rain (while still allowing thousand pounds of organic matter. How much is thatit to breathe). really? That thousand pounds of organic matter is ap- proximately 1-2% of the total organic matter reserveRain can be a tremendous enemy of a compost pile. in your soil.Once water saturates the pile it will stop the compost-ing process. On the other hand, it also prevents it from (Showing a slide with a table showing increase of or-drying out too much. You can imagine all that heat, ganic matter by sod and rapid decline following by cropyou can see here it is about 150 degrees, will dry the land) Most of these tables are based on the Bemestingpile out quite a bit. We use the same turner either to en Meststoffen textbook. It is translated in the table incool it down or when it is too dry to insert water. We your handout. It shows total organic matter. I find this acan spray water into the pile. Other places where the fascinating table because you can see how long it takesanalogy between a compost pile and an animal hold to build organic matter. Now look at that number 50.up is the following. When you have a cow, you check That is tons per acre. A little different numbers thanon it every day, right? Well it is somewhat similar with what John showed us. I think John showed us a tablea compost pile. You kind of look at it, you follow it. that was based on 6 inches. This one is based on 12You don’t have to feed it that is the nice thing about inches of topsoil and in 12 inches of topsoil, there is Iit. But, you do have to give it water and you have to think 2000 tons of soil or was it 4000 tons. But anyway,monitor what the condition is. If you are going to do 50 stand for about 2.5% organic matter if you want toa good job, it will be free of pathogens, it will be free convert it. So, we start at 2.5% and we are going to goof weed seeds, and ultimately if you do a good job, it up to approximately 3.2%. Over a period of 25 years,will have disease suppressant qualities. this is if you have it in continuous sod. So, we are talking about going from 2.5% to 3.2% by having it in(Showing a slide of a table of organic residue per continuous sod. The formation of the prairies, you cancrop) A most important contribution of compost is in now imagine how long that took. It is a slow process.raising organic matter effectively in comparison to So here, we are considering growing cover crops tocover crops. In your handout, I added the information raise organic matter. That is a great consideration, butof what ten tons of compost adds in organic matter, what we really need is 25 years of sod. And once wewhich is not on this slide here. It is very interesting go back to cropland we are back to where we startedwhen it comes to numbers. When you apply ten tons in 10 years. So to maintain organic mater levels, andof compost each year in comparison to what these dif- I do not know if I go out on a limb here, does thatferent crops are doing, you can see the winners of all mean then, that out of every one year of cropland youcrops are three years of a grass clover mix. But all of have to balance this with 2.5 years of sod? Well that isthis organic matter is relatively fresh organic matter where I think the compost has its place. The compostat plow down. Ten tons of compost results in about will effectively maintain the organic matter. I cautionsix and one-half thousand pounds of organic matter you though that too much compost can have negativeper acre. This is a substantial number, especially taken effects as well, (like raising phosphorus to levels thatinto consideration that after one year most of this is it will pollute the ground water).still going to be there. Even after growing three yearsof a grass clover mix; only a third of the organic mat- (Showing slides of a crop rotation) What I want to doter is left after one year of breakdown. Most of it gets next is to go into some crop rotations. My crop rota-broken down. tions have many cover crops in them and you mightSoil and Nutrient Management 39
  • 48. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.ask why I bother. I just showed you that cover crops year with oats and sweet clover. The reason why Idon’t increase organic mater levels. Well it is not so use oats as a nurse crop is because the sweet clovermuch the objective of raising organic matter when germinates relatively slow and the oats is a good waygrowing cover crops. The reason is more in support- to immediately help the soil, to anchor it so to structural fertility. I have not seen any evidence Later on after the oats is mowed down, the sweetby spreading compost, that I am supporting the soil clover will fill out.structure. I have not seen the relationship betweenadding a lot of organic matter and increasing the soil The following year we spaded the sweet clover in tostructure per-sé. Especially not if I raise vegetables in provide a wonderful nitrogen supply for my sweeta very intense way accompanied by an intense regime corn. We over seed the sweet corn with red clover,of tillage. I have grown two crops, sometimes three with the following year the red clover being followedcrops a year, which requires a lot of tillage. We used by a bare fallow. I incorporate the clover sometime intremendous amounts of compost because at that point the summer when the ammonia, there is a tremendousEarthworks was still in its early stages, heavily sup- amount of ammonia becoming available out of theported by grants and the best place to put it was on red clover, is then easily being taken up by the soilour fields. So, we were raising our organic matter in and being converted to nitrates. That freely availablesix years from 2.5 to 3.7. It was great. But was there nitrate then has to be anchored again by the oats andreally an increase in structural fertility? Not as much peas that are followed by potatoes. It is a challenge toas I hoped for. get enough of nitrogen to my potatoes, while getting potassium is usually not a problem. It is available inWhat I also saw was a weed cycle where we initially the compost or I can spread Sul-Po-Mag (an OMRIencountered a lot of pigweed and lambsquarters, approved potassium fertilizer). But getting enoughchickweed, galinsoga, and purslane came in. Tomor- nitrogen is difficult for both growing potatoes or cornrow there will be a lot more about weeds, and weed and it needs clover incorporated in the rotation.control, but let me say a few things about this in relationto rotations and cover crops. When you leave the soil The potatoes are followed with an oats and peas and you work it too hard by breaking down The potato crop serves almost as a bare fallow. Thereits structural fertility, I believe, and this might be too are hardly any weeds in the potatoes, first because aflowery for you guys, that the soil is self corrective by bare fallow preceded it, but also because the potato iswanting to cover itself up again. So, it is looking for the very easy to cultivate since you keep hilling them. Thecrop that will do this the quickest and most effective oats and peas are chosen as winter cover crop becauseway. Well, chickweed and purslane are perfect in doing winter kills both, since we don’t want to do a lot ofjust that. The wisdom in the soil is looking for ways tillage, especially deep tillage, in the spring. Whento cover up the mistakes that we make. As a result the you do deep tillage you are going to bring more weedcrop rotation I will show you has incorporated grasses seeds up again, this is not a good idea, especially notand legumes. Grasses and legumes are other crops that after a bare fallow.are very effective in covering the soil. They are able to,as was said before by Harold about nudity, put some So, here we follow the oats and peas with onions. Theclothes on that soil in a very effective way. onions come out of the ground sometime around the middle of August and are followed in September by ryeThe other component about the following crop rotation and hairy vetch. The rye and hairy vetch are mowedis that it allows doing some very aggressive weed con- down a few times and then incorporated to be followedtrol by introducing the bare fallow, which is possibly by fall broccoli, or we (mow it once and) harvest the ryedetrimental for some of the microorganisms and soil for straw. After the fall broccoli there is no cover crop.structure. The crop rotation serves the two purposes; There is nothing to protect the ground over the winterincrease structural fertility and providing control for and the ground is open. The good thing is that there isdiseases and weeds. very little plant debris and we can follow with a fine seeded crop like early greens or spinach or lettuces.I just want to walk through some of these rotations It can be anything as long as it is not a Brassica itself.with you. Here is one where we start the very first Any rotation keeps families following each other with40 Organic Vegetable Production
  • 49. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.the exception of the legumes and grains. the idea? The more air, the more pores you have the quicker the water will actually infiltrate. We heardNow lets move ahead for a moment. We are going to some remarkable numbers from Mary-Howell andshow a few pictures. Klaas Martens about their land. He was very much surprised. What I wonder about is that he was dealingQ:  When do you apply compost? with vegetable growers. Those people probably went out and cut their cover crops when they ran out ofA: Every time before a cash crop, ten tons of compost work everywhere else. Well, when do you think thatis applied in the spring. Right now we apply ten tons. happens? After it has rained a couple of inches. TheI think that at a certain point, you should be able to priority was to get your cash crops in. When they ranbring that number down, but I agree with Brian that in out of all that work, they mowed down their coverthe earlier years you really need to apply at least ten crops and compacted their soil. So, it wasn’t a surprisetons per acre. It is a lot of money, so you have to ask at all, that the land that had been in cover crops foryourself if you can afford that. Another option would three years was extremely compacted. You have tobe to spread smaller amounts of compost, and supple- look at your soil improvement crops as you treat yourment what you can’t get out of the compost from other vegetable crops. Be careful using heavy tractors whensources, either through side dressing or any other way. mowing them down. You are driving a lot on there. We are mowing up to three times a year, which greatlyQ: How do you incorporate your cover crops? helps in controlling weed populations, but you have to be careful. Those are heavy tractors, 7,000 poundsA: We use a spading plow followed after flail mowing. or more. I don’t know how many pounds per squareThe spading plow is the primary choice for incorpora- inch are underneath the tractor tires, but it does add up.tion of large amounts of organic matter. (Showing a slide of red clover) This is actually not(Showing a slide of mature oats) Here the oats were sweet clover it is red clover – we’ll come to it laternot cut down and I will never do it again, I’ll show in another rotation. This slide is taken around mid-you why. This was a very dry year and the oats very summer. You see we are treating the field in onemuch competed with the sweet clover it was a very piece. Now we are dividing the field in sections. Thepoor stand so we are not taking that risk anymore. This whole farm is divided up into sections with a varyingwas also kind of a dry soil to begin with, but you can length but eight beds wide. Each section is dividedsee what a poor stand of sweet clover we have there and separated by a harvest lane. The eight beds in(showing a slide of very small plants of sweet clover these sections, come close to being permanent. Theunder a crop of oats). It was right before we combined tire tracks will fall in the same place, year after year,it. At that point, I was greedy, I wanted to get the oats, after year. The grass and clover strips in between areand I wanted to get the grain. Right now, not having also permanent. It also allows for very good recordour cows anymore, there is no need for that. So, we keeping as far as rotation is concerned. The 70 acresmow the oats probably twice and then we mow it a that we operate, 30 acres at one time are in cash cropsthird time (the clover). and the other 40 acres are in soil improvement crops. The way that we keep track of it is section by section.This brings up another important thing; mowing your Here you can see that where one section is preparedcover crops. Ted Blomgren did an interesting study us- for seeding. We spaded in the clover and then seededing an infiltrometer. I don’t know what it looks like but down with oats and peas. That will be the followingI understand the concept. It measures how much water year in potatoes.the soil is able to take in. There were three plots – oneplot with three years of cover crops, one with one year Here is the last cultivation of the sweet corn (showingof cover crops and one year that was in vegetables. a slide of young corn plants). After the last cultivationGuess which had the highest infiltration – it was the of the sweet corn, the red clover is over seeded. Wevegetable land. That wasn’t what I expected. Weren’t do not wait a day, we have someone cultivating andcover crops supposed to create those nice pores and hilling up the corn with another person walking behindstructural fertility and everything else because that is with a cyclone seeder. It is one of those things you getSoil and Nutrient Management 41
  • 50. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use Johnny’s Selected Seeds. It looks somewhat silly to cut it). Has anyone tried to cut rye and hairy vetchbut it goes pretty fast. We are seeding our clover down with a haybine before? I destroyed a haybine with a rate of approximately 20 pounds to the acre. This It was an old haybine, I admit. But hairy vetch justis red clover. I tried sweet clover. It doesn’t handle clogs up the mower, which can be really awful. If youthe shade very well and it doesn’t handle the traffic want to make your own rye straw, a sickle bar mowervery well either. (Showing a close up shot of sweet would be the best thing to use. We use a lot of ryecorn) You can see these are not weeds. The ground is straw as mulch.clean at this point and you can see that the clover hasgerminated. You can see this is after harvest (showing This is garlic (showing a picture of a mulched field).corn stalks with a green cover on the ground). The We used a lot of mulch in between the black plastic.corn has been harvested. The clover has established I will really shoot through these ones (slides) veryitself successfully. We then mow the corn down fast because they are outdated. The reason why they(showing the sweet corn mowed down)– you can see are outdated is that our workers refused to work withthe stubbles there. It pretty much fills out. The rest of straw. The allergies that people develop these days arethe rotation follows. inhibiting us from using large amounts of rye straw, so we still use it in our strawberries and garlic, but IPretty much this rotation is based on a system that was had to find another solution for what to use in betweendescribed earlier. Oats and barley over seeded with the black plastic.legumes is a very common practice at biodynamic ororganic farms in Europe. I wondered how we could do The solution that we came up with is living mulch.this with vegetables. The last example I show you is This is annual rye grass in between tomatoes (showingone where we seed red clover at the beginning of the a slide of staked tomatoes with a living mulch). Therotation – by the way if it is a seven-year rotation –At three acres that we have in drip and black plastic isthe end it will start the following year back at year one seeded down with Dutch white clover. This is one ofagain. When you start red clover, you do not need a those examples of a successful combination of a cashnurse crop like with sweet clover. and cover crop in the same year. To establish the liv- ing mulch, you want to make sure you lay all of your(Showing a slide of a tractor pulling a grain drill in a plastic as early as you can to seed your Dutch whitelarge field) Just as a note: we operate those 70 acres of clover. Don’t wait as you may usually do and lay yourland with 30 acres of in cash crops by myself, my part- plastic as you need it because if you wait until May andner Jody Bolluyt, four apprentices and two seasonal you seed your Dutch white clover the weeds will getworkers. That is close to 10 acres per person and we ahead of you. I had a very interesting situation and if Ireally don’t work hard. We like to work 40-45 hours had a couple more hours to talk I would talk about thata week. It is a matter of approach. A lot has to do with more, but when we got the new farm we ended up withthe fact that we put systems in place. The down side three different pieces of land. One was in rotation ofis that it takes a lot of land. But we have been able to potatoes and corn, the other one was continuous corncut down on the number of hours per cash crop per and the other one had been in a corn/alfalfa rotation,acre. We spend most of our time harvesting, which with four years alfalfa, and four years in corn. Theis key. We spend very little time on insect or pest or one that was in corn and potatoes was heavily infestedweed control. Weed control is something that takes with purslane. I really did not know what to do with it.five to ten hours a week for one person, besides the I seeded some Dutch white clover to see what wouldfinely seeded crops that are being weeded by hand. happen and to my great surprise it suppressed theOtherwise, we never touch potatoes, corn, cabbage, purslane. When we laid black plastic in that field theetc. by hand. It has to be a weedy piece of ground for Dutch white clover suppressed the purslane the wholeus to hoe cabbage. season. It provided a beautiful cover. A note of cau- tion is to make sure you use Dutch white clover. WeAnother word on rye (showing a picture of rye and once seeded from a bag that said white clover on it. Itvetch in bloom). We grow quite a bit of rye and hairy was not white but red clover (which is an aggressivevetch. If we want to harvest the rye, we do not mix grower), it actually grows right over the plastic, andin the hairy vetch. It really becomes a mess (trying it starts invading your cash crop. Not a good idea. It42 Organic Vegetable Production
  • 51. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.has to be Dutch white clover, not because it is Dutch, for another five, six, or maybe even seven years sojust because it is small. disease is not a problem. The problem with the winter squash is when we work in our weed seeds to establishOver seeding of red clover in winter squash (showing a cover crop. These weed seeds that are buried can bea slide of winter squash getting hoed) should be done a problem in future years. With over seeding the weedat the last cultivation. Some people asked me earlier seeds, like lambsquarters or anything else that goes toif you don’t have to rake the clover in. Again, I don’t seed, dies down, and we’ll mow it. The weed seeds liethink I have stressed enough you don’t have to as long on top. The birds will get it, smaller insects will getas one person is following the cultivating tractor. The it, or it germinates the following year underneath theseeding happens within moments after the last culti- clover. It actually gives many advantages and does notvation. The ground is nice and soft and it falls right create a lot of between those cracks. It germinates quite well. Butif you wait, especially if you wait after a rainstorm to There are some problems though with having too manyseed your white clover, it is not going to work very cover crops. There are some problems associated withwell. You are going to have to roll it in, rake it in, or cover crops as well. We have all this raw organic mat-do something. The incorporation of the clover seed ter, which provides this incredibly nice environmenthappens by the ground being recently worked. This is for some of the insects that we don’t like to see. Weactually a member’s workday here. We have members have problems with thrips because they come flyingcome up once a month helping us with hoeing and out of our grains after we cut them down and infestharvesting. We have 700 shareholders that support our onions. We really need to think about that. It mightour farm. mean that we should always leave some grain standing up for them to go to instead of flying into the onions.Here you can see after the harvest (showing a slide ofclover). You can see it is completely filled out. This Q:  Are the cover crops hosts for leafhoppers?is actually another slide right after harvest. Here youcan see there are some patches that where underneath A:  I find it mostly with alfalfa. I have not seen it withthe plants that surprisingly well filled out. That was the clover. If clover is the host of that as well, wethe last slide. haven’t seen it, yet. Q:  Do you mow the clover?Questions A:  The living mulch we do not mow, but if you have red clover, you do have to mow it. Again, we had redQ:  When you over seed the clover to the previous clover because of a mistake we made and we mowed itcrop do you find any disease problems with keeping three or four times. We did not have a problem with tar-that crop on the ground through the fall/next year? nished plant bug; we had a problem with leafhoppers. Again, I am assuming that they came out of the coverA:  In the case of winter squash there were a couple of crops and came flying right in. I would say our big-reasons why I over seeded. Since we don’t like hand gest problems with insects right now are flea beetles,hoeing or hand weeding, winter squash is one of those cucumber beetles, thrips and leafhoppers. Coloradocrops where we always saw a few weeds going to seed. potato bugs are almost nonexistent. Why? I have noWe have members hoeing there, and that is great be- idea. I assume that some crops are serving as a host ofcause they can get those weeds that the cultivator did their predator either over the winter or at other times.not get. Normally speaking we would not have time forit and a few weeds would go to seed. The advantage of Q:  (Most of the question was inaudible) Somethingover seeding instead of disking in your winter squash about nitrogen in compost, when do you cut back,crop residue, which some people said they do to pre- will cover crops be enough? What are you thinkingvent diseases in future years is the following. First, in about in the long term?this crop rotation the cucurbits do not come back thereSoil and Nutrient Management 43
  • 52. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.A:  Long term is to involve animals and then a lot you to import less compost. Maybe that is somethingof the fertility (from the soil improvement crops) that you want to aim for at one point, which is to im-will be exported from the fields in the form of feed. port less compost. Lawrence B. Hill said, “PlowingIt means instead of cutting them down and plowing under a cover crop is like a crocodile in a fish pond”them in, you bring them to the barn and feed them to – it is a lot of activity and then it is very quiet again.the animals over the winter. Bringing the composted Soil life becomes very active and John said it earliermanure back will mean we will import less compost it is almost like applying liquid fertilizer. So, coverfrom the outside. In other words, it will be a cycle crops have their place for root formation, but maybewithin the farm. within the farm system as a whole system, there is more wisdom in feeding it to animals. Removing aQ:  Will you cut back on the compost? lot of the above ground plant matter, feeding it to the cows, building a compost pile and then bringing thatA:  I think compost is very important. I don’t think a back in the form of compost seems to be a lot moresystem within vegetables would ever work on cover sensible, while there is still a lot of that structuralcrops alone. I think you eventually will lose important fertility being built by the plant roots. That would benutrients that are needed. I think the animals play an the long-term picture.important role within the farm, and they will allow44 Organic Vegetable Production
  • 53. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Fertility Management at Roxbury Farm Jean-Paul Courtens Roxbury Farm Kinderhook, New YorkTo evaluate the fertility level of our soils, there are four The annual potash requirement for the hayfields aver-different characteristics to distinguish. ages around 80-110 lbs./acre. Roots and microorgan- ism can extract some potash out of the rock content of the soil or draw some it from the subsoil, provided1. Chemical fertility the soil has no hardpan. An annual gift of 14 tons of cow manure provides 110 lbs. in potash.a. Hayfields The annual need for phosphate is around 25 lbs./acre. Three tons of manure would cover that need (based onHayfields are generally self sufficient in nitrogen pro- average manure samples). Most manure contains rela-vided there are plenty of legumes part of the hay mix. tive high amounts of phosphate caused by the grainsYou might see your neighbors using generous amounts fed to the animals.of nitrogen fertilizers on their hayfields, and in Hol-land, they practice this as an indirect weed-killer. The b. Vegetablesonly plants that do well with an oversupply of nitrogenare the grasses. Grasses have a great ability to choke All vegetables have different nutritional requirements.other plants given they are supplied with lots of water A rule of thumb is that:and nitrogen. High nitrogen levels also reduce theuptake of nitrogen by rhizomes that live in symbiosis • Most vegetables have relatively low needs forwith the legumes. phosphorus.The best improvement in a hayfield is it to make it part • Leafy greens have higher than average needs forof a rotational grazing system, in which cows are al- potassium.lowed for very short periods (1 to 3 days) to graze. Inalternate years, the field is hayed with still allows for a • Most recent developed vegetable varieties do wellfall grazing period. The most productive hayfields are with high levels of nitrogen.usually the ones with the greatest number of species,considering the time an alfalfa field is out of production • Most vegetables need a pH between six and seven.for reseeding purposes. Compost or manure releases only about 40% of itsSoil and Nutrient Management 45
  • 54. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Table 1 Average Nutrient Absorption For Vegetables Nutrients in lbs./acre Vegetable Nitrogen Phosphate Potash Asparagus 11 3 6 Beans green 120 10 55 plants 50 6 45 Beets 140 14 140 Broccoli at 10,000 lbs. heads/acre 20 2 48 plants 145 8 160 Brussels Sprouts 140 20 125 plants 96 9 110 Carrots at 30,000 lbs. roots/acre 80 20 200 leaves 65 5 145 Cantaloupe at 22,500 lbs./acre 95 19 120 Vines 63 8 35 Celery at 100,000 lbs./acre 170 35 387 Roots 25 15 55 Lettuce at 35,000 lbs./acre 95 12 170 Pepper at 22,500 lbs./acre 45 6 50 Plants 95 6 90 Spinach at 20,000 lbs./acre 100 12 100 Sweet corn at 13,000 lbs./acre 55 8 30 Plants 100 12 75 Potato at 40,000 lbs./acre 150 19 200 Vines 60 11 75 Tomato at 60,000 lbs./acre 100 10 180 Vines 80 11 100 Adapted from Knott’s Handbook for vegetable growers Average uptake from vegetables is: •  81 lbs./acre nitrogen (available in ±8 tons of compost) •  31 lbs./acre phosphate (available in ±4 tons of compost) •  122 lbs./acre potash (available in ±10 tons of compost)nitrogen the first year with the remainder released in The nitrogen in manure consists for about half of am-the following two to three years. When we spread the monia and with the other half in nitrate, and in goodmanure in the fall, losses of soluble nitrogen are high compost, all ammonia is converted in nitrate.and we can only utilize 20% in the following year. A soil test will give some indication of where the stateNitrogen from cover crops, when plowed under, is of your soil is. But besides giving accurate numbers forreleased over a very short amount of time and care its pH and OM, It rarely allows for a good predictionshould be taken to avoid losses. Most of the nitrogen of what the yields will be in an organic system. I havefrom cover crops consists of ammonia (highly volatile). seen many instances where good soil health (good46 Organic Vegetable Production
  • 55. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Table 2Different Compositions of Several Organic Fertilizers All quantities in lbs./ton, except the first columnType of Per animal in Dry Org.fertilizer lbs./180 days Matter Matter N P K CaRoxbury Farm Compost 924 327 12.5 8.25 12.6 20.3Cow-dairy Solid 13,000 430 280 11 7.6 8 8 Urine 9,000 52 20 8 .4 16 .2 Slurry 22,000 190 120 9 4 10 4Pig Solid 770 460 320 15 18 7 1.8 Urine 990 40 10 13 1.8 9 1.2 Slurry 1,760 160 126 14 9 8 1.5Chicken Solid 44 640 460 25 37 18 47 Slurry 88 220 160 16 13 10 22 With bedding, 1,160 700 32 40 22 57 (Free range)Horse 620 500 10 6 11 6Adapted from: Bemesting en Meststoffen by W.T. Rinsema PhDstructure, good biological diversity, and good physical What crop is growing on it is a direct result of the soilqualities override its chemical contents. type we are working with. The presence of large rocks, steep slopes, or poor drainage makes some of this landThe reality is that hay would do very well with unsuitable for vegetable crop annual gift of 2 to 3 tons of cow manure to theacre, while vegetables need more than what the Good vegetable land has:numbers from a chemical analysis suggest in orderto produce a competitive yield. Vegetables do not • A high carrying capacity (carry the weight ofsupport structural and biological fertility and their equipment without creating irreversible compac-roots rarely extract minerals from the rock content tion)of the soil. • Good drainage2. Physical fertility • Good access to irrigation water • A deep A horizon (topsoil) that is free from stonesThere are about 250 acres under Roxbury’s manage-ment. • Is almost flat with slopes that do not exceed 2%.Soil and Nutrient Management 47
  • 56. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.• Is located in a long season micro climate 3. Structural fertility• Good exposure to sunlight The way soil-particles are connected and organized in• Good air drainage to avoid late frosts. relation to each other reflects on its structural fertility. We evaluate how the soil particles are spaced and how• Good access to farm roads many and how large the spaces are in between them. By the use of tillage tools and the compaction of tractors,At Roxbury Farm the 100 Acres that are suitable for the soil aggregates are broken. When the soil is workedvegetable crop production, only 30 are planted in cash too hard, it will not stand up to a heavy rainstorm andcrops each consecutive year. 40 acres are planted in will collapse and erode. Soils with stable aggregatessoil improvement crops with the remaining 30 rented are more stable. Some soils do not have the physicalout to a neighbor for hay. Almost all of the vegetable characteristics to create stable aggregates. In that case,land is rated category I or II (Occum, Unadilla, Knick- the only remedy is adding organic matter.erbocker, and Hoosick). The remainder of the land israted lower and divided between hayfields, pastures, A stable structure will have:woods, or wetlands. They are still important in provid-ing a broad biodiversity to the whole farm. • An equal distribution between mineral particles and pores.When we assess the physical quality of our soils, wedetermine its physical strength and limitations. Work- • Good ability for roots to with land is not unlike working with a horse. First,we need to know what horse we are dealing with. Is it a • Good ability to hold water.workhorse or a riding horse? Each has different quali-ties. We will not try to pull a heavy load with a riding • Good ability to drain excessive Within this analogy, a sandy soil has qualities ofa riding horse. Although it has its usefulness, we cannot Hay fields and pastures are in general self sufficientget a lot of work out of it. It might pull a plow but it in creating good soil structure. Their root systemlacks the persistence of a workhorse to complete the supports many microorganisms that feed directly ontask. Sandy soils, are great in the early spring since we plant matter or live off the conditions created by thehave early access, since they drain well and warm up. roots during growth as well as decay. In general, mostBut in the summer, they easily dry out, and can only grasses create a surplus of carbonaceous materials,achieve good yields with solid set drip irrigation. A and the organic matter content of the soil increases.workhorse on the other hand keeps moving, albeit at an This will help connect the soil particles into stableinitially slower pace, but with much greater resilience. aggregates. Microorganisms feed on the decayingA heavier soil, like a silt loam resembles a workhorse. organic matter and together with the extensive rootThey are a little later to warm up in the spring but their system of the grasses help the way in which the soilability to hold nutrients and water gives them a great particles are ordered. They leave many pores, whichadvantage over the summer months. will provide drainage and capillary action in times of drought. Vegetable crop production, by its nature ofNutrition is another analogy between horses and soils. exposing the soil and introducing equipment, do notDespite Too much compost to alter its physical charac- maintain soil structure. Besides this, most vegetableteristics, which results in excessive amounts of soluble crops do not have very well developed root systemsminerals, creates high disease and weed pressure. unlike most grasses.Starting off with a good soil is the best investment Strategies to support good structure are:a vegetable grower can make. Altering the state ofits soil is hardly ever cost effective. • Supply high amounts of organic matter that contain humus formative particles.48 Organic Vegetable Production
  • 57. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.• Add Calcium as building block for clay soils. that require extremely level ground with no clumps or stones on the surface a Buckeye bed former is used.• Avoid breaking up the soil beyond natural breaking This tool leaves a trench every 72 inches, creating a points soil surface that resembles raised beds. The planting surface of the bed is 54 inches wide and allows for• Increased root activity by using soil improvement three rows 18 inches apart. The trenches have proven crops. to be very successful in allowing the crops to stay dry much longer during periods of heavy rain. The• Increased root activity by using Biodynamic prepa- combination of better drainage and the level plant ration 500. bed prevents bottom rot and creates conditions for successful mechanical weed control.• Frost as an action to fracture compacted soil.To help determine how we treat the soil during the 4. Biological fertilityseason tillage tool should not fracture the soil morethan when we drop a clump of soil from a height ofthree feet. Ideal is to use tillage equipment that has Here we recognize three areas of importance:an action similar to that of a hand-fork. A hand forkfractures the soil at its own breaking points. A spade • The cycles in nature, that includes decay and de-and damages the aggregates where it slices the soil. composition of organic matter.The coloration at the back of the spade is an indicationof smeared soil particles. The aggregates that order the • The creation and maintenance of soils.soil have come apart. • The nutritional value of cultivated plants.Three different purposes of tillage: At Roxbury Farm this is addressed with the following• Aeration of the soil. (Depth anywhere between 8 measures. and 18 inches) A. Applying compost and incorporating soil• Incorporation of organic material. (How deep do improvement crops increases soil fertility you want to put your organic material?) Fresh organic matter, is important to add to the soil• Creating a seed or plant-bed. (How smooth and because: level does this have to be?) • It feeds the microorganism.Conventional equipment rarely combines all threetasks. Only a spading plow with secondary attachment • It keeps the nutrients in a cycle.will accomplish this and it will aerate at the same depthas it puts the organic materials. • It creates a better structure of the soil by acting like glue to the soil particles (Fungi).For primary tillage, a Chisel plow is used to aeratethe soil. In order to incorporate cover crops with this Ultimately a good soil transforms this organic mattertool the use of a shredder or flail-mower is necessary. into…The chisel plow does not turn the soil and leaves alot of plant matter on the surface. After the primary Humustillage, a Perfecta II Cultivator is used to smooth outthe field. This tool consists of a combination of sev- Humus, the most stable form of organic matter that:eral “S” tines, a leveling bar, and a set of crumblingrollers. It leaves the soil level and smooth enough to • Has the ability to absorb both nutrients and wa-plant: cover crops, Cole crops, potatoes, squash, and ter. Humus compared to clay can hold up to foureven lettuce-plugs. For crops that have small seeds and times as much water, and the nutrients in humusSoil and Nutrient Management 49
  • 58. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. are available to plants but cannot be washed out composting takes about 6 to 12 weeks. The compost, by excessive rainfall. when applied is not finished, but will have lost most of its odor. The ideal time of application is on a cloudy• It increases the structure of the soil. day with plenty of rain in the forecast. After applica- tion, the ground is chiseled or spaded. Manure handlingCompost can be the weakest link in the farm’s fertility cycle. At a biodynamic farm, it is important to keep nutrientRoxbury Farm works closely with the company Earth- losses as low as This company was formed with the help of thestate of New York to research the possibility of keeping Fibers play an important role in the composting pro-organic materials out of the landfill. Earthworks col- cess. Most fibers are “used up” at the end of the com-lects produce from supermarkets, horse bedding from posting process. Hay and straw are good examples offarms, and pulp from canneries. These materials are being good energy providers for the microorganism.mixed with a Sandburger compost turner and carefully Their presence is vital in the process, but it is impor-monitored for temperature and moisture. This machine tant to include materials that contain lignin. They takeis also utilized to make compost from cow manure to a longer time to break down, and this kind of carbonbe used at Roxbury Farm. compound is not readily available as an energy source for the microorganism. But at the end of the compost-The process of making compost at a biodynamic ing process, they contribute to the formation of humusfarm at a much higher rate than fibers do. All carbonaceous materials have a different ability to become humus.During the winter, the cows are usually kept in a free The materials with high lignin fractions, like peatstall setup. In this method, the hay is fed in the form moss, sawdust, and leaves have what we call a highof round bales inside the stall and placed on top of the humification coefficient. They alone cannot providepacked manure. The cows are kept off the manure by the microorganism with enough energy to start theapplying bedding on a regular basis. This can consist decomposition and hay, straw, or green material hasof old hay, straw, and or wood chips. If an adequate to be added to the pile to jump-start the process. Thesource is available, rock dust, like Basalt meal can manure contributes nitrogen and other building blocksbe added to the manure pack. After six months, the that are used by the microorganism to grow and mul-packed materials are about three feet deep. In May, tiply. By adding soil or rock dust to the manure, wethe manure is removed with a bucket loader. The pile create conditions that can occur only under ideal cir-is build with a manure spreader, with its final shape cumstances in very good soil. The humus can transformcreated by the turner. The biodynamic preparations are into a clay-humus complex. This aggregate representsinserted into the pile by pushing a long stick two feet the most stable soil component, which has a very highinto the pile. Only small amounts are needed in each capacity to hold nutrients and water.hole to prepare a pile. The eventual goal in applying good compost to the landA variety of materials in a manure-pile allows it to be is to increase the overall health of the soil. Compost ismostly self-sufficient in the process of transformation. also very effective in raising the Organic Matter levelA pile that has a variety of materials in it develops a of our soilscombination of aerobic and semi-anaerobic bacteria.The piles heat up 120° to 160° Fahrenheit and stay at B. Soil improvement and cover cropsthat point for quite a few weeks. A specially designedcover is placed over the piles to shed of any excessive The benefits of cover crops and soil improvementrain and to keep the moisture in. The cover functions cropslike a skin. It protects the pile from the elements with-out restricting it from breathing. A pile behaves like Reduction of soil erosion. A crop of rye seeded in Sep-any other organism on the farm: it breathes, consists tember and plowed under in April is able to keep themostly of water, and has body warmth, except it will soil from eroding away over the winter months. Ryenot break any fences. The piles are turned when nec- and hairy vetch as a mix are very effective. And willessary, and water can be added. The whole process of add to soil-life, though the humification coefficient can50 Organic Vegetable Production
  • 59. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use very low, soil life is greatly benefited by the mere if the particular rhizome is in your soil. Many legumesfact that the ground is not left exposed. The roots of the live in symbiosis with different rhizomes.cover crops after breakdown form the very importantcapillaries for drainage as well as water uptake. Disadvantages of cover cropsIncrease of pores in soils and breaking up hard pans. Sod can provide a cover for the eggs of many in-Sweet clover is known for its deep penetration of the sects. Flea beetle and carrot-fly take advantage ofsoil and breaking of hard pans. But any established this environment. Grains and Alfalfa hosts thrips andgrass will greatly increase the amount of pores in the leafhoppers. Once the grain is combined or the alfalfasoil. cut, the many insects including thrips and leafhoppers look for a new home. As we increased our acreage inIncrease in microbial activity. Soil particles are held grains and legumes so have our problems with thripstogether by microbial activity especially the group of and leafhoppers increased. One solution is to havefungi. Without activity of roots providing microorgan- another crop available (besides the vegetables) for theism the needed air, and carbon for their activity very insects to migrate to and to never mow all the coverlittle microbial action would exist. crops at once.Increase in organic matter content through carbon Another detriment from too much raw organic mate-intake. Grasses are known for their excellent ability to rial is the residual activity in the soil that can manifestfix carbon out of the air. For greatest uptake of carbon itself like fresh manure. Many diseases and pests likein one season, Japanese millet and sorghum-Sudan aphids’ increase when too much raw fertility is applied.are favorites. Lawrence D. Hills of the Henry Doubleday Soil As- sociation, once said: “Plowing under cover crops is notFixation of Nitrogen through rhizomes living in sym- unlike throwing a few fish in a pond filled with croco-biosis with legumes. diles.” Crocodiles are a beautiful metaphor of soil life.Weed management. Many crops are able to choke out What we seed in different months in New Yorkother weeds, and by frequently mowing of our covercrops, we reduce the number of weeds going to seed. April and MayPlant disease management. Most cover crops do not • Oats with red or sweet Cloverhost plant diseases known in cash crops • Rye with Dutch white clover on head lands (theOverall farm diversity. Most insects feed off the Rye will not form a seed head)pollen of the grains and grasses. In some instances,the cash crop acts as a beneficial host. The pollen of • Dutch white clover in between plasticthe sweet corn is a good example. For that reason,parsnips can be left in the ground to flower in the May and Junespring. The flowers that are formed in the followingspring provide a habitat for the trichogramma wasp. • Buckwheat after spinach or other early cropDill, which is another Umbelliferea, serves the samefunction. After the dill is cut, the plants remain alive • Sweet clover, red clover over seeded in the sweetand produce flowers at a time when the parsnips have corn and Winter squash.gone to seed. JulyThe roots of the legumes live in symbiosis with mi-croorganism called rhizomes. Look at the roots of the • Japanese Millet or Sorghum-Sudan with Hairylegume to find out if nitrogen is in the process of being Vetch mixed in.fixed: if the roots have nodules that are red or pinkcolored inside, it has active rhizomes. If the roots donot show nodules, find out if the soil pH is too low orSoil and Nutrient Management 51
  • 60. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Table 3Amounts of Organic Matter of Different Crops Remaining after Harvest in Same Year and Following All numbers in lbs./acre All numbers in lbs./acre Remains Remains after after Under Above one Under Above oneCrop ground ground Total year Crop ground ground Total yearRye 1100 3300 4400 1350 Grass-cloverOats 1250 3300 4550 1400 1 year 2250 1350 3600 1050Potatoes 450 3150 3600 750 2 years 6000 1350 7350 2300Beets 450 300 750 250 3 years 9500 1350 10850 3600Cabbage 900 3600 4500 1000 AlfalfaPeas 350 1400 1750 400 1 year 1800 900 2700 700Beans 350 1400 1750 400 2 years 2700 1350 4050 1200Onions 270 180 450 130 3 years 4500 1350 5850 1850Adapted from: Bemesting en meststoffen, by W.T. 10 tons of compost 6540 6000Rinsema PhD organic matter in tons/acre 68 Cropland Sod Cropland 64 60 56 Total Organic Matter 54 50 5 10 15 20 25 5 10 Time in YearsFigure 152 Organic Vegetable Production
  • 61. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.August • Brassicaceae: all the Cole crops including broccoli, arugula, turnips, etc.• Oats and Peas • Chenopodiaceae: all beets, chard, and spinach.September • Convolvulaceae: sweet potatoes• Rye with Hairy Vetch, Oats and peas. • Cucurbiticeae: all cucumbers, melons, squashesOctober and November etc.• Rye • Fabaceae or legumes: peas and beans.C. Crop rotation • Liliaceae or Alliums: all the members of the onion familyWithin the vegetable land have a system of permanentsections, that each contain eight beds. Permanent sec- • Poaceae: all grains including sweet corn.tions allow for keeping records of where the cropshave grown and aid in exact planning. There is no • Rosaceae: strawberriesguesswork in finding where last years crop was planted.The harvest lanes also serve as a means to get easily • Solanaceae: all nightshades, including eggplant,to the cash crops, a place to pull in the irrigation reel, peppers, tomatoes, etc.and as pasture for the bees (since they mostly containwhite clover). A few vegetables, herbs, or cut flowers are adopted in another family because they are relatively insignificant.Crop rotation is a tool used to break insect, weed, A rule of thumb in any crop rotation is that no familyand disease pressure in the vegetable fields. There follows itself in less than four years. Another guidelineare many reports of increased yields of cash crops to use is to have plants with opposite nutrient require-in fields that adopt rotations. In organic agriculture, ments followed each other. And lastly crops that seewe should not only rotate within the plant families of this pressure more in the spring or fall alternate cropsour cash crops but also include grasses and legumes that show great weed pressure in the summer. This isin our rotation mix. As seen in the graph above, they done to offset the cycle in which those plants go tofix decent amounts of organic matter and introduce a seed.broad spectrum of soil life to the farm. They can alsoform a habitat for beneficial insects. They are a neutral Use table 4 (page 54) as an example.crop in our rotation since they rarely host diseases thataffect our cash crops. Proper incorporation and time D. Mulchesto let the soil digest the plant matter is important. Toomuch raw organic matter can greatly affect the health Introduction of living mulches have become an im-of our cash crops in a negative way. Introduction of portant tool at Roxbury Farm to help create a goodbare fallow periods in “neutral” years are effective in environment for our cash crops. The use of Dutchbreaking up both weed cycles and incorporation of white clover in between the plastic has reduced Al-large amounts of plant matter. ternaria infections in tomatoes and keeps fruit clean in peppers, eggplant, cucumbers, melons, and squash.At Roxbury the different plant families are: Over seeding of red clover in sweet corn and winter squash allowed for nitrogen fixing for next year’s• Apiaceae or Umbelliferae: carrots, parsnips, pars- crop. We used to apply a lot of dead mulch like straw ley, celery, dill, etc. and leaves, but the dust and discomfort to our workers have limited the use of this to Strawberries and Garlic.• Asteraceae or Compositae: all the lettuces, esca- As an alternative to straw, the beds with garlic can be role, and certain cut flowers. covered with about six inches of leaves. Six inches isSoil and Nutrient Management 53
  • 62. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Table 4Crop rotation Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Greens Carrots Winter- Red Clover Potatoes Rye and Peas and Squash Hairy Vetch Beans Bare Fallow Bare fallow Red clover Rye and Bare Fallow Oats and Oats and Oats and Hairy Vetch Peas Peas Peas Oats Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Red Clover Red Clover Early Rye and Strawberries Strawberries Spinach Broccoli / Hairy Vetch Bare Fallow Cabbage Bare fallow Lettuce Bare Fallow Oats and Rye and Oats and Peas Hairy Vetch Oats and Peas Peas Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Oats with Sweet clover Red Clover Potatoes Onions Rye and Greens Sweet Hairy Vetch Clover Sweet-corn Bare Fallow Rye and Lettuce Oats and hairy Vetch Fall Broccoli Red Clover Oats and Peas peasa sufficient amount if you do not like to weed at all classified over 50,000 microorganisms in particularthe following year. The garlic pops right through in crops. After she tests a soil sample, she prescribesthe spring so this system works quite well if perennial particular teas to inoculate the soil with the missingweeds are not a problem. microorganism to provide for proper plant growth.E. Biodynamic preparations and compost Within the management practices of the biodynamicteas preparations, we can distinguish between two different kinds of applications.The use of Biodynamic preparation in the compostincreases its ability to suppress plant diseases and 1. The compost preparationsintroduce microorganisms needed for proper plantgrowth. Preparation 500 has shown to increase rooting The central thought behind the compost preparationsdepth of both cash and cover crops. is to give the compost a memory. When you make compost, the original material will transform intoResearch done by Elaine Ingham of the Soil Web has something completely new. Even chemical analysisdetermined what microorganism help plants grow. She cannot determine what the original material consisted54 Organic Vegetable Production
  • 63. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.of provided the original materials were of organic ori- The nettle preparation is the easiest to make and cangin and the process of composting was done correctly. be used as a foliar spray. The nettle is harvested beforeThe word organic does include all compounds that are the flowers go to seed. It is then directly placed in theof organic origin, including chemicals. earth, but not in direct contact with it. We place a layer of peat moss between the nettle and the moist earth.There are six different compost preparations: It is left there for a full season (summer and winter), and is then dug up and used as a preparation in theThe oak bark preparation is made of finely ground- compost pile. Nettle does not need an animal organ.up oak bark that is put inside the skull of a freshly The nettle preparation has a strong relationship to theslaughtered cow. Great care is taken when the brains iron processes in the plant.are removed to make place for the oak bark. Somepeople use a garden hose to flush out the brains but The dandelion preparation is made from the driedmost likely, even though it appears to be gentle, it has dandelion flowers. The flowers are picked in the morn-the effect of flushing the essential membrane out as ing. Only the flowers that have not yet fully opened arewell. The membrane should be left intact, since the useful. When they are dried, mature flowers becomeworking of this membrane has the desired influence seed. When we make this preparation in the fall, weon the transformation of the oak bark. The skull is then start by soaking the flowers in lukewarm dandelionplaced in water that is preferably mucky and moving. tea. The next step is to place this substance in littleThis preparation will, if made properly, give the capac- bags that we form out of the mesentery of a cow. Theity to the compost to make the plants, grown on the mesentery should be free of fat since that would inhibitcomposted soils, resistant to disease. proper transformation once it is placed in the soil. Also, when the bags are too large, there is a chanceThe chamomile preparation is made of dried chamo- that the substance will turn into silage. A good size ismile flowers that are briefly soaked in lukewarm about the amount of a baseball. These pockets are thenchamomile tea. This substance is then placed in freshly buried like chamomile. The dandelion preparation isobtained intestines of a cow. Again, we see people working through the compost in giving wisdom to theclean these intestines out a lot with water, but we rec- soil. All the positive influences from stream, pond,ommend leaving them the way they are to avoid dam- forest, meadow, and fields become available to theage. An intestine free from grass is ideal, but avoid any plant through the composted soil, giving the plant theintestine from a cow that was grain-fed. The stuffed, faculty to attract these sausages are then placed in the soil and keptthere over the winter. Great care is taken in what loca- The last is the valerian preparation. Here the flowerstion the preparations are buried. The ideal location is are collected and the juice is pressed out. We are notwhere snow usually accumulates. The intestines will blessed with having any significant amount of it grownhelp the chamomile transform into a substance that will around us, so I do not have any personal experiencegive the compost the ability to work in the processes with making this one. But I can describe how to makein which potash and calcium are involved. The manure it. First, make sure you have the real Valeriana offi-treated with the chamomile preparation shows greater cinalis. I have seen people using plants that look juststability of its nitrogen content. like the valerian, but if it is not the real thing, it will not do what we are expecting. What you are after isThe yarrow preparation is made with dried yarrow the juice of the flowers. You can use a press to squeezeflowers that are briefly soaked in lukewarm yarrow the juice out of the flowers. There are two variationstea. This substance is placed in the bladder of a stag available: one is fermented, which I prefer, and thethat is enlarged by simply having it blown up like a other is bottled up the way it comes out of the press.balloon. This little bag is hung up on the south side The smell of the fermented valerian is wonderful.of the barn during the summer months. In the fall This preparation is made without an animal compo-it is buried the same as the chamomile preparation. nent like the nettle. The finished tincture is diluted inThe yarrow preparation gives the treated manure lukewarm water, stirred vigorously, and sprayed ontothe ability to work in the soil in such a way so that the compost pile. The valerian acts like a skin andit is capable of adsorbing minute quantities of trace contributes an element of warmth to the pile. In theminerals. spring, I take advantage of this ability by spraying theSoil and Nutrient Management 55
  • 64. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.valerian tincture on tender plants to protect them from directly on the soil. If the soil has been worked, it canearly morning frost. readily adsorb the positive influences of this prepara- tion. Horn manure directly influences the way organic2. The field sprays matter is transformed in the soil. Its positive influences are similar to what organic matter does to the soil. InThe horn-manure and horn-silica preparations are both general, we notice that horn manure works on germi-made with the horn of a cow. The horn of the bull is nation, root development, and growth.too soft. This is an interesting phenomena, which mustfluster the Darwinist. The Horn-Silica preparation makes use of a cow- horn again and finely ground Silica. This is then placedIn the fall, we make the Horn-Manure preparation. in the ground during the summer months. A muchThe manure from a lactating cow is selected. The smaller quantity than the horn manure, no more than amanure should have enough form so that the shape pea-size amount, is stirred vigorously in 30 gallons ofof the intestines is somewhat visible. But avoid using water for one hour. This solution is sprayed directly onpies that start looking like sheep-manure. We place the plants. The Horn Silica has a strong connection tothe manure into the horns and then bury them with the light and warmth forces of the summer. Its positivethe points of the horns sticking up to avoid rainwater influences are similar to what the summer sun contrib-from collecting in them. In the month of May, this utes to the plants. It slows down growth but increasespreparation is dug up. The substance in the horns has the overall plant mass. Plants treated with this prepa-by then become odorless. If there is a smell to it or if ration will have better taste and keeping qualities. Allit still looks like manure, then you know that it has preparations with the exception of Horn-Silica shouldnot been properly transformed. Before this preparation be stored in peat moss, in a dark, cool, and damp applied to the fields as a spray, we have to dilute Horn-Silica is left in a glass jar in a in lukewarm water. About a baseball, size quantityper thirty gallons of water is sufficient. This is stirred A study published in “the Journal for Science” com-vigorously in one direction until a vortex is formed, pared organic, biodynamic and conventional researchthen the direction is reversed and stirred in the oppo- plots and found that the number and diversity on thesite direction to create another vortex, etc. The total biodynamic plots were far greater that the organictime of stirring is one hour. The solution will now ones. This research that was conducted over a 21-start smelling again, not like manure, but definitely year period showed that the biodynamic preparationsalive. For filtering the liquid I found paint bags to greatly improve soil life. Another study performed bybe the best, the ones painters use to filter their paint. the University in Washington compared organic andWe do the filtering to avoid wasting time in the field biodynamic pastures in New Zealand. This study fo-cleaning spray-nozzles. Our Solo backpack sprayer cused mostly on soil structure and rooting depth. Thecovers about one acre if filled up. This is about three biodynamic plots had greater root systems and betterto three and a half gallons. This preparation is sprayed soil structure.56 Organic Vegetable Production
  • 65. This page is from Organic Vegetable Production, NRAES-165. To purchase the book,visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. WeedManagement
  • 66. This page is from Organic Vegetable Production, NRAES-165. To purchase the book,visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.
  • 67. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Understanding Weed Biology Charles L. Mohler Senior Research Associate Crop and Soil Sciences Cornell UniversityWhat is a weed? for species that specialize on highly and repeatedly disturbed conditions, namely weeds as defined above.Weeds are commonly defined as plants that grow where The basic thesis of this paper is that understandingthey are not wanted. Although that definition has some the biology of weeds is a key to their control. Thepractical utility, it fails to recognize that weeds share reason is that killing weeds without harming the cropcertain properties in common. Only a handful of the depends on biological differences between the weedsspecies you see around show up in farm fields and and the crop. Weed biology becomes complicated,other places that you don’t want them. Understanding however, because weeds differ in their biology: therewhat makes certain plants grow in human manipulated are many ways to be a weed. Fortunately, the varietysites whereas others do not is a first step in planning of weeds can be grouped into a few categories basedmanagement programs. From an ecological point of on the life-history of the species. That is, for manage-view “weeds are plants that are especially successful at ment purposes, weeds can be grouped according tocolonizing disturbed, but potentially productive, sites, how long various life stages live, and how the plantand at maintaining their abundance under conditions reproduces. At the broadest scale, weeds can be di-of repeated disturbance” (Mohler 2001). vided into annuals and perennials, and I will begin with the perennials.Our crops are mostly annual species. That is, they com-plete their lifespan in less than one year. To make thehabitat suitable for annuals, we eliminate the natural Perennial weedsvegetation, which around here is broadleaf forest witha little hemlock and white pine. Annuals do not growin forest conditions or in undisturbed prairie either, Types of perennialsbecause little seedlings cannot compete with large,well-established plants that already occupy the site. A perennial weed is a weed that persists in the vegeta-So to make the land suitable for annuals, we clear off tive state for more that one year. The types of perennialsthe woody plants, and plow up the soil to disrupt the can be classified according to whether they reproduceperennial herbs. In ecological terms, plowed fields are vegetatively, and the nature of the perennating organperpetually held at year 0 of ecological succession. In (Table 1, page 60).other words, farming creates habitat that is suitableWeed Management 59
  • 68. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Table 1 Types of perennial weeds and examples. Nature of the root system Examples Stationary perennials Taprooted Dandelion, burdock Fibrous rooted Broadleaf plantain, tall buttercup Wandering perennials Bulb or tuber Yellow nutsedge, wild garlic Shallow storage organ Quackgrass, johnsongrass Deep storage organ Common bindweed, Canada thistleStationary perennials do not reproduce vegetatively, quently, if the population consists of a single clone, noexcept occasionally when the taproot or root crown is seed production is possible. For example, only aboutbroken by a tillage implement. Most reproduction is one yellow nutsedge population in 10 produces viableby seed, and they commonly produce copious quanti- seeds (Mulligan and Junkins 1976). For wanderingties of seeds that typically persist in the soil for many perennials, seed production is mainly a way to spreaddecades. Primarily, they are weeds of pastures, hay the species around rather than a way of maintaining themeadows and waste ground. When the soil is regu- population at a particular site. For that, the plant relieslarly tilled, they tend to disappear after a year or two, on sprouts from the root or rhizome system.except for species like dandelion that regularly blowin from adjacent habitats. The reason for the absence Below-ground apical dominance inof stationary perennials on tilled ground is two-fold. perennial weedsFirst, since the root system is not well built for vegeta-tive propagation, soil disturbance tends to damage the The key fact about the underground organs of perennialstorage organs and kill the plants. Second, stationary weeds is that they show what botanists refer to as apicalperennials are usually not very competitive the first dominance (Håkansson 1982). You are familiar withyear because they are putting energy into building the this phenomenon in the above ground shoots of plants:taproot or the root crown so that they will have the if you prune off the end of a branch, the nearest lateralresources to survive the winter. They are often highly bud (or buds if the leaves are opposite) will begin tocompetitive in subsequent years, however, because elongate much sooner than they would otherwise.they have these substantial reserves with which to This occurs because the growing point of the branchrapidly establish in the spring and compete with any produces hormones (auxins) that suppress the growthannuals present. These qualities explain both why they of the lateral buds. When the growing point is gone,are usually minimal problems in organic annual agri- so is the suppression and the lateral buds grow. Theyculture, and why they can reach substantial abundance then produce auxins that suppress the growth of budsin pastures, hayfields, and conventional no-till fields. further down the stem.Wandering perennials reproduce primarily by veg- Essentially the same phenomenon occurs in the rootetative reproduction. They spread underground by or rhizome system of wandering perennials (Figure 1).thickened storage roots or by horizontal underground The above ground shoots emerge from the terminal budstems (rhizomes). A few species also produce bulbs of the rhizome or storage root. If this shoot is removed,or tubers that are the overwintering storage organ for then the next bud in line is released and a new shootthe plant. Although many of the wandering perenni- grows up to take the place of the one that was killed.als do produce seeds under some conditions, typically More critically, if the root or rhizome is broken intoseed production is low, and the seeds usually do not pieces by a tillage implement, then the terminal budpersist long in the soil. Most of these species do not on each piece will be released from suppression, andself-pollinate (Mulligan and Findlay 1970), and conse- you will see lots of sprouts. Each of these sprouts will60 Organic Vegetable Production
  • 69. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Figure 1Due to hormonal suppression of most buds by the terminal shoot (apical dominance), breakage of rhizomes orperennating roots results in an increase in the number of shoots, but a decrease in the resources available to relatively weak, however, because it is backed up grass density; cultivation without using a prior tillageby small reserves of carbohydrate. practice that severely fragmented the weed would just spread the infestation around. Competitive crops areFrom a management perspective, this behavioral re- always helpful, but rarely sufficient to control peren-sponse of wandering perennials is either good or bad nial weeds unless the weeds have previously been setdepending on what you do. If you till up a stand of back by tillage and cultivation.quackgrass and then plant onions, you probably willhave worsened your weed problems. In contrast, if the Not all wandering perennial weeds sprout immediatelyfield is tilled, the fragments allowed to sprout, and then after fragmentation, but that is the usual pattern, andyou cultivate out the sprouts, you will have seriously most of the wandering perennials in the Northeast be-depleted the already weakened rhizome fragments. have in this way. Some species, notably the commonRepeating this process, or planting a fast growing, and hedge bindweed and Canada thistle are not easilyhighly competitive crop will further suppress the weed broken up by tillage because their root or rhizome sys-(Håkansson 1971). Since quackgrass is a cool season tems are so deep in the soil. To get at hedge bindweedgrass, sowing a fall cover crop of rye or winter wheat at or Canada thistle requires subsoiling equipment, anda high density is pretty effective. Note here that any one on a deep soil, much of the root system of commonof the several measures taken alone would probably bindweed will be completely out of reach. The onlybe insufficient to control the weed. Just fragmenting alternative then is to try to exhaust the whole mass ofthe rhizomes with tillage would likely increase quack- the root or rhizome system by repeated killing of theWeed Management 61
  • 70. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.emerged shoots. For many wandering perennials, the limited or absent. In natural conditions, the main thingshoot begins transporting food back to the root system that eliminates perennial vegetation is soil disturbance,at about the 3 to 4 leaf stage, so that is a good time to usually by animal activity. So some of the signals thatcultivate. Before that, the shoot is a net drain on the cue germination are related to soil disturbance, whereasperennating storage organs. others are simply related to the absence of vegetation or near surface conditions. Few of the cues are absolute requirements for any species. Rather, they change theWeed seeds percentage of seeds that germinate and work together to signal the appropriate conditions for germination. No species responds to all of the cues discussed below,Germination cues but most respond to several.Annual species are plants in which the individual The most common cue that weeds respond to is light.lives for less than one year. These species necessarily Most weed species show increased percentage germi-reproduce by seeds. Because reproduction by seeds nation in light relative to darkness (Table 2, page 64).is essential for annuals and they live in a frequently Some species, like common chickweed, germinate indisturbed environment, they produce many small the dark when first shed from the plant, but after burialseeds. They have been selected to produce many seeds in soil, show greatly increased germination if exposedso as to spread the risk of death by disturbance over to light (Wesson and Waring 1969). The amount ofmany offspring. Most weeds die young so they make light required to stimulate germination is sometimesa lot of seeds to compensate for that mortality. Since amazingly small. For example, redroot pigweed willeach individual plant has limited resources, producing germinate in response to a few thousandths of a secondmany seeds necessarily means that the seeds are small. of sunlight (Gallagher and Cardina 1998). Thus, if aI will return to the consequences of small seed size seed comes to the surface during tillage or cultivationrepeatedly. Another way in which annuals manage the and then is buried again it may be stimulated to ger-riskiness of specialization on disturbed environments minate. This is why tillage in the dark often reducesis by recognizing the most favorable conditions for the density of weed seedlings (Ascard 1994, Scopelgermination. et al 1994, Buhler 1997). Dark tillage is no panacea, however, since weeds respond to other cues as well.Since most weed species have small seeds, most weedseedlings lack the resources to be able to grow up from Even the type of light affects germination. Red lightdeep in the soil and most emergence is from seeds stimulates germination. Light filtered through a plantnear the soil surface (Chancellor 1964, Mohler 1993). canopy is green; which is to say, it is depleted in the redNearly all individuals of small seeded weeds (and most wavelengths. Thus, if a light sensitive seed is exposedweeds in the northeastern U.S.A. weigh less than 2 to green light, the seed senses that it is surrounded bymg), emerge from within the top inch of soil (Figure 2, competing vegetation, and germination is inhibitedlambsquarters, redroot pigweed). Even relatively large (Górski 1975, King 1975). Seeds behave oppositely toseeded weeds like velvetleaf (9.5 mg) mostly emerge cars: they stop on green and go on red, and ordinaryfrom within the top 2 inches of soil (Figure 2). Since sunlight is full of red wavelengths.seeds that germinate deep in the soil die, weed seedsthat recognize when they are near the soil surface have Another factor that stimulates germination of somebeen favored by natural selection. weed species is high soil temperature. For example, redroot pigweed germinates best at 86° to 104° FSince most weeds have small seeds, they make tiny (Table 3, page 64). Soil temperatures that high areseedlings. A lambsquarters seedling when it first comes rarely achieved except near the surface of bare soil.up has cotyledons that are about 1/32 of an inch wide Common purslane germinates best at similarly highand 1/8 inch long. Such tiny plants have no chance of temperatures (Vengris et al. 1972).survival in established perennial vegetation like a haymeadow or forest. Consequently, most weeds have When soil is bare, the high temperatures obtainedbeen selected for physiological mechanisms that allow during the day are often not retained during the nightthe seeds to recognize that competing vegetation is because the soil cools by emitting infrared radiation to62 Organic Vegetable Production
  • 71. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Figure 2Proportion of seeds planted at a given depth that emerged as seedlings for three common weed speciesSeeds were cold treated at 40° F in field soil for approximately two months and then placed at the indicated depth in earlyspring without exposure to light.(Redrawn from Mohler, in preparation)Weed Management 63
  • 72. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Table 2Germination response of some common weeds to light. % GerminationSpecies Light Dark ReferenceRedroot pigweed 98 14 Kigel (1994)Annual bluegrass 89 1 Froud-Williams (1985)Common purslane 28 12 Povilitis (1956)Table 3Percentage germination of redroot pigweed seeds in response to temperature in five northern states. Computed fromMcWilliams et al. (1968) Location Populations tested 68° F 95° F Michigan 1 0 90 Minnesota 1 15 100 New York 5 6 93 North Dakota 17 23 80 Vermont 1 15 93the sky. Consequently, surface soil temperature fluc- When diffusion of gasses is limited, for example, deeptuates much more for bare soil than for soil covered in the soil or in the interior of soil aggregates, oxygenby living or dead plants (Teasdale and Mohler 1993). may limit the respiration of seeds. Seeds are alive,Many weed species use this temperature fluctuation and moist seeds are particularly active a means for recognizing bare ground (Table 4). For When oxygen is limited, respiration cannot take car-curlydock, temperature fluctuation is nearly an absolute bohydrates all the way to carbon dioxide and water.requirement (Totterdell and Roberts 1980). Provided Instead the seed produces volatile organic compoundsthe seeds are exposed to light, percentage germination like ethanol and acetone. These leak from the seed andat any constant temperature from 35° to 95° F is near build up in its vicinity. These compounds indicate a0 but a variety of different fluctuating temperature terrible environment for establishment, and they inhibitregimens give 100% germination. germination of some species (e.g., velvetleaf). When the soil is stirred by tillage, the volatile products ofWeed seeds also germinate in response to chemical anaerobic respiration are vented to the breezes and thecues associated with soil disturbances like tillage. seeds germinate in response to their absence. I suspectAeration and warming of the soil by tillage stimulates this germination cueing mechanism is quite common,microbial decomposition of soil organic matter. This but few weed species have been tested. The seeds arereleases nitrogenous compounds that specialized apparently not responding to oxygen itself since flush-bacteria turn into nitrate. Nitrate in the soil solution ing the soil with pure nitrogen will prompt germinationstimulates germination of some weed species, like as readily as flushing with air (Holm 1972).lambsquarters (Roberts and Benjamin 1979). In addi-tion to the problems chemical fertilizers create for the As can be seen from Tables 2 to 4 and the discussionsoil, this is another good reason to avoid them. above, germination response to any one particular cue64 Organic Vegetable Production
  • 73. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Table 4 Effects of constant and fluctuating temperature on germination of common chickweed seeds in the dark. In the alternating temperature treatment, the high temperature was held for 8 h and the low temperature for 16 h. Extracted from Roberts and Lockett (1975). Regimen Temperature (°F) Germination (%) Extreme alternating 50/86 98 Constant low 50 48 Constant high 86 2 Constant middle 68 65 Low temperature alternating 59/77 97 Constant low 59 77 Constant high 77 12 Constant middle 68 65 High temperature alternating 68/86 84 Constant low 68 65 Constant high 86 2 Constant middle 77 12 Mean of alternating 96 Mean of middle 47is rarely absolute. Rather the cues act cumulatively, Season of germinationand one cue can often replace another (Vincent andRoberts 1977, Roberts and Benjamin 1979). If no cues All plants that live in a seasonal climate like theare present, a few seeds may germinate, essentially Northeast face the problem of knowing what time ofby mistake. If several cues are present, most seeds year to germinate, and weeds are no exception. Everywill germinate. If just one or two cues are present, season has weeds that are specialized on that time ofsome fraction will germinate. This partial response year (Figure 3, page 66).to multiple cues essentially hedges the bet each weedspecies is making about the suitability of the environ- A few weed species, like velvetleaf and common bind-ment for establishment and growth. If the environ- weed have hard seed coats that prevent the seeds fromment is maybe OK but not perfect, some individuals absorbing water. The seed coat changes with exposurewill germinate whereas others in a slightly different to soil conditions: organic acids, microorganisms andphysiological state or microenvironment will wait, freeze-thaw cycles produce cracks or open specializedperhaps for years. pores that allow water to enter the seed. Then, if the environmental cues are right, the seed germinates.The management consequences of weed seed response Since winter represents a long period for these changesto germination cues associated with near surface tilled to take place, species with hard seeds usually germi-conditions is that you can often trick weeds into ger- nate and emerge mostly in the spring with a trickle ofminating on command. A short period of bare fallow germination through the rest of the growing season.before or after the crop signals the weeds to germinatebut gives you the opportunity to then cultivate and get Most weed species, including many with hard seedrid of them. coats, have physiological mechanisms that controlWeed Management 65
  • 74. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Figure 3Seasonality of seedling emergence for eight weeds in the southern United Kingdom(Redrawn from Mohler 2001 based on data from Lawson et al 1974)66 Organic Vegetable Production
  • 75. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.when the seeds germinate. Some species will germi- to mature and this mechanism essentially protects thenate immediately after falling from the parent plant, if seeds from germinating in late summer or fall whenthe appropriate cues are present. These species follow successful reproduction would be unlikely.the path from no dormancy to immediate germinationshown on Figure 4. Subtleties abound with the annual germination-dor- mancy cycle. Shepherd’s-purse, for example, behavesMany weed species, however, cycle between a dormant much like ragweed, but with a slight difference. Itand nondormant state during the course of the year germinates best at relatively low temperatures and will(Baskin and Baskin 1985). For example, common germinate in the spring. Unlike ragweed, however,ragweed is primarily a spring germinating species. shepherd’s-purse only becomes conditionally dormantSeeds are shed from the parent plant in a dormant state. at high temperatures (Baskin and Baskin 1989). Con-As they are exposed to cold temperatures during the sequently, when temperatures cool in the fall, morewinter, they become “conditionally dormant.” That seeds will germinate, including some of those shedis, if conditions are just right, they will germinate. the previous spring. Thus the species behaves as bothAfter a longer exposure to cold (4-6 weeks) they lose a spring and a winter annual in the Northeast, and indormancy and will germinate under a wide range of cool, wet summers it will germinate all summer.conditions. So when the weather warms in the springyou often see a flush of ragweed seedlings. However, The management consequences of weed seasonalityif the appropriate germination cues are absent, and relates to crop rotation. A spring germinating speciesthe seed cooks at summer temperatures, it will again will fare poorly in a fall planted crop like spelt or abecome dormant (Baskin and Baskin 1980). That is, rye cover crop because the new seedlings will have toit will be unable to germinate even if given optimal compete with a dense stand of well established plants.germination conditions. Ragweed takes several months Similarly, summer germinating weeds like purslaneFigure 4Relationships among states of seed dormancy for weed seeds with physiologically controlled dormancy(reprinted with permission of Cambridge University Press; from Mohler 2001, Ecological Management of Agricultural Weeds)Weed Management 67
  • 76. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.will do poorly in a good stand of a long season crop to germinate. Some of these will appear as seedlingslike soybeans. In both these cases, many of the weed and have to be dealt with, but many others never makeseeds will not even germinate because the appropriate it out of the soil due to attack by soil organisms orcues are not there at the right time. Natural processes being buried too deeply for emergence. Regardless ofthen have another year in which to kill off the seeds. its other benefits or problems, tillage and cultivationThe extreme of this latter process occurs when the tends to deplete the soil seed bank.ground is planted with a sod crop for several years.Weed seeds under the sod do not receive the appro- Seed size and crop-weed competitionpriate germination cues, and any that germinate acci-dentally are killed by competition or mowing. Hairy I have mentioned several times that most weeds havegalinsoga is the worst weed problem many vegetable very small seeds. In particular their seeds are smallgrowers face because they grow annual crops every relative to the seeds of most crop species (Table 6).year. In contrast, I have never seen a dairy farm with This size differential gives the crops a critical heada galinsoga problem because they rotate annual crops start over the weeds. Of course, some vegetable cropswith sod crops, and the galinsoga seeds die out during also have small seeds (for example, lettuce, cole crops,the sod portion of the cycle. tomato, pepper). On organic farms, the great majority of small seeded vegetable species are transplantedSeed longevity into the field, which gives them the same sort of head start that the large seeded crops have over the weeds.This brings me to the topic of seed mortality and its A conventional vegetable grower may direct seed coleconverse, seed longevity. Unlike humans, weed seeds crops, tomatoes or leaks and use herbicides to controldo not have a more or less given lifespan. Rather, their the early weeds. For an organic farmer, the extra laborprobability of death remains about equal each year, as- of weeding a direct seeding is likely to exceed the costsuming the environment is constant. That is, weather, of growing practices, or other conditions may leadto greater or lesser mortality in any given year, but if The differential in seed size has several consequences.conditions are constant over a series of years, then a First, it makes within row weeding possible. For ex-constant percentage of seeds will tend to die each year. ample, you can take a tine weeder over many largeIf seeds took out life insurance, the annual payment seeded crops before they are up or while they arefor an 80 year old would be the same as for a 20 yearold. Consequently, asking how long a particular specieslasts in the soil is nearly meaningless. Table 5 Seed mortality as percentage loss per year in cultivatedVarious species differ in their rate of death (Table 5). and uncultivated soil over a 5 year period. CalculatedSome species survive well, with only a small per- from Roberts and Feast (1972).centage dying each year. In undisturbed agriculturalsoil the death rate of buried lambsquarters was less Species Cultivateda Uncultivatedthan 10%/year in the particular experiment shown inTable 5. In really favorable conditions the death rate Shepherd’s-purse 43 24is probably even lower: viable lambsquarters seeds Lambsquarters 31 8have been recovered from under the foundations of Black medic 30 22medieval European buildings. For other species, like Annual bluegrass 26 22common groundsel and hairy galinsoga, the seeds die Prostrate knotweed 47 16off rapidly, even when undisturbed. Wild buckwheat 50 25 Common groundsel High 45Of course, in an agricultural field the seeds are rarelyundisturbed. Rather, the field is tilled, a seedbed pre- Common chickweed 54 32pared and often the soil is cultivated later in the season. Persian speedwell 54 22Debris may be disked under in the fall or the ground Field violet 40 15chisel plowed in preparation for the next season. As Idiscussed previously, this soil disturbance cues seeds a Soil was stirred four times per year.68 Organic Vegetable Production
  • 77. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.still small without killing the crop. The crop is rooted Another important consequence of the seed size differ-below the depth of penetration of the weeder (usually ence between crops and weeds is that crops can emergeabout 1 inch), but as I pointed out earlier, most of the through substantial layers of mulch whereas weeds areweeds are emerging from the top inch of soil and are suppressed (Figure 5). If our weeds had seeds the sizetherefore susceptible. All in-row weeding tools rely of corn or beans, mulch would be a completely uselesson this differential between the size of the crop and way to suppress them.the size of the weeds, including rotary hoes, Buddinghfinger weeders and Bezzerides torsion weeders, spring Finally, because the crop usually gets a head start overhoes and spinners. the weeds, with some planning, it is often possible to Table 6 Propagule weight for the five most common annual weeds of field crops in New York state and for the five annual field crops with the greatest acreage in New York State. Weeds and crops are listed in order of seed size not importance or acreage. Excerpted from Mohler (1996). Propagule Propagule Weed species weight (mg)a Crop species weight (mg)a Velvetleaf 9.5 Corn 250 Common ragweed 4.4 Soybean 220 Wild mustard 2.2 Wheat 39 Lambsquarters 0.74 Oat 35 Redroot pigweed 0.44 Rye 27 a American units of weight do not include familiar units appropriate for expressing seed weights. One lettuce seed weighs about 1 mg.Figure 5Proportion of a large seeded crop (corn) and a small seeded weed (redroot pigweed) that emerged through variousrates of rye straw applied as a mulch at planting. Each species was planted at a depth that had produced highemergence rates without mulch in previous experiments.(Mohler, unpublished data)Weed Management 69
  • 78. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.keep the crop in a competitively superior position. a higher percentage of tissue in non-photosyntheticWeeds are gap fillers – they are adapted to grow rapidly parts like roots and stems relative to leaves. Conse-in the absence of competitors, and with few exceptions quently, the relative growth rate (that is, weight gain/they grow poorly in shade. Sometimes the crop can unit weight/day) of species with large seedlings is made more competitive by using a higher planting A financial analogy would be two individuals, onedensity, or planting multiple rows on a bed. If that is of which (the crop) starts with more capital, but thepractical, then the crop canopy will close sooner, and other (the weed) invest at a higher rate of compoundthe weeds will be at a greater disadvantage. Similarly, interest. Consequently, weeds that start out so smallif the row has a skip, that is an opportunity for weed you can barely see them may eventually overtop thegrowth. Consequently, skips should be replanted. If the crops. This is why early weeding while the weeds arecrop stand is poor over a large area, it may be cheaper still tiny and easy to kill is so critical to a good organicto disk the crop under and replant or plant some other weed control program.crop rather than cope with the extra expense of weedcontrol. In my experience, something like 80% or more Seed productionof weed control comes from crop competition ratherthan from cultivating or hand weeding. Make sure As I mentioned in the introduction, weeds have adaptedthere is always a crop or cover crop there to provide to frequent disturbance by partitioning their reproduc-that control. tive output into lots of small seeds rather than a few large ones. This spreads risk and increases the chanceAnother trick to increase crop competitiveness is to that one or more seeds will grow to water or nutrients toward the crop rather thanbroadcasting them generally over the field. Drip ir- The seed production capacity of weeds is astounding.rigation favors the crop relative to the weeds more A big lambsquarters or barnyardgrass plant can pro-than sprinkler irrigation because the water is released duce over 100,000 seeds. I once sampled a large, opennear the crop roots rather than over the whole field. grown pigweed that produced an estimated 250,000Similarly, if a concentrated nutrient source like bone seeds. A student of mine grew some hairy galinsoga inor blood meal is used to give the crop a boost, it is pots and carefully collected the seeds as they to weed first, and band or sidedress the material Plants a little bigger than a basketball produced 40,000near the crop. Most weeds are luxury feeders that will seeds apiece.rapidly take up and concentrate mineral nutrients.Several studies have shown that weeds often have I will emphasize that big plants have many more seedsone to three times higher concentrations of N, P and K than small plants. Compare, say, two redroot pigweedthan the crops with which they are competing (Vengris plants. If one is twice as tall, or twice as big around,et al. 1953, Qasem 1992). Some studies have shown it will not have twice as many seeds but rather, many,that the slow release of nutrients from green manure many times more seeds (Mohler and Callaway 1995).or compost favors growth of crops relative to weeds Consequently, removing large individual weeds is(Dyck et al. 1995, Gallandt et al. 1998). This makes important for long-term weed management, even ifsense biologically, but too few studies have been done it means hand rogueing the field. Fortunately, mostto make a generalization yet. weed seeds come from a few large plants (Figure 6). The little plants may produce enough seeds to maintainThe problem with the initial size advantage of crops the population, but they are unlikely to create a rapidis that it is usually short lived. This is because most increase in weed density.weeds have a higher relative growth rate than the cropswith which they compete. This is partially due to the Also, when rogueing mature or nearly mature plants,difference in seed size and partially due to differences be sure to remove them from the field. Many weed spe-in their growth forms and ability to take up nutrients. cies can set seeds even after they have been uprootedThe relation of seed size to growth rate is particularly if the flowers have opened. Dandelion flowers will setinteresting (Table 7). Large seeds make large seedlings, seeds even if they have been severed from the plantand these grow faster in an absolute sense of weight and incorporated into the soil!of tissue added per day. However, larger plants have70 Organic Vegetable Production
  • 79. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Table 7 Seed weight, initial growth rate, and relative growth rate of five annual plants with seeds of various sizes. Excerpted from Siebert and Pierce (1993) Initial Relative Seed growth growth weight rate rate Species (mg)a (mg/d) (mg/mg/d) Lambsquarters 0.41 0.14 0.36 Velvetleaf 7.8 1.9 0.24 Cocklebur 38 7.1 0.19 Sunflower 61 12 0.20 Soybean 158 24 0.16 a American units of weight do not include familiar units appropriate for expressing seed weights. One lettuce seed weighs about 1 mg.Figure 6Distribution of estimated seed production in a population of 231 redroot pigweed plants growing in sweet corn. Sweetcorn was planted in early June and weeds emerged primarily in July after the dissipation of atrazine(Redrawn from Mohler 2001, see Mohler and Callaway 1995)Weed Management 71
  • 80. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Seed dispersal question is, are new weed species still arriving on your farm?Many plant species have specializations that encouragethe dispersal of seeds by animals or by wind, including The spread of velvetleaf makes a good example offleshy fruits, hooks, bristles, fluffy hairs, and wings. the way civilization moves weed species around theA substantial portion of the perennial weeds found in landscape. The “Flora of the Cayuga Lake Basin, Newpastures and hay meadows possess such specializa- York” (Wiegand and Eames 1925) lists velvetleaf astions. This is reasonable since animals are regularly “infrequent” and gives six locations one could go toin contact with these plants, and vegetative reproduc- see this species in an area of about three counties.tion insures the persistence of the population even if Velvetleaf was introduced from India to the southernmany wind-dispersed seeds are blown into unfavorable colonies as a fiber crop in the Eighteenth Century. Ithabitats. subsequently spread to the Midwest with the westward migration of agriculture. During the late TwentiethIn contrast, few weeds of regularly tilled fields show Century it spread throughout the Northeast, probablyany of these adaptations. On the contrary, most weeds in feed corn as dairy farms began importing more con-of tilled ground have small, round, nearly smooth seeds centrates from the Midwest (Mt. Pleasant and Schlatherthat fall within a few feet of the parent plant. This 1994). Since the seeds readily pass through the bovineposes an apparent contradiction: some of the world’s digestive tract, the farmers spread the weed on theirmost widespread species appear to lack capacity for fields with the cattle manure. As a result, about halfdispersal. The resolution to the contradiction is, of the fields in New York now have velvetleaf. Since thecourse, that they have been moved around by people. seeds are very persistent in the soil, these fields willThey move in poorly cleaned crop seed, in feed grain probably have velvetleaf for as long as they are farmed.and then in the manure when it is spread, on tractortires and tillage machinery, and on combines and otherharvesting equipment (Mohler 2001). ConclusionsAn interesting bit of biology lurks within this dispersalby humans. As discussed previously, most species of Agricultural weeds are not simply unwanted plants.weed seeds are highly resistant to decomposition. They Rather they are species with particular biologicalpersist in the soil for long periods, and consequently characteristics that set them apart from most othercan build up to high densities that make dispersal species, including most crops. These characteristicson machinery likely. Moreover, most species pass adapt them to the frequently disturbed conditions andunharmed through the digestive tract of large grazing high resource availability of cropped fields. Thesemammals. Prior to human agriculture they probably characteristics include:thrived best in animal disturbed habitats (bare groundand high fertility), and moved about within the guts • Resprouting from damaged roots and rhizomes ofand in soil caked on the fur of migrating animal herds. perennial weeds,I can easily imagine ragweed seeds moving many milescaked to the fur of wandering bison or mammoths. • Ability of seeds to recognize suitable conditions for germination, including proximity to the soilProbably, however, none of the weeds on your farms surface, the absence of competing plants, thereached there in prehistoric times. The land survey presence of essential resources like nitrogen andrecords indicate that over 97% of the landscape of water, and an appropriate season of the year forwestern New York was forested in the 1790s, and subsequent growth,most of the balance was in wetlands, blowdowns andrecent burns (Marks and Gardescue 1992). With few • Massive production of small seeds that persist forexceptions, agricultural weeds do not grow in forests years to decades in the soil,or wetlands, even when they are disturbed by naturalprocesses. Rather, these weeds mostly arrived on your • Ability to rapidly take up and concentrate macro-farms after Europeans settled the land. The critical nutrients.72 Organic Vegetable Production
  • 81. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Although these characteristics adapt weed species to attractive.prosper in cropped fields, they also provide opportuni-ties for management. • Finally, the great difference in size between weed seeds and crop seeds or transplants allows for in-• Breaking up perennial roots and rhizomes increas- row mechanical weeding of many crops, and is a es the number of shoots of wandering perennials, fundamental reason organic mulches are effective but each of the subsequent shoots is weaker and for weed management. more easily managed by cultivation or competi- tion. Removal of above ground shoots forces the Much remains to be discovered about the biology of perennial to move resources from the storage organ weeds. Germination requirements have been fully into new shoots, thereby decreasing its ability to analyzed for only a few species. More critically, effects survive over the long term. of the soil environment on weed growth and competi- tion with crops has been little studied. In some cases,• Understanding of the germination biology of an- slow releasing forms of nitrogen like compost and nual weeds allows the farmer to trick the seeds green manure appears to favor crops whereas chemi- into germinating at times when they are easily cal fertilizers appear to favor weeds, but the generality controlled, for example, by a short period of clean of this phenomenon has not been demonstrated. The fallow or a smother crop. Rotation of crops with role of micronutrients and ratios of macronutrients are different seasonality presents some species with in- widely believed among organic farmers to be impor- appropriate conditions for germination each year, tant for both crop growth and weed competition, but thereby allowing attrition by natural processes to these topics have received little systematic research, decrease soil seed banks. particularly in organic systems where effects are less likely to be masked by intensive chemical management• Recognition of the seed production potential of of crops, weeds and soils. Hopefully, the recent growth weeds and how this varies with weed size makes in the organic sector will spur increased investigation the economics of preventing seed production more of these topics.Weed Management 73
  • 82. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.References Håkansson, S. 1971. Experiments with Agropyrop repens (L.) Beauv. X. Individual and combined effects of division and burial of the rhizomes and competitionAscard, J. 1994. Soil cultivation in darkness reduced from a crop. Swedish Journal of Agricultural Researchweed emergence. Acta Horticulturae 372:167-177. 1:239-246.Baskin, J. M. and C. C. Baskin. 1980. Ecophysiology Håkansson, S. 1982. Multiplication, growth and persis-of secondary dormancy in seeds of Ambrosia artemi- tence of perennial weeds. In Biology and Ecology ofsiifolia. Ecology 61:475-480. Weeds, ed. W. Holzner and N. Numata, pp. 123-135. Dr. W. Junk: The Hague.Baskin, J. M. and C. C. Baskin. 1985. The annualdormancy cycle in buried weed seeds: a continuum. Holm, R. E. 1972. Volatile metabolites controllingBioScience 35:492-498 germination in buried weed seeds. Plant Physiology 50:293-297.Baskin, J. M. and C. C. Baskin. 1989. Germinationresponses of buried seeds of Capsella bursa-pastoris King, T. J. 1975. Inhibition of seed germination underexposed to seasonal temperature changes. Weed Re- leaf canopies in Arenaria serpyllifolia, Veronica arven-search 29:205-212. sis and Cerastum (sic) holostoides. New Phytologist 75:87-90.Buhler, D. D. 1997. Effects of tillage and light en-vironment on emergence of 13 annual weeds. Weed Kigel, J. 1994. Development and ecophysiology ofTechnology 11:496-501. Amaranths. In Amaranth: Biology, Chemistry and Technology, ed. O. Paredes-López, pp. 39-73. CRCChancellor, R. J. 1964. The depth of weed seed ger- Press: Ann Arbor, MI.mination in the field. In Proceedings of the 7th BritishWeed Control Conference, pp. 607-607-613. British Lawson, H. M., P. D. Waister and R. J. Stephens. 1974.Crop Protection Council: London. Patterns of emergence of several important arable weed species. British Crop Protection ConferenceDyck, E., M. Liebman, and M. S. Erich, 1995, Crop- Monographs 9:121-135.weed interference as influenced by a leguminous orsynthetic fertilizer nitrogen source. I. Doublecropping Marks, P. L. and S. Gardescue. 1992. Vegetation ofexperiments with crimson clover, sweet corn, and the central Finger Lakes Region of New York in thelambsquarters. Agriculture, Ecosystems and Environ- 1790s. New York State Museum Bulletin No. 484.ment 56:93-108. pp. 1-35.Froud-Williams, R. J. 1985. Dormancy and germina- McWilliams, E. L., R. Q. Landers and J. P. Mahlst-tion of arable grass-weeds. Aspects of Applied Biology ede. 1968. Variation in seed weight and germination9:9-18. in populations of Amaranthus retroflexus L. Ecology 49:290-295.Gallagher, R. S. and J. Cardina. 1998 Ecophysiologi-cal aspects of phytochrome-mediated germination in Mohler, C. L. 1993. A model of the effects of tillagesoil seed banks. Aspects of Applied Biology 51:1-8. on emergence of weed seedlings. Ecological Applica- tions 3:53-73.Gallandt, E. R., M. Liebman, S. Corson, C. A. Porter,and S. D. Ulrich. 1998. Effects of pest and soil man- Mohler, C. L. 1996. Ecological bases for the culturalagement systems on weed dynamics in potato. Weed control of annual weeds. Journal of Production Agri-Science 46:238-248. culture 9:468-474.Górski, T. 1975. Germination of seeds in the shadow Mohler, C. L. 2001. Weed life history: identifying vul-of plants. Physiologia Plantarum 34:342-346. nerabilities. In Ecological Management of Agricultural74 Organic Vegetable Production
  • 83. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Weeds, ed. M. Liebman, C. L. Mohler and C. P. Staver, Scopel, A. L., C. L. Ballaré, and S. R. Radosevich.pp. 40-98. Cambridge University Press: New York. Photostimulation of seed germination during soil till- age. New Phytologist 126:145-152.Mohler, C. L. and M. B. Callaway. 1995. Effects of till-age and mulch on weed seed production and seed banks Seibert, A. C., and R. B. Pierce. 1993. Growth analysisin sweet corn. Journal of Applied Ecology. 32:627-639. of weed and crop species with reference to seed weight. Weed Science 41:52-56.Mt. Pleasant, J. and K. J. Schlather. 1994. Incidenceof weed seeds in cow (Bos sp.) manure and its impor- Teasdale, J. R. and C. L. Mohler. 1993. Light trans-tance as a weed source for cropland. Weed Technology mittance, soil temperature, and soil moisture under8:304-310. residue of hairy vetch and rye. Agronomy Journal 85:673:680.Mulligan, G. A. and J. N. Findlay. 1970. Reproductivesystems and colonization in Canadian weeds. Canadian Totterdell, S. and E. H. Roberts. 1980. CharacteristicsJournal of Botany 48:859-860. of alternating temperatures which stimulate loss of dormancy in seeds of Rumex abtusifolius L. and RumexMulligan, G. A. and B. E. Junkins. 1976. The biology crispus L. Plant, Cell and Environment 3:3-12.of Canadian weeds. 17. Cyperus esculentus L. Cana-dian Journal of Plant Science 56:339-350. Vengris, J., M. Drake, W. G. Colby, and J. Bart. 1953. Chemical composition of weeds and accompanyingPovilitis, B. 1956. Dormancy studies with seeds of crop plants. Agronomy Journal 45:213-218.various weed species. Proceedings of the InternationalSeed Testing Association 21:88-111. Vengris, J., S. Dunn, and M. Stacewicz-Sapuncakis. 1972. Life history studies as related to weed controlQasem, J. R. 1992. Nutrient accumulation by weeds in the Northeast. 7 — Common purslane. Researchand their associated vegetable crops. Journal of Hor- Bulletin 598, Agricultural Experiment Station, Theticultural Science 67:189-195. University of Massachusetts, Amherst, MA.Roberts, H. A. and S. K. Benjamin. 1979. The interac- Vincint, E. M. and E. H. Roberts. 1977. The interactiontion of light, nitrate and alternating temperature on the of light, nitrate and alternating temperature in promot-germination of Chenopodium album, Capsella bursa- ing the germination of dormant seeds of common weedpastoris and Poa annuua before and after chilling. Seed species. Seed Science and Technology 5:659-670.Science and Technology 7:379-392. Wesson, G. and P. F. Wareing. 1969. The induction ofRoberts, H. A., and P. M. Feast. 1972. Fate of seeds of light sensitivity in weed seeds by burial. Journal ofsome annual weeds in different depths of cultivated and Experimental Botany 20:414-425.undisturbed soil. Weed Research 12:316-324. Wiegand, K. M. and A. J. Eames. 1925. The Flora ofRoberts, H. A., and P. M. Lockett. 1975. Germination the Cayuga Lake Basin, New York: Vascular Plants.of buried and dry-stored seeds of Stellaria media. Weed Cornell Agricultural Experiment Station Memoir 92,Research 15:199-304. 491 p.Weed Management 75
  • 84. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Weed Management on Organic Vegetable Farms Vern Grubinger Vegetable and Berry Specialist University of Vermont Extension 157 Old Guilford Rd. #4 Brattleboro VT 05301-3669 (802) 257-7967 vernon.grubinger@uvm.eduMany organic vegetable growers consider weeds to Weed suppression techniques include:be their primary pest problem. Integrating a varietyof weed control techniques is the best way to achieve • Growing smother crops, intercrops and/or aggres-effective organic weed control. sive cash cropsWeed management techniques are aimed at prevent- • Hand-hoeing and hand-pullinging weeds before they appear, or at suppressing weedsonce they are present. • Mechanical cultivationWeed prevention techniques include: • Flame-weeding• Rotation of crops, fields and tillage tools • Applying post-emergent organic herbicide (soaps, acetic acid, etc.)• Composting animal manures to kill weed seeds Weed prevention is essential to organic weed man-• Cleaning farm implements between use in different agement. Otherwise the need for cultivation can be fields excessive, eating into time and profits, and potentially damaging soil structure. Hand weeding is obviously• Controlling weeds in hedgerows, alleys, ditches, costly and must be kept to a minimum. Weed preven- etc. before they set seed tion practices should begin in the years prior to planting a crop, with cover crops in a well-designed rotation. In• Growing allelopathic cover crops the cropping year, clean fallowing and stale seedbeds may prepare for crop planting. Then, weed-crop com-• Mulching with plastics or organic residues petition can be managed through various combinations of cultivation, mulching, intercropping, mowing, and• Applying pre-emergent organic herbicide (corn concentrating resources near the crop. gluten meal)76 Organic Vegetable Production
  • 85. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Cultural practices which it is critical to minimize soil movement when planting or transplanting. Early-season stale seed- beds are often ineffective, as most broadleaf weedsCrop rotation germinate in warm soils. Many growers create a stale seedbed only in the crop row using a hand-held flamer,Crop rotation subjects weeds to an ever-changing while cultivating between the rows. This works wellhabitat, reducing the opportunity for certain species with crops that are slow to establish, like carrots andto proliferate. Rotation strategies for weed control onions.include row versus sod crops, frequently versus rarelycultivated crops, deep versus shallow tillage crops, Composting animal manureearly- versus late-season crops, and fallow versuscash-cropped periods. Composting animal manure helps reduce the number of weed seeds added to the soil. In composting whereSmother cropping temperatures reach approximately 140 degrees F many weed seeds can be killed. Maintaining the proper C:NSmother cropping is cover cropping with competitive ratio, moisture and aeration, and turning piles inside-species in an attempt to starve weeds of light, nutrients, out several times is important to ensure that most ormoisture and space. Smothering can weaken perennial all of the compost does indeed get hot. Turning alsoweeds by depleting their carbohydrate reserves, and keeps weeds that sprout on the pile surface from go-can lessen annual weed pressure by slowing growth ing to seed.and reducing seed production. Fast-growing, high-biomass species make good smother crops because Mulchingthey can get a jump on, and over, weeds. Mulching the soil provides a physical barrier to weedWarm-season cover crops such as buckwheat, Japa- growth. Organic residues such as straw, leaves, etc.nese millet and sorghum-Sudangrass are good summer can suppress weeds for many weeks if put on thickly,smother crops in hot conditions, but they should not be but they keep soil temperatures cooler which mayplanted until soils are thoroughly warm. Cool season slow the growth of warm season crops. A thin layer ofcrops like oats, field pea, and ryegrass are candidates organic residues can be worse then none at all, sincefor smother cropping in the early spring and fall. weed prevention will be poor but cultivation may beHigh seeding rates, adequate moisture and fertility, hampered.and good soil-seed contact by drilling or otherwisecovering seed are important to establishing a thick Black plastic mulch completely blocks light fromsmother crop. weeds and is a very effective weed suppressor. Clear plastic mulches warm the soil to a greater extent thanStale seedbeds black plastic, but allow light to penetrate thereby encouraging weed growth. Selective wavelengthStale seedbeds takes advantage of the fact that most mulches, such as IRT, behave in between black andweeds have small seeds that germinate from the top clear plastic, allowing limited weed growth. If weedinch or two of the soil, usually within a couple of weeks pressure is high and canopy growth is slow then thereof preparing soil for planting. By letting these weeds may be a lot of weeds under clear or IRT plastic. How-germinate and then killing them without disturbing ever, under conditions of strong sunlight, solarizationthe soil and bringing up new weed seeds, subsequent may kill weeds that grow under clear plastic if it is leftweed pressure can be greatly reduced. In some cases, undisturbed for several weeks prior to making plantinggrowers using stale seedbeds actually encourage weed holes in it. Paper mulches have been used with limitedgermination with irrigation or row covers to overcome success since they tend to deteriorate during the season.dry or cool conditions that slow weed growth. Throwing soil up on the edges as they decompose has helped keep paper mulches in place for some growers.Weeds can be killed with flaming, nonselective Organic growers need to avoid paper mulches treated“organic” herbicides (potassium salts of fatty acids, with prohibited materials.acetic acid, etc.) or extremely shallow scraping, afterWeed Management 77
  • 86. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.The edges of plastic or paper mulch pose a special Crop establishmentchallenge because weeds often grow well there butthe mulch is easily ripped by close cultivation. To Crop establishment techniques that encourage the rapidavoid hand-weeding, some growers have developed early growth of vegetables and discourage rapid earlyinnovative cultivation tools to deal with this unique growth of weeds can minimize weed control These tools usually undercut then replace the Transplants give crops an obvious jump over weedsmulch, or cultivate extremely close it. Both approaches compared to direct seeding. Carefully placed starterrequire straight runs of mulch with uniformly buried fertilizer feeds crops not weeds.edges. The planting hole may require hand weedingwith slow-growing crops. Bulb planters, propanetorches and other devices have been used to create Cultivationsmall, uniform holes for planting into.Interseeding Cultivation equipment for weed control varies in ag- gressiveness and is usually suited to killing weedsInterseeding is a form of inter-cropping that can add to either before or after the crop emerges. Tools designedsoil organic matter, reduce soil erosion, improve field for use after a crop emerges provide either between-trafficability and also suppress weeds. To avoid com- row weed control or in-row weed control, or in somepetition with the cash crop it is advisable to interseed cases, both. Cultivation implements are designed tomoderately competitive cover crops like low-growing dislodge, cut and/or bury plants. Matching the tool toclovers and/or ryegrasses into relatively vigorous the weeds, crops and soil conditions is key. Jugglingcash crops like corn, potatoes or squash; to leave a the uncertainties of weather and other managementbare planting strip for the cash crop that is kept free demands on the farm is the challenge to using a culti-of intercrops as well as weeds; to sow the cover crop vation tool at the right time.after the cash crop is well-established, usually at lastcultivation; and to provide irrigation. Pre-emergence cultivationMowing Pre-emergence cultivation often involves shallow tillage of the soil with rotovators, various harrowsMowing (or weed-whacking) vegetation between the or field cultivators. If performed repeatedly, this ap-rows of a cash crop can control weeds, and or cer- proach is called a “clean fallow” that can occur beforetain intercrops. It also enhances the environment for or in-between plantings. The objective is to kill annualharvesting and pick-your-own sales. In most cases, weeds, reduce the soil weed seed bank and removebetween-row mowing is only practical on a small perennial weed growth. While rather harsh on soilscale, or where rows are wide enough to accommodate structure and organic matter, this technique can betractor-pulled mowers. Side-discharge mowers damage justified if used in combination with a good covercrops by blowing debris on them. crop rotation and/or addition of soil amendments to maintain soil structure.Placement of resources Disk harrowsPlacement of resources can be used to favor crops overweeds. By banding and sidedressing fertilizer, and Disk harrows are often used for clean fallowing, butin some cases by using drip irrigation, weeds can be they may not be the best choice with a perennial weeddenied nutrients or water needed for good growth. A problem like quackgrass, since rhizomes tend to beword of caution is that many plants send roots laterally chopped up and spread them throughout a field. Fieldto obtain resources, so locating water and fertilizer only cultivators are used to create a seedbed and incorpo-in the row may be more useful in limiting between-row rate residues and soil amendments, as well as for weedweed pressure only if the rows are far apart. control. Equipped with rows of S-tines and sweeps or shovel with lifting action, they can be used to dig up and lift quackgrass rhizomes to the surface of the soil where they will dry out and die in hot dry weather. A78 Organic Vegetable Production
  • 87. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.variety of field cultivators are on the market, they vary High clearance tractorsin tine shape, flexibility, action, and spacing, as well asoptions like rollers, cultipackers, crop shields, leveling High clearance tractors facilitate post-emergencebars, and gauge wheels. mechanical weed control since crops up to several feet tall can pass under the tractor, and tools can beBlind cultivation “belly-mounted” in view of the operator, increasing the precision of cultivation. Off-set high clearance tractorsBlind cultivation relies on tools that work the entire are even better for cultivating because the driver’s seatsurface of the soil ‘over the top’ of a recently seeded or is off to the side of the tractor body, further enhancingrecently emerged crop. The technique combines in-row vision of the row.and between-row cultivation, often to control weedsthat have germinated but not yet emerged, the so-called Cultivating tractors‘white-thread’ stage of growth. This disturbs and driesout small, vulnerable weeds before they start to size Cultivating tractors are small, low to the ground, easyup alongside the crop. Such fast, shallow cultivation to guide and used only for precision cultivation ofworks best on weeds that have been up for week or less. young or low-growing crops. The cultivation tools andLarge-seeded crops sown deeply and young vigorous the crop row(s) being cultivated are easily viewed bycrops are able to tolerate such cultivation, while very the operator. The Allis Chalmers “G” tractor, no longersmall annual weeds cannot. made, is the classic of this type. Other brands, Hyspan, Saulkville, and Friday, are currently available.Flex-tine weeders Basket weedersFlex-tine weeders can be used for blind cultivationon a number of vegetable crops. The weight of these Basket weeders are metal cages that roll on top of andunits may be borne by the numerous thin metal tines scuff the soil surface without moving soil sidewaysthat wiggle and dislodge weeds, or by gauge wheels into the crop rows. This action makes them ideal forattached to the frame. Gauge wheels help control tine crops like lettuce that have to be kept free of soil anddepth and avoid gouging soil on uneven fields. With are not suited to hilling. Buddingh basket weeders aresome units, the 3-point hitch can be used to adjust custom built for two to eight row beds. Angled basketsdownward pressure on the tines. Tine weeders width are available to work the sides of raised beds. Basketranges from narrow, bed-covering sizes to very wide widths range from 2 to 14 inches depending on theunits useful in large fields. Lely and Einbock are com- space between rows. For wider widths, and for innermon brands. row widths that change as crops grow, overlapping baskets are available that “telescope” or expand in andRotary hoe out to adjust for the width.A more aggressive blind cultivator is the rotary hoe. It Commonly used at speeds of 4 to 8 mph, straight rowshas many thin spider wheels each with 16 or 18 tips, or and an experienced operator are helpful to avoid cropspoons, which dislodge very small weeds. The spiders damage. The front row of baskets turn at ground speedmove independently and bear the weight of the unit, and a chain drives the rear row of baskets a little bitalthough gauge wheels are available. Rotary hoes come faster; these kick up soil, and dislodge weeds thatin widths of 6 feet and up. They are most often used survive the first baskets. This tool is almost alwaysfor weed control in corn and beans and for breaking belly-mounted to assist with close cultivation. Theup the surface of soils prone to crusting. Rocks will baskets handle some small stones but work best in finejam in the spiders of a rotary hoe, keeping them from soils free of clods and residues.turning properly. Plastic mulch pieces in the field willalso collect on spider wheels and require removal. Finger weedersDull spoons reduce the effectiveness of rotary hoeing. Finger weeders cultivate around the stems of crop plants that are sturdy enough to handle some contact. Rubber-coated metal fingers provide some in-rowWeed Management 79
  • 88. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.weeding. These are connected to a lower set of metal moved in and out of the row. The Reigi weeder hasfingers work deeper in the ground and drive the unit PTO-driven rotating hubs with stiff tines that can beat ground speed. These units can be used at just a few steered in and out of the row by an operator seatedmiles per hour since they are in such close proximity behind the the plants. They require belly-mounting, and areideal for a G-type tractor. Wet clayey soils can stick Row-crop cultivatorsto fingers and require frequent removal. Row-crop cultivators consist of toolbars on a tractor-Brush-hoe weeders pulled frame with various shanks and cultivation implements attached so as to leave space for the cropBrush-hoe weeders are European tools for close cul- rows to pass. These are much like field cultivatorstivation in narrow rows, not very common here, and except for the spacing of the shanks and the absenceexpensive. Shields protect plants from bristle wheels of implements that completely cover the soil such asthat rotate independently between the rows, “sweep- rolling baskets. Shields may be mounted on either sideing” weeds out of the soil. An operator sits behind the of the crop rows to protect them from soil and rockrotating wheels and steers the unit to assure precision. movement during cultivation.Sweeps, shovels, and knives Spyders, spring-hoes, and torsion weedersSweeps, shovels, and knives attach to the shanks Spyders, spring-hoes, and torsion weeders (made(vertical pieces of metal that attach to the toolbar). by Bezzerides) are used alone or in combination forDepending on their shape and orientation, these tools close between-row cultivation. The spyder wheel hasmove soil in different ways as they are pulled between staggered curved teeth and is ground-driven on a ball-crop rows. People are not consistent in how they name bearing hub. A pair of 12-inch spyders can be angledthese tools, so there can be some confusion. The shanks at 45 degrees toward or away from the row to eithercan be clamped to different places on the toolbar(s) to pull soil away or throw it back. Aggressive and rapidachieve an arrangement that provides the desired in- cultivation of a variety of row crops is possible, evenrow coverage and extent of soil movement. Toolbars on stony soils. Torsion weeders are square stock metalcan be rear-mounted, belly-mounted (underneath a bars that can be mounted to follow the spyders, level-high-clearance tractor), or with special attachments, ing the soil and flexing around the plants to clean upfront-mounted. spots missed by the spyders. Spring hoes are flat blades 16 inches long that are a bit more aggressive than theSweeps are wing-shaped, come in various sizes and torsion weeders, oscillating just below the soil surface.angles, and are used to dig up larger weeds betweencrop rows while throwing soil into the row. Big sweeps, Rolling cultivatorsor duckfeet, are used to cultivate wheel tracks. Half-sweeps have a wing on just one side, so the wingless- Rolling cultivators consist of gangs of heavy slicerside can cut closer to the crop rows or plastic edges. tines that aggressively dig up weeds and pulverize soilShovels are narrower than sweeps, throw less soil, and between rows. Individual gang width ranges from 10sometimes have 2 points that are reversible. Knives are to 16 inches depending on number of slicer tines, andlike angled shovels that are used to cut more horizon- units are available for one to 12 rows. Gangs can betally and closer to a crop. angled to hill up or throw soil into the row. Used with fertilizer attachments, sidedressing is possible whileWiggle-hoes cultivating. Rocks may jam in tines, and action may be unduly aggressive for sandy soils.Wiggle-hoes have shanks with half sweeps attachedthat can be hand-steered around plants in a row by Hilling disksan operator seated on the back of the tractor-pulledunit. Close cultivation is possible, but extra labor Hilling disks are used to aggressively throw soil intois required for the operator. Slow tractor speed and the rows of crops such as potatoes, leeks, sweet cornwide crop spacing must be used to allow shanks to be and other crops that tolerate or benefit from being80 Organic Vegetable Production
  • 89. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.buried. Properly timed, this results in excellent in-row and are available with different BTU ratings. Liquidweed control. burners can avoid ‘ice up’ of gas lines. Burners may be arranged in a row to flame the entire width of a bed,Flame weeding including wheel, or they may be aimed at or between the rows. They may be fixed to the unit, or adjustable.Flame weeding is the killing of weeds with intense, Having individual burner shut-off valves and angledirected heat, usually with a propane burner. Flame adjustments provides flexibility in how a flame weederweeding is used primarily to control small weeds in can be used.a stale seedbed (without disturbing the soil). Becauseweeds tend to emerge in ‘flushes’ stimulated by till- Tractor speed when flaming is just a few mph. Theage, the initial emergence of weeds represents a major larger the weeds or the heavier the dew, the slower trac-portion of the weed pressure in a given field, provided tor speed needs to be. Flaming is not intended to burnsubsequent tillage that brings new seeds to the surface the weeds, but to provide a short exposure to intenseis delayed or avoided. Prior to flaming, the soil is pre- heat which ‘blanches’ the weeds, and they collapsepared for planting in the normal fashion, then weeds and die within minutes or hours. Exceptions to thisare allowed, even encouraged, to emerge, so they can are grasses, with below-ground growing points, andbe killed with flame. After planting the crop, but just some succulent weeds like purslane, which can takebefore it emerges, another flaming may be applied the heat. These weeds require hotter temperatures and/to kill weeds that have emerged in the interim. With or subsequent cultivation to control.slow-to-germinate crops, this final flame weeding ismost critical to success. The propane containers used on tractor-mounted flamers must be ‘motor fuel’ tanks, which are ratherBackpack or hand-held flamers are the simplest, least expensive, but intended for mobile use, unlike station-expensive and safest method of flame weeding. A small ary propane canisters. The design of the system andcanister is carried by hand or in a backpack, while a the selection of valves and controls should be done insingle burner at the end of a wand is aimed at the area consultation with a propane professional. All tractorto be flamed. The burner size, walking speed, and flame mounts, canister straps, and lines should be carefullyadjustment determine how much heat is applied to an examined before using the flamer. Besides the potentialarea. This technique is popular for small plantings for explosion, concerns include: fires started in dryof crops that will later be close-cultivated between grass or hedgerows, liability insurance and regulations.the rows but will not tolerate soil being thrown intothe row. For example: carrot, lettuce, radish, spinach,herbs, etc. ConclusionTractor-mounted flame weeders have been custom-built by growers to flame multiple rows or wide beds. Effective organic weed control on vegetable farms isThe components include a tank (or several), valves, possible through the use of cultural practices, cultiva-gas lines, regulators, pilot lights, and emergency shut- tion and flaming. Organic weed control practices can beoff. Gas may flow directly to individual burners, or it economically viable when utilized as part of a whole-may be distributed through a manifold first. Burners farm management system that includes rigorous useare specific for propane in the gas or the liquid phase of cover crops, crop rotation, and sanitation.Weed Management 81
  • 90. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.References Chauncey Farm 119 Bridle Rd. Antrim, NH 03440Altieri, M. and M. Leibman, 1988. Weed-Crop Ecol- (603) 588-2857ogy: Principles in Weed Management. Breton Publish-ers, Boca Raton FL HWE Agricultural Technology (Einbock) B.P. 1515Colquhoun, J. and R. Bellinder. 1997. New Cultivation Embrun, ON K0A 1W0Tools for Mechanical Weed Control in Vegetables. CanadaIPM Fact Sheet, Cornell Cooperative Extension, (613) 443-3386Ithaca NY Market Farm ImplementBowman, G. (ed.) 1997. Steel in the Field: A Farmer’s 257 Fawn Hollow Rd.Guide to Weed Management Tools. Northeast SARE Friedens, PA 15541Program, UVM, Burlington VT (814) 443-1931Grubinger, V.P. and M.J. Else. 1996. Vegetable Farm- Lely Corp.ers and their Weed Control Equipment (video) Center P.O. Box 1060for Sustainable Agriculture, UVM, Burlington VT Wilson, NC 27894 (252) 291-7050Some sources of cultivation Univerco (Reigi weeder) 713 Route 219equipment Napierville, Quebec J0J 1L0 CanadaBartschi-Fobro LLC (800) 663-8423P.O. Box 651 (450) 245-7152Grand Haven, MI 49417(616) 847-0300 Unverferth Manufacturing P.O. Box 357Bezzerides Bros., Inc Kalida, OH 45853P.O. Box 211 (800) 322-6301Orosi, CA 93647(559) 528-3011 Wasco Hardfacing Co. P.O. Box 2476BDi Machinery Sales Co. Fresno, CA 93745430 E. Main St. (559) 485-5860Macunie, PA 18062(800) 808-0454 Mention of brand name equipment, suppliers, and prices is for information purposes only; no guarantee orBuddingh Weeder Co. endorsement is intended nor is discrimination implied7015 Hammond Ave. against those not mentioned.Dutton, MI 49316(616) 698-861382 Organic Vegetable Production
  • 91. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. How to Get 99% Weed Control without Chemicals Brian Caldwell Farm Education Coordinator Northeast Organic Farming Association of New YorkIn order to grow a vegetable crop to its full potential, Skipping one of these strategies will result in too manyweed control needs to be good, really good! weeds and a yield loss or the need for expensive hand labor to get rid of them.How good? Preplant weed controlOften, dozens or hundreds of weed seeds per squarefoot of vegetable field will sprout, ready to out‑compete Preplant weed control starts with the right tools. Theyour crop. Even if 90% of those seedlings are killed, strategies described here can be done with hand toolsthat can leave several survivors per square foot‑-more and walking tractors, but for operations of over an acre,than enough to hurt yields. 99% or more of emerging tractor-mounted equipment is worthwhile. Investing inweeds must be prevented from competing with the good used equipment will quickly pay off in reducedcrop. This translates to less than one weed per square labor and better results. Use compatible, effectivefoot (note: we’re not talking about a “99% clean” equipment to prepare the soil and seed and cultivate thefield‑-there still might be thousands of weeds per acre, crop. Seedbeds must be level. Rows must be straightjust not enough to hurt yields). Some growers do this and exactly the right distance apart for the cultivator.routinely, without herbicides and with minimal hand Belly‑mounted seeders and cultivators are best.weeding. Plan crops, cover crops, and tillage to stifle weed out-In order to consistently get this 99+% control, four breaks each year. If a long season heat‑loving crop orstrategies must be combined: cover crop is grown one year, follow it with an early or late cool weather crop. Vary tillage times and crop1. Preplant weed control types (long or short season, warm or cool weather crops) from year to year, in addition to not repeating2. Weed control between rows related crops in a field. Deep tillage at different times during the season will strongly suppress perennial3. Weed control within rows weeds like quackgrass, Canada thistle, and yellow nut- sedge. If you have these weeds, plan to rotovate or plow4. Reducing weed reproduction twice a season (followed by your crop or cover crop)Weed Management 83
  • 92. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.until they are gone. After a few years, discing or field several cultivations are needed. I often hear growerscultivating may be all the primary tillage you need. say, “It’s a mess now, but it was clean as a whistle 3 weeks ago.” They should have cultivated at least onceStale seedbed techniques can knock out your first 50‑ more, even though the weeds were barely visible.75% or more of the weeds. The best non‑chemicalapproach for this is to prepare a fine, firmed seedbed 2 If weed pressure has been reduced 75% by stale seed-or more weeks in advance. When it’s time to plant, go bed, and between row cultivation gets 80% of what’sover the seedbed using flaming or a shallow cultivation left, then we have 5% of the original weed pressurewith a basket weeder to kill the emerged weeds. Plant left‑mostly right in the rows next to the crop. We’re atyour crop right away, with no further soil disturbance. 95% weed control, close to our 99% goal.Many fewer annual weeds will emerge to compete withthe crop. This method works better for crops that areplanted during warm weather (June or later), so that Weed control within rowsweeds have had a chance to germinate. Weed control within the row is very tricky. For oneWeed control between the rows thing, research done by Dr. Chuck Mohler of Cornell and myself showed that annual weeds may come up 2‑3 times more thickly within the row. Why? Be-Weed control between the rows is relatively easy. cause they do best on a well‑firmed seedbed, just likePictures of some common types of cultivators can be your crops. (Similarly, be sure not to leave packed soilfound in Steel in the Field, edited by Greg Bowman, caused by your tractor tires. Mount sweeps behind thethe best reference on mechanical weed control. If you rear tractor tires.) That in‑row location is preciselywant to control weeds without chemicals, you need where weeds are hardest to kill and where they mostthis book. You can order it at 802‑656‑0471 for $18. reduce your yield.Growers on stone‑free soils tend to prefer basket “Broadcast” cultivation with a flexible tine (“tine­weeders, which allow cultivation very close to the tooth” or “finger”) weeder or a rotary hoe solvesrow and do an excellent job if weeds are less than 1 part of the problem for large‑seeded crops that caninch tall. For stonier soils or somewhat larger weeds, be planted deeply like corn, beans, peas, potatoes organgs of overlapping sweeps are also effective, but onion sets. The implements are pulled at high speedthey throw more soil and must be set further from the “blindly” right over the crop rows, scratching out therow. “Spyder” toothed disks can be mounted next to newly‑sprouting weeds while going right over deeperthe row to get closer. Without throwing any toward the crop seeds or better‑rooted crop seedlings. This isrow, they shear soil away, which is then thrown back usually done 4‑5 days after the crop is planted, then aby the following sweeps. week later, and perhaps once more. The crop shoots get a bit beat up by the process, and a few are pulledCultivate early on a sunny day for best results. If you out of the ground, but yield is reduced only slightlydon’t have an ideal cultivator, go over the rows twice or not at all. Most of the weeds within the rows are(i.e. in both directions), to do a more complete job on killed, so the broadcast cultivation is quite worthwhile.those weeds. But it must be done when the weeds are in the “white thread” stage—just before emergence—to be effective.If possible, cultivating a couple days after a good rainis an effective strategy for reducing weeds and holding After the crop is too big to broadcast cultivate, themoisture. The loosened surface soil may form a “dust between‑row cultivators are used. For the last onemulch,” which will hold moisture beneath, but which or two between‑row cultivations, soil can usually bewill not be a good seedbed for new weeds. purposely thrown at the base of the crop (“hilling”), smothering small weeds coming up in the row.While cultivators kill existing weed sprouts, new seedsare stirred up and will sprout after a rain. That’s why If we can kill 80% or more of the in‑row weeds with84 Organic Vegetable Production
  • 93. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.broadcast cultivation and hilling, our 5% of the original the other hand, undersown strips can reduce mud andweed pressure has been reduced to 1% or less. We have protect the soil during a wet harvest.reached our 99% goal. In addition to killing flushes of weeds before seedingThere are variations in this strategy for some crops. with the stale seedbed technique, the same idea canPotatoes, for instance, are deeply hilled. If this is done be applied after early‑maturing crops. Till the crop in,twice, good weed control is usually attained. Trans- wait for a flush of weeds, kill them, then plant yourplanted crops like brassicas cannot be blind cultivated, cover crop. You’ve gotten rid of another batch of weedbut they quickly grow to the point where they can take seedlings.some hilling. The trickiest crops are root crops likecarrots, parsnips, beets, direct‑seeded onions, or herbs Finally, avoid importing millions of weed seeds by notlike dill, cilantro, etc. They usually require some hand spreading manure from grain‑fed animals. Compostweeding. Turnips and daikon are often seeded after such manure before use.mid summer when weeds pressure is not so strong, sohand weeding is light. A special trick can be done withcarrots and parsnips, which are slow to germinate. Just Mulchingbefore the crop comes up, but after the main flush ofweeds has germinated, the rows can be flamed. Weedcontrol is excellent when this is done right. If a small Mulching controls weeds both in and between thepane of glass is placed over part of a carrot row, the rows. All transplanted crops and garlic are candidatescrop seeds under it will come up a day or two ahead for mulching.of the uncovered rows‑so the grower is alerted whenit’s time to flame. Garlic can be mulched immediately after planting with organic materials like weed‑free straw, hay, leaves, or wood chips, if the soil is well drained. Annual weedsReducing weed reproduction are suppressed and these materials provide organic matter and long‑term nutrients to the soil. Mulching with organic materials works well for other crops too,What we are trying to accomplish here is to limit as long as they grow well in cool soil and the field isyear‑to‑year weed pressure by reducing the soil weed free of perennial weeds. There is a labor cost in ap-seedbank. This is a long term process. The key prac- plying these mulches, but I’m convinced that growerstice here is to till under the crop as soon as harvest can figure out reasonable ways to apply them if theyis finished. This reduces new weed seed production, want to. For instance, much time is saved by laying theand also helps with disease and insect control. Seed a mulch down before the crop is transplanted (or beforecover crop at the same time. it comes up, as in the case of garlic). High‑residue no‑till transplanters are being developed that may workSome growers are able to send someone through the through organic mulch.field late in the season to hand pull large maturingweeds and get them out of the field‑-not a bad job if The other major mulching material is black or coloredweed control has been excellent. plastic. Weeds along the edge of the plastic can be a headache. Covering the bare soil between the plasticCover crops can also be used in other ways to compete with weed‑free organic materials is a good solution.against weeds. At the final cultivation, they can be Moisture retention, soilborne disease reduction, and“undersown” into the cash crop. The crop should be a dry picking lane are bonuses. Otherwise, rows canfar enough along that the cover crop will not compete be set far enough apart so that a narrow tractor withheavily against it once it gets going. Slower estab- a section of springtooth harrow or other cultivationlishing cover crops like red or sweet clover are better setup can be pulled through every two weeks or so.choices than oats or ryegrass for this purpose. In dry Hoeing or flaming will have to be done along the plasticyears, even late‑ interseeded cover crops will compete edges. Edge weeds that go to seed late in the seasonagainst the cash crop, unless the field is irrigated. On can be a real drawback to the use of plastic mulch. IfWeed Management 85
  • 94. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use use colored plastic mulches, make sure they are depending on row spacing and type of to fully shade out weeds. Some work well onlywith herbicides. Varying intensities of weed control are needed for dif- ferent crops, and much depends on crop mix and the scale of the operation. A typical sweet corn crop mightHow much does this cost? require two blind passes with a flexible tine weeder, then two between‑row cultivations with sweeps and hilling discs (roughly $60‑160/acre, depending onA rough estimate would be $30‑40 per equipment pass farm size). Carrots, which are worth a lot more perper acre (including amortized, pro‑rated equipment acre, might get stale seedbed prep, a delayed flamingcosts for tractor plus cultivator and flamer setups, just before emergence, three cultivations, and a handfuel, labor, etc., used on at least 10 acres per year). For weeding ($600/acre or higher).large operations, this cost could perhaps be cut in half.Hand weeding costs are likely to be at least $400/acre A crucial management issue that goes along with me-(50+ hrs @ $8/hr). Organic mulching materials could chanical weed control is the need for getting the jobrun on the order of $500/acre (clean straw—5 tons/A done on time. If you do it with the right equipment,@ $ 100/ton), plus considerable labor for spreading. at the right time, it’s easy. Otherwise, you may be inPlastic mulch materials are perhaps $200/acre or more, for a tough time, or a lot of healthy weeds!86 Organic Vegetable Production
  • 95. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Mulching for Weed Control and Organic Matter Transcript of a presentation by: Paul Arnold Pleasant Valley Farm Argyle, New YorkWe bought this land back in 1988 and put up the houses and market in the afternoon. Thursday is fieldwork,and the barns that you see. I started in my father’s back Friday is pick all day and Saturday is two markets. Soyard for a couple of years just because I grew up in that’s kind of a typical week for us. We try not to worksuburbia and I decided I wanted to farm and then went Sunday. Usually in the early spring we will be pushingto play around in his back yard for a few years then to do everything. Like I say, to get things planted andbought this place in ’88. Bought land and then put up get things cultivated at the same time. It gets kind ofthe house and all the barns you see and planted the pushing in June and May.orchard and just got things up and running. I woulddo a little work in the wintertime and then farmed in We grow about 35 different crops, small amounts ofthe summer. Met my wife Sandy right after I bought each one, constant planting right through from earlythe land, she knew she was going to marry a farmer February so we have crops from May 1st on. Usuallyand I wanted to make sure that she really liked farming spinach and lettuce the first week in May, and rhubarbbefore I married her. Since then we have had two kids, and asparagus. We grow a small amount of perennials.they are 10 and 7 and they help quite a bit on the farm. A lot of our mix of vegetables is to have a consistentKim and Robert. When we started out I had my father amount through the whole year and that is how weto help me and my step-mom and they helped me quite kind of control our income is to always have somethinga bit. About three years ago my father passed on, but coming on because we all know it is a good year andwe have been able to keep the farm going because it bad year for something. With the just two days a weekwas a threesome for a long time. It worked really well that we all have to do field work we have really had toand that is how we got the buildings up and houses up be efficient at our cultivation and be efficient at tryingand everything else kind of going on this farm. to prevent weeds. This is why we got into mulching. In Washington County we are a dairy county primar-What we do is raise about six acres of vegetables now, ily but right around me there are not really any dairywe probably have about ten acres that are available to farms. To haul manure or bring in stuff like that wasus and so some are kept in cover crop and rotation. difficult in the early years so we looked to what weWe sell at area farmers markets, four of them. So for had and one thing we did have around us a lot was hayus a typical week starting from May 1 to November fields that were being unused. That became our sourceis market on Monday afternoon so we are picking of building our soils. What we actually bought on thisMonday morning, market in the afternoon. Tuesday farm was a corn field. Probably continuous corn forto do field work, Wednesday is pick in the morning 30 years. So we had a couple of years of cover cropsWeed Management 87
  • 96. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.and we started right in after getting some equipment in the best place you can. You don’t want to put springputting on hay mulch trying to build up organic matter and fall crops in the lower areas.because it was only a little over 2%. This is where wekind of started. Here is a shot from the house showing all the diver- sity we have – little bits of a lot of different things.We have a slope here going down. From here to the We kind of break it up into knowing what crops arehouse is north and so we are kind of on a northeast going to be there all year and what crops are goingslope with good northwest protection of trees and this to be coming and going really quick like lettuce andmakes this ground very early. We have other fields and some of the ones that are there all year like tomatoesa 120 acre farm next door that we rent. We have plenty and peppers.of hay fields and ability to rotate. On top of growingvegetables we have about an acre of fruit and one thing This is going back toward the house. This is our mainwe set out to do to make sure is we always had fruit on field where we started and as we grew we did morethe table so we had a lot of different small fruits and and more acreage. We kind of started right from theapples on top of that. Not too much of anything. We beginning trying to put down mulch and we tried dif-hardly grow an acre of anything. ferent things. You can see right here we have zucchini and cucumbers and we tried sawdust from a horse farmOne of my goals of getting into farming, and I was and found that it really tied up nitrogen bad. After apretty naive when I got into it, was the fact that I did year, when this broke down it made the best soil onnot know that farmers did not make a living at farm- the farm but meanwhile there was a lot of starvationing. I got told that quite a bit when I first got started for nitrogen. It held things down pretty well. Thereand I told them this is what I am going to do and I am were a few escapees there but it made life a lot easiergoing to make a living at farming. I am going to make putting down mulch because there was just that mucha living at farming because I wanted that lifestyle of less area that I had to cultivate.staying home and raising food for my family and sell-ing. Even though I was told by pretty much everybody Just a little diversity of a lot of different crops thatand I hate to say the Extension Service that it wouldn’t we are growing, lettuce. This is where we are puttingwork but I don’t think they have the models at that time down mulch and after the mulch is turned under fromlike they have now to show that it does work. This is the year before trying to grow lettuce through thegoing on 15-16 years ago. So we set out to do it and summer. Looking for high organic matter for theseso far with the goals that I have it has worked very real high demand crops especially when it gets to bewell. We have been able to make a living at farming 90 degrees you are really happy it has a lot of organicfor 10 years. We have never worked outside the farm matter down. When we were putting a lot of mulchand have been able to reach our goals of making this down we were doing a lot of it for fertility. We havea good income. With being able to be so diversified gone on to now without a lot of extra hands, like myand having an unlimited water supply, a good irriga- father, around we have gone into doing compost be-tion system and good markets were we are we have cause it is a lot faster. We are constantly evolving andbeen able to have a consistent income and not really if I come here another three years from now I mighthave any of this roller coaster up and down. That has be doing something totally different again. I think thatbeen good for us. is one thing you always do is you are always evolving and changing and finding better ways and using theThis is shot from across the valley because we are best use of your time and equipment that you have.on the edge of the valley. The apple trees are grown Compost came around because we finally got a front-where they are because there is quite a slope. We have end loader and we just had to buy a manure spreadermade conscious decisions as to where to plant stuff and also it became available around our area to getand because we are up off the valley floor we really compost. Back when I first started we did not have astay away from the frost. What we have for soils is choice there wasn’t anything else to get. There was noup on top we have rocky silt looms and down below compost except for along long distance away. This isthe lower fields are sometimes a little heavier clay. It how we are holding our organic matter now.makes rotation sometimes tough because you can’talways put it where you should rotate but you put it88 Organic Vegetable Production
  • 97. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Let’s talk a little bit about cultivation that we use. in the fields and bringing it in and laying it down. ItBecause we are really tight spacing just because some- is kind of a whole farm approach. If you just lookedthing is older and not a new product – this still worked a the economics of just putting down the grass mulchvery well for the first few years on the farm. Somebody and just left it at that you would probably say it is agave it to me and I put it to use and it did very well. It losing venture but the fact is if you look at the wholeis like anything else, I talked about even with tractor farm approach and you are trying to increase organiccultivation, you can’t buy one cultivator and expect it matter, trying to make the most of your soil on top ofto do everything so this works well as long as you are single and double cropping on close spacing, havingusing it in combinations with other things. If you just that organic matter and rotating that around your farmuse this those few escapees are going to get by and you in these mulched areas you can build organic matter.are just going to have a problem with one weed. A lot We have gone from I think it was like 2.1% when weof these older tools work really well. This is a typical first got there and all these years we have never reallywheel hoe and it worked well for us for crops that are given that main field you have been seeing up therestraight up and down and with walk paths and wider a rest and we have been able to increase it to at leastareas where you can really go along quite quickly. A 4.5% now. Five years of mulching and a little bit oflot of different attachments you can get down at the compost the last few years. Mulching – you have tobottom here. Wider ones. You can also get kind of a be able to look at that and say it is a good whole farmduckbill one. approach not just a matter of what it is doing for you at that moment. So we are using grass mulch and weWhen we first got going a lot of our crops that we are also using straw mulch. We are buying in strawwere cultivating were on 12 inch centers. We were from a neighboring farm and this is something reallyjust packing stuff in. We did not have a lot of land. We important and I know people have gotten themselveswere land limited and we needed to get things in close, into trouble is that we work with the farmer and weclose spacing and so cultivation with these smaller ask him to cut the straw before it goes into pollen. Hetools were the most efficient thing. You do not need does that for us and we are paying a little extra for itto start out with tractors right off the bat. Starting out but the reason is there is no seed in it. If you are gettingwith these smaller tools like that push hoe I showed straw and if you are going to buy it for mulching andyou, the wheel hoe and that little push cultivator were they have already combined it there is plenty of seedvery effective up until five years ago for us and were a in it. There is a lot they can only get out so much. Youreal time savings. I think you get to a certain size and can get yourself a real weed problem. With using thetime when all of a sudden priorities change a little and straw mulching it is really important to either raise ityou find you can change and add some new tools, some yourself and cut it at the right time or hire somebodytractor mounted stuff when you finally can evolve to or get some farmer near by to do it for you.own tractors that will do the job that you want it to do.We do not have a picture of it but we depend mostly We mulch asparagus, that’s how we keep the weedson your Farmall 200s or Super-Cs that are a little bit out of that. Its funny with asparagus you think that it’sbigger than a cub or a little A that they sometimes a high value crop and its not. It barely breaks, whatshow. We found that we can do two rows at once and we call a $10,000 an acre rule, something has to makealso with the Super-C you can get real wide spacing. at least $10,000 an acre although of course you knowWe are doing four rows underneath our Super-C on 14 we barely grow an acre of anything. But the asparagusinch centers. That is very efficient to be doing four rows just barely makes it over that. It seems like a reallyunderneath the tractor than to be doing three because high value crop, but its just a nice thing to have inof the amount of rows you can get done within a time. May and June.As we have evolved we are still using push hoes, weare still using some tractor cultivation for crops that are We mulch raspberries and blueberries. I don’t havejust there for a short time like beets, carrots, lettuce, a picture of the blueberries but we mulch them bothspinach and crops like that. What happens is we start with wood chips. There are a lot of businesses that gogetting into using mulching. Where we use mulching along and they are chopping where the power linesis mostly the crops that are going to be there all year are going through so we get all of our wood chips for– tomatoes, peppers, cucumbers. Areas like that. A lot free. And also if we have any shavings left over fromof it is grass mulching. We are cutting the grass out the chickens they go on there. But we will go aheadWeed Management 89
  • 98. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.and cover this up with something that is going to stay ——————————there a long time. We do this once every few years justput down a lot of chips on this instead of putting hay Q:  What kind of transplanter are you using?down every year. These are the fall ones that we aregoing to turn under and we’ve got the drip irrigation A:  I don’t use a transplanter, I’m doing it all by hand.on them. And to make them come in a little earlier weput the row covers over the top of them. And so we can Q:  How do you make the holes?get Heritage raspberries coming in, in August. A:  What we have for prepping the soil is a five-footSome of the crops we are going to put out when we rototiller on the back of the tractor. And I’m goinggo out there are Swiss chard. We are using soil block along making the soil soft and I know where my rowslots of times on the bigger seeded stuff like this. Stuff are going to be so if I’m using that self unloadinglike lettuce is usually going in as seedlings and these wagon I’m very careful not to go where I’m going togrow really well on that. This is Swiss chard again and plant. I make one wheel track down the row whereparsley. This might have been that same year where it’s going to go and keep one out. Then I’ll just wad itwe saw it when it was a little bigger. But that is what kind of in the middle and then from there just throwit looks like after finishing planting it in and then we it to either side so it doesn’t take but half a day or sojust have to harvest. Everything is clean after that you to cover all that ground. So if the ground is really softdon’t have to whack any of the dirt off of the parsley then I can easily just put my fingers right into it andor weed it. You just go out there and grab a clump make the hole.without getting weeds with it. There is it when it getsbigger. It is easy to take care of that way. And you see ——————————there’s some smaller cucumbers that are coming on andthe late tomatoes coming on there. And the next year I Peppers sit there all year. Another great crop to put in.might move this whole batch right to here and then do This is something that you have to watch for. I’m notsomething with more mulch. I’ll just keep working it going to just show you all of the best things that happendown the field to constantly be doing more. to us, I’m going to show you some of the worst so we can all learn here. When you have plastic over the topAlso I like to mulch the garlic in the fall and then in of straw or you put a row cover over top of the strawthe spring we add a lot more so that we don’t have to this stuff is shiny and when the sun gets on it, it reallyweed it. So that we just go in planting it, mulching it, heats up. It can produce a tremendous amount of the spring adding a little more mulch and then just Probably if I put a row cover over this and didn’t haveharvesting it. I really don’t really have to do anything this it would be the same effect. It would burn all theelse with it. Again, it is another crop we just keep mov- plants right up. And if you put your hand in there youing around and then in July when it’s all out of there would probably burn your hand. It gets so hot. Youwe’ll be turning that under and probably putting in a can’t just go out and put straw down, plant your zuc-fall crop. That’s going to be tremendous ground after chinis and your cucumbers through and throw a rowa week or two of it breaking down. Any crop that you cover over it. If the sun gets on it, it’s going to burnput in there is going to grow the best. We are planting everything up, underneath it. There is something withlate kale. the shininess, it doesn’t do it with the hay mulch but it will do it with the straw mulch. After we started notic-Brussels sprouts are going to sit there all year long. ing what was going on here, and it took us a little whileWe are going to harvest them sometime in October or to figure out what was going on, we thought we had aNovember. Those are my lower fields right there and, problem underneath, but it worked out and these areagain, once I put down the mulch and I plant it, then I the peppers by late August. They filled in quite nicely.don’t have to go back in again. It’s all set. And it just Again, we’ve got clean peppers, we just have to pickkind of breaks down as you go along and it actually them, we don’t have to wash them hardly. It’s kind offeeds a little bit of nitrogen down there and the soil is nice, there are no weeds in there, nothing. Again youso much better for the next year for anything else you just send somebody out to pick all season long.want to grow like beets that are heavy feeders.90 Organic Vegetable Production
  • 99. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Here we are, I think this is annual bed strawberries hot they do not like that too much. The bad part ofgoing in. I believe, or it’s the matted row system but what you are running into with the straw, especially ifwe are covering up here. This has already been done you are talking about cucumbers and other things likebefore and we are adding more as we go. We’ve got that, is the fact that if there is a light frost out there,full irrigation so that kind of helps. That kind of gives this will not allow that heat from the ground in the fallyou what it looks like after throwing all of the mulch to keep your plants from frosting so much. These willdown. frost earlier. So you have to be much more diligent with getting row covers on. Realize that if you‘ve gotHere we are planting winter squash, the rows. All I mulch out there you are going to lose the plant doing is putting down a string and somebody is Because it doesn’t allow that heat from the ground todropping a plant every 18 inches or so. Pretty simple, come up and maybe save your plants when you areand as I said you end up with nice clean winter squash getting really close to 32.when you are done. We came across something really interesting thisSome of the time what we have is these field houses spring, we ended up in our area being one of the verythat we do, you can see that I am putting it up in the few that had strawberries because of that late Mayfall. We’ve thrown down the mulch on it and I can frost. We went out and we were doing the annualhave it ready for the next year for the peppers. We’ll bed strawberries and we were doing row covers onput this up and it will make sure that the ground stays them, we were doing triple row covers on them. Theyunfrozen and we can start other things in here too or started flowering the first week in April and floweredplant anything else I’ve thought about planting, toma- right through until the end of May. We went out onetoes or something, early and again it’s no weeding. The evening around 8:00 or so and it was 41 degrees on ourground stays warmer. There it is all finished. We move thermometer and we have a digital one so it is prettythese around the field also. accurate and it was 41 and the row covers were start- ing to freeze together. So most farmers probably didPutting down straw mulch or it’s all hay mulch I believe not go out and do any row covering or frost irrigationhere and were putting down the stakes for tomatoes. that night till it got much lower but the damage wasAnother nice crop to mulch, we don’t have to have already long done if you waited much longer thanany diseases that splash up onto the leaves, like early we did. It was already starting to freeze so it is reallyblight. That’s another good thing to not have to worry interesting that when you are talking about mulch orabout. Much more even with the irrigation. In other having something high up in the air like that when youwords it doesn’t dry out and get wet and dry out and get that radiational cooling it’s occurring much earlierget wet. So you don’t have a lot of cracking when you than when you think. You can’t wait for it to be 36 orhave some rain. 35 and start up that irrigation. Depending on the sky. —————————— ——————————Q:  So do you drip irrigate that? So they get a little bigger. We have found that now on our ground we cannot plant tomatoes up on theseA:  No, we do overhead irrigation because right next to fields were we have been doing this mulch for yearsit could be lettuce growing right here and I can’t stop because now the ground is so rich that we have toma-the water from splashing onto the tomatoes. But that toes that come up over the top and then come all ofis why we don’t have to worry so much about having the way down. These are all indeterminate types anddiseases splash up because of the mulch being on top. the ground has gotten too rich for that because we areIt kind of eliminates that. doing all of this mulching. We have to put it on some really poor ground. So this has really helped the soil,Q:  Doesn’t the mulch keep the ground too cool and but it has also changed a few things that we have done.slow the plants down? This is strawberries, this is the matted row system. WeA:  Not during the summer. Most plants like it warm don’t do matted row anymore but if people are stillon top and they like their feet cool. So if their feet get doing it I’ll show you what we did with that. When weWeed Management 91
  • 100. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.plant the strawberries, we will put down the mulch first made and this is where I am going to plant the annualor put it down afterward because you can kind of drop strawberries through. I’m going to cover the wholeit on between the plants. We’ll put mulch down after area, someone is laying them out and I’m going throughplanting the plants and then we don’t have to weed this and just planting them as we are going along. So onthing the whole rest of the season. The main question each side of that hill we’ve got annual bed strawberriespeople usually ask is “Well, how do the runners get going in. We just plant about 3,000 plants there. Gotset down in the mulch? It seems like they are far off some free help there. After planting them we put theof the ground.” Never had a problem. It is always too row covers on them for the fall. They look like thatmany runners that set and if a few don’t then fine but come May first. They are flowering pretty good. Againthis makes matters a whole lot easier than having to no weeds, clean fruit, with the annual bed system theyweed that whole year. And then in about the first week are all gone by the first of July. But again we turn thisin November we just go ahead and go in and rototill under and made a lot better soil. There is also no graythe rows right down and get it down to where it is the mold with this system. I’ve never encountered any graywidth that you want. We’ll have straw put on for the mold and that makes it a lot easier. They also pick aboutstrawberries and then pull the straw off of the walk three times faster because you can see them better.paths and then put the row cover on to finish it off un-til they are blooming. So we are adding more organic It’s a nice system. Everything is kind of open. Therematter. This is another thing that even though we had is not one touching another one. They all have got amatted row we moved it every year. It kind of confused ring of strawberries around each one. So the pickingthe insects, we did not build up the insect population goes fast.but we were also using it, again, as the whole farmapproach. We knew this was a reason to keep adding I also went ahead and we’ve got a lot of flowers aroundmore organic matter to our soil. Adding all this nice the house and I am mulching that so that we can enjoystraw. And then they would look like this when they the flowers without having to weed up and going. Moving them every year we reallydidn’t come up with any weeds. And putting down a lot Some of the benefits are that we had some investmentof the straw kept everything clean and again we didn’t in buying the equipment, but when we first started outhave problems with dirty fruit or with weeds. So they from one year to the next the only thing that we didcame out kind of nice. We got away from this system different was to put mulch down in the fall, turned itbecause of the gray mold problem and because they under in the spring and then started planting our cropstook up space on the farm all year long and didn’t re- through it. That first few years, when we started farm-ally pay us back anything. When you are a small farm ing because the soil did so much better, we found weand you are trying to make use of all your space that jumped $10,000 just the first year in gross income. Soseemed like kind of a waste to me. When you have one that more than paid for all of the equipment that wespot that is costing you money and not giving you back to buy and the time spent putting it on. So there wasanything. So we went to the annual bed system. So we immediate payback on healthier crops. It really doesare preparing ground now in the fall, around the first so much better. It feeds the soil incredibly and someweek in September. organisms that are there. It brings more of a balance to the soil and everything that happens with it. WhatAnd this is that tractor again and you can just barely also happened was, because this was a cornfield forsee it. I’m sorry for that. Its got two disks here and it is years and years. I think that it was continuous cornbasically like hilling potatoes. I’m building a hill right for 30 years. The dairy farmer had a program of sohere and that’s where I’m going to plant the strawber- many ton of 15-15-15 every year and never took soilries. It’s making two hills at a time. Then we are going tests. We had an enormous amount of potassium andalong and again it is the first week of September and phosphorus. We found that every year when we werethe grass seeds are not out of the grass. They usually building up that soil and getting more soil organismsfall down during the season and some hold on a little in there and a lot more freeing up of a lot of the nu-later so the first week of September it is not clean out trients that are there, that our soil tests started goingthere. I can’t just go out and get grass mulch and put up and up and up tremendously. We’re kind of off theit down the first week. I’m putting down straw mulch, charts for phosphorus and potassium because of whatjust shaking it out. You can see the hills that I have he put on more than 17 years ago. We have yet to use92 Organic Vegetable Production
  • 101. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use up, probably it is going to be there a whole lifetime it is cutting standing grass. Whether it’s the straw orand we will never have to put down phosphorous or grass and it will be green. You definitely don’t want topotassium. go out there in the early morning when there is a lot of dew on there because it will just plug up the machine.As I said we are going into more compost now with soilmanagement. Even then as we are using it I’m thinking Q:  Do you cut it and let it dry before you put itabout going back to more grass mulch because right down?now if I can control and hold my organic matter at4-5% or where some of them are a little closer to 6% A:  No, not with the grass especially. If it’s heavy inwe can maybe go back to a little more grass mulching clover, maybe heavy in alfalfa I do go out and do someand do more with rotation of that rather than buying with alfalfa. That is not so bad when it gets a littlein compost, where you can bring in weed seeds, you older but if you try to do it there is so much nitrogencan have problems with phosphorus levels. We are in there and there is so much water to it that it kind ofalready in trouble with our phosphorus levels. Just one turns sort of slimy and melts away real fast. It’s goneless thing that we have to do. within a month.We don’t use black plastic on our farm because we Q:  Do you add any nutrients to your hay mulchdidn’t want to deal with getting rid of it. There are fields?some things like melons that do much better withblack plastic. We choose still not to use it, we still A:  This is always the thing with organic farmers;put our melons down on the mulch. Our melons are we are kind of robbing Peter to pay Paul. Whether orthe last melons to come in for the year. The rest of not I’m hauling in compost or doing the hay mulchthe farmers, they get them all early in late July and is that we are always taking from something else andAugust. Ours come in September and that is fine with putting it on our most valuable fields. Right now weus because they are all out of them. It really isn’t a have gotten into, just this past year; we are going tobig problem for us. start fertilizing the fields. We have taken soil tests and we are bringing in organic fertilizers and spreading itWe don’t do this winter time or fall. We don’t throw on to build the soils back up. We could see a definitemulch down on the fields anymore. We don’t have the drop over these years in the production of these fieldshelp and the time. But when you are first getting go- because we don’t have the ability to bring in manureing that really helps the organic matter really quickly and spread it on the fields. So we are going just theand helps your plant health. Now we can go though fertilizer route at this point. Just putting on a 5-3-4 onspinach and lettuce and grow it right through the sum- it. Our lowest amount is phosphorus and potassium onmer because of our organic levels and the amount of these fields. In the early years the important thing wasnutrients it released. to get the vegetables paying, start paying ourselves, and now that we have got some extra money, we are starting to go back to the hay fields and giving themQuestions and answers their due. You have to maintain them or else they go downhill real quick over the years.Any questions? Q:  Do you get 100% weed suppression with the mulch?Q:  How do you control the pH? Do you check that? A:  I wouldn’t say that you are going to get like youA:  pH was 6.4 when we started and it is still 6.4. It have alluded to. You are never going to get a 100%has never changed in 16 years. Not at all. weed suppression with it. For us it is probably 90%. So the little 10% for us that comes through, because it isQ:  Are you harvesting the mulch when fresh? either breaking down really fast or there is a spot that someone let a transplant go through, a weed came upA:  Oh! As in green, yes. You are going out and you through because there was exposed light. But it is soare chopping it, that is what this flail chopper is doing minuscule the fact that when you are going down andWeed Management 93
  • 102. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.harvesting something, you can just pull the weed as lot of moisture, a lot of nice stuff that they can chewyou go along as long as it hasn’t gone to seed you can on, a nice habitat. It took a year or two after we reallyjust kind of drop it. But for the most part 90% weed started with that, to start to get some control of thereduction is it. Basically with our weed population, I slugs. One was we used some ducks because if you putthink you heard me say we don’t allow weeds to go to out grain and put out slugs, a dish of each, they willseed. If I grow carrots, lets say, and I seed them and a go for the slugs first. They love them. The other thingweek later I start to see them coming up through. Two that happens is that there is a little black beetle. He isweeks later you might see in a row 150 feet long or a about 1/4 to 1/2 of an inch and you see him scurryingbed of four 150 feet long you might be able to count around your farm. That is a lot of their main diet. To eat10 weeds in that area. What you mainly see, and I’ll slug eggs. So all of a sudden with one predator, and itsay any other type of weed but you will mainly see wasn’t like we were trying to go out and kill these slugsfor use is purslane because that is what is left is weeds because there is nothing you can do about them if theylike that, those three weeds galinsoga, purslane and are there, is that these black beetles became abundant.chickweed. If you don’t have them, be diligent that if They just went along and brought the balance back in,you see one to get rid of it on your farm or just make but we suffered for a year or two of having quite a fewsure you are not buying it in. We started getting a slugs. Now nothing is really out of kilter at all withlittle galinsoga and chickweed because we brought what we are somebody’s compost and it was in the potting soilmix. Wherever we planted it that one year we’ve got With molds and stuff like that I don’t think it makes anylittle bits of it. We keep a bucket hanging around, so difference. When you are stepping and walking throughthat when we see those two weeds, it doesn’t matter it you are not seeing this puff of mold. I want to makewhat you are doing, you drop it, go get the bucket and sure that is said. Very little bit is mold. It is either inyou get rid of that one weed and put it in the bucket the breakdown period right close to the surface, or itand then we just take it off of the farm. So we are is dry on the very top.trying to control the two weeds. Of course trying tocontrol purslane is bad enough. It comes up and within Q:  How are you doing your direct seeded crops?a week or two or three weeks it can start to set seed.If it is big enough no matter how hot it is, if you go A:  Well we are not using any mulch, of course, be-along with your push hoe and cut it off it will live long cause that crop goes in and out. For us we are using anenough to produce seed and it does not need to go to Earth-Way precision seeder, the plastic one. We haveflower. That’s how we killed ourselves with the fact used the Planet Jr. and we have used the other type andthat, that one weed does not have to go to flower. It they both have their strengths and weaknesses. Whencan produce, within its bud, viable seed. Only when you are doing a lot of different things, a lot of crops thatit feels kind of comfortable and hanging out during day, and you are putting four types of carrots and threethe heat of the summer, will you see a yellow flower types of beets and stuff like that, you will find that theon it. But for the most part it will never flower and Planet Jr. can get pretty cumbersome. With changingit produces it. We thought in the fall one year when plates and changing shoes we found with the Earthwe had a bunch of it, Oh, we are OK because it is not Way, even though, it seems like such a crude piece ofgoing to go to seed; and then we realized way too late machinery it’s so much faster. You can cut your seedingthat it doesn’t need to flower. The adaptation of this time down from 3 to 4 hours with a Planet Jr. downweed is so tremendous. to 45 minutes with an Earth Way. So it really makes a difference. Just having to buy in some fertilizers,Q:  Do you have any problems with molds or insects when you are thinking about how you are going to getunder the mulch? your farm up and going and trying to keep your farm together, using just what you have on your farm forA:  No. The only thing it can do when you say insects. your own fertility. When you have hay available, andWhat we had the first few years, because we had quite you can use it then you know you are not importing aan imbalance on the farm of not having organic mat- lot of stuff that may hurt you eventually with weeds.ter and then all of a sudden having a lot of organic Some day somebody is going to say something aboutmatter free flowing around the place, is that you can compost, that it’s got something in it. Using your ownstart to have a problem with slugs. Because there is a mulch and hay can really keep you out of that one94 Organic Vegetable Production
  • 103. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.problem in your area. The longer you are in business stale seedbed and get things ahead.the more these little things pop up. We may try a little bit of flaming this year. It was inter-Q:  Have you ever tried using sawdust as a mulch? esting just talking about the mulch and using flaming. Because we were thinking about the few escapees thatA:  We only used the sawdust mulch once. That was get into asparagus and that is a big thing is the peren-going to be it because it just took too long for it to break nial type weeds. The fall annuals and perennials thatdown in a situation where you are changing crops rap- will get in there. It seems they have a long taprootidly. In the end it really made nice soil. In the interim, that can get down and below where other ones can’t.within a year period, you couldn’t grow anything in We were just kicking that around. Maybe it will be ait because it was just too much nitrogen uptake by it. fire hazard.You can get by using a little soybean meal as a nitro-gen source. That has 7% nitrogen. That works very Q:  Can you talk a little bit about your crop analy-nice if you need to put a little bit of nitrogen around sis. How you set what is making you money andthe Swiss chard after it has been there a long time to what’s not.add a little nitrogen. Or if you are turning under thismulch and you are going to plant. For us we would A:  For us, we keep just two kinds of records. We keepturn under mulch in the spring in the early years and records to know how much we are making on a perthen transplant lettuce right into it. It was a lot of gobs acre basis on each crop so that we can judge whetherof mulch that hadn’t broken down completely during or not we need to do something with that crop. Do wethe winter. By throwing down a little bit of soybean need to put it closer or not grow it or charge more ormeal on it makes it so that there isn’t that starvation something else. We need to know if it is making usof nitrogen for the lettuce plants while the mulch is money because if we are trying to make enough moneybreaking down the rest of the way. on six acres of land than as I have said you have to produce $10,000 to $20,000 an acre to really makeI found the list here of what we do, about 15 crops that any money with this. So we are doing our $10,000 anwe mulch. Rhubarb, asparagus, Swiss chard, garlic, acre rule which probably should be at least $15,000 atwinter squash, cukes, melons, eggplant, tomatoes, this point. The records we are keeping tell how muchBrussels sprouts, raspberries, blueberries, parsley, pep- space things are taking up. So if I’m putting in fourpers and strawberries. We also mulch our basil that we rows of carrots every week for so many weeks I willkeep all year long. It’s much cleaner. That’s the crops know how much square footage that is taking up. Wewe are working with when we mulch. will add up the square footage and because we are keeping records on our yield, every time when we areQ:  How deep are you tilling with your roto-tiller? getting ready for market things are getting weighed I can tell you how many pounds of carrots we produceA:  We are probably going down a good six inches with in a year. Then from there we know how much we sellit. We do it in the spring or sometime during the year the pound for and we can figure out about how muchwe try to get around with our neighbor’s big 4-wheel carrots are making us on a per acre basis. Or how muchdrive tractor. We put chisel plows on it and if we have they have made us on a square foot. Whatever way yougot ground that is open or in the early spring we will want to figure it out it is called extrapolation. So wehit it with chisels to make sure that we don’t end up are keeping that record. That takes two records, yieldwith plow pans. You know the kind that you get with records and how much space things are taking up. Thenrototillers or really with a lot of different tillage you we keep records on how long it is taking us to harvestcan end up with that. That’s about the depth. Very few something and how long did it take us to harvest 400times we will use it just to go along the surface. But pounds of carrots. We don’t do that every day or everyfor us, we don’t do any stale seed bedding because other day. It might take four crops or five crops thatmost of our weeds are very much under control and I season and do a good analysis of those over severalguess it’s an organizational factor. We always seem to weeks. When it’s good or when it’s worse dependingbe running behind so you are going out there and just on how things are coming out of the ground. So you gettilling the soil and planting right off the bat. There’s a a good average. We keep an average of that and that’sfew people out there that are more organized that can how we make decisions on whether or not we need toWeed Management 95
  • 104. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.invest in a certain piece of equipment that will make our meeting, you are going to hear a lot more aboutharvesting faster or better. That also gives us an idea NEON over the years, North East Organic Network.of how much these crops are worth and helps us all in We participated in that and it was interesting talkingpricing. Between how much it is costing us to harvest because we had a room full of sizes of growers. Someand how much it is worth to have that crop sit on that small, some big and what was interesting, we were allland are the only two things that we keep track of. We accomplished farmers, been in it for a long time andhave no idea how much it costs us to raise a carrot. the small growers that were down in my scale, tenThere doesn’t seem to be any reason to know. As you acres or less, were very intensive. A lot of them, coverknow when you are doing 35 crops that would be an crops, some of them didn’t use any. Some of us wereenormous record keeping. To know I push hoed down just in the winter rye mode because we were just usinga row of carrots and then went on to do the beets and every bit of land intensively all of the time. So we arethen went on … It’s just too much record keeping. always having these guilt feelings that we should beThat’s basically how we are making decisions on the using a lot more cover crops. We never seem to havefarm as to what our pricing is going to be and what time to put them in or the land that you can kind of putequipment we are going to buy and how to make things stuff on. What we came to realize is that the guys whomore efficient for our employees or what we are doing were bigger, cover cropping was everything for them.or how we are selling a crop. Whether we decide to They couldn’t afford to buy compost or work things asdrop a crop. So the last thing you want to do is drop intensively to make that soil rich. The were workingcrops because then you ruin your diversity. If lettuce more on the fact of half their land was in cover cropsdoes terrible next year it really won’t show up on the building organic matter to turn under for crops to comeradar screen. Something else will probably be doing because that was the way they had to deal with it. Soterrific. So keeping a lot of crops out there makes the they were using cover crops more judiciously. Lotsbig difference. of different kinds, different spots they were sticking them in. So it basically took off the guilt feelings of usDoing things that control your overhead is also impor- small farmers. The fact that none of us were doing it. Itant. Irrigation for us, we decided to go electric. Electric think its something not to get too worried about, coverpumps, and valves. So we can irrigate at the drop of a cropping when you are really small because you arehat. It takes ten minutes to irrigate. I just go in, throw using that land really intensively. I am getting into thissome valves and throw on a switch and I’m irrigating. mulching and adding organic matter. That’s what youIrrigating for me cost $0.48 an hour. So I can irrigate are really trying to do—you are trying to protect theall night for ten hours for $4.80. That’s a lot less for soil from erosion, trying to keep your nutrients theremost people than what it costs to run a tractor for an and trying to improve your soil while you are usinghour. So I have a tendency to irrigate more and when it. I think mulching kind of covers that area for me.the crops really need it because it is easy to irrigate I don’t have to feel quite so guilty about not havingand also it doesn’t cost me much. So if I want to do all of this nice perfect cover cropping that everyonesome frost irrigation on some raspberries, I only have really focuses sell two half-pints of raspberries to pay for the wholenight’s irrigation in October. That’s the record keeping Q:  Do you think mulching would work on a largerthat we keep. So we know whether or not what we are scale?doing is worth while. A:  I think for a lot of crops anything is possible atQ:  Are you doing any cover cropping? whatever scale you want to have it at. It just depends on if you have a lot of soil that doesn’t have a lot ofA:  What we are doing now for cover cropping is organic matter and it is performing poorly you finddoing winter rye. We are re-seeding a lot of these ways to try and build that soil up and if you reallycrops; you saw how much stuff we have at the end of build it with cover crops you are going to be in it forthe season. So crops are growing all the way to the long term. If you are looking to get it into productionend. And with that, winter rye is something that we next year then trying to find some straw mulch that’sget on and that’s about the only cover crop that we good and trying to add organic matter, it’s going towork a lot with. For the most part we do very little of make you money. For us all of a sudden jumpinganything else. What was very interesting last year in $10,000 from one year to the next was quite a jump.96 Organic Vegetable Production
  • 105. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.On a larger scale you are just looking at that much you will not have a problem with that. You are alsomore. There is the cost there but that mulch is there looking at the other benefits of mulching. The fact thatand the benefits are there for a few years. It isn’t like it is basically sheet composting because you are build-the cost is all gone after one year. I think it can really ing your worm population. You are basically feedingmake a difference. your worms. By putting down all this mulch you are feeding your worms. Obviously that’s going to makeQ:  Is it ever a problem for the mulch to get moldy? more biological activity and you are going to end up with a better soil.A:  It’s okay if it does get a little moldy. If you’re put-ting grass mulch over the top of strawberries, some It’s also the weed management. If I’m planting apeople will think, “Well, I’ve got grass mulch I’ll throw long term crop that’s going to be there. Like toma-it on top of strawberries for the winter.” It’s going to toes and cucumbers and zucchini and stuff. I’m notmat down, turn slimy and get moldy, that’s the worse going to have to weed that the rest of the season. Wefor it. But just covering the ground, getting a little are putting it down between six and seven inchesmoldy is okay. It’s not really something that is going sometimes more than that. Because as your soil getsto hurt your crop at all. more biologically active, we find that lots of times we can’t even make it to the end of the season evenQ:  Are you talking about lawn clippings? at six or seven inches thick. Because there are more worms, more bacteria it’s breaking down at a fasterA:  I’m talking about hay fields. This is something else rate. Also it depends on what mulch you’re using. Ifyou need to learn. If you are going to go out and do that. you are using alfalfa or clovers, it looks great but itWhen does it have seed and when does it not? What can burn up fast. There is not a lot of substance towe are doing is that we are cutting hay out in the fields it like a thick stemmed grass would be. Like we useright up to the point of the fact that it is going to pollen. canary grass. That will stay around longer. Straw willDifferent varieties go to pollen at different times. Like stay around longer. You will have less problems atthis past year we had this farm nearby, we seeded it to the end of the season with spots coming through andreed canary grass which gets a lot more bulk matter having some weeds.out there and goes to seed much later. I got a biggerwindow of opportunity of getting it. You are looking You are obviously controlling the water that is there.for, obviously, the most mass out there. You are look- Some of the downsides are, if it’s really wet it willing for hay fields that when you are going across them stay really wet in the spring. Sometimes it doesn’tyou are getting what you want out of it. Not, like you help with trying to get it broken down or trying to getsay with grass clippings where it’s going to take you a it turned under at times. It stays sometimes too wetlong time. Because we’re talking, I’d probably do more for the a third of an acre or a half an acre of mulching.If you are putting all of the pieces together and added ——————————it up. With that movement around on the six acres, itis every few years that we are really getting a lot of All right, As I have said we sell at the farmers’ market.mulch down on an area. We are using it in other ways You can see all the different array of things that wetoo, just getting it down. What I’ve noticed for years, are doing a lot of different crops, a lot of different op-is after dealing with the grass mulch is that the soil is portunities to put mulch down. This is the last day inactually a lot more alive and a lot more activity than November. This is all the different crops that we havewhen you are just putting down compost. Compost is that we are selling in the week before Thanksgiving.something that’s already finished. The mulch needs We are zone four. We are not exactly the warmest spotto break down. That causes a lot of biological activity but we have learned season extension on top of this.within the soil. It makes your soil much more alive This is one of our best days because this is the Saturdayat that point. This is kind of anecdotal, I realize, but before Thanksgiving. That is the biggest sale day ofit seemed like the plants grew much better that way the year, the last day for us. Pretty opposed to just putting down compost. Any mulchyou are going to hold or add will also not bring down So there’s compost. I’m getting it down. We boughtas much phosphorus or potassium as the compost and the manure spreader. This one place, H & D, that weWeed Management 97
  • 106. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use this from. They actually make spreaders that have wouldn’t produce on the soil with the organic matterdifferent types of beaters on the back. One is made for that was there. In the fall we would just go along andcompost, spreading it more evenly. So that is why we just cover the whole ground. No cover cropping just putwent with this style. We had to get a new one because down on the ground. This was just adding tremendousif you bought old ones they are usually just death amounts of organic matter and in the spring we wouldworn out by the time somebody traded it in. Cultiva- turn it under.tors. Wheel hoe. There I am push hoeing. This is thetechnique of going up and down these rows at a real There we are going down. We are actually putting itclose spacing. This is where we went to some use of in between a field house we are going to put up. Thisthe tractor, using the basket weeders that they were was quite a few years ago but now we’ve got a self-showing. I can go up and down this and this will take unloading wagon. I’m covering for winter squash,me probably 25 minutes or more to go up and down that is what I’m doing. I’m making an area for winterthese rows and if I did it with the tractor it would take squash to go down so I don’t have to weed it and it justsomewhere in the neighborhood of about four minutes makes for clean fruit and everything else that comesto go up and down twice. Like we showed, going up along with it. I’m just kind of going along, blobbingone side and then going to the other. it out, very quick and then somebody is going along and just spreading them the last little bit. This is whereThis tractor is what we use for a lot of cultivation. It’s we are putting in some late tomatoes here in this the mid-mount and we’ve got these regular culti- Putting it right next to Swiss chard and parsley. Thisvators on the front, on the mid. After these potatoes was put in real early. This was put in the beginning ofgo in. This is a potato planter. On the back I’ll carry May. There is obviously no hay out there to get.a Leily tine weeder. That will be the first thing I goover it with after the potatoes are planted is the Leily This is where we use some straw. There are times whentine weeder. I’ll go over that at least twice. On the I cannot get out there and get hay, like in the middle ofsecond time I might be cultivating at the same time summer if I need it. Or in the very early spring thereI’m using the Leily tine weeder. That works. Then isn’t anything out there to chop. This is where we keepfor finishing, I’m just using the cultivators. So I can straw in the barn in bales that we have bought and weput hillers on the front of these. We can do a lot of will put it down and then plant through it. You don’tcultivation that way. want to go ahead and plant this and then try to put the straw. It just doesn’t work. You’ve got to put the strawThis is our equipment that is used for getting straw down first and then plant right through it. This worksor hay off the fields. This is called a flail chopper. It very well. Now I don’t have to weed this the rest ofwas used by the dairy industry for a number of years the year. It’s much easier on the plants. It’s cooler.and then, like anything else, they kind of moved on. All plants like to be warm on top with cool roots. TheSo these things are a dime a dozen. I think we paid next year I’m going to have better ground than when$400 for it. I don’t know how many years ago, twelve, I started. This is what the whole farm plan is. The factthirteen, fourteen years ago and I’ve probably only put of just trying to improve the ground along with doing$100 into it. It’s basically, for every foot width this is some intensive planting along the takes nine horsepower. So ours is six-foot so it takesfifty-four horsepower. This thing puts out fifty-three This is buying straw from somebody. Bringing it when this is trying to take on too much it’s slowing One thing we did try one year just to see if it wouldthe tractor down and I know I’m not going to hurt this work is a bedding chopper that you can get from athing by putting an 80 horse power tractor on it and dairy farm. They do it in the barn and it is for choppingjust kind of ram-rodding through. This is a real good their bedding. You throw a bale right down in therestand of rye that we are putting in and that will really and it spreads it out. It nicely chops it down, becausefill the wagon quickly. sometimes working with long pieces of straw is a little difficult. We just had somebody driving alongThis is how we did it in the early years, with just a with the tractor and bales of straw sitting on top andwagon like that. This is how we built organic matter up went ahead with somebody just throwing it out. Byreally quickly in the first few years. So we could grow the time we got it all done it looked pretty good andspinach or lettuce because we couldn’t grow it even. It we were able to plant through it. We’ve never tried98 Organic Vegetable Production
  • 107. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.that again. This was a borrowed piece of equipment we go in and put straw on it, mulch it. In 14 years thatjust to see if it worked. I think these things are quite we have had it we have never weeded it once or donea few thousand dollars. So we haven’t gotten into the anything other than put straw on it, put row cover on it.practice of doing it all the time. But it just gives you We put row cover on it the first of April. Whenever theideas if you had that thought, gee this is one way to snow is gone, take it off first of May when we want itget the bales out there and chopped up nice. It did put to start selling. This was just taken off you can see theit out nice and even. dandelions are just flowering. So this is around the first of May and this is what it looks like. As you know I’m —————————— from zone four. So it’s pretty rich ground there with having straw for all those years and with the row coversQ:  Did the chopped straw control weeds better you can have full size rhubarb right off the bat. Andthan the regular straw? again we just go in, we are harvesting it and when we are done harvesting it at the end of May it’s done. WeA:  Didn’t make any difference. They both control walk away. There is no weeding to be done. There’sweeds it was just the fact that planting through it was nothing. So it makes it kind of nice with rhubarb. Whena lot easier. you say, “well when you mulch is it really worth it to do it?” You are sometimes picking crops that you canQ:  Why wouldn’t you use the chopped straw all make a lot of money on. This little rhubarb patch isthe time? on 0.0186 of an acre. When you bring it right down to what it is. We sold about 774 lbs., this is back inA:  It would be the cost of the machine and the time. 1999, with a total value of, I’m trying to think if weI can’t say I figured out how long it would have taken sold it for $1.50 a pound or whatever. If somebodyme to put it down by hand. You know just break the has got a quick calculator. $1,161.00 came out of thisbales out and spread it as opposed to doing this. I re- little patch. If you work that out to what it is worth onally didn’t make a cost comparison with that. I knew an acre basis, because this is where a lot of our cropsthe machine was more than we really wanted to spend if they are worth doing, a lot of this mulch bed is ex-for that little bit that we do with it. trapolating out, that if we had an acre’s worth than this is how much it is worth. This is what we base all of ourQ:  What kind of transplanter did you use to plant crops on is the fact that we know the yield because wethrough that. are keeping records and we are also keeping track of how much we are planting all the time so that we canA:  We do all of our plantings by hand. We don’t add up at the end of the year about how much squarehave any transplanter. Whether it’s on bare ground or footage everything took. Then we know the yield andthrough that. We are just lining stuff out and putting we know how much we sold it for. So you can kind ofit through. We don’t own a transplanter. I’m basically extrapolate out using that system. Some people do itthe person who transplants. on square footage. We just happen to do it on acreage basis because in the world of dairy farms and every- —————————— body else, they are doing it on a per acre basis. But this little thing is worth $62,000 an acre. This little rhubarbThis is a little section. We are on a steep slope and patch. If we are doing not too much work with it andwe basically wanted anything that was already on we can spread that a few bales of straw on it. Ten orthis steeper slope to be mulched or in grass. So that is 15 bales of straw on it really thickly is well worth thewhy you see that the orchard is here. We started out, money spent on it. That’s where a lot of our crops arefrom somebody’s garden they gave us rhubarb. So we well over the $10,000 or $20,000 an acre and with thatstarted splitting it and splitting it and splitting it and you can start to make a living at this. But this is howafter a few years we ended up with 72 rhubarb plants we keep the overhead down and be able to bring someon a three by three grid here. So every spring or late fall money home. After finding this out it is well worth putting down a few bales of straw on it.Weed Management 99
  • 108. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Bio-Extensive Approach to Market Gardening Anne and Eric Nordell Beech Grove Farm Beech Grove, PennsylvaniaPart One: rewards for taking time to develop this system were twofold: we could now afford to grow staple, storageA Strategy for Weed‑Free Onions items, such as onions, carrots and potatoes; and we could devote more time during the busiest months in Reprinted from Organic Farms, Folks and the market garden to high value perishables and spe- Foods, the quarterly newsletter of the Northeast cialty items for restaurant sales and farmers market. Organic Farming Association of New York, Inc., an organization dedicated to the creation of a We begin weed control for onions a full year in ad- sustainable regional food system which is eco- vance of planting. This “fallow year” usually includes logically sound and economically viable. For two winter cover crops sandwiching a bare fallow permission to reproduce more copies contact midsummer. We have tailored this cover crop/fallow NOFA-NY at (518) 534-5495. Please include sequence to take advantage of the growing‑conditions this message in any reprints. on our farm and the life cycle of the weeds we needed to control.Onions can be a real challenge in terms of weed con-trol because of their slow growth and sparse canopy. The cover crop/fallow sequence leads off with rye es-Given that our original goals for the farm included tablished after the previous cash crop in the rotation. Ifremaining debt free, keeping the market garden a circumstances prevent us from plant­ng rye in the fall, itwo‑person‑opera­ ion, and relying on the internal t then we plant oats the following spring. We manageresources of the farm as much as pos­ ible, we needed s these small grain covers by clipping them repeatedlya way‑to reduce weed pressure in onions that relied before they shoot to head. Mowing them at this timemore on management than off‑farm inputs and that encourages them to tiller and regrow, creating thecarefully distributed our labor over the course of the mulch effect you see in figure 1. This shot capturesgrowing season. We also decided to lean heavily on the the second clipping of rye at the end of May 1992.most available resource close at hand, namely the land. Cut‑and­come‑again cover crop management prevents spring weeds, such as the mustard family, from set-It took us five years to develop the following system, ting seed and makes incorporation of the cover cropwhich has kept in-the‑row hand weeding of onions well easier a than letting the rye grow to its full height ofbelow 15 hours an acre, regardless of the weather. The four to‑ five feet.100 Organic Vegetable Production
  • 109. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.We plow the first cover crop down after it has put on fields. The composting process kills most weed seedsthe bulk of its biomass but before summer weeds have in the manure and bedding, and the resulting stable soilhad a chance to set seed. For rye, in our climate, that amendment does not seem to stimulate weed growth inmeans after the third clipping at the end of June; for the fields like fresh manures or fast‑acting fertilizers.oats, after the second clipping in mid‑July. Incorporat- Applying the compost during the fallow year gives iting these carbonaceous residues during the biologically more time to break down before early planted cashactive summer months gives them plenty of time to crops, saves a step in spring, and enhances the root andbreak down without robbing nitrogen from the next top growth of the second soil improving cover crop inspring’s crop of onions. This may‑seem farfetched, this fallow sequence leading up to onions.but we think the soil has less “need” to grow weedswhen we use these high carbon cover crops and their The bare fallow ends the first or second week of Au-aggressive root systems to repair the damage done to gust when we seed down the field to the second coversoil struc­ure by the preceding cultivated crop. t crop. This planting date takes advantage of the fact that most annual weeds which germinate now are likely toMore to the point, plowing deeply at this time of year frost kill before setting seed here in the mountains oftargets perennial weeds at the weakest point in their north‑central Pennsylvania. Our preference of a coverlife cycle. Likewise, harrowing the ground every two crop before onions is Canadian field peas because theyto three weeks during the following bare fallow period fix nitrogen, put on a lot of top growth in fall and tendbrings the roots and rhizomes of perennial weeds to die back over winter.the surface to dry in the sun while preventing annualweeds from getting established at a time of year when The big advantage of winterkilled cover crops is thatthey are likely to grow quickly and run to seed. As a they are so easy to incorporate first thing in spring,result of religiously fallow­ ng our fields every other i making timely planting of onions more dependable.year this way, quackgrass no longer exists in the Thanks to winterkilled field peas, we got the 1993 cropmar­ et garden and broadleaf weeds like pigweed and k in the ground in plenty of time despite receiving twolamb’s-quarter are rare visitors. In fact, in recent years inches of rain every week that spring.we have been able to reduce the bare fallow periodto as little as two to three weeks without sacrificing In terms of weed control, an easily incorporated coverweed control. crop allows us to restrict tillage to just the top two to three inches of the soil. For example, in figure 2, takenHowever, the transition from very manageable to mini- the last week of April 1993, you can see that discing themal weed pressure was only realized when we began winterkilled field peas lightly is not as likely to bringcomposting the horse manure we use to fertilize theFigure 1 Figure 2Clipping small grain covers repeatedly makes Discing winter-killed field peas lightly in spring brings upincorporation easier fewer weed seedsWeed Management 101
  • 110. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use weed seeds to the surface as plowing or rotovat-ing deeply. Keeping the residues near the surface alsohelps with erosion and moisture control.Figure 3 shows the 1993 onion crop the middle ofJune. We had yet to do any in‑the‑row hand weedingat this time even though the extremely wet conditionsextended through May. We usually do plan on cultivat-ing onions three or four times. But because we havebeen able to reduce weed pressure during the previousfallow year, we target cultivation more for moisturecontrol than weed control. That means getting into thefields as soon as possible after a heavy rain to break Figure 3the crust and create a mulch of loose soil around the Cultivating three or four times is done mainly forplants to slow evaporation. moisture controlFigure 4 shows the onion crop three hot, rainless weekslater. We spent a total of six hours hand weeding thishalf‑acre field by the time harvest was complete themiddle of August. By hand weeding, we mean simplywalking the field and pulling those few weeds thatthreaten to go to seed‑not a rescue effort to save thecrop. Nor is this an attempt to completely clean thefield of weeds. Those weeds that manifest themselveslater in July or August, such as blown‑in dandelions,volunteer clover and a few smartweed, we plan onplowing out after harvest when preparing the field forseeding the winter cover crop and starting the fallowcycle over again.Keep in mind that a single fallow year is not likely to Figure 4work miracles. And that the types and timing of cover A half-acre field of onions with only six hours of handcrops to get this kind of control will depend on your weedingclimate, soil and weeds. For example, we can wellimagine that the bare fallow period between two wintercover crops might be excessively long in a warmerclimate than ours, causing unnecessary damage to maturely before the chickweed had a chance to reseed.soil structure. By the same token, the life cycle and We planted a cover of quick‑growing buckwheat thegrowth habits of winter weeds might require a very first of June to avoid an extended bare fallow period,different cover crop/fallow sequence than the one we and followed the buckwheat with the usual fall coverhave described for controlling weeks like quackgrass, of winter killed field peas. Both years, this outwittedlandcrest, pigweed and lamb’s-quarter. the chickweed.We learned this firsthand the past two years when To be truthful, some of our time is tied up managingwe saw chickweed creeping into the field slated for the cover crops and that needs to be figured into theonion production. Based on past experience with labor equation. As we see it, the total hours devotedisolated patches of this intruder, we were afraid our to cover crop management are a small fraction of theusual sequence might proliferate rather than control time spend hand‑hoeing an otherwise weedy crop ofchickweeds since it sets seed well ahead of the normal onions. Besides, we find the fieldwork involved is abare fallow period and is too low growing to control by welcome balance to all the stoop labor that goes withmowing. So we plowed down the first cover crop pre- market gardening. Of more practical importance, this102 Organic Vegetable Production
  • 111. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.integrated approach to weed management allows us to structure for the next year’s heavy feeding cashspread the weed control effort over the course of the crops of…growing season to suit our schedule rather than lettingthe weeds set the pace. 2. LATE planted mixed vegetables, such as squash, celery, tomatoes, and corn.While many growers may feel they cannot afford toidle productive land for weed control alone, bear in 3. To the right, winter hardy rye, seeded after themind that the cover crops in the fallow fields serve previous year’s LATE planted cash crop, has beenmany purposes. We count on cover crops to help re- plowed down to begin the bare fallow period. Westore fertility, structure and moisture holding capacity count on the summer fallow, in conjunction withafter cultivated cash crops. And we depend on them the cover crops, to create weed-free conditions forto minimize erosion, interrupt the cycles of insects the next year’s crop of….and disease and attract beneficials. The beauty of thefallow years is that it gives us the opportunity to use 4. EARLY planted onions to the far right. To startthe cover crops to their fullest potential, in this way the rotation over again, we seed the clover rightincreasing biodiversity on the farm. into-or immediately after-these early cash crops so the clover is well established before winter.Part Two: By the time we plow down the sweet clover the next July, almost a full year later, the tap roots have tilledA Whole Farm Overview and fiberized the soil much deeper than plow depth or the root zone of most market garden crops. If we can Reprinted from OEFFA News, which is pub- use the cover crops to improve soil structure, then the lished bimonthly as part of the educational weeds, which often come in to perform this important mission of the Ohio Ecological Food and Farm role, have less reason to grow. Association, a nonprofit organization for farm- ers, gardeners, and citizens interested in eco- The four-year rotation then repeats itself three times logical agriculture and creating a sustainable over the twelve-field market garden. We simply sub- alternative food system.“A Strategy for Weed-Free Onions” (part one) de-scribes the cover crop sequence of rye/bare fallow/ Sweet clover EARLY onionswinter-killed peas we use in the fallow year before Summer fallowEARLY planted cash crops like onions, spring spin-ach, lettuce and snap peas. In the fallow year beforeLATE planted cash crops like tomatoes, squash, maincrop potatoes, or fall greens, we employ a cover cropsequence of clover/bare fallow/rye and vetch. Alter-nating the cash crops between those planted EARLYand LATE sets in motion these two distinct cover cropsequences which help to keep weeds off balance andadds more diversity to the overall farm system.The four-field photo (figure 5) shows how the covercrop sequences and cash crop rotation work together.For instance, in this shot taken around the fourth ofJuly in 1991 you see:1. A cover crop of yellow sweet clover in the fallow LATE-planted mixed vegetables field to the left, fixing nitrogen and building soil Figure 5 Four-field crop rotationWeed Management 103
  • 112. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.stitute different cash crops into the EARLY and LATE mind, deer control, marketing, and animal-poweredslots as shown in figure 6 (lower half). Even the depth composting. Tapes are available for $10 (which in-of tillage can be rotated to the benefit of the crops and cludes postage) from Anne and Eric Nordell, RD 1,discouragement of the weeds. Box 205, Trout Run, PA 17771.Of course, the details of the rotation have changed overthe years as we adapt to the changes in the climate,marketplace and insect pressure. The principle wekeep in mind as we fine tune the system is simply torotate the types and timing of cover crops in the fallowfields to create the best conditions and control for thecash crop to follow. In this way we have been able tomaintain our original objective of substituting land foroff-farm inputs and pain labor. Rotating the half-acre strips between cash crops and fallow lands is the key to our two-prong weed-controlThis land-extensive, or bio-extensive, approach to strategymarket gardening is much easier to visualize in the Following half of the market garden each year allows usslide presentation we had videotaped at the 1996 Penn- to utilize the bare fallow period midsummer to reducesylvania Association for Sustainable Agriculture Con- the weed seed bank in the soil and to realize the full soilference. The 52-minute video also includes segments structuring potential of the cover crops so that weeds haveon designing the market garden with work horses in less need to fill this important role. Four-year rotation shown in figure 5 (page 99) SPRING rye and rye lettuce clover rye & rye onions clover rye & oats herbs clover vetch peas vetch vetch berries & herbs spinach flowers potatoes celery clover kale clover fall oats & rye & squash oats & rye & coles clover & rye & peas vetch peas vetch spinach oats & mulch vetch FALL rye rye lettuce peas CROPS cash fallow cash fallow cash fallow cash fallow cash fallow cash fallow crop crop crop crop crop crop BY TYPE root leaf leaf & root leaf leaf & fruit flowerBY PLANT/HARVEST late early late early late early TILLAGE shallow shallow shallow shallow shallow shallow deep deep deep deep deep deepCOMPOST 1. light application (5 tons/acre) in fallow year before root and early crops 2. light applications sheet composted with rye and vetch cover crop 6 weeks before late, heavy feeding crops 3. light application topdressed on leguminous cover cropsFigure 6Rotation of cash crops, cover crops, tillage, and compost applications to enhance weed control, moisturepreservation, and soil tilth.104 Organic Vegetable Production
  • 113. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. A Few Long Furrows on Horsedrawn Tillage Eric Nordell Beech Grove Farm Beech Grove, Pennsylvania Photos by Anne Nordell Beech Grove Farm Beech Grove, Pennsylvania Illustration by Edward H. Ochsner IISkim plow Skim plow rye and vetch before late cropsA well sodded cover crop is necessary to provide suction Raw organic matter breaks down quickly near the soilfor such shallow plowing and to maintain soil structure and surface into homegrown starter fertilizer for the heavycapillary action throughout the growing season. feeding cash crops to follow. First printed in Small Farmer’s Journal, Vol. Our third year here the spring winds blew hot and dry, 17 No. 2 sucking moisture out of the loose topsoil to plow depth. Seeding carrots into six inches of dust was a disaster.When we settled in northern Pennsylvania 10 years Even under less severe conditions we noticed the siltyago, we tilled in the conventional manner of the area, soil on our exposed hilltop site dried to the depth it hadplowing deep with the moldboard plow, repeatedly har- been tilled in as little as a week or two without rain,rowing with the spring tooth or disc, then rolling with then crusted after the first downpour.the cultipacker. The result was a deep, loose seedbedof finely pulverized soil. Under ideal conditions, crops Enough humidity remained in the topsoil to germinateseemed to thrive, but under less than ideal conditions large seeded field crops, like corn or oats, which couldthis seedbed had a lot to be desired. quickly put their roots down to moist ground beneath,Weed Management 105
  • 114. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.but small seeded root crops and succulent transplants sure that we took notice! They claimed the cornstalksreally suffered. Without irrigation, we needed to find broke down faster when worked into the soil surface,some way to hold precious moisture near the soil reducing erosion and improving tilth. Well, we just hadsurface where shallow rooted market crops did most to put this idea to the test in the market garden. Withof their growing. some good humored help from friends near and far, we had some fun rigging up miniaturized versions ofMore typically, these mountain soils stayed wet and offset discs, chisel plows and field cultivators suitablecool. Deep plowed cover crops and manures decom- for a lightweight team.posed slowly, if at all. After a damp, cold spring, itwas not unusual to dig up raw manure or pieces of The machines may not have looked like much, butstill-green rye as late as the end of June. We kind of the results in the fields were impressive. Cover cropssuspected these pickled animal and green manures and manures decayed quickly when tilled into the soilmay have contributed to incidences of uneven and surface close to the warmth of the sun and the air above.unbalanced plant growth those first years. Discovering This sort of sheet composting led to more uniform andmushrooms sprouted above buried chunks of horse disease resistant crop growth. And the farm was nowmanure reinforced in our minds the idea that what mushroom‑free.happens below ground often expresses itself aboveground as well. Since surface tillage did not disrupt the soil life like deep plowing, weed growth became more predictable.Weed growth seemed to follow the same pattern. Instead of a delayed reaction, annuals germinatedWe found the clean look of deep plowed fields to be readily after surface tilling, making preplant culti-deceiving. Many perennial weeds just seemed to be vation a very effective technique. As for shallowlytransplanted by the plow – granted, upside down ‑ only undercut perennials, they simply dried and died into raise their ugly heads a few weeks later. More to the sun.the point, we noticed a sort of delayed reaction withannual weeds. It almost appeared as if their seeds Additionally, the ground rarely dried deeper than thewould not germinate until the soil life in the inverted shallowly disturbed soil. In fact, the firm earth belowsod had a chance to regroup and eat their fill of raw maintained capillary action much better than plowedand rotting organic matter. Inconveniently, that meant ground, drawing subsoil moisture to the surface whereweeds came on at the same time the crop did. Pre‑plant an inch or two mulch of loose topsoil slowed evapora-cultivation for weed control was recreational at best. tion. Where it might take two or more inches of rainAs if this delayed reaction was not perplexing enough, to thoroughly re‑wet deep plowed ground often onlyplowing brought up a whole new batch of weed seeds a few tenths of an inch moistened surface tilled soilfrom down deep, so we never really knew what sort adequately for seeding or transplanting market crops.of weeds to expect. Cover crop residues decaying on the surface not only helped to hold moisture, but fiberized our silty soilA final concern was conventional tillage did not seem so it did not wash or crust as badly after heavy a good match for our lightweight team. We mayhave set some speed-plowing records those first years Last but not least, the mares approved of this newwith the Standardbreds, but soft and sassy after a long technique. Spring tillage was now much easier forwinter’s rest it almost seemed like deep plowing was these soft and spirited horses. Follow‑up passes withmore than their minds, if not bodies, could bear. One the harrow on relatively firm ground were much kindersolution was to work our way up to a somewhat heavier on man and beast than walking in deep plowed ground.and steadier team of crossbreds. That change only Indeed, surface tillage seemed like a much better wayavoided what we thought the Standardbred mares were to condition the horses, both psychologically andtrying to tell us: Does it really make sense to greet the physically, for the rest of the growing season.soil first thing in the spring with the most disruptiveand toughest tillage of the year? Pleased with our new tools, we intended to use them all the time. We just barely scratched the surface ofWhen we saw our neighbors park their two bottom the farm before planting cash crops, before seedingplow and hitch nine head to an offset disc you can be down cover crops, and before the summer fallow.106 Organic Vegetable Production
  • 115. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.In short, we surface tilled whenever and wherever before winter.we could. Secondly, we had learned that vigorous, winter‑hardyIn a few years time, some disadvantages to this single- covers, such as a mix of rye and hairy vetch, requiredminded approach began to become clear. To kill and significantly more time to kill and decompose in theincorporate well-established cover crops, like clover spring than winter‑killed cover crops. It just madesod or August seeded rye, required repeated trips with sense to use rye and vetch before later planted cashour lightweight two-horse equip­ ent. Sometimes it m crops like tomatoes, celery and fall coles. Rye turnedseemed that in an effort to improve the soil through out to be the only cover crop tough enough to establishsurface tillage, instead, we were wearing it out. In a wet after these late harvested cash crops.spring, successfully knocking back these covers wasnearly impossible, at least to do so in a timely fashion The trick to making this second crop sequence workbefore early planted cash crops. Likewise, weeds and was finding an appropriate and efficient way to in-cover crops during the fallow required many passes corporate a live cover crop in the spring. We did notwith the harrow, disc and field cultivator at a time of want to return to deep plowing given the problems ityear when we were busy enough with the demands caused with our soil and crops, but trying to work upof cultivating, picking, packing and marketing veg­ a well-sodded cover crop of rye and vetch with ouretables and herbs. And all of that nice mulchy material lightweight two horse chisel was a joke. So we triedon the surface protecting the soil during heavy rains a compromise approach and plowed as shallowly asoften splashed into the cash crops themselves, making we could set the old Leroy walking plow to run. Withwashing lettuce and spinach quite a chore. a little experience, we discovered we could turn a furrow just two to three inches deep. We called thisConcentrating nutrients and organic matter near the “skim plowing” as the plow just peeled the sod rightsurface with these new tools may not have been such over, leaving the cover crop residues near the surfacea bad idea in wet years, but crops seemed to suffer and the coarsest portion of the root mass intact below.doubly in drought conditions as their roots workedtheir way downward, leaving the dry nutrient zone in We were really pleased with the results. First of all,search for water. At the same time, that nutrient rich undercutting the cover crop so close to the surface wasmulch at the surface encouraged weeds to germinate sure and sudden death for rye, vetch and volunteerand take hold. Perhaps most surprising of all, after weeds. Secondly, the horses walked along withoutthree years of surface tilling some fields became both a hint of hesitation or even breaking a sweat. Mostexcessively well drained and firm. importantly, skim plowed cover crops and manures decomposed quickly at this warm, aerobic and well-We were not willing to give up on surface tillage alto- protected depth into homegrown starter fertilizergether, but these observations certainly made us think placed at just the right level for the heavy feeding cashyou can do too much of a good thing. That thought crops to follow. Lastly, a pass or two with the springthen led us to the idea that the benefits of rotating crops tooth harrow brought up a good deal of skim plowedmight apply to tillage as well. Why not rotate tillage top growth and coarse root mass to the surface to helptechniques according to the needs of the crops, soil, hold and fiberize the soil.and seasons of the year? Wow, were we both surprised and encouraged to readPractical considerations more or less showed us the this past year of two others advocating skim plow-way. First off, surface tillage in the spring had proved ing under certain circumstances. We were just naiveto be fool proof and effective after winter killed cover enough to think we were the only ones to stumble oncrops such as oats and Canadian field peas. Planted late this technique and crazy enough to actually pursue it.summer, these spring annuals died back at the onset of In the Fall 1992 Small Farmer’s Journal, British horsewinter making incorporation and seedbed preparation farmer Jeff Peterson writes:a snap with just a disc and a harrow before the earliestplanted market crops, like spinach, onions and peas. As “…What I really like about the moldboard,most of these cash crops were also harvested early in pulled by horses, is one can bring it down to athe season, a cover crop of clover could be established fine art and make it a very tidy job, after enoughWeed Management 107
  • 116. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. practice. It is possible to plow very shallow, 3” 1. Surface tilled oats and peas  →  early cash (7.5 cm) or maybe even less. When I plough I crops  →  clover like the organic matter as near to the surface as possible and tidily turned over…” 2. Skim plowed rye and vetch  →  late cash crops  →  ryeAnd from Michael Jost’s Field Advisory File in theSummer 1992 Biodynamics come these comments It did not take us long to realize that we could pieceon improving the sandy soils on Greg and Marley these two crop sequences together by way of the sum-Niewendorp’s Belgian‑powered farm: mer fallow into the full blown crop rotation illustrated in the chart (see figure 6, page 100). We were amazed to “…A remark about tilling the soil and good see how a simple notion like rotating tillage techniques stewardship: There is an advantage of shallow had brought so much more diversity and complexity turning (e.g. 2”) of thin layers of soil. Better in to the whole farm. two steps than in one. Timing: 2‑3 weeks apart, then sow. Plow should not move layers that are One question remained. How to incorporate full term not enlivened. The old fashioned horse plow has cover crops before the summer fallow? Chiselling, the advantage that it can indeed be adjusted in discing and field cultivating had proved too time- such a way that it removes only very thin slices consuming with tools suited for a team. Skim plowing of soil…” could be difficult if the ground turned hard and dry. And such shallow tillage did not solve the problem ofWhether or not skim plowing holds up to the test of how to deepen the topsoil to create a larger zone oftime, we think it is exciting and important that farm- moisture and fertility for shallow rooted market cropsers are putting old tools to new purposes, adapting to draw on in times of drought. It finally dawned on uslow horsepower implements to the needs of the land, that this might be the appropriate place to plow deeply.and proving that new and expensive equipment is notnecessary for conscientious soil management. We can usually count on these mountain soils to warm up and dry out by the summer solstice. Deep plowingHere are a few things we learned the hard way about at this time would not be as likely to pickle organicskim plowing: It is essential to work with a well-sodded matter, cause compaction or fail to kill perennial weedscover crop for at least two reasons. First off, without as turning wet, cold soil in the spring. Also, there woulddeep tillage we are relying on the undisturbed and ex- be plenty of time during the summer fallow to set backtensive root system beneath the skim plowed layer to a new crop of plowed up annual weeds.maintain soil structure and capillary action throughoutthe growing season. In fact, the results seemed much If we were going to plow deeply, we decided we shouldbetter than after deep plowing. Secondly, a strong sod is plow as conscientiously as we could. So we plowedabsolutely necessary to create suction for such shallow the way Raymond Smoker showed us. Raymond notplowing. Likewise, a good share and landside are even only taught us how to work horses, but also taught usmore important for skim plowing than conventional the love of working horses, a gift for which we willdeep plowing. be forever grateful.We would not recommend this unorthodox form of Raymond warned that this method of plowing mightplowing for rocky, compacted or unimproved land. not win many ribbons at a plowing contest, but thatOr for beginner teamsters. With the plow planted so it was the way the walking plow was intended to belightly in the soil, it seems to have a little more life of used. He simply removed the jointer from the plowits own and may require, at least at first, faster reflexes. and set the clevis to cut a fairly narrow (10‑12”) andTo be sure, we are using Leroy in a way for which he deep (6‑8”) furrow, laying the furrow slice on its sidewas never intended. rather than flipping it all the way over. Plowed in this fashion, manures, cover crop residues and the aerobicThanks to skim plowing, we now had two reliable crop portion of the soil were not completely buried, butsequences based on two types of tillage: distributed vertically in the good earth. Raymond also pointed out that furrows laid on edge allowed moisture,108 Organic Vegetable Production
  • 117. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Skim plowing (left) and vertical furrow plowing (right)Plowing depth matches biological activity of the soil and conditioning of the horses.warmth and air to penetrate the soil easily for quick best features of conventional moldboard and chiseland proper decomposition of raw organic matter. And plowing. Like conventional moldboard plowing, thehe recommended setting the teeth of the harrow deeper walking plow adjusted in this manner provided quickwith each pass, bringing crop residues to the surface and effective weed control while mixing stratifiedto speed decomposition and slow erosion. layers of organic matter, minerals and acidity. Like chiselling, vertical furrow plowing loosened the groundAlthough Raymond likes nothing better than walking deeply without burying all the organic matter and thebarefoot behind the horses, he made it clear that this live portion of the soil. At any rate, it seemed the cropsstyle of plowing was not limited to the walking plow. grew better in the following year.It was possible with sulky plows, gang plows andtractor plows, just so long as the moldboards were not Those Standardbred mares were right! Depth of tillagetoo wide. For example, a trailer plow with four 12” ought to reflect the natural procession of the seasons,bottoms would work just fine, but a three bottom plow from surface tillage in the spring to deep plowing inwith 16” shares, although turning the same amount the summer months. Although plowing in the heat ofof land, would not lay the furrow on edge unless the the summer can be hard work for horses, the team,plows were set excessively deep. Choice of ground already toughened by a few months of fieldwork,speed and moldboard design would also influence the took it in stride. The soil also seemed ready, with theroll of the furrow. earthworms and other soil life now active throughout the whole plow layer, and the cover crop roots so muchWe found vertical furrow plowing to be an ideal way thicker and deeper than in the spring. Looking from theto start the summer fallow because it combined the plow handles, it appeared that the conditioning of theWeed Management 109
  • 118. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.soil followed closely the conditioning of the horses.For more information on the summer fallow, hogcomposted manure and our neighbors’ offset disc,please see:• “The Summer Fallow,” Summer, 1991, Small Farmer’s Journal• “Work Hogs and Horse Manure,” Spring, 1991, Small Farmer’s Journal• “Alternative Horsedrawn Tillage,” Spring, 1987, Vertical furrow plow, cover crop of clover in fallow year Small Farmer’s Journal before late crops110 Organic Vegetable Production
  • 119. This page is from Organic Vegetable Production, NRAES-165. To purchase the book,visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Insect and DiseaseManagement
  • 120. This page is from Organic Vegetable Production, NRAES-165. To purchase the book,visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.
  • 121. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Impacts of Soil Quality on Disease and Insect Resistance in Plants Anusuya Rangarajan Dept. of Horticulture Cornell University Ithaca, NYOrganic farmers have long claimed that, on their farms, type). These findings suggest that trying to predict ainsect and disease pressure is less than on conventional suppressive soil is nearly impossible, and that focusingfarms. They believe their emphasis on good soil man- on any one trait does not appreciate the complexityagement and soil quality results in improved plant of the interactions between soils, microorganismshealth and resistance to infection or infestation. Soil and plants.quality includes those biological, chemical and physi-cal traits that enhance the ability of a soil to support We know that plants can respond to their environ-healthy plant growth (among other things). While there ment and adapt to some stressful conditions, such asis little conclusive scientific data about the relationship moisture stress or low light levels. Recently, researchbetween soil quality and pest suppression, there are has found that some of these plant responses are quiteseveral plant and soil interactions may contribute to instantaneous and suggest that plants are much morethese phenomena. active in adapting and responding to the environment than previously believed. Some of these rapid respons-Different soil biological, chemical and physical traits es affect crop susceptibility to pests. These responseshave been associated with disease suppression. Many are induced by cues from the environment and some ofresearchers have tried to identify biological indicators these cues are based upon root interactions with soilsfor soil health and disease suppression (van Bruggen and soil microorganisms. To understand how soilsand Semenov, 2000). However, many of these mea- affect crop susceptibility to pests, we must considersurements are sensitive to the environment or short- some these different plant responses and evaluate howterm management effects, minimizing their usefulness. they may be optimized to reduce plant losses (FigureOther researchers have found that soil physical and 1, page 114). This discussion will:chemical characteristics can also influence diseaselevels, including organic matter quality and quantity, a. review some of the strategies of pest resistance inpH, calcium, iron, micronutrients, compaction, soil plants,texture, structure, parent material and the predominateclay type, and soil moisture (Hoper and Alabouvette, b. soil and rhizosphere effects on this plant resistance,1996). The relative importance of any trait varied by andthe specific disease, and no generalizations could bemade for all diseases. In many cases, trying to manipu- c. suggest some strategies to maintain or enhancelate these traits within a soil is impossible (e.g. clay pest suppression in vegetable systems.Insect and Disease Management 113
  • 122. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Plant Health Plant Growth Environment Host Plant Resistance Induced Resistance Plant Nutrients and Rooting Media Disease Suppressive Soil and Amendments Rhizosphere OrganismsFigure 1Factors affecting plant resistance in insect and disease pests.Plant resistance to pests not expressing those genes. Common examples of host plant resistance can be found in vegetable varieties that have disease resistance, e.g. tomatoes with resis-Plants may escape damage by pests by associating tance to verticillium, fusarium and nematodes. Thesewith other species, developing in times with reduced physical or chemical attributes make the plant lesspest pressure, having some tolerance to the herbivore appealing or even toxic to pests. Some physical traitsor confronting the pest with physical or chemical that confer host plant resistance include hairiness ofchallenges. These physical and chemical challenges leaves (trichomes) or toughness (lignification) of plantto pests include host plant resistance and systemic or parts (e.g. stem solidness in wheat). Hairiness of leavesinduced resistance. Both of these modes of resistance can reduce ability of sucking insects to land and feedcan be affected by plant growth and soil conditions. on leaves, and lignification can restrict insect boring into stems or restrict fungal spread into plant tissue.Host Plant Resistance Chemical factors include secondary plant compounds or phytochemicals, such as alkaloids, glucosinolates,Host Plant Resistance occurs from the expression of terpenoids or polyphenols. These chemicals are theplant genes that result in physical or chemical attributes primary mode of host plant resistance and often havethat interfere with the ability of an herbivore (insect, very specific effects on pests.disease or animal) to utilize a plant compared to a plant114 Organic Vegetable Production
  • 123. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.In some cases, these phytochemicals associated with then viruses. For example, anthracnose inoculation ofhost plant resistance are always present in the plant. In cucumbers provides systemic protection against theother cases, they are affected by factors, such as plant same and other fungi, some viruses, wilt fungi andage, previous plant injury, planting arrangement and bacteria, but not spider mites or beet armyworm. In cot-crop competition, light levels, ultraviolet radiation, and ton: spider mites on cotyledons protect against mites,soil nutrients. Fully expanded, maximally photosynthe- caterpillars, thrips, whiteflies, true bugs and vascularsizing leaves have the highest carbon, nitrogen and wa- wilt fungi, but not bacterial blight. However, inducedter, and are likely best for herbivores. When leaves age resistance will not protect against very aggressiveand develop toughness, they often are less nutritious to pathogens such as Sclerotina white mold, late blightpests. Previous plant injury by one plant-feeding insect or some post-harvest rots.(herbivore) can lead to resistance to other herbivores.Infection by a plant pathogen can change suitability For induced resistance, the plant first must be stimu-of a host to other pathogens or herbivores for better or lated or challenged (given the “shot”). The challengeworse. Planting arrangement and density can increase may be via an organism (e.g. insect, fungi or bacteriaor decrease plant stress and subsequent susceptibility that are pathogenic or nonpathogenic) or a specificby affecting plant health and vigor. chemical (Figure 2, page 116). Induced resistance has been elicited by several different organisms, in-An example of host plant resistance in vegetables is cluding pathogens, insects, plant-growth-promotingthe effect of cucurbitacin in cucurbit leaves on the rhizobacteria (see below), composts and compostfeeding by cucumber beetle and two-spotted mite. extracts. Several chemicals shown to induce resistanceThis compound is a powerful feeding stimulant for include salicylic acid, potassium phosphate, bicarbon-cucumber beetle but confers resistance to mites. The ate, oxalic acid (spinach or rhubarb extracts), somelevel of cucurbitacin varies among species and even new chemicals such as Actigard, Bion (salicylic acidcultivars of cucurbits. Cucumbers that lack cucurbita- mimic), Milsana (giant knotweed extract) or Messen-cin are resistant to the beetles but susceptible to mites. ger, and some plant hormones (cytokinin and abscisic acid). Thus, the inducer or elicitor is important forAnother example is the production of glycoalkaloids what it does, not what the structure is. The modes ofin potatoes. These compounds confer resistance of action of these different inducing agents are beingleaves to the Colorado potato beetle. These glyco­ actively explored by researchers. Interestingly, ap-alkaloids in tubers, however, can be toxic to humans. plication of larger amounts of an inducing agent willA beetle-resistant cultivar “Lenape” was pulled from not give greater resistance, and the response can varythe market due to the high levels of glycoalkaloids by cultivars of the tubers. Some time must pass after applying an inducing agentInduced Plant Resistance before resistance can be observed. The amount of time varies by the species as well as the pathogen. In ad-Induced plant resistance is an enhanced defense dition, the inducing agent often needs to be reappliedcapacity developed in a plant after being stimulated to keep up the resistance. For example, some of the(Kuc, 2001). In some ways, this could be described chemical inducers must be applied every two weeksas priming or vaccinating plants—after receiving a to maintain the resistance levels (e.g. Messenger).“shot” (inducing agent) in a single part of the plant, Induced resistance can cause reductions in yield inthe whole plant becomes more resistant to future at- some cases, but losses to the pest need to be balancedtack. Induced resistance does not, however, require with yield depression.application of antibiotics. The potential for induced resistance in agriculturalThis induced resistance is different than host plant settings seems obvious, but is difficult to documentresistance in that the effects tend to be non-specific for consistent effects. Treatment of crops with inducingthe target pest. Induced resistance has been described agents has shown improved resistance to pests in somefor pathogens in 30 species and for herbivores in 100 cases, but not all. New information on soil microor-species. For diseases, induced resistance is most ef- ganisms indicates that even root infections can inducefective at suppressing fungi, followed by bacteria and resistance in plant tops.Insect and Disease Management 115
  • 124. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. pathogens Plant signals that activate Elicitors of Induced Resistance: induced resistance Disease and insect pests Potassium phosphate Bicarbonate Spinach/rhubarb extract New chemical products: Actigard, Sonata, Messenger, Serenade, Plant Growth Promoting Composts Rhizobacteria, Hormones (cytokinin, ABA) Mycorrhizal fungiFigure 2Induced resistance requires that the plant be challenged by a pest or by some other compound (elicitor).Once challenged, the crop quickly sends signals to other parts of the plant that cause the plant to enhance resistance, incase of future attacks. The nature of this plant signal will vary by the crop. In some crops, up to two weeks are requiredafter the initial challenge for induced resistance to have an effect.Soil organisms and amendments isms living in this nutrient rich zone are plant growth promoting rhizobacteria (PGPR) and plant growththat affect plant resistance promoting fungi (PGPF). PGPR stimulate plant growth and performance under stress in severalPlant growth promoting rhizobacteria ways. Some suppress growth of pathogens through(PGPR) a) direct competition for resources or nutrients like iron; b) by predation; or c) by producing antibioticThe rhizosphere is the 2-5 mm region immediately or antifungal compounds. Fluorescent pseudomonadsaround plant roots, into which plants pump large species are some of the most effective bacteria foramounts of carbon as exudates. Free-living rhizo- suppressing soil borne diseases. Other organismssphere organisms survive on plant root exudates supply nutrients such as phosphorous or nitrogen,and can affect plant growth rate and defend against or produce or metabolize plant hormones, affectingplant diseases (Whipps 2001). Some of the organ- crop growth. The types of PGPR often vary by plant116 Organic Vegetable Production
  • 125. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.species and sometimes even variety, making inocula- inoculation with some specific suppressive fungi,tion of plants for crop protection challenging. The such as Trichoderma or Bacillus spp. Not all compostsamount of organisms needed to affect crop growth suppress diseases, and some composts may actuallyis unknown. increase disease levels. Those high in salts have been shown to increase levels of Pythium, and those notSixteen different commonly occurring soil bacteria sufficiently cured, especially if they have high nitrogenhave been found to induce plant resistance. A link content, may increase disease.between PGPRs and induced resistance has been re-ported for anthracnose of cucumber, fusarium wilt on To maximize benefits of compost in potting media,carnation and halo blight on beans (Ramamoorthy et al select well-cured (6 to 12 months) composts. Mix and2001). Mixtures of these PGPRs have been more effec- pot the media before planting, and water to leach anytive at inducing resistance than application of just one salts out of the media that may inhibit germination andPGPR. These bacteria are applied as seed treatments growth. In fields, if the maturity of the product is un-or drenches to transplants. One interesting interaction known, apply the compost well in advance of the crophas been found between a PGPR and cucurbitacin to allow for stabilization of the compost (and reducecontent of cucumbers. Seed inoculation followed by nitrogen tie-up) and leaching of any salts.drenching with a Bacillus species led to reduced cu-curbitacin content in both bitter (high concentrationof cucurbitacin) as well as non-bitter cultivars. This Strategies to optimize pestconsequently reduced feeding by cucumber beetlesand reduced transmission of bacterial wilt (Zehnder suppression through soilet al 2001). Thus, a rhizobacteria, growing around the managementroots affected the expression of a host plant gene, andthat in turn affected both insect and disease incidencein the crop. We are only beginning to understand these Organic matter additions to soil become part of a com-complex interactions between soil PGPR and the crop’s plex food web of soil organisms. Regular additions ofcomposition and disease resistance. fresh organic matter (active soil organic matter) will increase microbial activity as it is decomposed byCompost and disease suppression different groups of organisms. In turn, these microbes will affect soil disease suppressiveness, as well as soilManure and compost amendments are typically applied physical and chemical characteristics and nutrientto soil to recycle nutrients and build soil organic matter. availability. Older, more stable organic matter (passiveComposts have also been shown to suppress soil borne organic matter) is that humus fraction in the soil thatdiseases and induce resistance in crops (Hoitink and contributes to cation exchange capacity and aggregateGrebus, 1994). In a study with cucumbers grown in stability—factors that enhance plant growth.either compost-amended or no-compost media, thosegrown in compost showed a higher level of induced re- Since soil organic matter is dynamic, the effect of anysistance (after being challenged) than those not grown particular amendment on soil quality will change overin a compost media (Zhang et al 1998). This indicates time. Trying to predict the response of various soilthat multiple organisms may affect plant resistance microbial functional groups with the addition of any(soil organisms as well as above-ground challengers) specific amendment is incredibly complex. Compost,without causing disease (Figure 2). Microorganisms while disease suppressive, should be considered onlyin compost may also control diseases by competing one part of a systems approach to disease management.with the pathogen for food, by producing compounds A good approach is to use repeated (not just single)that kill the pathogen, or by attacking the pathogen applications of different types of organic amendments.directly. Several researchers have explored this type These amendments will feed different microbes as theyof disease suppression in compost-based media used are decomposed and increase soil microbial diversityfor ornamentals and food crops. The ability of com- and activity. Evaluate your soil amendments to providepost to suppress diseases has been associated with the a diversity of food choices to the “soil micro-herd”composting conditions (food stocks, management), can (Figure 3, page 118). An analogy to the human nutri-change with maturity, and can be enhanced through tion food guide pyramid could be applied here. AvoidInsect and Disease Management 117
  • 126. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use on any one type of soil amendment, e.g. only ers have found that in organically managed systems,rye as a cover crop, to enhance soil health. there is greater diversity in soil biota, higher microbial activity which could contribute to greater competi-Organic agriculture requires use of organic matter tion, antagonism and predation of disease organisms,amendments to improve soil quality and provide higher populations of fluorescent pseudomonads andnutrients to growing crops. In one study, field corn actinomycetes (important biocontrol organisms), andwas grown (in the greenhouse) in soils collected from generally a lower incidence of soilborne diseases (vanorganic and conventional farms. European corn borers Bruggen, 1995).laid more eggs on plants grown in the conventionalsoils. The researchers concluded that the overall soil There are several components that growers must keepmanagement approach was more important than any in mind to make full use of the benefits of healthy soilspecific soil amendments or nutrient levels to predict on crop health and pest suppression. First, alwaysthe insect behavior (Phelan et al, 1995). Other research- strive to optimize plant growth conditions, including Diversify the Food Choices A blend of roots and shoots from different food groups High N Availability, Hot Chemical Fertilizers No Carbon content food Grass Clippings, Moderate N Availability, New or used Grain Meals, Green Lower C content green food and Animal Manures Compost, Straw, Low N Availability Stable, dead food High C content Leaves, Non- Legume Covers Micro-herd Food TriangleFigure 3Soil organic matter amendments have different rates of decomposition in soilEach phase of degradation will support different functional groups of soil organisms. The analogy of the food pyramidis helpful to remember to provide different types of soil amendments to encourage a diverse and active population ofsoil organisms. Prioritize carbon additions to soil, with nitrogen additions (as green or animal manures) that are moremoderate, and aim to minimize chemical fertilizers.118 Organic Vegetable Production
  • 127. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.minimizing crop stress and competition, and using crop plants against pests and diseases. Crop Protec-the best cultural practices for your region. Second, tion. 20:1-11.always try to select resistant varieties. Third, provide adiversity of organic matter residues to your soils. These Van Bruggen, A.H.C. 1995. Plant disease severity inresidues, as they are degraded, will enhance microbial high-input compared to reduced input and organicdiversity and abundance. Some of these microbes will farming systems. Plant Disease. 79(10):976-984.reduce soil pathogens as well as induce resistance inplants, making the plants more able to defend against Van Bruggen, A.H.C and A.M. Semenov. 2000. Infuture pest attacks. search of biological indicators for soil health and disease suppression. Applied Soil Ecology. 15:13-24.Literature Cited Whipps, J. M. 2001. Microbial interactions and bio- control in the rhizosphere. Journal of Experimental Botany. 52: 487-511.Hoitink, H.A.J and M.E. Grebus. 1994. Status ofbiological control of plant disease with composts. Zehnder, G.W., J.F. Murphy, E.J. Sikora, and J. W.Compost Science and Utilization. 2(2):6-12. Kloepper. 2001. Application of rhizobacteria for in- duced resistance. European Journal of Plant Pathology.H. Hoper and C. Alabouvette. 1996. Importance of 107:39-50.physical and chemical soil properties in the suppres-sion of soils to plant diseases. European Journal of Soil Zhang, W., D.Y Han, W.A Dick, K.R. Davis, H.A.J.Biology. 32(1):41-58. Hoitink. 1998. Compost and compost water extract- induced systemic acquired resistance in cucumber andKuc, J. 2001. Concepts and direction of induced sys- Arabidopsis. Phytopathology. 88(5) p. 450-455.temic resistance in plants and its application. EuropeanJournal of Plant Pathology. 107:7-12. Zhang,-W.; Dick,-W.A.; Hoitink,-H.A.J. 1996. Com- post-induced systemic acquired resistance in cucumberRamamoorthy, V., R. Viswanathan, T. Raguchander, V. to Pythium root rot and anthracnose. Phytopathology.Prakasam, R. Samiyappan. 2001. Induction of systemic 86 (10):1066-1070.resistance byplant growth promoting rhizo­ acteria in bInsect and Disease Management 119
  • 128. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Disease Management Strategies: Cultural Practices Helene R. Dillard Professor  •  Department of Plant Pathology New York State Agricultural Experiment Station  •  Geneva, New York Director  •  Cornell Cooperative ExtensionPurchase seed or transplants that are certified disease Plant several smaller transplant beds rather than fewerfree. large transplant beds. With smaller transplant beds, individual seed lots from different sources can beSelect resistant or tolerant varieties. isolated from each other. Then, if one seed lot has an undesirable disease, you can destroy plants in that lot inConsider using hot water seed treatment to reduce con- order to prevent spread to the remainder of your plants.tamination. Unfortunately, this treatment can reducegermination and vigor in some varieties, and may not Keep varieties separated in the greenhouse and ineradicate disease from heavily infested lots. It is not seedbeds. Pathogens and especially bacteria are rapidlya 100% guarantee that the seed will be disease free. spread in water; close spacing in seedbeds and in the greenhouse is ideal for rapid disease development.Direct seed when possible. Spread is slower in direct Keeping the varieties separate will help you identifyseeded systems. This is basically due to the ability of problematic varieties.pathogens to spread among dense plantings found intransplant production areas. Destroy volunteer plants and weeds growing in and near the transplant bed and production fields. TheseScout greenhouses and seedbeds on a weekly basis. plants may harbor pathogens. Symptoms on weedLook for spots, wilts, or other symptoms characteristic species may or may not be present.of disease or disorder. Destroy all remaining plants in a seedbed as soon asSelect sites for seedbeds and crops where rotation has transplanting operations are completed. Transplantsbeen practiced. should only be handled when the foliage is dry.Select sites for disease‑prone crops that have good air Do not dip or water transplants in crates or boxes—thisflow and good soil structure that promotes drainage. will very effectively spread pathogens.Raise transplant beds above the surrounding area or Some bacterial diseases are highly contagious. Fortrench the periphery to provide for drainage of excess example, if black rot is detected in a seedbed considerrainfall. Flooding of the seedbed area can result in all plants at the location to be contaminated. Do notwidespread infection. attempt to separate healthy from diseased plants. Many120 Organic Vegetable Production
  • 129. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.plants will be contaminated, but will not be showing ing inoculum of pathogens. When disease pressure issymptoms until the environmental conditions are fa- not severe, mulching can provide as good control asvorable for symptom development. conventional chemicals.Do not plant transplants showing disease symptoms. Achieve good weed and insect control. Weeds mayThese plants will continue to be problematic through- harbor pathogens, rob the soil of valuable nutrients,out the growing season. and encourage moisture retention in the canopy that is favorable for disease development. Insects may serveInsects should be controlled because insect feeding as vectors for pathogens and/or their feeding injuryinjury provides wounds that are a large target of op- may provide a site of entry for pathogens.portunity for infection. Plant residues should be incorporated after harvest toOnly new crates should be used for shipping trans- encourage breakdown of diseased tissues.plants. Reusable plastic or wooden plant containersbrought to the field should be cleaned and disinfested Cover crops and compost should incorporated into soil.before returning them to the seedbed area for reuse. Both have been shown to build overall soil health and promote buildup of beneficial microorganisms.Clean all transplanting equipment before and aftereach use. Various natural teas have been shown to provide disease suppression in specific pathogen systems. InA well‑balanced nutrient program will suppress disease general, compost teas hold the most promise for pro-development. For example, studies have shown that moting, plant health and suppressing buildup of patho-excess nitrogen causes lush vegetative growth and can gens. Excellent information was recently publishedmake crucifers more susceptible to black rot. Results by the Organic Farming Research Foundation in thefrom a recent study showed that boron applied alone Winter 2001 number 9 information bulletin. Compostor with nitrogen reduced the disease severity of black teas are very complex and require precise handling torot in cabbage. produce efficacious teas.Avoid using overhead irrigation, but if necessary ir- Cull piles with infested debris should not be dumped onrigate during the time of day when the plants will dry fields scheduled to grow the same crop the followingquickly. year. Research conducted in the Netherlands has shown that fresh infested cull piles are a significant source ofContaminated equipment, people, animals, overhead pathogenic bacteria that resulted in the developmentirrigation, and wind‑driven rain will spread patho- of a black rot epidemic.gens. Always work in diseased fields last and restrictactivities in fields until later in the day when plants Rotation to a non host crop is always recommended.are completely dry to reduce the potential spread ofthe disease. Helpful Disease ManagementTools used for pruning, staking, and tying should bedisinfested frequently, and especially when used on Referencesdifferent varieties. Wounding plants during these op-erations should be avoided, as wounds provide a sitefor entry of pathogens. Sustainable Vegetable Production From Start‑Up to Market. Vernon P. Grubinger. NRAES-104, ISBN 0Planting on raised beds allows excess water to drain 935817 45 Xfrom around plant foliage and roots. Removal of exces-sive moisture is a deterrent to disease development. Plant Disease Control; towards environmentally ac- ceptable methods. Richard N. Strange. Chapman andMulching has been shown to provide a physical bar- Hall, 1993, ISBN 0 442 31666 6rier between susceptible plant tissue and overwinter-Insect and Disease Management 121
  • 130. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Alternative Agriculture. National Research Council. • Aspire, Ecogen, Candida oleophiia isolate 1‑182National Academy Press, Washington, DC 1989, ISBN0 309 03987 8 • Serenade (QRD 137), AgraQuest, Bacillus subtilis QST 713 strainThe Real Dirt. Edited by Miranda Smith and membersof NOFA. 1994, NESARE • SoilGard 12G, Thermo Trilogy, Gliocladium virens GL‑21Plant Diseases: their biology and social impact. GailL. Schumann. 1991 APS Press, ISBN 0 89054 116 7 • AQ10, Ecogen, Ampelomyces quisqualisCompost Tea Manual. Karl Rubenberger, 1999. Avail- • Contans, Encore Technologies, Coniothyriumable from Organic Farming Research Foundation minitansWeb site for info on soil health, etc. Soil Food Web Products from organic origins, Manufacturer, ActiveIncorporated. Dr. Elaine Ingham. http://www. soil- • Elexa, Safe Science, chitosanBiocontrol Products, Manufacturer, Active Ingredient • Trilogy, Thermo Trilogy, clarified hydrophobic• Mycostop, Kemira Agro Oy, Streptomyces griseo- extract of neem oil viridis strain K61 • Milsana (a.k.a. BAS 114 UBF and KHHUBF‑• RootShield and PlantShield, Bioworks, Tricho- 99‑001), KHH BioSci, Reynoutria sachalinensis derma harzianum Rifai strain KRL‑AG2 (giant knotweed) extract122 Organic Vegetable Production
  • 131. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Cultural Practices for Disease Management Curtis Petzoldt Vegetable IPM Coordinator Integrated Pest Management Program New York State Agricultural Experiment Station Geneva, New YorkResources for Disease and Pest 6. Processing Sweet Corn Scouting ProceduresManagement proc/prswcorn99.htmlNortheast IPM Web site: 7. Cucurbit Scouting ProceduresNew York Resources proc/cuke00.html1. A Growers’ Guide to Cabbage Pest Management 8. Tomato Scouting Procedures in New York Snap Bean Pest Management: A guide to regular proc/tom00.html field monitoring in New York (manual and video) 9. IPM Elements3. Integrated Pest Management for Onions (manual and video) html4. Integrated Crop and Pest Management Guidelines for Commercial Vegetable Production 10. Hoffmann, M and A. Frodsham, 1993. Natural Enemies of Vegetable Insect Pests. CCE 11. Biological Control: A Guide to Natural Enemies5. Fresh Market Sweet Corn Scouting Procedures in North America proc/fmsc99.html index.htmlInsect and Disease Management 123
  • 132. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.New York Contacts Maine Contact C. Petzoldt Jim Dill Phone: (207) 581-3880 A. Seaman E-mail: J. Mishanec New Jersey ResourcesMassachusetts Resources 1. Web page has link set up for scouting procedure location but they are not currently present1. General vegetable page with many links 2. Web page includes IPM Elements for several vegetable crops2. Specific crop page with scouting procedures for many crops including: Crucifers, Cucurbits, Herbs, Hydroponics, Legumes, Lettuce and Greens, Pep- New Jersey Contact pers, Potatoes, Specialty Crops, Root Crops, Sweet Corn, Tomatoes Joe Ingerson-Mahar Phone: (732) 932-9802 E-mail: pest_mgt/specific_crops.html Connecticut ResourcesMassachusetts Contact Ruth V. Hazzard Phone: (413) 545-3696 1. Vegetable IPM information and fact sheets for pep- E-mail: pers, tomatoes, beans, cole crops, corn, cucurbits, lettuce, potatoes, eggplant and squashMaine Resources Connecticut Contact1. Potato IPM page T. Jude Boucher Phone: (860) 875-3331 E-mail: tboucher@canr.cag.uconn.edu2. Broccoli IPM page Delaware Resources htm Sweet Corn IPM page 1. Sampling Guidelines and action thresholds for Cabbage, muskmelons, potatoes, sweet corn, wa- termelons Organic Vegetable Production
  • 133. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.2. Insect trap catches and disease forecasts plus other Maryland Resources reference publications IPM page does not currently contain much specificDelaware Contact vegetable information. Joanne Whalen Maryland Contact Phone: (302) 831-1303 E-mail: Sandra Sardanelli Phone: (301) 405-7877Rhode Island Resources E-mail: ss11@umail.umd.edu New Hampshire ResourcesIPM page does not currently contain much specific scouting information. htmRhode Island Contact IPM page does not currently contain much specific vegetable information. Richard A. Casagrande Phone: (401) 8742924 New Hampshire Contact E-mail: Dr. Alan T. EatonVermont Resources Phone: (603) 862-1734 E-mail: alan.eaton@unh.edu Pennsylvania ResourcesIPM page does not currently contain much specificvegetable scouting information. IPM page does not currently contain much specific vegetable scouting information.Vermont Contact Ann Hazelrigg Phone: (802) 656-0493 Pennsylvania Contact E-mail: Dr. Ed RajotteWest Virginia Resources Phone: (814) 863-4641 E-mail: egrajotte@psu.edu page does not currently contain much specificvegetable scouting information.West Virginia Contact Rakesh S. Chandran. Phone: (304) 293-6131 Ext. 4225Insect and Disease Management 125
  • 134. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Regional/U.S. References Crucifers University of California IPM program. 1985. Inte-Peppers grated Pest Management for Cole Crops and Lettuce. UC Publication 3307.Boucher, T. Jude and Richard Ashley. 2000 NortheastPepper IPM Manual. University of Connecticut, Com- Schooley, Jan. 1995. Integrated Pest Management formunications and Information Technology, 1376 Storrs Crucifers in Ontario: A Handbook for Growers, ScoutsRd., U-4035 Storrs, CT 06269-4035. $19.95 and Consultants. OMAFRAPotatoes Cucuzza, James, J. Dodson, B. Gabor, J. Jiang, J. Kao, D. Randleas, V. Stravato, and J. Watterson. 199?.Western Regional IPM Project. 1986. Integrated Pet Crucifer Diseases: A Practical Guide for Seedsmen,Management for Potatoes in the Western US. Univer- Growers, and Agricultural Advisors. PetoSeed.sity of California Publication 3316. Sweet CornHollingsworth, Craig S, David Ferro, and William Coli.1986. Potato Production in the Northeast: A Guide to Adams, Roger and Jennifer Clark. 1995. NortheastIntegrated Pest Management. Massachusetts Coopera- Sweet Corn Production and Integrated Pest Manage-tive Extension Publication C-178. ment Manual. University of Connecticut Cooperative Extension.Rowe, Randall C. 1993. Potato Health Management.APS Press. 3340 Pilot Knob Road, St. Paul, Minne- Shurtleff, Malcolm. 1980. Compendium of Cornsota. 55121. Diseases. APS Press. 3340 Pilot Knob Road, St. Paul, Minnesota. 55121.Hooker, W.J. 1981. Compendium of Potato Diseases.APS Press. 3340 Pilot Knob Road, St. Paul, Minne- Blair, B.D. et al. 198?. Corn Pest Management for thesota. 55121. Midwest. North Central Regional Publication No. 98.Cucurbits TomatoesMotes, Jim and Gerrit Cuperus. 199?. Cucurbit Pro- University of California IPM Program. 1985. Inte-duction and Pest Management. Oklahoma Cooperative grated Pest Management for Tomatoes. UC Publica-Extension Service Circular E-853. tion 3274.Bernhardt, Elizabeth, Jeff Dodson, John Watterson. Jones, J.B., John Paul Jones, R.E. Stall, T.A. Zitter.1988. Cucurbit Diseases: A practical Guide for 1991. Compendium of Tomato Diseases. APS Press.Seedsmen, Growers, and Agricultural Advisors. 3340 Pilot Knob Road, St. Paul, Minnesota. 55121.PetoSeed. Pernezny, K et al. 1995. Florida Tomato ScoutingZitter, Thomas, Donald Hopkins, and Claude Thomas. Guide. University of Florida Publication SP-221996. Compendium of Cucurbit Diseases. APS Press.3340 Pilot Knob Road, St. Paul, Minnesota. 55121. IPM, Organic, and Sustainable AgricultureOnions Appropriate Technology Transfer for Rural AreasSchwartz, Howard F. and S. Krishna Mohan. 1995. Press. 3340 Pilot Knob Road, St. Paul, Minne-sota. 55121.126 Organic Vegetable Production
  • 135. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Table 1 Cultural Practices for Controlling Plant Diseases Practice Conditions Affected Disease Prevented Use resistant varieties Slows or stops disease development Many diseases Manage vectors of diseases Staking, pruning Increase air movement Many foliar diseases Wide-row spacing and leaf drying Timely irrigation Minimize leaf wetness period Many foliar diseases Use drip instead of sprinkler irrigation Slows or stops disease development Rogue or destroy infected plants Slows or stops disease development Many diseases Windbreaks Limit spread of airborne spores Many foliar diseases Plastic or straw mulches Prevent soil splashing onto foliage, fruit Many foliar diseases Do not work in fields with wet foliage Reduce spread of inoculum Raised beds Improve water drainage Many root and crown rots Chisel plow or subsoiling Careful cultivation Promote healthy root growth Many root and crown rots Floating row covers Reduce aphid (vector) feeding Many viruses Reflective mulches Use disease free seed or transplants Reduce source of inoculum Many diseases Physically separate plantings Good weed control-on farm Reduce source of inoculum Many viruses Gentle harvest methods Avoid cuts, bruises Postharvest diseases Rapid cooling at harvest Slow microbial activity Postharvest diseases Store at cool temperatures Optimize NPK fertility Reduce stress, avoid rank growth Diseases in general Rotate crops Incorporate crop residues Reduce inoculum buildup Diseases in general Remove infected crop debris Wash equipment frequently Reduce spread of inoculum Diseases in general C. Petzoldt adapted from H. DillardInsect and Disease Management 127
  • 136. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Identifying and Encouraging Beneficial Insects Michael P. Hoffmann NYS IPM Program and Department of Entomology Cornell University Ithaca, NY 14853Insect and mite pests plague vegetable farmers, caus- Predatorsing damage to almost all crops. Many tactics areavailable to manage insect pests and the integratedpest management (IPM) strategy encompasses them Predators such as lady beetles and lacewings, areall. Integrated pest management is fundamentally the mainly free-living species that consume a large num-same as organic pest management except in organic ber of prey during their lifetime. They include manysystems there may exist more long-term stability or beetle, bug, fly, mite, and spider species. Both adultsbalance in the overall system for a number of reasons and immatures are relatively mobile and search forincluding a more diversified farming system. The two prey. In some species such as lady beetles, both theapproaches also differ when it comes to the use of larvae and the adults feed upon prey. In others, suchpesticides. If pesticides are used in organic farming as syrphid flies or lacewings, only the larvae consumethe options are limited to a relatively few “natural” insect prey. The adults may obtain nourishment byproducts. In contrast, the conventional farmer has a feeding on nectar or pollen. Examples of some com-multitude of synthetic and natural compounds to use. mon predators include:Like organic pest management, IPM is ecologicallybased and promotes pest control tactics such as pest- Lady beetlesresistant plants, and cultural, mechanical, physical andbiological control methods. Regardless, all farmers Adult lady beetles are small, round to oval, and dome-want to produce safe food with minimal risks to health shaped and live for a few months to over a year. Ladyand the environment. beetle larvae are dark and alligator-like with three pairs of prominent legs. Both adults and larvae areOne pest management tactic that is common to all veg- predacious. Lady beetles overwinter as adults, oftenetable farms and is generally free is biological control. in aggregations along hedgerows, beneath leaf litter,All insect pests have natural enemies. These organ- under rocks and bark, and in other protected placesisms may be predators, parasitoids or disease-causing including buildings. In spring, the adults disperse inpathogens. The use of these organisms to manage pests search of prey and suitable egg laying known as biological control. The emphasis here ison the biological control of insects, though biological Female lady beetles may lay from 200 to more thancontrol is also very important for the control of weeds 1,000 eggs over a one to three month period, commenc-and plant diseases. ing in spring or early summer. Eggs are usually depos-128 Organic Vegetable Production
  • 137. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.ited near prey such as aphids, often in small clusters in Lacewing larvae are generalist beneficials but are bestprotected sites on leaves and stems. The more common known as aphid predators. The larvae are sometimesspecies typically have one to two generations per year. called aphid lions. Various reports suggest that de- veloping lacewing larvae eat from 100 to 600 aphids.Most lady beetles found in vegetable crops and gardens Larvae and adults may be common in sweet corn andare aphid predators. Some species prefer certain aphid field crops through summer.species while others will attack several species on avariety of crops. If aphids are scarce, lady beetle adults Hover or syrphid fliesand larvae may feed on the eggs of moths and beetles,and mites, thrips, and other small insects, as well as Adult hover flies resemble bees or wasps and arepollen and nectar. They may also be cannibalistic. usually seen on or near flowers. The male flies haveBecause of their ability to survive on other prey when a distinctive hovering and darting habit. Hover fliesaphids are in short supply, lady beetles are particularly range in size from quite small to a little larger andvaluable natural enemies. narrower than houseflies. The female hover fly lays single elongated eggs near or among aphid infestations.Lady beetles are voracious feeders and may be numer- Females may lay several hundred eggs through mid-ous where prey are plentiful. Lady beetles need to eat summer; the larvae hatch after two to three days. Themany aphids per day so that they can lay eggs. The small, cylindrical, legless maggots vary in color fromconvergent lady beetle may eat its weight in aphids cream to green to brown, depending on the species andevery day as a larva and consume as many as 50 aphids prey consumed. They develop a “slug-like” form, up toper day as an adult. Sevenspotted lady beetle adults ~1/2” long, tapered towards the head. The larvae canmay consume several hundred aphids per day and each move around leaves and through the canopy in searchlarva eats 200 to 300 aphids as it grows. of prey. The period from egg to adult ranges from two to six weeks, depending on the temperature, species,Green lacewings and availability of aphids. If aphids are plentiful, there may be five to seven generations per year.The common green lacewing is native to much ofNorth America. Adults feed only on nectar and aphid Hover flies larvae feed on aphids, small caterpillars,honeydew, but their larvae are active predators. Adult and, possibly, thrips. Hover fly larvae have been re-green lacewings are pale to bright green, about ~1/2 corded as predators of the larvae of European cornto 3/4” long, with long antennae. Large, transparent borer and corn earworm. In vegetable crops hover flywings are held upright over a fragile body. Some larvae may be most apparent from mid-summer tospecies have prominent, golden eyes. Adults are ac- fall. This may be after the initial aphid infestation hastive fliers, particularly during the evening and night. established, depending on the crop, species, and region.Through spring and summer, the female lays several Hover fly larvae are voracious aphid predators. A singlehundred small eggs, each at the end of a long silk stalk, larva may consume up to 400 aphids during develop-sometimes in clusters, on leaves or twigs in the vicinity ment, depending on species of hover fly and aphid.of aphids. The larvae are pinkish brown and cream,and alligator-like with well-developed legs and large, Batsprominent pincer jaws, used to suck the juices fromprey. They are very mobile and grow through three These natural predators are often overlooked as pos-instars, in about two to three weeks. sible biological control agents. One reason is the dif- ficulty in proving that they actually reduce pest infesta-Reported prey include several species of aphids; tions. However piecing together the existing informa-thrips; mites; whiteflies; eggs of leafhoppers, moths, tion and knowing that they consume large numbers ofincluding diamondback moth, cabbage looper, and insects strongly implies that they do provide farmerscorn earworm, Colorado potato beetle, asparagus some benefit. Another point to bear in mind is thatbeetle, and, possibly, leafminers; small caterpillars bats feed at night in contrast to most beneficial insects,and beetle larvae, including small larvae of Colorado which seek prey during the day. Thus bats complementpotato beetle. the benefits derived from insect natural enemies. The reason not much is known about the potential benefitInsect and Disease Management 129
  • 138. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.derived from bats and birds is that they prey mostly Egg parasitoidson highly mobile adult insects and the impact on thisstage has been exceedingly difficult to study. Trichogramma species are egg parasitoids with a very wide host range, especially among the moths. SeveralThe bats common to central New York include the species have been mass reared for use in biologicallittle brown bat (Myotis lucifugus), big brown bats control programs. The adult wasps are minute, mostly(Eptesicus fuscus), hoary bats (Lasiurus cinereus) 1/50” long. The female wasp lays one or more eggs inand red bats (Lasiurus borealis). Little brown bats can an egg of the host insect, and one or several parasitoidseat up to 1200 mosquito sized insects in an hour. Big may develop. Trichogramma species pupate withinbrown bats consume insects at a rate of 500 per hour. the host egg. Adult wasps emerge seven to 10 daysBats are free to farmers and there are no environmental after the egg is deposited. Warm temperatures favorside effects associated with their use. development and many generations may be produced each season. Trichogramma overwinter in the host egg, emerging as adults the following spring. Eggs usuallyParasitoids turn black as the parasitoids develop inside. A small hole in the black host egg indicates that the wasps have emerged. Reported hosts include eggs of caterpillarParasitoids are species which have an immature (worm) pests such as European corn borer, corn ear-stage that develops on or within a single insect host, worm, imported cabbageworm, diamondback moth,ultimately killing the host. The adult parasitoid lays cabbage looper, and tomato and tobacco hornworm.her eggs on, within, or near the host. The immature Trichogramma are particularly good natural enemiesparasitoids, which hatch from the eggs, are entirely of caterpillars because they parasitize and kill the pestdependent on their host for nourishment. They feed in the egg stage, before the crop is damaged.(internally or externally) on the host, developing tomaturity and eventually leaving the host as adults or Worldwide, no other group of parasitoids has beento complete development. Adult parasitoids may be used as extensively as the Trichogramma for directpredatory or they may seek other food sources. Many control of pests, and considerable effort has gone intospecies of wasps and some flies are beneficial parasit- the mass rearing and release technology. Experimen-oids. Examples include: tal or commercial biological control programs with Tricho­ ramma have been undertaken or are available gAphid parasitoids for control of pests of corn, cotton, cabbage, pea, avo- cado, tomato, forests, soybean, rice, and citrus. TheAphidiid wasps attack only aphids. Adults are very successful use of commercially reared Trichogrammasmall (~1/8”) and dark, with long antennae. Typically, requires that the correct species be used, that it be offemales lay up to several hundred eggs. One larva de- high quality, and that the parasitoid be released at thevelops within each aphid. The larva either emerges to appropriate rate and when the host eggs are present. Us-spin a cocoon under the dead aphid or pupates within ers should follow directions very carefully and examinethe tanned and mummified aphid body. The adult wasp the release units before, and several days after, placingemerges after cutting a circular hole in its cocoon. them in the field to see if the material is viable and toAdults live from one to three weeks, and there can be determine if the Trichogramma actually emerged (exitmany generations per year. Some species overwinter holes should be present in each egg). To determine ifwithin the mummified aphid host. the releases are providing some control, pest eggs can be collected at the release site and observed for para-The most conspicuous sign of aphidiid activity is the sitism. Note, however, that naturally occurring (notpresence of aphid “mummies.” The mummies may oc- released) Trichogramma may also be present.cur within an aphid colony or be found singly on leavesor stems. Praon species spin their cocoon beneath the Tachinid fliesaphid body to encase the developing parasitoid pupa.Most aphid species will be parasitized to some extent Adult tachinid flies are often gray, reddish, or yel-if aphidiid wasps are present. Different wasp species lowish-brown, heavily bristled (or fuzzy), and aboutmay parasitize different aphid species. 3/8 to 1/2” long. Some tachinid flies resemble large,130 Organic Vegetable Production
  • 139. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.bristly house flies. Females may place their small eggs ditions). Under the correct environmental conditions,directly on their host. Some species inject living larvae certain diseases can decimate insect populations.directly into the host; others lay eggs or larvae on aleaf surface where they can be eaten by the host, or at Bacteriathe entrance of a host cavity or feeding tunnel fromwhere the larvae seek the host. Over 90 species of naturally occurring, insect-specific (entomopathogenic) bacteria have been isolated fromThe larvae or maggots are grayish or greenish-white; insects, plants, and the soil, but only a few have beenthey may have thick bodies with tiny spines or even studied intensively. Much attention has been given toplates. Usually only one larva survives per host. The Bacillus thuringiensis (Bt), a species that has beenlarvae of many tachinid species bore out of the host developed as a microbial insecticide. Bacillus thurin­to pupate, often in the soil. The time spent as larvae or giensis occurs naturally in the soil and on plants.pupae can be days or months, depending on the species. Different varieties of this bacterium produce a crystalTachinids overwinter as larvae or pupae within the host protein that is toxic to specific groups of insects. Btbody. There may be one or several generations each has been available in North America as a commer-season. Tachinid adults searching for hosts may walk cial microbial insecticide since the 1960s and is soldrapidly over leaf or soil surfaces, moving in hops and under various trade names. These products have ansmall flights around their target. Caterpillars and beetle excellent safety record and can be used on cropslarvae become extremely agitated in their efforts to until close to the day of harvest. Bt can be appliedfend off attack by a fly and will attempt to remove the using conventional spray equipment but, because theeggs from their body. Reported Tachinid hosts include bacteria must be eaten to be effective, good spraylarvae of European corn borer, corn earworm, imported coverage is essential.cabbageworm, cabbage looper, potato stem borer, stalkborer, cutworms, armyworms, Mexican bean beetle, Fungiand Colorado potato beetle; stink bug and squash bugnymphs and adults; and adult tarnished plant bugs and Some insect species, including many pests, are particu-cucumber beetles. larly susceptible to infection by naturally occurring, insect-pathogenic fungi. These fungi are very specificImmature insects parasitized by tachinids and other to insects, often to particular species, and do not infectparasitoid flies invariably die. Parasitized adults may animals or plants. Fungal growth is favored by moistcontinue to lay eggs before succumbing but parasitized conditions but fungi also have resistant stages thathosts are generally less able to survive environmental maintain infection potential under dry conditions.stresses and consequently their lifespan is shorter than Fungi can spread quickly through an insect popula-unparasitized individuals. Some adult tachinids also tion and cause its collapse. Because fungi penetratefeed on pest insects. Tachinid populations can increase the insect body, they can infect sucking insects suchvery quickly and their high fecundity and relatively as aphids and whiteflies that are not susceptible toshort life cycle give them a competitive edge over bacteria and viruses.many of their hosts. Fungi invade insects by penetrating their cuticle or “skin.” Once inside the insect, the fungus rapidly mul-Pathogens tiplies throughout the body. Death is caused by tissue destruction and occasionally by toxins produced by the fungus. The fungus frequently emerges from thePathogens are disease-causing organisms including insect’s body to produce spores that, when spread bybacteria, fungi, viruses and nematodes. They kill or wind, rain, or contact with other insects, can spreaddebilitate their host and are relatively specific to certain infection. Infected insects stop feeding and becomeinsect groups. Their effectiveness can be dependent lethargic. They may die relatively rapidly, sometimes inon environmental conditions such as humidity and an upright position still attached to a leaf or stem, per-frequently they are most effective when the susceptible haps in an elevated location or concentrated near cropinsect species occurs at high densities (crowded con- borders. Infected root maggot flies may be clustered on shoot tips, tall grasses, or other prominent features.Insect and Disease Management 131
  • 140. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Most insect pests of vegetables are susceptible to fun- ample while searching for suitable hosts for egg laying,gal pathogens. Some fungi, such as the Entomophthora beneficial insects such as parasitoids may physicallyand related species, are fairly specific with regard to the spread a virus through the pest population. Insectgroups of insects affected; others, such as Beauveria, viruses pose no threat to humans or wildlife. Viruseshave a wider host range. can overwinter in the environment or in overwintering insects to re-establish infection in subsequent seasons.Insect-pathogenic fungi usually need moisture to The successful commercialization of insect-pathogenicenable infection, and natural epizootics are most viruses has been limited.common during wet or humid conditions. The effec-tiveness of these fungi against pest insects depends Viruses invade an insect’s body via the gut. Theyon having the correct fungal species and strain with replicate in many tissues and can disrupt componentsthe susceptible insect life stage, at the appropriate of an insect’s physiology, interfering with feeding,humidity, soil texture (to reach ground-dwelling pest egg laying, and movement. Different viruses causespecies), and temperature. The fungal spores, which different symptoms. NPV-infected larvae may ini-can be carried by wind or water, must contact the pest tially turn white and granular or very dark. Someinsect to cause infection. Naturally occurring fungal may climb to the top of the crop canopy, stop feed-epizootics may decimate aphid, root maggot fly, ing, become limp, and hang from the upper leaves orcaterpillar, leafhopper, and thrips populations. Some stems, hence the common name “caterpillar wilt” orexamples include: “tree top” disease. Victims of a granulosis virus may turn milky white and stop feeding. In both cases, the• Entomophthora muscae infects flies. Susceptible body contents of the dead larvae are liquefied and pest species include the adults of the onion mag- the cuticle ruptures easily to release infectious viral got, cabbage maggot, and seedcorn maggot. The particles. Death from a virus infection usually occurs fungus multiplies within the body of the adult within three to eight days. fly which becomes enlarged; yellowish bands of fungal spores stripe the abdomen. Naturally occurring viruses may affect many caterpillar pests of vegetables. Isolates of NPV have been suc-• Beauveria bassiana is an insect-pathogenic fungus cessfully tested in field trials against corn earworm, found naturally on some plants and in the soil. imported cabbageworm, cabbage looper, armyworms, Epizootics are favored by warm, humid weather. It and European corn borer. Preparations of granulosis is known as the white muscardine fungus because virus have been isolated from several caterpillar infected insect larvae eventually turn white or gray. species, including imported cabbageworm, cabbage Susceptible insects include the larvae of European looper, armyworm, and fall webworm. corn borer, Colorado potato beetle, and Mexican bean beetle. Unfortunately, natural enemies, such Nematodes as some lady beetles, can be susceptible to some fungi. These are not the plant-attacking species of nematode, but beneficial, insect-attacking nematodes (or veryViruses small roundworms). Many species of naturally occur- ring, beneficial nematodes live both in the soil and onInsect-specific viruses can be highly effective natural plant material. The role of many of these species is notcontrols of several caterpillar pests of vegetable crops. well known, but some nematode species have receivedDifferent strains of naturally occurring nuclear poly- attention as potential biological control agents. Severalhedrosis virus (NPV) and granulosis virus are present species can now be mass produced and some are avail-at low levels in many insect populations. Epizootics able commercially.can occasionally devastate populations of some pests,especially when insect numbers are high. The commercially available nematodes are species of Steinernema and Heterorhabditis. Mass reared nema-Insect viruses need to be eaten by an insect to cause todes are shipped live as a suspension within a speciallyinfection, but may also spread from insect to insect formulated gel, as a slurry adhering to sponge mate-during mating or egg laying. In some cases, for ex- rial, or in clay. When water is added, the nematodes132 Organic Vegetable Production
  • 141. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.are released from their carrier. These nematodes are instances the importance of these naturally occurringtoo small to see without a microscope and there may beneficials has not been adequately studied. The bestbe millions of squirming little worms in each handful we can often do is to recognize that these factors areof soupy mixture. present and minimize negative impacts on them.Some nematodes actively seek suitable hosts, often Classical biological controlattracted by the carbon dioxide emitted by their prey.Others wait for passing prey. They carry insect-patho- In many instances the complex of natural enemies as-genic bacteria within their gut. Different nematode sociated with an insect pest may be inadequate. This isspecies carry different species of bacteria. Once the especially evident when an insect pest is accidentallynematode penetrates its host, usually through any introduced into a new geographic area without itsavailable opening, the bacteria multiply and kill the associated natural enemies. These introduced pestspest by septicemia. The nematodes feed on the bacteria comprise about 40% of the insect pests in the U.S.and insect tissue, then mate, and reproduce. After one Examples include the European corn borer, cerealto two weeks, young nematodes emerge from the dead leaf beetle, and Japanese beetle. To obtain the neededinsect to seek out and colonize new hosts. Affected natural enemies we turn to classical biological control.insects usually die within one or two days. Those Classical biological control is the practice of import-killed by Steinernema species turn a brownish-yellow ing and releasing natural enemies to help controlcolor from the bacterial infection. Insects killed by introduced pests, although it is also practiced againstHeterorhabditis nematodes become red and gummy. native insect pests. The first step in the process is to determine the origin of the introduced pest and thenMany vegetable pests are susceptible to attack by collect appropriate natural enemies (from that locationnematodes but, for many, the potential of nematodes or similar locations) associated with the pest or closelyfor field control has yet to be evaluated. Candidates related species. The natural enemy is then passedfor control include soil-dwelling larvae such as those through a rigorous quarantine process to ensure thatof cucumber beetles, cutworms, and armyworms, no unwanted organisms are introduced. The naturalcarrot, sweet potato, and other root weevils, Japanese enemy is then reared, ideally in large numbers, andbeetle, squash borers, root and seed maggots, and fall released. Follow-up studies are conducted to deter-armyworm and corn earworm in corn. mine if the natural enemy successfully establishes at the site of release and the long-term impact (benefit) of its presence.Types of biological control There are many examples of successful classical biological control programs. Damage from the al-Conservation falfa weevil, a serious introduced pest of forage, was substantially reduced by the introduction of severalThe conservation of natural enemies is probably the natural enemies. There are many classical biologicalmost important and readily available biological control control programs underway across the U.S. and aroundpractice available. Natural enemies occur in all veg- the world.etable production systems, from the backyard gardento the commercial field, they are adapted to the local Augmentationenvironment and to the target pest, and their conser-vation is generally simple and cost-effective. With The third type of biological control is augmentation,relatively little effort the activity of these naturally which involves the supplemental release of naturaloccurring beneficials can be observed. Lacewings, enemies. A relatively few natural enemies may belady beetles, syrphid fly larvae, and parasitized aphid released at a critical time of the season (inoculativemummies are almost always present in aphid colonies. release), or literally millions may be released (inunda-Fungus-infected adult flies are often common follow- tive release). Additionally, the cropping system maying periods of high humidity. These natural controls be modified (habitat manipulation) to favor or aug-are important and need to be conserved and considered ment the natural enemies. An example of inoculativewhen making pest management decisions. In many release occurs in greenhouse production of tomatoesInsect and Disease Management 133
  • 142. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.and cucumbers. Periodic releases of the parasitic wasp, Most beneficial wasps, flies, and many of the predatoryEncarsia formosa, are used to control greenhouse insects benefit from sources of nectar and the protec-whitefly; the predacious mite, Phytoseilius persimilis, tion provided by refuges such as hedgerows, coveris used for control of the two-spotted spider mite. crops, and weedy borders. Mixed plantings and the provision of flowering borders can increase the diver-Lady beetles, lacewings, or parasitic wasps such as sity of habitats and provide shelter and alternative foodTrichogramma are frequently released in large num- sources. Examples of habitat manipulation includebers. Recommended release rates for Trichogramma in the planting of flowering plants (pollen and nectarvegetable or field crops ranges from 5,000 to 200,000 sources) near crops to attract and maintain populationsper acre per week depending on level of pest infesta- of natural enemies. For example, syrphid fly adultstion. Research over the past several years has demon- can be attracted to umbelliferous plants in bloom.strated the Trichogramma ostriniae, an egg parasitoid Caution should be used with this tactic because someoriginally from China, is effective for suppression of plants attractive to natural enemies may also be hostsEuropean corn borer in sweet corn. Releases of 30,000 for certain plant diseases, especially plant viruses thatwasps per acre when corn is 18 inches tall and corn could be vectored by insect pests to the crop. Althoughborer is active should result in suppression of the pest the tactic appears to hold much promise there are onlyand damage. The released female wasps seek out and a few examples that have been adequately researchedinsert their eggs into eggs of European corn borer. and developed.Larvae hatch from the eggs and consume the contentsof the corn borer egg, killing the developing borer Lady beetles. Some species, in particular Coleomegillalarvae in the process. From these eggs emerge more maculata, consume pollen as an important part of theirmoths and the process continues through the season. adult diet. A source of nectar and pollen, or an artificialT. ostriniae does not survive winters in New York so substitute, in the vicinity of the crop may attract adultit has to be released each year – fields need to be “in- beetles and may reduce dispersal of this and other ladyoculated” each season. This species is now available beetle species. Lady beetle adults also benefit fromfor purchase and release. Recent work has shown that high humidity and nearby shelter, for protection fromT. ostriniae also holds potential against corn borer in adverse weather and to provide overwintering sites.peppers and potatoes. Early season populations of some lady beetles mayMany commercial insectaries rear and market a variety develop on aphid-infested perennials or shrubs. Col-of natural enemies including predaceous mites, lady lection and redistribution of lady beetles is effectivebeetles, lacewings, praying mantids, and several spe- but time consuming. The beetles should be handledcies of parasitoids. Success with such releases requires gently and placed in groups at the base of plants, ratherappropriate timing (the host must be present or the than broadcast. Hibernating adults, congregating innatural enemy will simply die or leave the area) and protected spaces, should not be disturbed as they arerelease of the correct number of natural enemies per vulnerable to attack by predators and parasitoids ifunit area (release rate). In many cases, the most effec- uncovered.tive release rate has not been identified as it will varydepending on crop type and target host density. Suc- Lastly, a healthy soil with ample organic matter iscess also requires a healthy and robust natural enemy. not only good for crops, but can profoundly influence the nematode community structure. A healthy soil can increase the total number of nematodes so thatConserving and encouraging predaceous nematodes and nematode attacking fungi can flourish. Generally, a healthy soil tends to reducenatural enemies plant-attacking nematodes. Given the lack of our full understanding of naturalNatural enemies are present all systems and their enemies and their interactions with pests, the best weconservation and enhancement should be encouraged. can often do is to learn what they look like or signsManipulating the farm system to augment the effective- of their activity and then minimize disturbance of theness of a natural enemy is relatively straightforward. system.134 Organic Vegetable Production
  • 143. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.References and additional University < http :// www . nysaes . cornell . edu / ent / biocontrol/>reading Credit, excerpted materialBat Conservation International. 2000. <>. Some of the material contained in this proceedings wasCunningham, S. J. 1998. Great Garden Companions— excerpted from the following publications.A companion planting system for a beautiful chemical-free vegetable garden. Rodale Press: Emmaus. Hoffmann, M. P. 1999. Biological control of insects: Past, present and future. pp. 9-12. In K. Stoner (ed.).Flint, M. L. and S. H. Dreistadt, 1998. Natural En- Proceedings, Farmer/Scientist Conference on Alterna-emies Handbook—the illustrated guide to biological tives to Insecticides in Managing Vegetable Insectspest control. Univ. Calif. Div. Agric. and Nat. Res. Dec. 6-7, 1998, New Haven, CT. NRAES-138, Ithaca,Publication 3386. NY.Weeden, C., A. M. Shelton, L. Yi and M. P. Hoffmann. Hoffmann, M. P. and A. C. Frodsham. 1993. NaturalBiological control: A guide to natural enemies in enemies of vegetable insect pests. Cooperative Exten-North America. World Wide Web Document. Cornell sion, Cornell University. 64 pp.Insect and Disease Management 135
  • 144. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Insect Management: Managing Beneficial Habitats, Using Organic Insecticides Ruth Hazzard Dept. of Entomology University of Massachusetts Extension Amherst, MA 01003 Phone: (413) 545-3696 Email: rhazzard@umext.umass.eduWhat’s different about insect I’ll just hope they tough it out and outgrow it; OR leafhoppers brought down my potatoes early, so I’llmanagement on organic farms? just harvest them now, put them in small bags, and charge extra for small potatoes). Another approachScale and diversity is, if one crop is too difficult to grow organically, I’ll grow a different crop.While its not always the case, organic vegetable farmstend to be smaller in acreage and at least as, if not Market demandsmore, diversified than conventional farms. This hasthe benefit that there are smaller plantings of any given While wholesale organic markets can be just as de-crop at any given time (no massive monocultures), but manding (zero tolerance for damage) as conventionalthe disadvantage that it can be difficult to rotate as far markets, many organic growers choose markets thatas is needed to escape a given pest. Another benefit is have more tolerance for damage, and this providesthat is spreads the risk. If you lose one crop in a given some leeway. This includes farmers markets andyear, you have 70 others to sell. If you lose the early CSA’s. Holey brassica greens (from flea beetle dam-planting, there will be several more coming along. age) go over OK in a CSA box or at a farmers market, but they would not do so well in a pallet going to BreadAttitude and Circus. NO markets get excited about wormy corn. However, I know organic farmers who are succeedingI find that organic farmers are willing to tolerate very well in very demanding wholesale markets andhigher levels of damage as the crop grows, and I know organic CSA’s and farm stands who only putsometimes in the final product. Sometimes this is out the very best quality.based on a certain philosophical view of nature andfarming (nature is basically benign; as a farmer I More attention to rotation, soil buildingam working with nature, not trying to overcome and cover cropsit; there is abundance enough to provide for whatI need and the bugs, too) or sometimes its just ac- On most organic farms, there is more willingness tocepting and making the best of what you can’t do invest in long-term soil building and to take land outanything about (the flea beetles are munching on of active production for a year or more and put it intomy early brassicas, but I can’t afford row cover and cover crops. There may be more thought given to136 Organic Vegetable Production
  • 145. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.rotational planning (though I find that conventional have to find other means and you are willing to tryfarmers do a lot this planning, too). more expensive, creative, and innovative strategies.More commitment and interest in long-term Costs are higherwhole-system strategies This all adds up to the fact that it costs more to produceThere are organic farms that have been able to reach a bushel of a given organic produce than it does tothe point where they don’t spray any organic pesti- produce a bushel of conventional produce.cides and they have high-quality crops all season long.This represents the outcome of years of watching, Prices are higher (sometimes)adjusting, fine tuning, combining a whole array ofpractices and choices to create a whole system that The price differential is especially noticeable at theworks. It also requires adjusting what you grow and wholesale level, especially when demand is high andwhen, as well as using a host of cultural practices to supply is low in the organic channels. The value of aminimize pests. box of wholesale organic produce in mid-season is the envy of any conventional farmer. At the farmersBeneficial insects (predators and parasites) market, consumers may or may not care enough tohave more opportunity to build up spend more at your stand than someone else’s who is not organic. CSA growers get essentially retail prices,Beneficial insects (predators and parasites) have more without as much of the cost of running a retail stand.opportunity to build up to higher population levels,and very likely have more impact on pest populations.These natural enemies include lady beetles, spiders, What insect pests are the biggestspined soldier bugs, insidious flower bugs, green lace-wings, syrphid fly larvae, and a host of parasitic wasps. challenges?Often you don’t know these are present until you knockthem out. There are only a few broad-spectrum toxinsthat organic growers can use (rotenone, pyrethrin), and Beetlesmost use them very sparingly. Beetles, especially the leaf-feeding beetles (Chrysome-The most striking example I’ve seen of this is corn leaf lids): Colorado potato beetle, flea beetles, cucumberaphids in sweet corn. Aphids colonize organic corn just beetles. The options for beetle control (rotenone, py-as they do conventional corn, but in years of scouting rethrin) are short-lived and not very effective. Theseboth types of farms, I’ve never (really, not ever! as beetles overwinter as adults in field borders, colonizestrange as it may seem) seen the huge buildup of aphids the crop very fast, and cause immediate damage. Somein tassels on organic farms that is fairly common in (e.g. striped cucumber beetles) also vector diseases.conventional sweet corn. The difference: conventional Lack of control in one year or one generation canfarms routinely use broad-spectrum insecticides at result in buildup of populations in the next generationleast once in most corn plantings, knocking out natural or next year. In a small-scale farm, it is difficult toenemies. Another factor may be the type of fertilizer. rotate far enough to escape them. However, the ar-High levels of nitrogen from soluble fertilizers tend to rival of spinosad as a control option will make somefoster higher aphid populations. In peppers, we have of these easier.documented that use of permethrin results in aphidoutbreaks, compared to very low numbers where no Migratory pestsbroad-spectrum insecticides were used. These arrive suddenly in large numbers, do not haveYou can’t just knock out the pest, so you many natural enemies, and can be difficult to control.get creative These include corn earworm in corn, and potato leaf- hopper in beans, and potatoes.There are a number of key pests for which there is noknockdown organic insecticide. This means that youInsect and Disease Management 137
  • 146. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Root maggots uses the pheromone traps to detect corn earworm flight, and applies oil to fresh silks when the flight reachesRoot maggots, such as cabbage root maggot fly, which damaging levels.attacks spring brassica crops. Efforts to find effectivebiocontrols have failed. Row covers, soil health, crop Timing of plantingsrotation, and plant timing are key strategies. Timing of plantings can help avoid periods of highThrips pest pressure.Thrips attack onions and cole crops. Often not a pest, Plant earlybut can bring crops down at high numbers and if cropsare otherwise stressed. Sweet corn: plant by mid May to avoid corn earworm, which migrates into the region in late July or August.Tarnished plant bug Plant lateThis pest has a huge host range and causes damage tofruit (e.g. strawberries) and leaves (e.g. basil, pepper) Potato: plant early or mid June to avoid Colorado potato beetle, which emerges from overwintering sitesMexican bean beetle late May to mid June. If beetles find no food source, they migrate elsewhere in search of host crops. Use early varieties to ensure maturity before season’s end.What pests are easy to deal with? Crucifers: plant after mid-May to avoid spring cabbage root maggot fly (first flight active from late April to midCaterpillars, especially those on brassicas. Bacillus May); plant after mid July to avoid the first generationthuringiensis (Bt) products work very well. Euro- of flea beetle.pean corn borer in sweet corn also can be effectivelycontrolled with Bt sprays. Spinosad will add another Vine crops: set out transplants after the middle of Juneeffective tool. to avoid the worst of the striped cucumber beetle, and get past the most susceptible early stages (cotyledon to 3 leaves).What strategies help organic Floating row covers. There are several differentgrowers successfully prevent weights of floating row covers (e.g., Reemay, Typar),losses to insects? spun-bonded polypropylene covers, which can be laid directly over the crop or supported by hoops. Air and water travel through the cloth, but insects cannotSoil health, good production practices (assuming edges are sealed). This is an excellent pest control as well as providing some frost protection andHealthier crops do sustain less damage or tolerate and added air and soil warmth for earlier yields. Widelyoutgrow damage more readily. used by organic growers for:Using IPM tools 1. Cabbage root maggot fly on spring crucifers. Eggs are laid at the base of the stem by first-generationPrevent pests using cultural practices, monitor pest adults, which fly from late April to mid May.conditions in the field; spray at the critical time the pest Maggots feed on roots and kill early cole cropreaches economic thresholds. An example: an organic seedlings. Row covers are a very effective control.pepper grower who uses pheromone traps to detectEuropean corn borer flight, then when the threshold 2. Flea beetles on greens (crucifers and others). Tinyis reached, applies Bt every 4-5 days during the flight black beetles cause shot-hole feeding. Can be usedperiod. Another example is a sweet corn grower who all summer on direct-seeded crops, or in spring138 Organic Vegetable Production
  • 147. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. or fall on transplants. Too hot for transplants in Bt tenebrionis (e.g. Novodor, Beetle Beater) against midsummer. Colorado potato beetle. These are only good against larval stages. Some products contain prohibited inerts3. Leaf miner on spring spinach and chard. A fly (e.g. mineral oil in Dipel ES) or have been genetically which lays eggs on underside of leaves, maggots manipulated (e.g. Raven, Mattch) so are not allowed. tunnel inside leaf. And transgenic Bt plants are prohibited (as are contami- nated kernels that might have resulted from the pollen4. Cucumber beetle on melons, summer squash, of your neighbor’s Bt corn). The manufacturer of Dipel cukes, winter squash. Protects both from feeding has produced a special formulation of Dipel ES for the damage and vectoring of bacterial wilt. Must be organic market, and it is making its way through the removed at flowering. approval process. This is an indication that the organic farming industry has grown to a significant size.5. European corn borer on early corn. Speeds growth of early corn and protects from moths if left on Insecticidal soaps into mid to late June, after first flight has peaked. Apply loosely to allow for corn growth. Insecticidal soaps are made from the soaps of fatty acids, and are used as contact insecticides to controlInterplanting and bio-strip intercropping soft-bodied pests such as aphids, thrips, whiteflies, leafhoppers, some immature caterpillars, and mites.Build into the farm plan plants which provide resources Good coverage and repeated applications are impor-for natural enemies, including those in the Umbelli­ tant, but it does work. Non-persistent, low toxicity.ferrae and Compositae families, which attract parasitic (M-Pede, Safer’s Soap, Concern).wasps and predaceous flies and beetles because theirflowers have short nectaries. These resources can also Vegetable oilbe provided in sod strips between beds, or in borderareas. May be mowed at key times to encourage flow- Used against corn earworm in direct silk applicationsering, or produce mulch. to sweet corn. Corn oil or soybean oil may be used. Acts by creating a suffocating barrier to larvae crawl-Mulch or cover crops ing down the silk channel. Most effective when mixed with a Bt product. Exempt from FIFRA and food toler-Using strips of unmowed rye between rows of potato or ance requirements. A specially-designed oil applicatorcucurbits can reduce colonization by beetles. Similarly, (Zealater) is available from Johnny’s. For more info,rye or straw mulch has been shown to reduce coloniza- see <>.tion of potato by Colorado potato beetles. Beauvaria bassianaOrganic pesticides: using the tools we have One of several naturally-occurring fungal pathogensMany organic growers do spray for insect pests, but of insects. Spores are applied directly to insects or tothe tool box is very limited. Active ingredients and plant surfaces or other habitats (e.g. soil), where insectsspecific formulated products have to be approved by pick them up on their bodies. Under favorable condi-the National Organic Program. Several new options tions (warmth and high humidity), spores germinatehave recently been developed and approved, or are and penetrate the cuticle, and produce toxins that killexpected in the next year or two. the insect. Hyphae grow fill the insect’s body, often producing fuzzy white growth that is visible on theBacillus thuringiensis (Bt) outside. Most effective when used in high humidity environments. (Naturalis-O, Botanigard 22W, ES,Derived from a naturally-occurring bacterial patho- Mycotrol) GH, field. Note that Botanigard ES cangen, Bt has been isolated and formulated for use as cause oedema in greenhouse tomatoes; use the 22Wa foliar spray. A tried-and-true organic tool. Organic formulation on tomato.growers use Bt kurstaki (Dipel DF, Javelin WG or Btaizawi (e.g. Xentari) products against caterpillars andInsect and Disease Management 139
  • 148. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Kaolin clay Hot pepper waxFine white clay which disturbs insects’ visual and Capsacin (the “hot” component in hot peppers) micro-tactile cues on host plants; adheres to insects. Beetles, encapsulated in a mixture of mineral oil and paraffin,soft-bodied insects. Labeled for flea beetles on fruit- which adheres to plant surfaces. Acts primarily asing crops, and cucumber beetle on cucurbits, thrips on an insect repellent, but is also a toxin to insects andonions. (Surround WP). Wear a mask or respirator to mites. Looked promising vs. flea beetle in brassicaprotect from inhalation. greens in a UMass trial in 2002. (Hot Pepper Wax Insect Repellent)Spinosad Garlic oilDerived from an actinomycete fungus that is patho-genic to insects. Spintor 2SC has been on the market for (Envirepel, Garlic Barrier, Garlic Grow)several years, but was not allowed for organic produc-tion. In 2003 there will be a newly labeled formulation(Entrust) that has NOP approval. It is effective against More on biological controlcaterpillars, Colorado potato beetle (CPB), thripsand leafminers and is labeled for fruiting vegetables,potatoes, brassicas, and cucurbits. This will be a big Conservation of natural enemiesboon for CPB control, because it works against adults. As mentioned above, using selective insecticides thatBotanicals (extracted from plants) do not harm beneficials, and providing them with re- sources such as nectar and shelter, increase the levelNeem of biocontrol that is taking place. In certain instances, augmentation, or the release of mass-reared benefi­Extracts from the tropical neem tree have been used cials, can also help in suppressing pests. This tends tofor centuries in insect control. Neem oil acts upon be more successful in greenhouses than in the field, butimmature insects an insect growth regulator, disrupt- there are now several instances where releases in theing their molting process. It is also an antifeedant and field have been proven to suppress, if not completelyoviposition deterrent. It works slowly and should be control, key pests.applied several times well before numbers reach dam-aging levels to get the best results. (Azadirect, Azatin, A useful directory for choosing a natural enemy sup-Neemix, Bioneem, Align; Trilogy 90, Neemazad, plier is Suppliers of Beneficial Organisms in NorthTriact; active ingredient is azadirachtin). America available from the California Environmental Protection Agency, Dept. of Pesticide Regulation, En-Rotenone vironmental Monitoring and Pest Management, 1020 N St., Rm. 161, Sacramento, Calif. 95814-5604. tel.Broad activity against a wide range of insects, espe- 916-324-4100 ( beetles. Hard on beneficials; highly toxic to fish; bensuppl.htm).applicators should use protective gear. Two helpful sources for biological controls locatedPyrethrin here in the Northeast are:From the flowers of certain species of Chrysanthemum. The Green Spot, Ltd.Broad activity as a nervous system toxin, against a wide 93 Priest Rd.range of insects. Hard on beneficials, but low mam- Nottingham, NH 03290-6204malian toxicity. Often mixed with piperonyl butoxide (603) 942-8925(PBO) as a synergist, but this makes it prohibited.Pyganic Crop Protectant is currently the only approved IPM Laboratories, Inc.pyrethrin product. Locke, NY 13092-0300 (315) 497-2063140 Organic Vegetable Production
  • 149. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.Examples of mass-reared biocontrol organisms 943-8925 For more information, you can contact:for vegetable crops Carol A. Holko, Maryland Department of Agri- culture, Plant Protection and Weed Management1. Beneficial nematodes. Nematodes are very small Section, 410-841-5920 (http://www.mda. state. roundworms. Some species are plant pathogens, but some attack soil-dwelling insects and two in particular (Steinernema and Heterorhabditis) 3. Other species in this family include Edovum put- have been mass-reared for commercial use. These lerii, also an egg parsitoid, which can be released seek out and penetrate their host insects, multiply to control Colorado potato beetle in eggplant (not within the host and kill it. Most likely to be effec- effective in potato). tive against the soil-dwelling immature stages of susceptible hosts, such as root weevils, cutworms, 4. Trichogramma spp. These tiny wasps lay their white grubs (use Heterorhabditis), wireworms, and eggs inside the eggs of insects, and wasp larvae maggots. Require moist soil conditions to survive. develop inside, killing the egg. Several species are commercially available, but the most useful2. Pediobius faveolatus is a small parasitic wasp in gardens would be T. pretiosum for caterpillar of the Eulophid family, which attacks larvae of eggs. Releases should be timed to coincide with the Mexican bean beetle. To purchase Pediobius, egg-laying. Another species, T. ostriniae, is now contact: ARBICO, (800) 827-2847 (AZ), (http:// available and is very effective against European; The Beneficial Insect Com- corn borer. Ask supplier for instructions on release. pany (NC), 336-973-8490 (http://bugfarm. com/) Sources for T. ostriniae: Beneficial Insectaries, ; Rincon Vitova (CA), 800-248-2847 (http://www. 800-477-3715, IPM Labs (see above). or The Green Spot (NH), 603-Insect and Disease Management 141
  • 150. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information. Pest Management on Applefield Farm Transcript of a presentation by: Steve Mong Applefield Farm Stow, MassachusettsThis kind of meeting is great. When I first started out 90-95% of our crop that we grow goes to our farmthere was no research, people, anything about how to stand so that makes the market different than a lot ofgrow a crop organically. There was nothing. There was other people. We can talk to our customers. They canno information, no interest, and in the last 10 to 15 ask us questions.years it is amazing how much good research is going onfor our benefit. A lot of it’s for ground water protection Insect and disease control is what I am supposed to beand other issues but it is benefiting us organic people talking about. I think in organic farming that is almosttremendously. Most of us farmers won’t change unless one of the easier subjects. To some extent there are notthe research is there to show us that things actually that many things we can do. I would guess that I spendwork. Any of you that have been farming for a while less on 25 acres of property, where we are grossingknow that it’s always an ongoing research project. The $100,000 or something like that in vegetables, weyears are never the same. You’ve got different growing spend less than $200 a year on average on chemicals.conditions, different crops, different bug pressures. Most of insect and disease control revolves aroundThings that work one year don’t work at all the next. your cultural practices. Whether it’s planting a little bitSo it’s not an exact science, which is what is part of later, going to transplants instead of seed. All of thosethe fun of farming. things that they talked about earlier today. The cultural practices are probably the number one resource that weWe started out 20 some odd years ago, self-serve have to take care of the insects and disease.with a bench. Then the next year another bench andthe next year another bench then put some people, Tremendous amount of beneficials out there. Once youstarted hiring full time and a steady progression over start looking you realize that, yeah, there are aphids onfifteen years adding up to where we are presently do- those plants but don’t spray them because you’ve goting around 20 to 25 acres of field crops and around a four different kinds of beneficials out there taking carehalf acre of greenhouse. We’ve been trying everything of it. Give it some time. In 20 years I think I had toover the years. We don’t have a single system on the spray a pepper crop once. Because the aphid populationfarm that works, we have a bunch of systems and we was just too high and I didn’t think it could balancekeep trying new things and we keep going to meet- out. It was probably there from in the greenhouse. I’veings and learning more. We’ve done a bunch, we try gotten better. They don’t go out in the field with aphidsa bunch and for the most part it is working out pretty already on them. I don’t know if that is what it waswell. We are a direct retail. We have a farm stand. but in 20 years I’ve only had to spray pepper plants142 Organic Vegetable Production
  • 151. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.once for aphids. Tomato plants the same way. I think Corn, Ruth mentioned. I’ve worked with Ruth Hazzardone year the balance was out of whack. The hornworm for almost 10 years on that corn earworm project. Builtwas just too big. We sprayed them once. Many times my own applicators for a while. People used oil cansI have thought about spraying. I didn’t want to affect and little bits. It doesn’t have to be high tech. I startedthe natural population. I lost a few leaves but then sure out the first year I actually tried it I had my acres ofenough the natural beneficial comes in and takes care corn and I just did, I think, four rows. Two down andof the problem. two back, and I tried to time it so that I could pick that on the weekend.A couple of other notes. I do a lot of beneficial stuff.Our greenhouse, we have almost up to a half acre of Because we have regular customers where we are pick-greenhouse now, its getting to be one of the bigger ing and they learned about the worm and they didn’tparts of the operation. I rely tremendously on brought like it when it showed up. But we left a knife on thein beneficials. In that enclosed environment they work table they could leave the worm with us. It was okayextremely well for almost all of the insect pests that but your sales do go down. But weekends it was ayou might have. I’ve been doing the Trichogramma for whole other crowd there is enough tourist activity andyears, ostriniae now and the pretiosum before that. I new people driving by and boy the customer comes inthink that there is a lot of new research coming out and and your whole farm stand is judged by that one earthe rearing processes for some of these beneficials is of corn. It’s so disturbing to have them just “Ugh” andgetting better so the price is coming down. It is becom- just run out of the door and you will never see theming more of a viable option on some of these crops. again. I saved this corn and I only picked it for the weekends. It only lasted that one weekend but I saw aI’m going to rely a lot on individual questions. The remarkable difference in the numbers of ears. It wasn’tdisease and insect control is so dependent on what is 100% but it probably went from 40% clean to 60% orgoing on in your own farms. I’m happy to tell you what 75% clean. I’m not a researcher but if you don’t hearI do. A couple of the major crops I’ll talk on briefly is too many squeals it is better. And so Ruth started thissomething like tomatoes. For us and for anybody prob- program, so we have been doing this for quite a while.ably it’s one of the number one value crops we grow.Insects to me are not a problem on tomatoes; I have This past year we had such a drought where I am thatnever had, like I said once I had hornworm. Disease I had a choice to water the corn or do the oiling and Iis an issue and what we’ve worked out is we plant watered the corn and the customers dealt with it. Butthree distinct crops of tomatoes. An early planting, the the year prior to that I oiled almost all of the late seasonmain season planting and I’ll put in a late planting of corn. It doesn’t come in in the early season, it’s the lasttomatoes so that they are just starting to bear for the month or so. It’s not that daunting of a project and thefirst of September which I consider the hardest time corn was pretty darn good. I’m disappointed becauseto keep tomatoes coming in. So they are young, they I did put the ostriniae out there because I was thinkinghaven’t even produced yet, they are coming in at the okay now I’ve got the corn borer protection and I justend of the season. never followed up with the earworm protection. So those are the two main crops, corn, and I don’t haveWe will work hard not to pick one crop of tomatoes and aphids on the corn there are just tremendous beneficialsanother crop in the same day. I don’t want to spread out there. You have to be careful picking your corndisease from one to another. Keep them separated, stay to not squeeze the immature ladybug larvae that areout of them. Disease management. When the plants are running all over it.wet don’t go in there. And you can really significantlyextend your tomato-growing season without anything. Two other of the major pests that Ruth just mentioned.I have to say I have in the last couple of years used Leafhoppers, what a pain. And striped cucumber beetlea new product called Oxidate. Sometimes known as primarily. But cucumber beetles there are so manyZerotol. With this mist blower have been able to go even in the rotation all the pumpkins and squash andthrough and have a surprisingly good late season crop cucumbers and zucchini and gourds get mixed upof tomatoes. The cleanest I’ve ever seen. around. But they are everywhere. Our answer for the striped cucumber beetle for the most part is we have gone back to all transplants so the plants are biggerInsect and Disease Management 143
  • 152. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.when they go in. Take off quicker. A lot of things we to spray acres of corn?” I sorted it out. I could spraywill plant a little bit later so the ground is warmer. They with one tankful; I sprayed close to a half acre plus.will grow quicker and it gets them out of that most Which is the concept of a sprayer like this. They call itsusceptible stage. We did do the Surround two years low volume. Which means low volume water. You’veago in the transplant trays. That does make a difference. got the same amount of material going on per acre.I don’t like working with the Surround. I’m not sure if Instead of using 50 gallons of water or 25 gallons ofI will keep working with it. We were never a certified water you are using two or three gallons of water. Veryorganic operation, being a direct retail we could talk. low water with a very high concentration in the tankI followed MOFGA’s rules, which is Maine organic but the application, as the droplets come out it dropsfarmers. Currently we are probably not going to go into the air stream and it gets sheared off so it breaksthrough the certification. I’m not sure how close we are whatever chemical you happen to be using into verygoing to follow. If we had to go around with a pump small particles. To give a complete coating of whateversprayer to spray a little bit with a rotenone pyrethrin you are what we used to use. But again cultural practice andI think with some of this new trap cropping there are It is really difficult to get used to the concept of us-some improvements on that end. ing a tool like this because the concentrations are so high. I might put a quarter pound of BT in that twoLeafhopper that is one that to some extent we like the and a half gallons of water. It’s a hard concept but forleafhopper coming in. That’s our natural burn down. certain crops it makes a lot more sense than spendingThe plants decline so it hardens the potatoes off, so a few thousand dollars on a sprayer that you wouldlong as it doesn’t come too early. There were a few use once or twice a year or every three or four years.times that I had to spray and that is one of the few It is just something to keep in mind. This is the leasttimes I used this machine here (backpack mist blower) expensive thing I know for a mechanized sprayerand rotenone pyrethrin was allowed, this was probably that can do some acreage. People who have a smallthree years ago. Last year we didn’t really have much orchard application these things are great. If you areof a leafhopper problem. I don’t know why. We were just doing ten or 15 trees. Peaches, apples, whatever.lucky. They do vary tremendously year to year. That It’s an interesting the problem with some of these pests. They all fireup one year and the next year they are not there. It’s I can talk more about any of this stuff, so questionsa tough one. would be great at this point because I don’t have much material.When I was spraying the pumpkin field. One of theadvantages and I guess I’ll briefly talk about themist blower. This is a motorized backpack sprayer. Questions and answersI bought it primarily to use in the greenhouse. Theyrun about $500. Some of these other sprayers peoplebuy are $2,000-$3,000 and I don’t have that big of an Q:  How far does the mist go from the nozzle?operation. I’m real surprised; we use that in the field alittle bit. Primarily we rely on the pump sprayers and A:  If there was a hanging basket hanging up in thefor the most part they do pretty good. The really nice corner I could spin it. Roughly a 200-mile per hourthing about having a wind coming out is if you want wind coming out. That’s probably pushing it. If youto get material under, sometimes I have used it on the were trying to do full sized apple trees you would havepumpkins and watermelons, real low rpm, walk around to walk into the tree and really work on it. It’s got someand you can just see that the plant is just blowing over. distance and that’s why I like it in the greenhouse. It’sYou are getting material all over it and I was real leery. why I bought it in particular, because I can walk down the greenhouse and get what I need and then actuallyThe project we had last year with the corn project see the hanging baskets doing this. I’ve got coverage.where Ruth wanted everyone participating to spraytwo applications with BT for corn borer. I’m going Q:  Is there a concern with spray drift? Sometimes“I don’t have a sprayer. I can get over little corn but I you only want to spray one crop.can’t drive the tractor over big corn. How am I going144 Organic Vegetable Production
  • 153. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.A:  True. Again you can adjust the airflow; you can finally figured out that in my greenhouse operation Iadjust the droplet, so that when I spray I’ve got like treat that 2 1/5 gallons as if it was 25 gallons. Thattwo rows of tomatoes side by side on plastic. I’m con- seems to work pretty good for me. I am treating thecentrating my spray on the tomato plant. You’ve got equivalent area that 100 gallons dilute would take carevery good control. If I was trying to grow an organic of. You have to gain some experience and it is not thatcrop next to a non-organic crop I couldn’t guarantee easy and it is not that hard either.that there isn’t going to be a little bit of a drift but thereisn’t much. So if you are worried about that you can Q:  You’re using Oxidate against tomato diseases?walk down the other side of the plant. But pretty muchif you need it to go the distance you can wait for it to A:  Yeah OxiDate, ZeroTol. Are people familiar withget out there or you can adjust the droplet size, slow it it at all? Zero tolerance is what it first came out as anddown. They also have a diffuser; and different nozzles that was registered for greenhouse for cleanup so itthat you can put on to broaden or do different things wasn’t registered specifically for vegetables. So theywith the exhaust. It’s certainly no more of a problem, had to come out with the exact same formulation, butyou have the same problem with the pump up sprayers it’s got the vegetable label and it is called OxiDate.if you’ve got two or three rows and if the wind is blow- It is a hydrogen peroxide type. There is some gooding there is some drift. Whenever you spray anything proprietary stuff I don’t know.there is always a concern with drift. No more than, Idon’t think, any more than most things. I use it a lot in the greenhouse. We do a lot of sub ir- rigation and to keep the water clean and to keep algaeQ:  How do you calibrate a mist sprayer? from forming, as a disinfectant it has been wonderful. But because of it being a disinfectant it does kill sporesA:  That’s what I say it’s really a tough thing. The on contact. It has got no residual effect. You spray it,very best thing to do is fill it up with water, walk down 10 minutes later it’s gone. But as a disinfectant forwhatever area you are going to be doing. Some of it is some of the bacterial diseases, fungus and stuff I thinkgoing to depend on, do you like to stroll, do you want it has a just take your time or are you willing to walk as fastas you can walk. It all depends on your pace to how But again, as a person I don’t know if I have mentionedlong the water lasts. So if you know an area and go and this but as a grower I have always hated to spray. If Ispray that so you know OK that’s a quarter acre. Now can avoid spraying, I will do anything to avoid spray-you know if you can only do half of that well then. ing. I read the label, just about six or seven yearsYou are only doing a quarter of it so it’s all individual, ago, I bought this stuff because we had smut, it wasit’s going to depend. determined to be smut on our cosmos that we use as a real good cut-your-own flower. When you are cuttingSome people it takes some knowledge, because you and you go cutting down the row and it looks a lot likecan adjust the droplets going in there. So you can powdery mildew but I identified it as smut. Anywaymake flow fast so you see a bunch of material or you it was starting to take over a row and my wife saidcan make it flow so you almost don’t see that there is do something with it. I looked at this label and I said,anything coming out. So it’s all in your comfort, but “God, it says spray three days in a row and then spraymany people make the mistake of using this and to do once a week for the next two or three weeks.” So that’sa half acre they would fill up the tank eight times. It is a lot of spraying.just too much work. Once you get a little comfortablewith it concentrate that spray material, but you have Part of the theory is there is now a sodium, a potassiumto gain the experience. bicarbonate. There are a number of products out there and ZeroTol is kind of in this same category. Part of theIn the greenhouse I have gotten to the point where I reason they said to spray three times is 90% coverageknow, because out in the fields they talk about so many is not good enough for a lot of these diseases and evenpounds per acre. You know all of us small farmers we some of the insects. If you are doing apple trees andare doing a couple hundred of row feet, how much of have mite problems. If you don’t get 100% coatingan acre is that. In the greenhouse everything is done on the tree for mites or 100% coverage for some ofby amount of material per hundred gallons. Well I’ve these soft biologicals, the diseases multiply so fast youInsect and Disease Management 145
  • 154. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.almost might as well not bother. So you need 100% Q:  Does the mist blower work with Surround?coverage. The way to get 100% coverage, since thestuff is basically harmless, they have you spray three A:  I used it. I also painted the car beside me and it tooktimes in a row. So that you hit it one day and now you a while for that whitewash to come off. I have no ideahave got 80% of the plant, and you hit it again and you what label rate I used. I called up the manufacturer, Iget some more, you hit it again and you might get the go look, because the concept is not to be used a lowrest. With the mist blower, I went through, and it’s got volume. I more or less said “well I have got to make itthe advantage that it does a better job. You hit the front thick, but I can’t be too thick to go through the nozzle.side of the plant and it tends to draw back around. But I I forget what rate I used, but I’m fairly impressed bywent back around the rows and hit from one direction, how well it performed and the reason I did it with thethe next day I went and made sure that my application mist blower is you just cannot get disturbance. Youwas going the opposite way. Dr. Wick, he didn’t think are only going to be painting the tops and sides of thethat we would get rid of it. leaves. What I would consider if you are doing it in flats, I don’t know if anybody has tried this as a dip,That cleaned that crop up and let us get a harvest and whether or not you could make a solution and dipnear the end of the season I saw it starting to come the flat in so that you have got the stuff soaked. Thatback again, but by then it didn’t matter so much. I might even be a better way and not as messy either.don’t think it is a Godsend. I don’t think there has been We had two hay wagons full of flats and I just stoodmuch research done on it. But two years ago I tried it, up and stood back and just painted the trailer and thenI used one cup of OxiDate per tankful and with one we took them out to the field a couple of days latertankful I could do about four 500-foot rows. So I just and planted them.walked down pretty quick. Easy to fill up, easy to gospray it. Five or six days later do it again. I didn’t do Q:  What crop and pest were you using Surroundany trials. It’s like all right it’s late in the season, the on?dew is on the plants until 11:00 in the morning, thedew is back on at 4:00 in the afternoon. It is a tough A:  For striped cucumber beetle before we put themtime for tomatoes and we never got around to staking out in the field. That was something that Ruth hadthese particular tomatoes up. They are Mountain Fresh, thought might work and I said “Hey I’m a farmer, wewhich is a nice tomato, just coming into production. try anything.”There is always foliage cramped down in. I’ve got toget something in there and I do not like using copper Q:  What do you do for powdery mildew control?sulfate. I avoid it like the plague if I can. I use it veryvery little. It worked for me and I don’t know if it is A:  Nothing. Variety selection, rotation, but no I can’t.the answer but I had it, I liked the results. A lot of The big crops that could be a problem with powderyfarming is like that. You guys must do the same thing, mildew there is no way I am going to think about go-try things. Is that enough of an answer for OxiDate. ing and spray. I mean I possibly could, but I have not found it to be a serious enough issue to worry aboutQ:  How much does it cost? it. Benign neglect works pretty good for most things. I just don’t worry about it to a large extent. If I saw itA:  Very expensive, I believe it is a hundred and some- on a high value crop I would use the OxiDate. I thinkthing dollars for a 2 1/2 gallon jug. You don’t need it would work. I don’t see those kinds of disease pres-a whole lot on the rates. I use so much of it on the sures enough. When I am thinking of powdery mildew,greenhouse operation I buy it by the 15 gallon drum I am thinking of it primarily on the pumpkin leaves atwhich brings it down a little bit. It’s just now being the end of the season start getting white, and zucchinisreleased, they just got a new product for sanitation, and stuff like that. We don’t lose enough fruit to worryfor a wash dip. If you wanted to dip your tomatoes, about it too much from my experience.or dip things for helping to preserve instead of usingchlorine or whatever, this is now registered and it is Q:  What are your favorite three tomato varieties?certified it will be an OMRI approved product. I thinkit is basically the same material. A:  Three? Oh, well it’s not any individual. So I may grow four or five different types that I plant for an146 Organic Vegetable Production
  • 155. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.early planting that I will pick for the farm as an early Q:  What kind of tomato diseases are you runningtomato. Early Cascade I use, and some of the cherry into?tomatoes. I have never liked Early Girl. But there is anew one this year I have done. Names I can’t remem- A:  The primary disease that I am worried about is Iber, but there is a new version of Early Girl out there think late blight. I have not identified it. Late in thethat I think. No never done those. Everybody has their season, I think everybody, especially if you are pickingdifferent areas. off plants that have been being harvested for a while. You are coming into cultural conditions where you justWell Mountain Fresh I consider to be a late tomato, don’t have much daylight. Late August and getting inand when I first saw Mountain Fresh, this is getting to September the plants aren’t even dry until 10:00 oroff of the subject, but that is probably okay. Mountain 11:00 in the morning. The period of leaf wetness is justFresh scared me when I first saw the tomato because the incredible. The temperature is up and the amount ofplants were gorgeous, huge and healthy, the tomatoes disease that is blowing around in the field from yourlooked good and I was worried that when I bit into it, fields, your neighbor’s fields or your earlier plantingsit would be like some of these tomatoes – looks great is a problem.but the skin is still in your mouth after you chew it up.It is a firm flesh, but I thought it was quite acceptable Q:  Are you thinking late blight or early blight?flavor and the customers don’t seem to mind it so I amreal impressed. A:  Early blight is the more common tomato disease and then late blight is a really devastating tomatoWe grow almost all determinant varieties. I used to disease that comes in kind of sporadically. Somedo trellising and I wish I had the time because some years we have it and some years we don’t but thatyears the trellised tomatoes, some years the ones on really common one that we get every year is earlythe ground or on short stakes work better. It depends blight. Don’t worry about that earliness or latenesson the year and amount of rain or dryness. Ideally you part of the a little bit of all of these different things. We areprimarily doing short stake. We have done the Best It is a blight and it comes in late. I am sure Abby isBoy, Bush Big Boy, it is a Burpee one that has been right. I don’t need to identify all these things exactly.pretty good. So it is not the old fashioned Big Boy it is I know it is a problem and I am trying to learn waysa dwarf version with more disease resistance. I gave up to deal with those individual problems.Mountain Pride for Mountain Fresh. A lot less diseaseissues, much healthier plant. Very similar tomato we Beneficials – we talked about these. Do many peoplejust have had better luck with it. buy or are many people working on beneficials? Using beneficials? Buying in Trichogrammas?The big secret or what I am trying to convey is not somuch variety as being sure that whatever you choose Q:  When you bring beneficials into the greenhouseto plant for early tomatoes you know that those early how long before you see results?tomatoes do not last. Some of them do not taste goodor the plants get tired, they get early blight. We do A:  Part of the trick in the greenhouses and for pre-this with many crops, beans, zucchini. You succession ventative measure is you want to not wait. Thrips isplant. The thing is you do not want to succession plant probably the number one problem in the greenhouse.side by side by side because that disease is just follow- Last year was the first year that I went to 100% using aing you right along or the insects. The big thing is to beneficial mite. I was real nervous because I hunted allisolate some of these earlier plantings from your main season long and never saw any. I spent probably $1000season plantings from your later plantings so that you on these beneficial insects and never saw them. Thehave a chance. Whether it is insects you are trying to only thing I know for sure is that it just could not beavoid or disease. To a large extent I think it is disease the first year in 15 years that the thrips just magicallyfor tomatoes in particular. With good cultural practices did not show up. I am pretty sure. That is the problemyou can avoid many, many of these problems. with the beneficials. Research people can get out there and put them in a cage and count how many holes are in the leaf and some of this stuff. We can’t do that. IInsect and Disease Management 147
  • 156. This page is from Organic Vegetable Production, NRAES-165. To purchase the book, visit, or call (607) 255-7654. Page 1 of this PDF has fair use information.looked at the research. It looked promising. I did it on are sprayed with a pesticide it is a biological, but fora small scale a year before. I felt fairly comfortable the last couple of years having the beneficial waspsand I continued scouti