Grow Your Own, Nevada! Fall 2011: Season Extension
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Grow Your Own, Nevada! Fall 2011: Season Extension






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Grow Your Own, Nevada! Fall 2011: Season Extension Grow Your Own, Nevada! Fall 2011: Season Extension Presentation Transcript

  • Season Extension Susan Donaldson
  • What is season extension? Increasing the growing season at either end, spring and/or fall
  • Why try to extend theseason? Allow more time for crops to mature Grow different varieties Move toward year-round production and income potential Fresh greens in the winter
  • Frost-free period We’ll define the length of a frost- free period as the number of days between the date of the last 32°F temperature in the spring and the date of the first 32°F temperature in the fall.
  • What’s “freezing”? The National Weather Service defines a “freeze” as occurring “when the surface air temperature is 32°F or below over a widespread area for a climatologically significant period of time (greater than one hour).” (U.S. Department of Commerce, 2005)
  • How long are our frost-free periods? Lots of variation among periods for the last 100 years Some years have had frost-free periods of over 150 days (approximately 5 months) Other years have had frost-free periods of less than 90 days. (Reno data) KEY: lots of varibility, so you have to watch the weather predictions!
  • Do frost-free periods everchange? For the 30-year period of 1971-2000, the average date of the last 32° temperature in the spring was May 21 while the date of first 32° temperature in the autumn was October 3 (134 days).
  • 1991-2005 The date of last 32° reading was May 3, and the date of first 32° reading in the autumn was October 19 The average length of the frost- free period grew from 134 days (for 1971-2000) to 168 days for the more recent 15-year period This is an increase of a full month!
  • Hard freeze A hard freeze is sometimes defined as occurring on a date when the temperature drops to 28°F But…you can expect damage when temps drop to 32°F
  • City Frost-Free Days Carson City 90 - 116 Elko 57 - 87 Ely 53 - 81 Fallon 106 - 131 Lovelock 111 - 140 Reno 85 - 125 Tonopah 107 - 147 Winnemucca 75 - 107Based on historical data indicating 90% (first number)- 121 Yerington with temperatures above50% (second number) 82 to 32°F.probability of consecutive days
  • Cold damage Plants lose heat faster than the air! Anything that reflects the radiating heat back down will prevent or at least greatly reduce frost formation (for example, clouds)
  • Season Extension:Start with cultural practices Site selection and microclimates Soil and moisture content Windbreaks and shade Irrigation Cultivar selection Transplants
  • Take advantage ofmicroclimates Some areas around your property warm up faster in the spring, stay cooler or warmer in the summer, or are protected from the wind South-facing slopes will be warmer Cold air settles into valleys
  • Site selection #1: Hours of sunlight Prevailing winds
  • Windbreaks and shade • At right angles to prevailin g winter winds • Consider effect on sunlight
  • Shade fabrics
  • Shade fabric Creates a cooler microclimate to help prevent bolting and bitterness Faster germination of cool-weather fall crops Shading 30 -50% in midsummer can lower leaf temps by 10 degrees or more
  • Managing moisture Plants under drought stress can be more susceptible to cold damage Water holds warmth and releases it slowly So…water before frost is expected
  • Alter soil temperatures Use clear plastic mulch to warm soil in spring and retain extra heat in fall Cover the edges of the plastic with soil to anchor it in place Temps increase by 8 to 14 degrees to a depth of 2 inches and 6 to 9 degrees to a depth of 4 inches
  • Mulch to insulate plantsOrganic mulches such as straw alsodecrease radiated heat and conservemoisture, preventing cold (and hot)extremes
  • Choose hardy crops Start and end with cold-hardy vegetables that tolerate frost Look for short-season varieties Other varieties are specially adapted to growing in long, hot days, extending your growing season into the summer (ex. slow bolting lettuces) Read seed packets and catalog descriptions
  • Spring crop transplants Start plants early Start seeds of tomatoes, peppers, and eggplants 8 weeks early Start seeds of cole crops about 4 to 6 weeks early Start vine crops 1 week early
  • Fall crop transplants Start plants for late-season crops in late summer Seed a second season of quick- maturing vegetables, such as snap beans, peas, greens, radishes, cole crops, and turnips later in the season Grow cold-tolerant species in the fall
  • Examples of late-seasoncrops  Kale  Collards  Lettuce  Spinach  Mustard greens  Arugula  Broccoli  Broccoli rabe  Mache  Beets Lettuce, kale and rabe  Peas
  • Winter harvest Decreasing levels of light in fall/winter slow plant growth to near-dormancy Lowest light in December and January Many cold-weather crops must be harvested by the end of fall
  • Vegetable planting dates Planting dates depend upon the plant cold-hardiness. Semi-hardy vegetables can be planted two to four weeks before the average last killing frost date of May 15, or in cool fall temps
  • Vegetable planting dates Plant frost-tender and cold- sensitive vegetables after the last frost date Buy transplants, or start from seed indoors from mid-March through mid-April Earlier transplanting can be done when hotcaps, row covers or other protection is used
  • More tips Grow cold- tender herbs, dwarf fruit trees, etc. in containers that you can move indoors
  • Usingprotection
  • Protect from early and late frosts Cover early and late season plantings with mini-greenhouses made from clear plastic, old window sashes set on hay bales, or fabric row covers Vent the covers on warm days to prevent excessive heat buildup
  • • Use hot caps in spring• Need to vent them• Works for small plants• Blocks some light
  • Light penetration not good; minimal frost protection
  • Walls of Water Good frostprotection but expensive
  • Fall freeze protection Use old sheets, blankets, draperies, etc. Cover plants before sundown to trap heat
  • October 5-9, 2011Elevation 5400 ft
  • Fall freeze protection Extend the covering all the way to the ground so cold air can’t seep in Put in place before sundown Especially useful for the first few frosts when warmer weather is then expected
  • More tips Cover hardy root crops with a 6- to 12-inch-thick layer of straw or other organic mulch in fall to prevent the soil from freezing. Harvest as needed throughout the winter.
  • Row covers •Agribon, Reemay, Harvest Guard, etc. •Come in different weights Can provide 3to 5 degrees offrost protection
  • Row covers Warm and speed the growth of seedlings in spring Slow the evaporation of soil moisture Protect plants from wind, heavy rain, and hail Heavier fabrics provide more frost protection but block more light
  • Row covers Keep pests off plants but need to remove covers for insect pollination Protect late summer crops from fall frost Protect crops from hot temperatures and burning sun rays Must anchor with soil, wood, rocks, etc.
  • Cloches•Lightweight•Portable•Reusable
  • Cold frames Can provide 5 – 7 degrees of protection Can be used in the spring to start plants or in the fall for cold-hardy crops Use old windows or glass doors to make your own No standard size; keep width narrow enough that you can easily reach across
  • Can add black containersfilled with water to store heat for the night
  • Cold frames Don’t use wood treated with preservatives! Slope the lid to the south Place on south side of house
  • Cold frames Provide for ventilation of excess heat when temps rise above 55 degrees Cover to protect against freezing, or stack straw bales against the frame
  • Cold frame tips Ventilate on warm days Checktemperatures with a thermometer Protectduring freezing weather: Remember that cold frames give only 5-10 degrees of warmth.
  • More cold frame tips Water: make sure plants aren’t getting too much or too little water. Hardening plants: open the lid of your cold frame longer and longer each day
  • Low tunnels:Hoop-supported row covers
  • Benefits of low tunnels About five to six weeks earlier production in the spring Several weeks later production in the fall Some protection from insects and foraging animals Some protection from extreme weather conditions, such as strong winds, hail or frost
  • Tips for low tunnels Use UV-stabilized tubing Don’t expect protection from hard freezes Plan for access and ventilation
  • Building materials to construct one minitunnel for 40-inch by 30-foot raised bedQuantity Item Description Unit Price Total200 feet 1/4-inch nylon rope $0.08/ft $16.001,8-ft by 38- 6-mil greenhouse poly $0.13/sq $39.52ft sheet film ft 1/2-inch sch 40 PVC80 foot $0.22/ft $17.60 pipe20 foot 1-inch sch 40 PVC pipe$0.44/ft $8.8044 2-inch wood screw $0.05 $2.202 3/8-inch by 2-foot rebar $0.75 $1.502 Eye screw $0.50 $1.00*Prices may vary depending on Total $86.62location, etc.
  • High tunnels (aka hoophouses) Big enough to walk into Size them to meet your needs Plant in-ground or in raised beds Does not have an added source of heat or ventilation Can extend the season through the winter by up to three zones, or a month in the fall
  • Orient in an east-west direction tomaximize sunlight, but also consider
  • Structural elements Can be mobile or fixed in place End walls are most important to strength Can incorporate an opening for ventilation in the end walls Hoops no more than 4 feet apart Peaked-roof (vs. U shape) stronger in snowy climates
  • Structural elements Use a center support to increase stability Use 6-mil, greenhouse-grade, UV stabilized polyethylene Roll-up sides allow for ventilation
  • How to Build a High Tunnel (video) see
  • Minnesota study On average, tunnel vegetables such as lettuce, tomatoes and cucumbers were harvested about six weeks earlier than those grown in the open, while peppers were ready nearly ten weeks ahead. Many of the tunnel plants produced as much as double the output of the outdoor crops
  • What about winds? High tunnels placed perpendicular to prevailing winds typically receive the most damage, so consider placing parallel The best protection against uplift is to ensure that posts are driven at least 24 inches into the ground Use stretch cord over the top of the plastic from one side to the other, every fourth rib
  • What about snow? A high tunnel built from ribs of 20 foot pipe bent to create a 14 foot wide X 6 foot high structure will withstand only about 10 psf This is about 2 inches of water as snow Might be as little as one foot of snow
  • More tips for dealing with snow Use a center roof rib Orient the structure so prevailing winds blow the snow off the high tunnel Remove the plastic in the winter if not under production Brush off snow using a long-handled broom (carefully!)
  • NRCS High Tunnel PilotProjectEligibility Requirements: To qualify, the applicant must: ◦ be an agricultural producer ◦ install the high tunnel(s) on cultivated land which includes existing gardens, irrigated hayland and irrigated pasture ◦ have raised or sold $1,000 worth of agricultural products /NV_high_tunnels.html
  • GreenhousesWalk-in, permanently placed The most expensive solution Usually have venting and heating systems (requires energy inputs but gives more control) In some areas, can be used year round Can add mass for thermal storage (water barrels, etc.)
  • Do your homework Many types on the market Many plans available as well Look at the alternatives before investing Can use to insulate your house when attached Consider a solar greenhouse
  • Bozeman, MT
  • GreenhousesWalk-in, movable Less expensive Can be disassembled and stored away when not in use Usually used one to two months before the last frost in the spring.
  • Whatever you do… Keep good records! Consider a journal that includes varieties, dates planted, dates matured, freezes, etc. Nurture your soil with lots of organic amendments Keep a map of what was planted where
  • Crop rotation: varyingfamilies
  • Why rotate crops? Breaks the cycle of disease and pests Helps to maintain adequate nutrients Can help improve soil structure (alternate deep-rooted plants with shallow-rooted plants) Can decrease costs
  • Considerations in crop rotationschemes Heavy feeders: leafy veggies, brassicas, corn Soil conserving/improving: legumes (peas and beans) Lighter feeders: bulb and root crops, many herbs
  • Simpler rotation Legumes Nightshades •Beans •Tomatoes •Peas •Peppers •Lentils •Potato Brassicas Cucurbits •Broccoli •Cucumbers •Cabbage •Squashes •Cauliflower •Melons
  • Another simple rotation Root Legumes crops, and onions brassicas Sweet Nightshades corn, - cucurbits tomatoes and peppers
  • End-of-season maintenance Clean up! Remove dead vegetation and windfalls, compost healthy material. Remove fallen fruit and dead leaves to decrease pest problems. Think about cover crops to enrich and stabilize soil (winter rye, triticale)
  • End-of-season maintenance Enrich garden beds with compost or manure; add mulch or leaves; think about nutrient needs for your specific crops Collect dried seed from open pollinated flowers & veggies Clean out cold frames for winter use
  • End-of-season maintenance Clean and oil lawnmower, other garden equipment and tools before storing for winter Take equipment in to be sharpened (mower blades, pruning equipment) Drain and store hoses carefully to avoid damage from freezing Clean, sand and oil garden tools before storing them for the winter
  • Questions?Sue Donaldsondonaldsons@unce.unr.edu775-336-0242