2217 Washington StreetGreenville, Texas 75401(903)455-9885 April 3, 2009TO: Greenville Herald Banner Tawakoni News Country World News Wolfe City Mirror Commerce Journal Kuumba Heritage Celeste Tribune Lone Oak NewsletterFROM: Thomas Clark Master Gardener Hunt CountySUBJECT: Weekly News Column B On the Grow Are you a people person? The theory of companion planting is largely the same.Just as not all children on the playground play well with others, there are plants that bringout the best in others and plants that inhibit others. This idea is not new. Allelopathywas described in 1937 by plant physiologist Hans Molisch as inhibitory or stimulatorybiochemical interactions between plants. The history of these concepts goes back todates BC. Research this on the Texas Agrilife Extension website if you would like moreinformation on the history. Companion planting is a method that may enable you to have better and morequality yields from your vegetable garden or a better landscape with less effort. Thismethodology is part folklore, part research. If you walk in the woods, certain plantsflourish next to each other, but in other areas they may not live. You may be witnessinga natural example of companion planting. Companion planting is a more general term
than allelopathy. Allelopathy focuses more on the chemical relationships and how theymay affect the plant. An example is pine bark and needles on some trees may havesufficient tannins that over time become concentrated near the tree to the point ofinhibiting nitrogen fixing microorganisms in the soil. This affects the growth of grassand other nearby plants. Shade is not always the culprit. Companion planting takes in many general ideas. Recall the three sisters. NativeAmericans planted corn, squash, and beans together. Corn uses a lot of nutrients, butbeans, being nitrogen fixing, help restore the soil while the corn gives them a naturaltrellis. Squash grows low and shades the soil to help retain moisture and shut out weeds.Real teamwork! Trap cropping is when a sacrificial plant is placed in with desirableones. The idea is that the pests can be attracted by a decoy and killed or removed with it.Monoculture often brings in more pest load. So breaking up plantings with other cropscan lower the attraction your plantings have for pests. Positive hosting is planting targetsthat attract beneficial insects that feed on pests. Pest suppression is planting to repelcritters and pests. Various flowers and plants such as garlic are seen as undesirable bymuch of the pest and critter world. The challenge is to compare lists of companion plantsand develop a garden layout that grows compatible plants in a manner to stimulategrowth, taste, and overall quality, while decreasing the downside of pest load and plantsthat might compete with each other. For example tomatoes are said to do better next tocarrots and asparagus but potatoes and cabbage may hinder them. You can find all sortsof sources. Organic Gardening and Farming in 1972 reported that borage could detertomato worms and improve growth and flavor. This statement leaves a bit to learn. Tryit but keep records, certain varieties may be affected but not others. As well as the Texas
Agrilife Extension, you can also search the National Sustainable Agricultural InformationService for information on companion planting. Roses Love Garlic and Carrots Love Tomatoes are two books directly speaking tocompanion planting. Many other authors such as John Jeavons in How to Grow MoreVegetables have written on the subject as well.