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The myth of companion planting

By Laura Pottorff, Colorado State University Cooperative Extension, Horticulture/Pathology

Do marigolds and nasturtiums repel certain insects? Does basil, planted near tomatoes, enhance the flavor of the tomato? These are nice ideas, but science can't prove them. The only aspect of "enemy plant" lore that has merit is "allelopathy," whereby one plant releases toxins that inhibit the development of another plant growing nearby. Even then, the toxins occur in such small quantities that their effects are barely noticeable. So, plant your chrysanthemums and lettuce, garlic and roses, mustard and turnip together. Planted in a suitable location with correct spacing, fertilizer and water, they all will do just fine.

Photo: Judy Sedbrook

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Date last revised: 01/05/2010