When Henry Homeye returned to Cameroon in 1999 to visit his Peace Corps village, he learned that farmers there understood that some plants provide the benefits of manure
The benefits of companion planting
Once upon a time there lived a people who lived simply, growing their own food.
hey tilled the soil, working in compost and manure, and ate their produce fresh from the garden.
They neither sprayed insecticides nor used any chemicals. And although they lived in harmony with nature, sometimes insects descended on their crops. But the wise ones noticed which plants repelled pests on others and then planted them together.
They and their crops were healthy, and they lived happily ever after.
Although that may sound like a fairy tale in this era of modern chemical agriculture, a hundred years ago the tale was true. Farmers did just fine without chemicals of any sort. Many of our grandparents knew what plants to grow together to minimize pest problems, but few gardeners today even think about companion planting, as it is called. Perhaps we should have listened—and remembered—better.
Plants can affect each other in a variety of ways. They can nourish and attract beneficial insects that will keep pests at a minimum. Some plants give off odors or chemicals from their leaves or roots that repel the pests of neighboring plants. And some just seem to do better growing together.
In the first category, I plant lots of flowers around the edges of our vegetable garden. These provide pollen and nectar all summer long to the little wasps that parasitize larval forms of many insect pests. They also serve as a distraction, of sorts, to damaging insects. A large planting of anything is thought to serve as a magnet and a breeding ground to insects that feed on them. An acre of cabbages is more likely to attract cabbage loopers than a garden patch with cabbages interspersed with flowers. A low-growing annual flower, white sweet alyssum, is supposed to be particularly good for attracting and feeding beneficial insects.
Marigolds have been shown to give off chemicals that repel or destroy detrimental nematode worms, and their strong fragrance is also thought to ward off some insects. I like their cheery faces, and plant them for their looks, and it’s hard to know if they are serving another purpose. I’ve read that they also repel whiteflies, bean beetles and asparagus beetles, among others.
Onion family plants (including onions, garlic, leeks and chives) are known for their strong odors and flavors in cooking, but they can also be used as companions to repel insects in the garden. According to Carrots Love Tomatoes: Secrets of Companion Planting for Successful Gardening by Louise Riotte, onions and leeks acts as repellents to the carrot fly. She also reported planting garlic between her tomato plants to repel red spider mites.
Japanese beetles are a problem for many gardeners. Louise Riotte’s book suggests planting garlic to repel them. Leeks, if allowed to overwinter, will bloom in their second year, and I sometimes use them in flower beds—perhaps inadvertently protecting my roses and other flowers.
Datura, a lovely (though poisonous) ornamental flower also known as Angel’s Trumpet, is also listed in her book as a repellent of Japanese beetles. Its big white flowers are a beautiful complement to roses. Catnip, I was recently told, also repels Japanese beetles, though I’ve never tried it.
Years ago organic farmer Nancy Clark of Charlestown, N.H., advised me to plant nasturtiums with squash family plants to repel striped cucumber beetles, and I generally do so. As with all folk remedies, it’s hard to know if the nasturtiums really do the job. Just to be on the safe side, I also protect my young squashes by covering the hills with a lightweight agricultural fabric known as Reemay or row cover. This physically keeps the beetles away when the plants are young. I remove it when the squashes blossom, as they are insect-pollinated.
Riotte’s book suggests planting two or three icicle radishes in each hill of squash to repel beetles. Radishes are also very attractive to flea beetles, and can be planted as an alternative crop to lure them away from more valued crops. If you see leaves of broccoli, for example, peppered with little holes, you may wish to plant some radishes nearby.
Basil and tomatoes are traditionally cooked together, and planted together. I’ve read that basil helps repel tomato horn worms, so plant some between your tomatoes this year if you had a problem with those large unpleasant caterpillars last year.
When I returned to Cameroon in 1999 to visit my Peace Corps village, I learned that farmers there understood that some plants provide the benefits of manure.
We learned in school that beans and other legumes can fix nitrogen in the soil, but it was interesting to me that uneducated farmers in rural Africa knew this, even though “nitrogen” was not a part of their vocabulary.
Of course native Americans have been growing beans and corn together for centuries, having determined that doing so was beneficial to both.
Good farmers and gardeners are observant. Science has much to teach us, but observation is also key. And if your grandmother told you to plant parsley or basil with your tomatoes, there was probably a good reason for it.
— Henry Homeyer
Henry Homeyer is the author of Notes from the Garden: Reflections and Observations of an Organic Gardener. Write him at P.O. Box 364, Cornish Flat, N.H. 03746; send e-mail to gardening.guy@valley.net; his Web site is gardening-guy.com
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