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
