by Dr. Paul Bosland
Companion planting is a gardening technique in which plants are interplanted in close proximity to chile peppers. Companion planting increases yields, reduces pests and diseases and adds an aesthetic component to the chile pepper patch. The late Louise Rotte wrote a classic book on companion planting, Carrots Love Tomatoes, in which she extolls the virtues of interplanting to reduce pesticide use.
Companion planting is not a new idea. In fact, in pre-Columbian times in the southwest United States, Native Americans planted squash, corn and beans together, creating the “Three Sisters” in their gardens. Each crop contributed something beneficial: Corn provided support for the beans and the beans added nitrogen to the soil. The large, prickly squash leaves shaded the soil, prevented weed growth and discouraged animal pests.
A chile pepper patch with a diversity of various plants can provide not only more chile pepper fruits, but also crops that are great for barbecuing. Instead of growing a row of only chile peppers, consider companion planting a variety of plants that have beneficial effects. For instance, okra, a tall, sun-loving plant, is the perfect companion for chile peppers when the chile pepper plant needs a little shelter from the sun. Hot weather can cause chile peppers to lose their blossoms, and thus fruit, so providing shade via okra can help.
One technique is to plant several small plots of chile peppers in various areas of the pepper patch and to mix in other vegetables, herbs and flowers. Interplanting is also a good way to use the chile pepper patch space to harvest the most in the least amount of garden space. Plant fast-maturing crops, like baby carrots, lettuce and green onions among the chile pepper plants, and the vegetables will be harvested by the time the chile peppers need more space.
I will be the first to admit that some companion planting information is based on old wives’ tales. Although there is limited scientific research regarding companion planting, there is evidence from gardening experiments and some scientific studies that show potential benefits from this technique. Professor Brian Kahn at Oklahoma State University reviewed the scientific literature from around the world and showed that interplanting chile peppers with corn was beneficial; Corn acted as a barrier crop for aphids and reduced virus infection in chile peppers. Eggplant had a similar effect in acting as a “trap” crop for aphids and reduced viral infection on chile peppers. With fewer aphids on the chile pepper plants, spreading of virus declined.
Many companion planting guides warn not to plant beans near chile peppers. However, scientific studies in India and Sri Lanka indicated beans made a good companion crop for chile peppers. The research studies found chile peppers produced more when interplanted with beans than when grown by themselves. Another fallacy in the companion planting guides is the recommendation to not plant cabbage with chile peppers. Research has actually indicated that interplanting cabbage and chile peppers results in higher yields than when chile peppers are grown by themselves in a monoculture.
Which companion plants are good for the chile pepper patch and the barbecue? There are many varieties of herbs, vegetables and flowers that can be used as companion plants in the chile pepper patch. Basil, oregano, borage, parsley, rosemary and marjoram make excellent companions. Basil has been shown to repel thrips, aphids, flies, spider mites and mosquitoes.
A number of vegetables make onderful companions and taste great on the grill. Onions, garlic, chives, squash, cucumbers, spinach, muskmelons, eggplants, celery, maize and carrots make great companions in the chile pepper patch. Garlic is a natural repellant to bugs that are attracted to chile pepper plants, such as beetles, aphids and snails. Scientific studies with leeks and chives have shown that the odor they give off repels aphids. (Chile peppers actually have an odor that is attractive to aphids.) Because both leeks and chives can disrupt the aphid from finding the chile pepper plant, both plants can be interplanted among the chile pepper plants to protect from aphids.
Companion planting can also combine aesthetics and healthy benefits. Flowers look nice both in the chile pepper patch and on the serving dish, when the barbecue is ready to serve. Planting nasturtiums and marigolds around the border of the chile pepper patch can repel beetles. Marigolds exude chemicals from roots and leaves that suppress or repel pests, thus protecting neighboring chile pepper plants. Sunflowers, gazanias, geraniums and cosmos are all good companions when interplanted among the chile peppers to add color and to keep insects at bay.
Many flowers and herbs increase the attraction of beneficial insects that are natural predators to those pests that damage chile peppers. The odors that flowers and herbs release confuse and deter pests from finding the chile pepper plants. Furthermore, they may act as nurse plants to provide a desirable habitat and breeding grounds for the beneficial insects. Flowers and herbs are considered good nursery plants for beneficial insects by providing shelter, nectar, pollen, and sometimes dark, cool moist spots for lacewings, lady beetles, parasitic flies and wasps. The combination of basil and French marigold is reported to keep tomato hornworms at bay because of hosting beneficial insects.
There are unlimited choices and an abundance of crop combinations to incorporate companion planting in the chile pepper patch. Be open to experimenting to find what works best in your area.
Dr. Paul Bosland is a Regents Professor of Horticulture and the Director of the Chile Pepper Institute at New Mexico State University.