Good companions: planting tips for vegetables

Plants thrive on the companionship of others

By Sheena Adams | Image: Terry Guscott

Does it make a difference in our gardens where things are planted? Do certain plants behave better when they're around certain other plants? The answer to both questions is yes, as plants, much like people, thrive on the companionship of others.

When surrounded by the right friends, vegetable plants, fruit trees and berry bushes will produce higher yields and tastier fruit, and be more vigorous and healthy. The trick is to know where and what to plant to confuse pests, attract beneficial insects and realize the particular properties that certain plants can bring to the garden. Known as "companion planting," the practice of growing compatible plants together has been followed by gardeners for centuries, since as early as the days of Pliny the Elder (around 50 AD), and it has long been a valuable tool in organic gardening.

The following are some useful companion planting tips that you can incorporate into the planning of your vegetable garden. You may find that not all plants are friends and that certain ones are better planted away from each other. While there are no such things as plant enemies per se, you'll find that some are simply better off planted on the other side of the fence.

Annuals
A few annual flowers have proven to be valuable when planted anywhere in the garden. Flowers not only add colour and fragrance, but they also attract pollinators and deter many unwanted pests. Marigolds, petunias and white geraniums are said to help ward off harmful nematodes, cutworms, beetles and tomato hornworms, and in the greenhouse, marigolds can help control the whitefly population. Nasturtiums are beneficial in reducing aphid and flea beetle populations by trapping them with their stickiness. Cosmos, when sown into a bed of carrots, not only look lovely on top of the ferny foliage, but they also scare away the pesky carrot rust fly. For maximum effect, pick up a few packs of each flower, mix and match them throughout the garden, and you'll enjoy both their benefits and their beauty.

Herbs
Herbs such as basil, coriander and garlic are very helpful in our vegetable gardens. Garlic is commonly planted to repel aphids, spider mites, and fruit tree borers, which are a common problem for peach, plum and cherry trees. You'll know you have them when you see a clear gummy sap excreting from small holes in the limbs of the tree. Planting garlic at the base of your tree each season is a good solution. Basil is famous for improving the performance and flavour of tomato plants, so you'll want to alternate your tomatoes with

basil plants. Coriander, on the other hand, is an easy-to-grow herb that is useful for its spider mite-repelling fragrance. And, of course, any plant (such as peppers) that requires extra help from pollinating insects will benefit from the nearby planting of any aromatic herb, my own favourite being silver thyme. Keep in mind, however, that dill will attract the tomato hornworm, so always plant dill and tomatoes at opposite ends of the garden.

Vegetables
Vegetable plants can be particular about whom they want to be planted near and whom they would rather keep their distance from. Two standard rules are to keep tomatoes away from all members of the cabbage family, and all peas and beans separate from the onion family.

Radishes are beneficial when planted in the hills of your cucumber, zucchini and watermelon, as they help discourage the dreaded cucumber beetle, a pest that not only devours crops, but also spreads disease. Radishes will also help protect beans, corn and peas.

Cabbage loopers are a common problem in broccoli, cabbage and cauliflower plants. To help confuse these pests, alternate each planting with a few Walla Walla onion plants. The onions will discourage the cabbage worm adults (butterflies) from landing on the plant to lay larvae, and the onion plant will also benefit from the broken rows, as the onion maggot will not be able to move from onion to onion.

Aphids, a common problem for tomatoes, peppers and fruit trees, are a natural food source for hover flies and ladybugs. To attract hover flies, plant plenty of parsley throughout the garden and orchard. Parsley also has the added benefit of improving the taste and vigour of asparagus.

Eggplants are beneficial to all parts of the vegetable garden. Perhaps their best asset, next to their wonderful fruit, is their large sticky leaves, which attract and trap pests such as the Colorado potato beetle, aphids, flea beetles and white fly.

Corn is a wonderful treat for raccoons that can be protected by a close planting of cucumbers; apparently they make the raccoons shy. Other great companions for corn are peas and soybeans, as they help to restore the nitrogen in the garden that corn is notorious for hogging.

Root maggots, the babies of the carrot rust fly, can destroy carrot crops quickly. Interplanting carrots with leeks will reduce the chances of infestation, and the roots of the leeks will help to loosen up the soil.

Another aspect of companion planting is nurse cropping, or simply put, using larger plants to provide shade for smaller varieties less tolerant of sun or heat. Planting lettuce or spinach amongst the shade of peas or beans will reduce summer bolting, for example, and cucumbers and squash will appreciate the late afternoon shade of a summer corn crop. When planting, consider where shadows will be cast on late summer afternoons and be sure to take advantage of this naturally created shade.

With care and attention, companion gardening will certainly reward you with a bountiful harvest and fewer pest and disease problems. Be sure to take note of what you planted near which plant, and which combinations worked well. Within several growing seasons you will have accumulated some valuable information to make your companion cropping even more successful in the seasons to come.

Colorado Potato Beetle

Companion Planting Tips

Plant potatoes with horseradish to protect plants from the Colorado potato beetle. Be sure to remove all the horseradish at harvest to prevent it from spreading.
Plant summer radish beside your leaf lettuce to make the radish more tender.
Under-plant your fruit trees with mint to help repel the common summer problem of ants.
To scare away carrot rust fly, plant carrots and rosemary together.
Plant garlic near your peach tree to prevent peach tree borer.