Companion Planting - Benefits for Your Garden
Why Companion Planting?
Just exactly what is meant by 'companion planting'?
Companion planting is the intentional interplanting of two or more species with the idea they'll benefit or assist each other in some way. Some of the desirable benefits are:
- Companions improve plant growth - Legumes, for example, benefit their neighbors by enriching the soil with nitrogen.
- Companions help each other grow - Tall plants can provide shade for sun-sensitive shorter plants.
- Companions use garden space efficiently - Vining plants cover the ground, upright plants grow up. Two plants in one patch.
- Companions prevent pest problems - Aromatic plants repel some pests. Other plants can lure pests away from more desirable plants.
- Companions attract beneficial insects - Every successful garden needs plants that attract pollinators.
By using combinations of plantings that benefit each other, you are able to grow your garden much more organically - less requirement for pesticides and chemical fertilizers. The best thing about companion planting is that it increases the biodiversity of your patch; that is, the variety of life forms in your garden. We're not just talking about the plants, but also the beneficial insects and animals (yes, earthworms are animals, too) that will be part of your garden.
So much has been written about this topic, along with a lot of unsubstantiated claims and wishful thinking, that its hard to separate fact from fiction. Although there is a wealth of information on its historic use, there is limited available scientific research on the real effectiveness. Most information about companion planting comes from observation, folklore, traditional mouth-to-mouth lore, and history.
The Roman naturalist, Pliny, recommended planting chick peas with cabbabe to repel the white cabbage butterfly. Roman farmers planted grain between fruit trees and grapevines. Chinese gardeners centuries ago planted beans with their grain crops.
Veggie Garden Companions
There are some combinations that really work, and other combinations that definitely dislike each other. The following list is some of the more popular folklore pairings that are reputed to work, or that should be avoided, in a vegetable garden:
- Beans grow well next to celery and cucumbers but dislike onions and fennel.
- Beets like bush beans, lettuce, onions, kohlrabi, and most members of the cabbage family, but not pole beans and mustard.
- Cabbage grows better next to celery, dill, onions and potatoes, but dislikes being near strawberries, tomatoes, and pole beans.
- Carrots like leaf lettuce, radish, onions and tomatoes, but plant dill at the opposite end of the garden.
- Corn grows well with pumpkins, peas, beans, cucumbers and potatoes, but keep tomatoes away.
- Cucumbers like corn, peas, radishes, beans and sunflowers and dislike aromatic herbs and potatoes.
- Lettuce grows especially well with onions, strawberries carrots, radishes and cucumbers.
- Onions do well near lettuce, beets, strawberries and tomatoes but keep them away from peas and beans.
- Peas like carrots, cucumbers, corn, turnips and radishes, beans, potatoes and aromatic herbs. Keep the peas away from onions, garlic, leek, and shallots.
- Radishes grow well with beets, carrots, spinach and parsnips, cucumbers and beans. Avoid planting radishes near members of the cabbage family.
- Squash likes icicle radishes, cucumbers and corn.
- Tomatoes love carrots, onions, basil and parsley, but keep cabbage and cauliflower away from them.
The opposite side of companion planting is growth suppression. One of the best-known plants that suppresses growth of other plants is the black walnut tree. It produces juglone, a strong toxin that not only retards growth, but also prevents seeds from germinating.
Other plants that have growth-suppressing qualities are eucalyptus, sunflowers, goldenrod, quack grass, and foxtail grass. Plants produce these toxins in an attempt to define and extend their territory, elimitating competition for nutrients, water and sun.
Books about Companion Planting
Planting to Control Pests
Experiment in Your Garden
The long tradition of intentionally interplanting indicates that there is truth in the benefits of companion planting. Much of the information you can find about companion planting is based on long-standing traditions, and not supported by actual scientific proof. Your home garden is the best place to conduct your own experiments, and see what actually works for you.
If you decide to try companion planting, set up your plots of planting carefully, and keep records of what you observe. Because weather, soil types, and insect populations are variables that can affect growth, your trials and experiments should be repeated over a period of years. Don't expect miracles, but instead use companion planting as just one part of your garden management program.
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