Companion planting is a method of organic gardening that makes use of plants' natural abilities to help each other grow, protect each other from harmful pests and produce a bigger harvest. The benefits can be as simple as providing shade for heat-sensitive companions, or as complex as releasing compounds through their root systems to keep pests from attacking the vegetables planted nearby. The backyard gardener must know which pairings of plants encourage the desired results, and what pairings should be avoided for reasons that include possible transmission of disease.
Pick the vegetables you want to plant. Ask family members which are their favorite vegetables and which they prefer not to eat regularly. Make these choices the basis of your garden plan, but add plants that provide powerful benefits when planted near your favorites. You may not like radishes, for example, but they are marvelous at controlling pests that damage squash and cucumber plants.
Learn about the best plant pairings and do a garden plan. Vegetables can be assisted by other vegetable plants, but also by flowers and herbs. Incorporating all three plant types in your design can help you get the most out of a companion planting strategy.
Choose plants that enrich the soil. Plant beans, which draw nitrogen from the air and return it to the garden soil when their growing season is over and they decay. Pair them with vegetables that thrive in nitrogen-rich soil such as corn. Plant borage to add potassium and calcium to the soil--and to brighten the garden with their beautiful blue flowers. Include beets in your design and they will contribute magnesium.
Pair plants that protect each other. Extend the late spring growing season for heat-sensitive vegetables like lettuce and spinach by planting them close enough to taller peas and beans so they are shaded part of the day. Use okra for the shade it provides as well as the wind protection it offers to young and fragile pepper plants.
Use spreading plants to choke out weeds. Pumpkin and squash plants spread so quickly that they can keep weeds from getting established and stealing soil nutrients needed by their nearby good companions like beans and corn.
Select plants that attract beneficial insects. Increase your population of insects that consume garden pests by planting parsley, dill, carrots and coriander, which have a strong fragrance that attracts good insects. Ladybugs, spiders, wasps and some types of flies can provide this organic pest control.
Utilize the herb rosemary and marigolds. Let the potent fragrance of the rosemary plant keep pests such as bean beetles, carrot flies and cabbage moths away from your vegetables. Plant marigolds at the edge of your garden. They will release chemical compounds down through their roots that discourage pests in the soil.
Plant vegetables that help each other grow. Boost the growth rate of carrots and onions by planting leeks nearby. Plant garlic to support a healthier crop of beets. Put in celery to speed up the growth of cabbage plants.