Vegetable companion planting is an age-old practice of interplanting two or more vegetable or herb crops together to save space and to share nutrients and water. Companions benefit the others by offering protection from pests, providing support, shelter from sun and wind, attracting beneficial insects and butterflies or by adding nutrient value to the soil.
Vegetable companion gardening is accomplished when two or more vegetable types are planted within the same gardening bed. Often herbs are interplanted (planted together in the same bed or area) with vegetables.
Early Native Americans used vegetable companion planting when they interplanted corn, beans and squash. Called "Three Sisters" gardening, this practice rose out of practicalities of the time to ease the task of hand-carrying water from the source, to assist in maintaining soil fertility and to make the best use of crop space. Corn uses a great amount of space and is a heavy feeder. Beans fix nitrogen in the soil and require support, so the seeds were planted at the base of the young corn plants to eventually climb the strong stalks. Squash requires ground space to spread its long-reaching stems and likes a bit of shade, so squash seeds were planted between the rows of corn where they were allowed to amble freely along the ground, in turn giving shade back to the roots of the corn, which cools the soil temperature and protects the soil from drying out.
Reasons for Companion Selection
Conservation of water, nutrients, and space are the primary reasons to companion plant vegetables. With the re-birth of home gardening, whether it be a small kitchen garden or containers of vegetables and herbs on a patio, companion planting is a space-saver that works well in either situation. Water and nutrients are conserved when vegetables share the resources. Additionally, the desire to garden organically is realized when certain vegetables and herbs are planted together to deter pests and to encourage visits of beneficial insects and pollinators. Some vegetables and herbs even enhance the flavor of their companions.
Criteria for Companion Selection
Companion vegetables must share the same cultivation needs. If one of the vegetables prefers daily watering, it's companion/s should also be as thirsty. For example, lettuce and sweet bell peppers both need regular watering for crisp, succulent leaves and juicy fruits. Corn and melons are heavy feeders that require supplemental fertilizing throughout the growing season, so they make good companions. Vegetables with differing sun/shade exposure requirements can make good companions. Full-sun plants provide shade to the crops that prefer some shade or are typically quick to bolt (set seed) in the heat. A combo of a tomato with lettuce planted at its feet works well together.
Specific vegetables, fruits and herbs can actually work against each other. For example, tomatoes and corn should not be interplanted because they both attract similar fruitworm and earworm species that can be devastating to those crops. Check gardening guides before finalizing the planting plan to make sure it is companion friendly.
Suggested Garden Companions
There are many different combinations of vegetables that make good companions. Tomatoes may be interplanted with asparagus, lettuce, carrots, chives, onion, parsley, garlic, marigold and nasturtium. Corn can be interplanted with beans, squash, melons, potatoes, peas, cucumbers and pumpkins.
Basil, when planted with sweet bell pepper, sweetens the fruit. Bell peppers may also be interplanted with okra and lettuce to save space. Radishes can be used as row markers for slow-to-germinate beets and parsnips. Radishes are also interplanted with cucumbers, squash and melons. Leek and carrots are long-season crops and may be interplanted and harvested at the same time.