Companion planting is the practice of planting different species in close proximity in the garden because they offer some mutual benefits to one another. One species may deter an insect pest that feeds on the other plant, for example, while that plant may improve the first plant's uptake of soil nutrients. As many gardeners learn, beans are a plant that is recommended companion for many different vegetables, because beans and other legumes "fix" nitrogen in the soil, providing nutrients to surrounding plants.
Here's an example of the synergy of companion planting:
Planting corn with pole beans benefits both plants. Add a squash to the mix and you have the classic Native American "Three Sisters" planting combination. The beans attract beneficial insects that prey on corn pests, such as leaf beetles, fall armyworms, and leafhoppers. In return, the bean vines are supported as they climb up the corn stalks. The squash benefits from the nitrogen fixed in the soil by the bean plant, while the large leaves of the squash shade out weeds near the corn stalk. Everybody wins.
Companion planting in gardens maximizes efficiency of garden space, attracts beneficial insects and pollinators, and lures insect pests away from other food crops. Sometimes the companion plant pairings benefit one plant more than another, but there is rarely a downside to following accepted companion plant suggestions. Nature designed some plants to protect and help others.
When you take advantage of these beneficial relationships, you are better able to grow crops organically.
Best Companion Plants for Beans
- Marigolds: Marigolds deter Mexican bean beetles and other insects from many garden plants including beans. African and French marigolds both produce a substance that suppresses nematodes—the microscopic worms that attack the roots of plants. Marigolds, in fact, are a recommended companion for many different edible plants.
- Corn: Bush beans tolerate the light shade that is cast by corn. Since the roots of the bean plants occupy a different level in the soil than the roots of the corn, the two plants don't compete for water and nutrients. And for pole beans, the corn stalks can serve as the "poles" to secure the beans upright. This saves space in the garden, leaving room for the gardener to add additional plants.
- Potatoes: Potatoes repel Mexican bean beetles.
- Catnip: Catnip repels flea beetles.
- Summer savory, nasturtium and rosemary: Summer savory repels bean beetles and improves the flavor and overall growth of bean plants. Plant it near the base of the plant but not so close that it is shaded by it. Nasturtium and rosemary both deter bean beetles.
- Eggplants, radishes, and cucumbers: These edibles stimulate and encourage strong bean growth.
Other plants that are good companions to bean plants in the garden include:
Plants to Avoid Planting With Beans
- Avoid planting beans near all members of the allium family—onions, leeks, garlic, and scallions. Members of that family will inhibit growth in beans. Also keep beans away from kohlrabi, basil, and fennel.
- Beans grow poorly with sunflowers nearby. They don't get along at all.
Experts disagree on the wisdom of planting beans and peppers close together. When in doubt, don't.
Pole beans and bush beans share all the same companion plant recommendations, with the exception of beets. Pole beans do not thrive when beets are planted nearby, but bush beans aren't affected.
Plants Helped by Beans
Because beans fix nitrogen in the soil, they are great helper plants in the garden. They are particularly good to plant with the following vegetables, which need nitrogen to thrive:
- Brussels sprouts
- Swiss chard