Companion planting allows you to select plants that benefit each other.

Plant Plant Companions Plant Allies Plant Enemies
TurnipsPea
TomatoesAsparagus, carrot, celery, cucumber, onion, parsley, pepper.Basil repels flies and mosquitoes, improves growth and flavor. Bee balm, chives and mint improve health and flavor. Borage deters tomato worm, improves growth and flavor. Dill, until mature, improves growth and health. Once mature, it stunts tomato growth. Marigold deters nematodes. Pot marigold deters tomato worm and general garden pests.Corn and tomato are attacked by the same worm. Mature dill retards tomato growth. Kohlrabi stunts tomato growth. Potatoes and tomatoes are attacked by the same blight.
SquashCorn, melon, pumpkin.Borage deters worms, improves growth and flavor. Marigold deters beetles. Nasturtium deters squash bugs and beetles. Oregano provides general pest protection.
SpinachCabbage family, strawberryCabbage family, strawberry
PumpkinsCorn, melon, squash.Marigold deters beetles. Nasturtium deters bugs, beetles. Oregano provides general pest protection.
RadishesBean, carrot, cucumber, lettuce, melon, pea.Chervil and nasturtium improve growth and flavor.Hyssop
PotatoesBeans, cabbage family, corn, eggplant, pea.Horseradish, planted at the corners of the potato patch, provides general protection. Marigold deters beetles.Tomatoes and potatoes are attacked by the same blight.
PeppersCarrot, eggplant, onion and tomato
PeasBean, carrot, corn, cucumber, radish, turnip.Chives deter aphids. Mint improves health and flavor.Garlic and onion stunt the growth of peas.
OnionsBeet, cabbage family, carrot, chard, lettuce, pepper, strawberry, tomato.Chamomile and summer savory improve growth and flavor. Pigweed raises nutrients from subsoil and makes them available to the onions. Sow thistle improves growth and health.Onions stunt bean, pea.
MelonsCorn, pumpkin, radish, squash.Marigold deters beetles. Nasturtium deters bugs and beetles. Oregano provides general pest protection.
LettuceBeet, cabbage family, carrot, onion, radish, strawberry.Chives and garlic deter aphids.
EggplantBean, pepper.Marigold deters nematodes.
CucumberBean, cabbage family, corn, pea, radish, tomatoMarigold deters beetles. Nasturtium deters aphids, beetles and bugs, improves growth and flavor. Oregano deters pests in general. Tansy deters ants, beetles, bugs, flying insects.Sage is generally injurious to cucumber.
CornBean, cucumber, melon, parsley, pea, potato, pumpkin, squash.Odorless marigold and white geranium deter Japanese beetles. Pigweed raises nutrients from the subsoil to where the corn can reach them.Tomatoes and corn are attacked by the same worm.
CeleryBean, cabbage family and tomato.Chives and garlic deter aphids. Nasturtium deters bugs and aphids.
Cabbage Family (Broccoli, Brussels Sprouts, Cabbage, Cauliflower, Chinese Cabbage, Kale, and Kohlrabi)Beet, celery, chard, cucumber, lettuce, onion, potato, spinach.Chamomile and garlic improve growth and flavor. Catnip, hyssop, rosemary and sage deter cabbage moth. Dill improves growth and health. Mint deters cabbage moth and ants, improves health and flavor. Nasturtium deters bugs, beetles, aphids. Southernwood deters cabbage moth, improves growth and flavor. Tansy deters cabbageworm and cutworm. Thyme deters cabbageworm.
StrawberryBean, lettuce, onion, spinach, thyme.CabbageBorage strengthens resistance to insects and disease. Thyme, as a border, deters worms.
BeetsBush beans, cabbage family, lettuce, onion.Garlic improves growth and flavor.Pole beans and beets stunt each other's growth.
BeansBeet (to bush beans only), cabbage family, carrot, celery, chard, corn, cucumber, eggplant, pea, potatoes, radish, strawberry.Marigold deters Mexican bean beetles. Nasturtium and rosemary deter bean beetles. Summer savory deters bean beetles, improves growth and flavor.Garlic, onion and shallot stunt the growth of beans.
CarrotsBean, lettuce, onion, pea, pepper, radish, tomato.Chives improve growth and flavor. Rosemary and sage deter carrot fly.Dill retards growth.
AsparagusBasil, parsley, tomatoPot marigold deters beetles.
ChardBean, cabbage family and onion
ParsleyAsparagus, corn, tomato