UC Master Gardeners of Tulare and Kings County
Article

Companion Planting Chart for Home Gardens

Crop

Compatible Companions

Incompatible

Why Incompatible

AsparagusTomato, parsley, basil  
BeansMost vegetables & herbsOnion, garlic, gladiolusOnions, garlic, and gladiolus can inhibit bean growth.
Beans, BushIrish potato, cucumber, corn, strawberry, celery, summer savoryOnion familyOnions can inhibit bush bean growth.
Beans, PoleCorn, summer savory, radish

Onion, beets, kohlrabi, sunflower

Onions, beets, kohlrabi, and sunflowers can inhibit pole bean growth by releasing chemicals into the soil.
BeetsCabbage & onion families, lettucePole beansBoth can stunt the other's growth.
Cabbage family

Aromatic herbs, celery, beets, onion family, chamomile, spinach, chard

Strawberry, pole  beans, tomato

Tomatoes, Pole Beans, and strawberries will stunt members of the Brassica family (cabbage, broccoli, kale, cauliflower).

CarrotsEnglish pea, lettuce, rosemary, onion family, sage, tomatoDill

Don't plant carrots next to dill because they are in the same plant family, which can cause them to cross-pollinate. This can stunt carrot growth.

CeleryOnion & cabbage families, tomato, bush beans, nasturtiumCornCompetes for nutrients and sunlight.
Corn

Irish potato, beans, English pea, pumpkin, cucumber, squash

TomatoBoth plants are heavy feeders and can deplete the soil's nutrients.
CucumberBeans, corn, English pea, sunflowers, radishIrish potato, aromatic herbs

Potatoes will compete for water and nutrients, and they have some of the same diseases as cucumbers. Aromatic herbs can inhibit growth and affect flavor.

EggplantBeans, marigoldGeraniums

Geraniums may spread commonflower diseases thatcan stunt eggplant growth.

LettuceCarrot, radish, strawberry, cucumberFennel, parsley, brassicaFennel secretes a chemical that stunts growth. Parsley can cause lettuce to bolt. Brassica (cabbage, broccoli, kale, cauliflower) secrete a substance from their roots that prevents lettuce germination.
Onion familyBeets, carrot, lettuce, cabbage family, summer savoryBeans, English peaOnions can inhibit the growth of beans and peas.
ParsleyTomato, asparagus  
Pea, EnglishCarrots, radish, turnip, cucumber, corn, beans

Onion family, gladiolus, Irish potato

Onions and gladiolus can inhibit pea growth.
Potato, IrishBeans, corn, cabbage family, marigolds, horseradish

Pumpkin, squash, tomato, cucumber, sunflower

Pumpkin has a high water requirement, which can increase the risk of brown rot in potatoes. The others compete for nutrients and have similar diseases.
PumpkinsCorn, marigoldIrish potato

Potatoes can increase the chance of blight in pumpkins when planted together.

Radish

English pea, nasturtium, lettuce, cucumber

HyssopHyssop can inhibit radishes' growth.
SpinachStrawberry, fava beanNONE 
SquashNasturtium, corn, marigoldIrish potatoPotatoes can deplete the soil of nutrients and starve nearby squash.
Tomato

Basil, onion family, nasturtium, marigold, cucumber, carrot, asparagus, parsley, 

Corn, Irish potato, fennel, cabbage familyThe Cabbage family and fennel can stunt tomato growth. Potatoes are susceptible to the same diseases as tomatoes. Corn is a heavy feeder and competes for nutrients.
TurnipEnglish PeaIrish potatoBoth can compete for nutrients and space.