Companion planting chart

What to plant next to what, for 31 common vegetables and herbs. A pair is on this chart only when at least two university extension guides list it.

The short version: most companion pairings are garden tradition. Of the 86 pairings we checked for our crop pages, 29 have research behind them, mostly flowers that feed helpful insects, trap crops, keeping one plant family apart, and giving tall crops room so they do not shade short ones.

The chart

Plant	Grows well with	Keep apart from
Asparagus	tomatoes, parsley, basil	-
Basil	tomatoes, peppers, asparagus	-
Beans	corn, carrots, cucumbers, cabbage family, potatoes, celery, beets (bush beans), strawberries	onions, garlic, shallots, chives
Beets	bush beans, onions, cabbage family	pole beans
Cabbage family	beets, onions, celery, potatoes, spinach, chamomile, sage, rosemary, mint	tomatoes, strawberries, pole beans
Carrots	onions, lettuce, tomatoes, beans, radishes, chives, rosemary, sage	dill
Celery	beans, cabbage family	-
Chives	carrots, tomatoes	beans
Corn	beans, cucumbers, squash and pumpkins, peas, potatoes	tomatoes
Cucumbers	beans, corn, peas, radishes, sunflowers, nasturtiums, dill	potatoes, sage and strong aromatic herbs
Dill	cabbage family, lettuce, onions, cucumbers	carrots, tomatoes (once dill is mature)
Eggplant	thyme	-
Garlic	roses, cabbage family	beans
Lettuce	carrots, radishes, strawberries, cucumbers, onions, tomatoes	-
Marigolds	tomatoes, potatoes, squash	-
Mint	cabbage family	-
Nasturtiums	cucumbers, squash, cabbage family	-
Onions	beets, cabbage family, carrots, lettuce, strawberries, tomatoes, chamomile, summer savory	beans, peas
Parsley	tomatoes, asparagus	-
Peas	corn, cucumbers	onions
Peppers	basil	fennel
Potatoes	beans, corn, cabbage family, marigolds, horseradish	tomatoes, squash and pumpkins, cucumbers, sunflowers
Radishes	cucumbers, squash, lettuce, carrots, chervil	-
Rosemary	beans, cabbage family, carrots	-
Sage	cabbage family, carrots	cucumbers
Spinach	cabbage family	-
Squash and zucchini	corn, nasturtiums, radishes, marigolds	potatoes
Strawberries	bush beans, lettuce, onions, borage, thyme	cabbage family
Sunflowers	cucumbers, corn	potatoes
Thyme	cabbage family, strawberries, eggplant	-
Tomatoes	basil, carrots, onions, parsley, asparagus, marigolds, chives, lettuce	potatoes, cabbage family, fennel, corn, mature dill

Which pairings actually work

Most companion pairings in extension charts are passed-down garden tradition; the charts themselves often say no study backs them, and a Washington State review calls classic charts entertainment rather than science. The pairings with real evidence are a small group: trap crops such as Blue Hubbard squash, flowers that feed beneficial insects and pollinators, black walnut juglone, and physical conflicts like shared plant families, shade from tall crops and crowding. We label every pairing as research or tradition and only add a pair to the chart when at least two extension sources list it.

The pairings that hold up share a physical reason you can see. Flowers such as sweet alyssum, dill and other small-flowered herbs feed hoverflies and tiny wasps whose young eat aphids and caterpillars. A trap crop draws a pest away from the main crop. Crops in the same family, such as tomatoes, peppers, eggplant and potatoes, share soil-borne problems, so they are kept apart and rotated. Tall corn or trellised cucumbers shade low crops, which helps lettuce in summer and hurts peppers.

Traditional pairs, such as basil with tomatoes or carrots with onions, rarely do harm, so plant them if you like them. Just do not count on them to keep pests off.

Compiled from 28 university extension publications, listed on the sources page and on each crop page. Not a guarantee against pests; your local extension office can advise on problems in your area.