
Plants interact with each other, and behave a lot like us: some get along, some don’t. The following list is of plants that get along with each other or offer some benefit to another such as enhancing fertility or handicapping pests or diseases.
Plant beans (string and French) with celery, cucumber, zucchini, melons, pumpkins, squashes, potatoes, strawberries, and corn
Plant beets and chard with most beans, any from the cabbage family, allium family (garlic, onion, shallot, chives, leeks, scallion), parsnips, and turnips
Plant the cabbage family (broccoli, cauliflower, white and red cabbage) with beet and chards, allium family, celery, dill, nasturtiums, peas, and potatoes
Plant carrots with the allium family, lettuce, peas and tomatoes
Plant celery and celeriac with cabbage family, beans, leeks and tomatoes
Plant cucumber–zucchini–melons–pumpkins–squashes with French and string beans and corn
Plant leeks with carrots, celery and onions
Plant lettuce with carrots, cucumber, zucchini, melons, pumpkins, squashes, radish, strawberries and chervil
Plant alliums(onions family) with beet and chards, lettuce, strawberry, and tomatoes
Plant peas with beans, carrots, cucumber, zucchini, melons, pumpkins, squashes, corn, turnips and potatoes
Plant potatoes with peas, beans, cabbage family, asparagus, and corn
Plant corn with beans (string, French and broad), peas, cabbage family, cucumber, zucchini, melons, pumpkins, squashes, potatoes and sunflowers
Plant sweet and chili peppers with basil
Plant sunflowers with cucumbers, zucchini, melons, pumpkins, squashes and nasturtiums
Plant tomatoes with asparagus, basil, carrots, cabbage family, allium family and parsley
Plant turnips with peas
Excerpted from Companion Planting by Bob Flowerdew