Companion planting

Friendly neighbors and a few combinations to give extra space. Pairs with What can I grow? when you are sketching beds. For fallow gaps and soil recovery, see cover crops.

Type

All Good neighbors Give space

Crop focus

Any Tomato Pepper / eggplant Brassicas Squash / cucumber Beans / peas Carrot / root crops Corn Lettuce / greens Radish Onion / garlic Herbs

Benefit

Any Pest confusion / trap Pollinators Shade or shelter Soil / roots Kitchen / flavor

Tomato & marigoldPair
Tomatoes · French marigold (Tagetes patula)
Traditional companion: strong scent may mask tomato host cues for some pests; root exudates are debated—treat as a helpful row edge, not a pesticide.
Carrot & onion familyPair
Carrots · Onions or leeks
Onion scent can help mask carrot rows from carrot rust fly in backyard scales; different root depths reduce direct competition.
Brassicas & dill (early season)Pair
Broccoli / kale / cabbage · Dill
Young dill can attract beneficial wasps and hoverflies; mature dill near heading brassicas is more controversial—plan dill as an early neighbor or at row ends.
Cucumber & radishPair
Cucumbers · Radishes
Radishes mark rows and mature fast while cucumbers warm up; radishes can flag soil crusting issues early.
Nasturtium & cucurbits (trap crop idea)Pair
Nasturtium · Cucumber / squash
Aphids often prefer nasturtium; some growers sacrificially host aphids there. You must still scout—this is not automatic control.
Chives & carrotsPair
Chives · Carrots
Low allium scent along a carrot row is easy to tuck in; perennial chives need a permanent edge so you do not disturb carrot roots yearly.
Calendula near vegetablesPair
Calendula · Mixed veg bed
Long-blooming calendula supports generalist pollinators; some predatory insects visit composite flowers—pair with good habitat, not sprays.