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

Avoid: tomato & fennelAvoid
Tomatoes · Fennel
Fennel can allelopathically stress some neighbors; tomatoes near vigorous fennel often look unhappy. Keep fennel in its own corner or container.
Avoid: tight tomato + brassica spacingAvoid
Tomatoes · Broccoli / kale
Both are heavy feeders with big root systems; crammed together they compete for water and nutrients and reduce airflow.
Avoid: vegetables under black walnutAvoid
Nightshades / cucurbits (many) · Black walnut canopy / roots
Juglone from walnut roots and litter harms many vegetables. Map walnut driplines and keep food beds outside that zone or use raised beds with barriers—research your species.