Tomato Companion Plants: What to Grow and What to Avoid

Tomatoes are the heart of the summer garden, and the plants you set beside them can decide how healthy and productive they turn out. The best tomato companion plants repel the pests that love tomato leaves, pull in bees and beneficial insects, make smart use of the soil and space around each plant, and even help the fruit taste better. Here is exactly what to plant with tomatoes, what to keep away from them, and how to lay it all out.

The best companion plants for tomatoes

These are the companions that earn their place in a tomato bed. Each one solves a specific problem, whether that is pests, pollination, soil, or space. If you grow other crops too, the same thinking carries over to our pepper companion plants and cucumber companion plants guides.

1. Basil

Basil is the classic partner for tomatoes, and for good reason. Its strong aromatic oils help repel aphids, whiteflies, and tomato hornworms, and many gardeners swear it improves the flavor of the fruit growing beside it. Basil also loves the same warm sun and steady moisture tomatoes crave, so the two thrive under identical care. Tuck a few plants between your tomatoes and let them grow together all season.

2. Marigolds

Marigolds are a garden workhorse for pest control. Their roots release compounds that help deter root-knot nematodes in the soil, a hidden threat that can stunt tomato roots. Above ground, their strong scent confuses many pest insects while the bright blooms attract beneficial ones like ladybugs and hoverflies. Ring the edges of the tomato bed with marigolds for easy, colorful protection.

3. Nasturtiums

Nasturtiums work as a trap crop, drawing aphids to themselves and away from your tomato leaves. Their open flowers also pull in bees and hoverflies, and the trailing leaves shade the soil like a living mulch. As a bonus, the peppery leaves and blooms are edible, so they earn their keep on the plate as well as in the bed.

4. Borage

Borage may be the single best flower to plant near tomatoes. Its true-blue, star-shaped blooms are a magnet for bees and other pollinators, and it is widely credited with deterring the tomato hornworm, one of the most destructive tomato pests. Borage is also thought to improve the vigor and flavor of its neighbors. Plant it at the edge of the patch and let the bees do the rest.

5. Carrots

Carrots are a smart underground partner for tomatoes. Their deep, slender roots break up and loosen the soil, improving drainage and air flow around the tomato roots. Because carrots mature down low and tomatoes grow up high, the two make efficient use of the same square of ground. Sow carrots early, before the tomato canopy fills in and shades the bed.

6. Lettuce and low greens

Lettuce and other low, leafy greens make an excellent living mulch beneath tomato plants. They carpet the soil, hold in moisture, and crowd out weeds, all while enjoying the light shade the taller tomatoes provide during the heat of summer. Because they finish fast, you can harvest a crop of greens before the tomatoes take over the space entirely.

7. Onions, chives, and garlic

Alliums like onions, chives, and garlic carry a pungent scent that helps mask tomatoes from aphids and other soft-bodied pests hunting by smell. They take up little room, so they slip easily into gaps around the base of the plants. Chives in particular are an easy perennial edge that keeps working year after year. For more on this family, see our onion companion plants guide.

8. Parsley

Parsley is a quiet but valuable companion. When allowed to flower, it draws in beneficial insects like hoverflies and parasitic wasps that prey on aphids and hornworms. It also fills the low space around tomato stems without competing for light. Let a plant or two bolt and bloom near the end of the season to keep those helpers coming.

What not to plant near tomatoes

A few neighbors do more harm than good. These are the ones to keep out of the tomato bed.

Brassicas (cabbage, broccoli, and kin)

Cabbage, broccoli, cauliflower, and other brassicas are heavy feeders that compete hard with tomatoes for the same nutrients and water. Grown side by side, they tend to stunt each other, and neither crop reaches its full potential. Give the cabbage family its own bed well away from the tomatoes.

Fennel

Fennel is famously a poor companion for almost everything. It is allelopathic, releasing compounds that can slow or inhibit the growth of most nearby vegetables, tomatoes included. If you grow fennel, give it its own corner far from the tomato patch.

Potatoes

Potatoes and tomatoes are both members of the nightshade family, which means they share the same serious disease: late blight. Planted close together, a blight outbreak in one can quickly sweep into the other. Keep them well separated in the garden and rotate where you plant each one from year to year.

Corn

Corn attracts the corn earworm, the very same caterpillar that becomes the tomato fruitworm and bores into ripening tomatoes. Growing the two crops near each other simply gives that pest a bigger buffet. Site your corn on the far side of the garden from the tomatoes.

Black walnut

Black walnut trees release a natural compound called juglone from their roots and leaves that is toxic to tomatoes and can cause wilting and death. Never plant tomatoes within the root zone of a black walnut, and keep raised beds well clear of the drip line.

Why companion planting works for tomatoes

Companion planting is not folklore alone. With tomatoes, it lines up with a few very practical needs of the crop.

• Pest control. Aromatic plants like basil, onions, and marigolds mask or repel the aphids, whiteflies, and hornworms that target tomatoes, while trap crops like nasturtiums draw pests away from the fruit.
• Pollination and beneficial insects. Flowers like borage, nasturtiums, and parsley in bloom pull in bees for better fruit set and invite the ladybugs, hoverflies, and wasps that hunt tomato pests.
• Healthier soil and roots. Deep-rooted carrots loosen the soil, and marigolds help suppress root-knot nematodes that damage tomato roots below the surface.
• Living mulch and space. Low greens like lettuce shade the soil, hold moisture, and crowd out weeds, while quick crops fill the gaps before the tomato canopy takes over.

How to lay out a tomato companion garden

A little planning makes companion planting easy. Tomatoes grow tall and need airflow, so build the companions around that.

• Space the tomatoes first. Set plants 18 to 36 inches apart with stakes or cages so air moves freely and disease pressure stays low. Good spacing matters more than any single companion.
• Interplant basil and low greens. Tuck basil and lettuce between the tomato plants, where they enjoy the light shade and help cover the soil.
• Ring the edges with flowers. Plant marigolds, nasturtiums, and borage around the border of the bed to draw pollinators in and steer pests away from the fruit.
• Sow quick crops early. Get carrots and onions in early in the season, before the tomato canopy fills out and shades the ground around the stems.

Get the neighbors right and your tomato patch will be better pollinated, better protected, and more productive, with tastier fruit for your trouble. For the full planting playbook, see our how to grow tomatoes guide, and browse heirloom varieties in the tomato and tomatillo seeds collection. Below you will find the exact non-GMO, heirloom seeds we grow alongside our own tomatoes.