Best Plants to Grow with Tomatoes: Top Companions

By Jennifer Lee · May 1, 2025

When growing tomatoes, companion planting can significantly improve yield, deter pests, and enhance soil health. The best plants to grow with tomatoes include basil, marigolds, onions, garlic, carrots, and nasturtiums—each offering specific benefits such as pest repulsion, pollination support, or improved flavor.

Why Companion Planting Benefits Tomato Gardens

Companion planting is a time-tested agricultural practice that involves growing different crops in proximity for mutual benefit. When applied to tomato cultivation, it enhances growth, reduces disease pressure, and naturally controls pests without chemicals.

Key Advantages of Pairing Plants with Tomatoes

Repels common pests like aphids, whiteflies, and tomato hornworms
Attracts beneficial insects such as ladybugs and pollinators
Improves soil structure and nutrient availability
Maximizes garden space through intercropping
Enhances the flavor of tomatoes (e.g., basil)

Best Companion Plants for Tomatoes

Certain plants have synergistic relationships with tomatoes. Below are some of the most effective companions backed by horticultural research and gardener experience.

Basil (Ocimum basilicum)

Basil is one of the most popular companions for tomatoes. It repels thrips, mosquitoes, and whiteflies while enhancing tomato flavor. Its aromatic oils may also suppress certain fungal diseases.

Marigolds (Tagetes spp.)

Marigolds emit alpha-terthienyl, a compound that deters nematodes in the soil. French and Mexican marigolds are particularly effective at protecting tomato roots from microscopic worms.

Onions and Garlic (Allium spp.)

Alliums help repel aphids, spider mites, and slugs. Their strong scent masks the aroma of tomatoes, making them less attractive to pests.

Carrots (Daucus carota)

Carrots break up compacted soil with their taproots, improving aeration and water infiltration around tomato roots. They also don’t compete heavily for nutrients since they occupy a different root zone.

Nasturtiums (Tropaeolum majus)

Nasturtiums act as trap crops, luring aphids and cabbage moths away from tomatoes. They also attract predatory insects and bloom throughout the season, adding visual appeal.

Plants to Avoid Growing with Tomatoes

Some plants hinder tomato growth due to allelopathic effects, nutrient competition, or shared pests and diseases.

Brassicas (e.g., cabbage, broccoli): Compete for nutrients and may stunt tomato growth.
Potatoes: Share common diseases like early blight and late blight; also compete for space and nutrients.
Corn: Attracts tomato fruitworms (same pest as corn earworm).
Fennel: Releases compounds that inhibit the growth of many plants, including tomatoes.
Dill (mature plants): Can inhibit tomato growth, though young dill may attract beneficial wasps.

Scientific Data on Tomato Companion Planting Efficacy

Research supports the effectiveness of certain companion plants in increasing tomato yield and reducing pest infestation.

Companion Plant	Pest Reduction (%)	Yield Increase (%)	Study Duration	Location
Basil	45	20	12 weeks	California, USA
Marigold (French)	60	27	16 weeks	Kentucky, USA
Onion	35	15	14 weeks	Oregon, USA
Nasturtium	50	18	13 weeks	Colorado, USA
Garlic	40	12	15 weeks	Washington, USA

Table data source:1, 2

The data shows that marigolds offer the highest pest reduction (60%) and yield increase (27%), likely due to their nematicidal properties. Basil and nasturtiums also demonstrate strong performance, combining significant pest control with notable yield improvements. These findings validate traditional gardening practices with measurable outcomes.

Common Questions About Plants to Grow with Tomatoes

Can I plant basil with tomatoes?

Yes, basil is one of the best companions for tomatoes. It repels pests like thrips and whiteflies, improves tomato flavor, and may reduce the incidence of fungal diseases. Plant basil around the base of tomato plants, ensuring both receive adequate sunlight.

Do marigolds keep pests away from tomatoes?

Yes, marigolds—especially French and Mexican varieties—emit compounds that repel nematodes and other soil-borne pests. Interplant marigolds around the perimeter of your tomato bed for optimal protection.

What herbs grow well with tomatoes?

Basil, oregano, parsley, and chives grow well with tomatoes. These herbs attract beneficial insects, improve flavor, and do not compete aggressively for nutrients. Avoid mature dill and fennel, which can inhibit tomato growth.

Can I grow peppers with tomatoes?

Yes, peppers (both sweet and hot) are compatible with tomatoes as they share similar growing conditions. However, avoid overcrowding and rotate crops annually to prevent disease buildup, especially for nightshade-family pathogens like blight.

Does mint grow well with tomatoes?

Mint can repel pests like ants and flea beetles, but it’s highly invasive and may compete aggressively for space. If grown, keep mint in containers near, but not within, the tomato bed to prevent root spread.