Tomato Companion Plants – Carrots, Marigolds, Petunias, and more…

companion planting for tomatoes

Tomato companion planting. When ‘companion plants’ are applied throughout the garden, they can be an effective form of pest management, allowing nature to do its’ job.

Companion planting can discourage harmful insects and pests in your garden without harming the beneficial ones.

Many plants have natural substances in their roots, flowers, and leaves that can repel or attract insects and can enhance the growth and flavor of other varieties of plants.

The following are a few companion plants to consider with your tomatoes.

Tomato Plant Companions

Companion plants for tomatoes include Basil, Oregano, Parsley, Carrots, Marigold, Geraniums, Petunias, Borage, any type of Onion or Chives.

By the way, an excellent book on the subject. I purchased it years ago:

Secrets of Companion Planting for Successful Gardening
(view on amzn)

Companion Planting Guide

Borage Flowering Tomato Companion

BORAGE, Borage is a large, sprawling, hairy annual with star-shaped, blue flowers. It is an edible flower (with edible leaves), and is one particularly good companion plant for tomatoes. It is an excellent plant for attracting bees.

When planted nearby, it deters tomato hornworms (a type of caterpillar that will eat the leaves), a voracious eater of tomato plants. Borage is considered a magic bullet of companion plants (predict a square yard for its adult size).

In addition, borage’s sprawling growth habit and large leaves can shade the bases of tomato plants, keeping them cooler and helping to retain moisture in the soil.

Planting Considerations:

“To reap these benefits, simply substitute a borage plant for a tomato every third or fourth plant if you grow them in a line. If you plant tomatoes in cages, plant borage outside of the cage on the side that gets the most sun. In fertile soil and full-sun conditions, borage plants can grow 3 to 4 feet tall. Or you can simply scatter borage seed in your garden and allow plants to come up randomly.”

~ from an article on SFGATE


Marigold and tomato companion planting is a tried and true technique used by gardeners for hundreds of years.

Research studies have indicated that planting marigolds between tomatoes helps protect the tomato plants from harmful root-knot nematodes in the soil.

[ Read: Which are French Marigolds? ]

Basil | Tomato Companion

Basil companion with tomatoes.

Basil is an excellent culinary partner to fresh tomatoes in the kitchen. They are great partners in the garden too… making them one of the many tomato companion plants.

Some say that “basil actually rivals marigolds in the pest repelling category. It is extremely effective in repelling whiteflies, aphids and tomato hookworm. All three of which can spell big trouble for a tomato plant’s health.”

Some reports also suggest that basil may improve the flavor of tomatoes when grown in close proximity.

Oh, and apparently basil detracts mosquitoes to an extent too.

Carrots | Tomato Companion?

Is this one really true? All I can say is that I’ve done this… Growing carrots all around the perimeter of a tomato garden bed. Everything grew okay.

“While many people grow both tomatoes and carrots in the same garden beds, alongside one another, quite successfully, there is no real evidence that either plant does better in the same neighborhood.”

“In fact there is some suggestion that tomato plants can stunt the growth of carrots – which stands to reason if they are grown too close to one another, since the one is a root plant and the other grows above the ground.”

Perhaps the idea came from Louise Riotte, author of the famous book Carrots Love Tomatoes (linked above) who came up with the book title, or maybe her editors suggested it. The idea has taken root, and writers and vegetable growers have perpetuated this idea ever since…


Chives are another tomato companion plant.

Chives help repel pests like aphids, which love to feed on tomatoes. They also repel nematodes, and mites. Another good tomato companion plant.

Petunia | Tomato Companion

Grow petunias as a tomato companion plant.

PETUNIA, an edible flower (with edible leaves), will repel tomato worms.

Not only do petunias attract hummingbirds and butterflies, which are pollinators, but they may help repel tomato worms, beetles and aphids. They are anecdotally recommended in vegetable gardens, and, another good tomato companion plant.

A Few Tips:


Be aware that if you plant carrots too close and under the eventual canopy of the tomato ‘bush’, there won’t be enough light to get good carrots. Ask me how I know… Since then, I’ve planted on the perimeter with success.

Ants Hate Marigolds

There are a few flowers that are known to deter ants from their area. One of the best known is the marigold. Plant a few of these around the borders of your garden or near plants you want really well protected.

“Be careful with marigolds as they can take over. I had to thin them way back so my veggies could breathe. They reseed really well.” said a commenter on Modern Survival Blog


Don’t forget to ‘harden off’ your tomato plants. Basically you’re getting them accustomed to life outside of a greenhouse or your home.


Plant tomatoes DEEP to promote good root growth. In other words don’t be afraid to bury ~25% of the lower trunk with its leaves and all…

Lets hear your success stories (or otherwise) about your tomato plants (and/or tomato companion planting)…

[ Read: Ways to Tie UP your Tomato Plants ]

[ Read: Ways to keep Weeds Down in your Garden ]