7 Companions You Should Never Plant With Tomatoes (And 4 You Should)

Friend or foe?

Tomatoes are one of the most rewarding plants to have in the garden. They are relatively easy to grow, making them great for beginning gardeners while still offering a challenge to established green thumbs. If all goes well, they produce gorgeous fruit (vegetables? both?) to eat in sandwiches, thrown on pasta, stuffed, pickled, fried, roasted, broiled, marinated, and so much more. (Tomato jam, anyone?) However, before you start cooking and eating, you must get your plants to grow.

One of the best ways to make sure your tomato plants thrive is to put them in the ground surrounded by companion plants that can help them by offering soil enrichment or pest deterrence. It also helps to keep them far away from plants which can rob them of nutrients, block their sun, attract disease, or otherwise harm them. Here are seven plants to avoid growing near tomatoes.

Tomatoes on the Vine
Jed Share / Kaoru Share / Getty

Companion Plants To Avoid Growing Near Tomatoes

1. Brassicas

Cabbage, broccoli, cauliflower, kale, Brussels sprouts, and kohlrabi can stunt the growth of your tomato plant because they out-compete them for the same nutrients. These vegetables are in the brassica family. Cabbage and tomato seeds both need a lot of nutrients to thrive, so the competition makes one plant suffer—the tomato. Tomatoes may not produce buds, resulting in no fruit and a wasted harvest.

2. Corn

Corn and tomatoes may be great for cooking but not planted together. They both attract the same sort of pests and fungal infections. Moth larvae feed on both corn and tomato crops, destroying any possibility for growth. Putting the vegetables near each other in a garden makes them doubly attractive to bugs.

3. Fennel

Like brassicas, fennel will inhibit the growth of tomatoes. Fennel isn't a good companion for most garden vegetables and should be grown in a little patch or pot by itself. This licorice-scented plant may work well with other vegetables in your recipes but not in the garden.

4. Dill

While many herbs grow well with tomatoes, dill is the exception. Young dill does well next to tomatoes as it can help repel aphids, a tiny bug pest affecting many plants. When dill matures and is ready to seed, these plants can inhibit tomato plant growth.

5. Potatoes

Tomatoes and potatoes are members of the nightshade family, meaning they need the same nutrients to grow. That means they will compete with each other, which doesn't benefit either and can make them susceptible to the same diseases. These diseases can spread through the soil, ruining both plants if one is affected. Also, the proximity of these two plants matters as tomato roots can be damaged when harvesting.

6. Eggplant

Like potatoes, eggplant is in the nightshade family, making them competitors. Eggplant is also susceptible to blight, making tomatoes planted nearby more vulnerable to blight. Blight is a fungal disease that rapidly spreads through a harvested area through spores blown by the wind. When sudden browning, yellowing, spotting, or dying leaves appears on crops, this is a sign of blight.

7. Walnuts

While unlikely, choosing to plant tomatoes near a walnut tree can also negatively affect your crop. Walnut trees release chemicals in the soil that stunt the growth of surrounding plants.

Plants That Thrive as Tomato Growing Companions

1. Asparagus

Asparagus and tomatoes are the dynamic duos of the garden. Tomatoes repel obnoxious asparagus beetles, while asparagus keeps away nematodes in the soil, which can harm tomatoes.

2. Chives

Not only are chives a delicious herb to have in the garden, but they repel aphids, nematodes, and mites, making them excellent companion plants for keeping your tomatoes safe.

3. Lettuce

Plant lettuce near tomato plants to create a ground cover that will help keep the soil moist and cut down on weeds (and weeding). In return, the shade from tomato plants can help provide some cover for the lettuce and stop it from bolting.

4. Marigolds

These bright blooms attract bees and ladybugs, which are good for a garden, but they also keep away aphids, slugs, tomato worms, and snails that love to munch on tomatoes. These helpful plants also help keep the soil healthy for tomatoes.

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