Growing healthy tomatoes can be a challenge for new gardeners, and there's a lot of advice on the internet about how to do it better. Learning how to prune tomatoes, the difference between determinate and indeterminate varieties, when to plant tomatoes out, and how to deter their pests-- it can be overwhelming. Luckily, one of the best solutions for growing beautiful tomatoes is also the easiest: companion planting.
Companion planting tomatoes with vegetables, herbs, and flowers is a surefire way to improve the overall health of your garden and its contents. Tomato companions like marigolds, basil, and onions are a joy to grow and they also help each other by providing a range of benefits: deterring pests, attracting beneficial insects, and improving the soil quality, among others.
Companion planting doesn't have to be overwhelming. In fact, it should be a fun aspect of garden design that helps you maximize your yields and grow a more beautiful garden. This guide will go over everything you need to know about what to plant with your tomatoes-- and what to avoid planting near tomatoes-- for a more productive growing season.
Skip Ahead: Benefits of companion planting •Best tomato companion plants •What not to plant with tomatoes •Companion planting chart •Tomato pests
Benefits of companion planting for tomatoes
Before we get into how companion vegetables, herbs, and flowers can help tomatoes, here are a few ways that tomatoes can benefit their companion plants:
- Providing shade: Whether they're determinate or indeterminate, tomatoes will take all the sun they can get-- and in the process, they'll create partial shade for companions like cilantro and parsley.
- Maximizing space: Trellised tomatoes leave plenty of ground space for root crops and low-growing companions.
- Deterring pests: Tomatoes, like other nightshades, produce a natural insecticide called solanine, which may deter pests from some companion plants.
The best tomato companion plants
Categorically, plants that grow well with tomatoes share tomatoes' need for rich soil that's fairly moisture retentive. All of the companion plants on this list also need either full sun or partial shade, which tomatoes can provide. And finally, all of these companions offer some benefit to tomatoes that will help maximize space and produce a better harvest.
Here are the best tomato companions for repelling pests, improving the soil, attracting beneficial insects, and improving yields:
- Marigolds
- Basil
- Onions
- Chives
- Carrots
- Radish
- Parsley
- Cilantro
- Calendula
- Nasturtium
- Borage
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1. Marigolds
Marigolds are possibly the all-around best companion flower for vegetable gardens. When planted with tomatoes, marigolds prevent damage from root-knot nematodes. Companion planting with French marigolds protects tomatoes from whiteflies, and both French and African marigolds reduce aphid populations. There's evidence that marigolds might even support parasitic wasps that prey on stink bugs.
To take advantage of all these benefits, plant marigolds at the base of tomato plants, either facing the sun or in partial shade. Combining this pairing with other companions like basil or calendula will bring even more benefits.
Read More: The 16 Best Companion Plants for Marigolds
2. Basil
Basil and tomato are probably the most well-known garden pairing, thanks to their culinary compatibility. But companion planting with basil offers tomatoes a long list of benefits: basil attracts lacewings and ladybugs, which prey on common tomato pests; it deters thrips, tomato hornworms, and whitefly; and it can reduce aphid damage.
Plant tomatoes with basil and marigolds, calendula, or nasturtiums to keep pests at bay and grow a better harvest.
3. Onions
As with other alliums, companion planting with onions is one of the best ways to minimize pest damage in an organic garden. Thanks to their strong aroma, onions can actually mask the scent of nearby plants, preventing pests from finding their targets. When planted with tomatoes, onions can reduce damage from aphids, mites, and flea beetles.
4. Chives
As alliums, chives are excellent for confusing pests like aphids and mites. It's also rumored that chives improve tomato flavor, though that's for you to judge. Chives thrive in moist, rich soil and benefit from part sun during the summer, so it's best to plant them in the shade of trellised tomato plants.
Read More: The 12 Best Companion Plants for Chives
5. Carrots
Planting carrots with tomatoes can maximize space, improve the soil, and benefit both plants. Carrots' long taproots won't compete with tomato roots for space or nutrients, and the carrots will benefit from being in the partial shade cast by tomatoes in peak summer. Carrots planted next to tomatoes may also see less damage from carrot fly, as tomatoes produce a natural insecticide call solanine that's thought to repel the pests.
Read More: The 10 Best Companion Plants for Carrots
6. Radish
If your tomatoes struggle with flea beetles, try sowing radish nearby as a trap crop. Flea beetles strongly prefer radish leaves, which will grow abundantly in the rich soil around tomatoes. Radishes can also attract parasitic wasps, further helping with your tomato pest problems.
For a trap crop to be successful, it needs to become established before the plant you're trying to protect. So in this case, direct sow radish seeds one or two weeks before planting out tomatoes.
7. Parsley
Parsley is a fantastic companion plant for tomatoes and other main crop vegetables, as it attracts beneficial insects that prey on common pests like aphids and hornworms. Those predatory insects include lacewings, ladybugs, hoverflies, and parasitic wasps and flies, all of which are attracted to other umbellifers like carrots and dill.
To grow parsley with tomatoes, prepare the soil with a generous amount of compost. Although highly nitrogenous soil promotes leafy growth, this comes at the expense of tomato production. Adding too much nitrogen to the soil also makes these plants more susceptible to pest damage.
Read More: The Best and Worst Companion Plants for Parsley
8. Cilantro
Research shows that planting cilantro with tomatoes can reduce whitefly damage and may have a small effect on aphid, mite, and thrip populations. As an umbellifer, cilantro also supports the same beneficial insects as parsley and carrots: lacewings, hoverflies, and parasitic wasps and flies.
It's ideal to grow cilantro in more nitrogenous soil, but it will grow well enough planted next to tomatoes. For the best pest-deterring results, let the cilantro flower over the summer and collect the coriander seeds in the fall.
Read More: The 9 Best Companion Plants for Cilantro
9. Calendula
Also known as pot marigolds, calendula is an excellent companion flower for deterring pests. Calendula attracts some parasitoids that prey on aphids, and itself repels green peach aphids. Like marigolds, calendula grows best in rich soil and full sun or part shade. Interplant calendula flowers between tomatoes, or in a parallel row along with other companion flowers or herbs.
10. Nasturtium
Nasturtiums help reduce whitefly populations, but their biggest contribution as a companion plant for tomatoes is acting as a trap crop for nematodes and aphids. Nasturtiums are low-growing plants that like full sun, so you'll see the best results from planting them in front of trellised tomatoes.
11. Borage
Companion planting with borage can increase tomato yields by attracting hoverflies, lacewings, and other beneficial insects. Research shows that borage is an effective trap crop for aphids, which also allows it to attract parasitic wasps that prey on aphids. Plant borage near your tomatoes in well-draining soil, in either full sun or part shade.
What not to plant with tomatoes
Tomatoes have some of the most well known companion pairings of any main crop vegetable, but they also don't grow well with entire families of plants. Because tomatoes are heavy feeders, they're uncompromising in their soil and water needs-- which makes them difficult to grow well next to plants with different needs.
Here are some notably bad companion plants for tomatoes:
- Nightshades (peppers, potatoes, eggplants)
- Cucurbits (cucumbers, melons, squash, pumpkins)
- Mediterranean herbs (rosemary, oregano, marjoram, sage, thyme)
- Brassicas (kale, cabbage, cauliflower, broccoli)
- Strawberries
- Legumes
- Mint
- Dill
- Fennel
1. Nightshades
Tomatoes shouldn't be grown next to other nightshades like peppers, potatoes, and eggplants. All of these vegetables share the same pests and diseases, so planting them together makes them more susceptible to damage.
Read More: The 16 Best Companion Plants for Peppers
2. Cucurbits
Planting cucumbers and tomatoes together makes it difficult for both to get the nutrients they need. Cucumbers and other cucurbits, like melons, watermelons, pumpkins, and zucchini, will compete with tomatoes for root space, sun, water, and nutrition.
Read More: The 13 Best Companion Plants for Cucumbers
3. Mediterranean herbs
Similarly, tomatoes need too much nutrition to grow well with most popular Mediterranean herbs. But while they won't grow well together in the soil, tomatoes are actually one of the best companion plants for rosemary and other aromatic herbs like sage, oregano, marjoram, and thyme. All of these herbs can help reduce pest damage by masking tomatoes' scent when planted in nearby pots. (In fact, rosemary is particularly effective at deterring green peach aphids.)
4. Brassicas
Tomatoes don't grow well with brassicas like kale, cabbage, cauliflower, and broccoli. Brassicas prefer a less rich soil, and they'll do much better planted in a successional rotation where they replace tomatoes once the soil has been slightly depleted.
Read More: The 10 Best Companion Plants for Broccoli
5. Strawberries
Companion planting tomatoes and strawberries can make both more susceptible to fungal diseases. This is a particular danger to strawberries, whose low-hanging fruit make them more prone to infection.
6. Legumes
Beans and peas have the same growing requirements as tomatoes, but they would compete for space when grown as companions. Bush beans could work well in front of tomatoes in a small space, but they don't offer any particular benefit as companion plants.
Read More: The 10 Best Companion Plants for Peas
7. Mint
Mint is notorious for spreading so aggressively that it takes over the soil and chokes out anything planted nearby. The same would be apply if you planted mint with tomatoes. That said, as a strong aromatic herb, there are a few good companion plants for mint, as long as you keep it in a pot-- and tomatoes are one of them.
8. Dill
Companion planting dill with tomatoes can help protect them from aphids, mites, tomato hornworms, and other common tomato pests. Like other members of the carrot family, dill supports parasitic wasps and other beneficial insects that prey on pests like aphids and mites. Dill can also be used as a trap crop for tomato hornworms.
Unfortunately, once dill flowers and goes to seed, it can stunt tomatoes and other nightshades. Either continuously harvest your dill to prevent it from flowering or keep it in a pot near tomatoes. The latter offers additional benefits, as dill flowers support predators like lacewings and ladybugs.
9. Fennel
Fennel, a relative of dill, releases a chemical that suppresses the growth of nearby plants. Like mint, it's fantastic to grow in a container-- it will attract beneficial insects and cut back on pests-- but it's not a good companion in the soil.
Common tomato pests
The most common tomato pests include:
- Hornworms (tobacco and tomato hornworms)
- Stink bugs
- Tomato fruitworms
- Aphids (green peach aphid, potato aphid)
- Whitefly (silverleaf whitefly)
- Mites (two-spotted spider mites, red spider mites)
Some of the best companion plants for tomatoes to keep pests away are marigolds, calendula, nasturtium, basil, and borage. For the best results, use these plants together to create a push-pull effect. For example, planting calendula or marigolds with tomatoes will 'push' pests away; nearby radishes and nasturtium will 'pull' them toward their own roots.
Tomato companion planting chart
