27 Tomato Companion Plants & What Not To Plant With Tomatoes

Tomatoes are one of the tastiest and most rewarding plants to grow in the garden. Whether cherry tomatoes or heirloom slicers, these juicy fruits are the quintessential homegrown summer treat.

But tomatoes are also subject to a range of pest and disease issues that can destroy months of hard work. If you don’t want to use sprays or chemical methods of dealing with tomato problems, you can plant certain species alongside your crop to reduce their susceptibility to insects and pathogens.

Companion planting increases the biodiversity and resilience of your garden. Plus, you can optimize unused spaces within your tomato beds to maximize diverse yields from a small space. Let’s dig into the top 27 best companion plants for optimizing tomato growth, as well as what not to plant in your tomato beds.

What is Companion Planting?

Companion planting is growing specific vegetables, herbs, and flowers alongside your crops to help improve their health and vigor. There is significant evidence that companion plants work synergistically with your crop to reduce pest pressure and supply a range of other benefits.

Essentially, these support-plants create an ecosystem in your garden so you don’t have to work quite so hard to keep your plants healthy.

Tomatoes are particularly compatible with many different species of companion plants. Some of them serve multiple functions in the garden as well as the kitchen.  

Does Companion Planting Work?

A number of scientific studies have demonstrated that companion planting with tomatoes can significantly reduce pest damage. Let’s take a look at some of these studies, and the companion plants that accompany them:

Though many companion species remain unstudied, anecdotal evidence and ancient practices also provide plenty of evidence that companion planting really does provide benefits to your crops. At the very least, it offers the chance for a greater yield from spaces that would otherwise be bare soil.

How Companions Help Tomatoes

Research shows that biodiversity is linked to greater ecological resilience.

Organic gardening is all about mimicking nature through ecological growing methods. In nature, there are no chemical pesticides or fertilizer applications, instead the Earth uses its own “checks and balances” with plants that work in symbiosis to help eachother grow.

One of the easiest ways to create more symbiotic connections is through expanding the diversity of your garden with companion plants. In contrast to monoculture (growing lots of one species in a small space), polyculture plantings have been proven to reduce pest pressure by making it harder for them to find their hosts.

Interplantings of diverse species have been used for thousands of years to improve the health of farm fields, but recently this ancient practice is being revitalized as a means to reduce the use of pesticides. The main ways that companion plants work to reduce pest pressure and pesticide include:

• Releasing aromatic compounds that repel pests.
• Confusing pests so they can’t find their hosts.
• Attracting beneficial predators to eat pests.

In addition to their pest control benefits, companions of tomatoes can improve nutrient bioavailability, prevent soil-borne diseases, reduce weed competition, and add some more tasty ingredients to your garden-fresh menu.

27 Companion Plants for Tomatoes

The yield, flavor, and pest resistance of tomatoes can be improved by planting them alongside a variety of herbs, flowers, and vegetables.

Each of these species has unique qualities that complement tomato growth. Whether you’re growing with a tomato cage, trellis system, or a greenhouse, these companions can be tucked in along the sides of beds or the ends of rows.

Herb Companions

While there are a number of different popular companions for tomatoes, there are many herbs that can benefit them by not only repelling insects, but adding additional nutrients to help your tomatoes grow. Let’s look at some of the best herb companions for tomatoes!

Basil

A popular culinary partner for tomatoes in the kitchen, basil is one of the most well-studied companion plants. This delicious fragrant herb repels flies and aphids while improving the flavor of tomatoes through the release of certain aromatic compounds. Basil also grows easily and is low maintenance. Better yet, basil excels at repelling those nasty tomato hornworms.

The only problem basil can pose is it’s tendency to grow very bushy and tall near the base of tomato plants. This could lead to reduced air flow and disease problems in the tomatoes. It is important to plant basil at least 8-12” from the base of your tomatoes so that all your plants get enough space to thrive.

You can also regularly prune and harvest basil to keep it from overcrowding your tomatoes. During harvest, pinch the top leaflets to encourage it to bush out rather than growing too tall and bolting.

Scallions

Also called “green onions”, this mildly onion-flavored garnish takes very little space to grow and thrives in the aisles beneath tomato plants. Quick to mature, these spring onions don’t mind a bit of shade and can be planted at the same time as tomatoes for an additional early summer harvest.

Scallions are members of the Allium, or onion, family. These plants have repellant properties that keep many insects and moths at bay. The aroma of scallions is particularly beneficial for repelling five-spotted hawk moths, which lay tomato hornworm larvae on host plants.

Parsley

Another aromatic herb that happens to be compatible with tomatoes in the garden is Parsley. Parsley attracts swallowtail butterflies, which lay their eggs on the herb leaves. When allowed the flower, parsley blossoms also attract hoverflies, which are predators of thrips and aphids. Parsley is also known to repel harmful beetles.

This low-growing, low-maintenance herb acts as a ground cover to hold in soil moisture and keep weeds at bay. It also readily thrives in a little bit of shade from your tomato plants during the heat of the summer.

Garlic

This pungent flavorful allium grows on an opposite schedule than most plants in your garden. Garlic is typically planted in the fall and harvested in mid-summer. But if you time it right, garlic can make a great companion for your young establishing tomato plants. Garlic is also easy to grow, and hardy in many conditions.

Garlic is an extremely fragrant bulb that acts as a powerful insect repellant. Whether in the ground or in a homemade garden spray, garlic will repel most crawling and flying insects. Aphids, caterpillars, cutworms, slugs, beetles, mosquitoes, flies, and mites are all repulsed by the strong aroma of garlic.

Some studies have even shown that the vapors and oils released by garlic are toxic to insect pests (but not animals or humans of course). This is likely due to compounds such as garlic leaf agglutinin (ASAL) that is found in garlic plant juices. As a result, there are very few pests that attack this allium plant and its powerful oils benefit your tomatoes as well. Garlic does not have any negative impacts on beneficial insects, so it is perfectly safe for biocontrol plantings.

Either leave space during your garlic plantings to transplant tomatoes in the late spring, or plant garlic bulbs at the same time as tomatoes for harvest as “green garlic”.

Cilantro

In spite of its popularity as a salsa ingredient, cilantro is technically a cool-weather crop. Tomatoes help cilantro by keeping them shaded in the heat of the summer, which prevents quick bolting so you can harvest plenty of aromatic leaves.

However, when cilantro is allowed to go to flower alongside tomato plants, it attracts hoverflies, parasitic wasps, and other beneficial predatory insects. The nectar of cilantro flowers is attractive to bees that can also help pollinate your tomatoes. When the flowers fade, you can even harvest the young or mature cilantro seeds for use as coriander!

Cilantro is known to improve the flavor of tomatoes when planted in the same bed. It also repels common tomato pests like aphids, spider mites and beetles.

Mint

As you can tell, strongly fragrant herbs tend to be the most effective companions for tomatoes. Mint has been used for centuries to keep ants, cockroaches, and flies at bay. Planting this Labiatae-family herb alongside tomatoes improves the health of your tomato plants while also spreading around the base of your crops to provide weed-fighting ground cover.

However, some varieties of mint can be too aggressive for interplanting. They spread via underground stolons that can rapidly take over an area under moist, favorable conditions. Mint is best planted in its own patch or bed as a ground cover adjacent to your tomato beds (rather than inside the bed itself). You can even plant mint in pots that are placed near your tomato plants to avoid letting it overtake your vegetable beds. 

A natural compound called dolichodial is stored in the leaves as the plant’s main defensive mechanism against pests. Studies show that “injuring” the leaves (by cutting, brushing against them, or lightly crushing the leaves between your fingers) releases the highest volume of insect repellant. So be sure to regularly touch and harvest your mint to provide the most benefit to tomato plants.

Sage

Garden sage is gorgeous and delightfully fragrant. It grows very well near tomatoes (as long as it isn’t too shaded by their canopy) and blooms beautiful flowers that pollinators love.

Sage attracts parasitic wasps that can help keep tomato hornworms at bay. If you haven’t seen a tomato hornworm infested with parasitic wasp larvae, you will definitely want to check out this cool video to see how nature keeps these giant tomato-eating caterpillars under control without pesticides:

Oregano

Whether you are interested in its culinary or medicinal uses, oregano has been revered for centuries as an Italian herb that is excellent for your health. It also provides habitat and food for important predators like lacewings. The lacewing larvae are hungry predators of whiteflies, aphids, and cutworms.

When oregano flowers, its nectar-loaded flowers magnetize bees and pollinators to your tomato patch. The strong scent simultaneously confuses potential tomato pests. Oregano is deer resistant and makes an excellent living mulch or ground cover to reduce weeds near tomatoes.

Flower Companions

There are many flowers that can companion plant quite well with tomatoes too. Let’s take a look at some of the top flowers that will not only help tomatoes repel pests and improve soil biodiversity, but also make your garden look lush and beautiful with some variety.

Borage

The bright blue star-shaped flowers of Borago officinalis are as dazzling as they are functional. When planted on the ends of tomato beds, borage attracts an important aphid parasitoid called Aphidius colemani that can help keep aphid populations in your tomatoes at bay. Borage also deters tomato hornworms while attracting pollinators and bees.

The great thing about borage is that it flowers for a very long period of time, growing abundantly alongside tomatoes until the first frosts of fall. Remember that borage plants can grow quite large, so be sure to provide plenty of space between your tomatoes and borage sowings.

Marigolds

Another great friend in the vegetable garden, marigolds are among the most well-researched companion plants for tomatoes. These lovely vibrant flowers help prevent tomato diseases, nematodes, fruit borers, and other pets.

Reputable studies have shown that intercropping tomatoes and marigolds can:

• Increase tomato yields by up to 50%.
• Suppress tomato root knot nematodes.
• Reduce relative humidity in tomato canopy.
• Reduce leaf damage from early tomato blight.
• Act as trap crop for tomato fruit borer.

This quintessential Dia De Los Muertos ceremonial flower can be tucked into tomato beds at any angle. The relatively compact plants add a beautiful splash of color to tomato plantings. You can also use the flowers to create natural garden sprays. 

Nasturtiums

These lovely flowers are stunning edible flowers that can actually act as a trap crop for tomato pests. Planting nasturtiums a small distance from your tomato crop allows them to lure aphids and squash bugs to eat them instead of your prized tomatoes. The flowers simultaneously attract beneficial predators like hoverflies.

Nasturtiums can grow into large bushes that vine wildly up anything they can find, so be sure to provide plenty of space around them so they don’t crowd your tomatoes.

Calendula

You can interplant calendula with tomatoes by sowing the C-shaped seeds in between plants, in the aisleways, or on the borders of tomato beds. Calendula (Calendula officinalis) is sometimes called “pot marigold”, but it is not related to marigolds (Tagetes erecta).

It is an edible and medicinal flower known for its healing resinous blossoms. The aroma and stickiness of these flowers attracts beneficial insects and pollinators as it blooms throughout the entire summer. It also repels tomato hornworms, thrips, beetles, and nematodes.

Cosmos

One of the easiest to grow flowers, cosmos blooms in great abundance throughout the growing season. These tomato-friendly wildflowers bring loads of bees, predators, and other beneficial insects to your tomato patch, facilitating tomato pollination while keeping pests under control.

Green lacewings (a voracious predator of aphids, thrips, and scales) are one beneficial species that is absolutely obsessed with cosmos, specifically the orange-flowered varieties). Cosmos flowers are fast growers, and come in a rainbow of floral colors. However, keep in mind that these domesticated wildflowers can grow up to 6 feet tall and 1-3 feet wide. Plant them on the margins of tomato beds rather than inside them.

Sweet Alyssum

Another tomato friendly herb, Sweet alyssum (Lobularia maritime) is among the most important companion plants for attracting natural enemies to the garden. Studies show that this flower is a powerful “habitat manipulator” that enhances biological control of pests throughout the garden, including in the tomato patch.

I have never planted a garden without growing white alyssum. Sweet Alyssum is a low-growing plant perfect to tuck in between rows or at row ends. It won’t compete with your tomatoes for nutrients or water, instead of adding splashes of color in their under canopy and bringing all the ecological pest control you could hope for.

Sweet Alyssum can even grow into a little “floral blanket” that acts as the perfect ground cover to suppress weeds and maintain soil moisture. Alyssum flowers profusely all season long with tiny white or purple four-petaled flowers that smell delightful. 

Yarrow

A ladybug’s best friend, this flat-topped carrot-family is scientifically proven to be one of the best companion plants for attracting predatory insects. Yarrow is irresistible to ladybugs, syrphid flies, braconid wasps, ground beetles, and damselflies. These aggressive predators help keep tomato aphids, flea beetles, and hornworm caterpillars in check so that you don’t have to worry about scouting or spraying anything.

Yarrow is also a gorgeous cut flower with medicinal uses. Wild-type varieties are a creamy-white colored, while ornamental types come in brilliant pinks, purples, reds, orange, and gold. Yarrow can bush out quite large, so it is another companion plant great for row ends or the margins of the tomato garden.  

Wildflower Blends

If you don’t feel like picking out specific floral species, or you’d prefer to grow a mini-meadow on the border of your garden, opt for a wildflower blend that includes a diverse selection of native species to your region.

Wildflower blends should be broadcasted (lightly toss the seed into the soil and rake in) in the margins of a tomato bed, leaving plenty of space for the flowers to grow a little wild without encroaching on the tomatoes’ space.

Because they can be a little unpredictable, avoid planting wildflowers directly in your tomato beds. Even when planted 10 or more feet away, these floral blends will still attract a tremendous diversity of buzzing beneficial insects and pollinators to your garden. Not to mention, they’ll put on a dazzling show throughout the summer.

Vegetables

Now that we’ve talked about great flower companions, let’s take a look at vegetable companions. The following veggies will work well with tomatoes as they aren’t competing for the same nutritional needs, and they aren’t attracting pests by being part of the same plant family. Here’s a list of great veggies to go with your tomatoes.

Squash

Many traditional plant guilds (such as the indigenous ‘three sisters’ plantings of squash, corn, and beans) use different types of squash as a ground cover, weed-suppressor, and vining undergrowth food crop.

With its broad flat leaves and vining habit, winter squash is a particularly advantageous companion for tomatoes. Both crops require similar growing conditions (rich well-drained soil and an abundance of moisture). Squash can ramble beneath the canopy of trellised tomato plants, shading out weeds and conserving water. Both crops love the hot, sunny days of summer and are often transplanted at the same time, right after the last frosts of spring.

If you are growing vining (indeterminate) tomatoes, be sure to trellis them upward and let the vining squash grow below. If you are growing bush (determinate) tomatoes, consider choosing a bush variety of zucchini or summer squash and plant at least 24-36” away from the tomato plants. An alternating zig zag pattern of tomato-zucchini-tomato-zucchini has worked well in my gardens.

Either way, provide ample water and fertility for these fast-growing companions. Prune the lower leaves of tomatoes to provide plenty of airflow in the lower canopy.   

Carrots

There’s a reason an entire book called Carrots Love Tomatoes was written about companion planting in 1975. This classic combo draws on the earliest understanding of traditional interplantings and makes use of even the smallest garden spaces.

The slender orange root vegetables grow perfectly along rows of tomato plants without interfering with their water or fertility needs. The carrots can be tucked in just about anywhere in a tomato bed to create yield from otherwise bare spaces.

Carrots help loosen the soil next to tomatoes for greater aeration in the root zone. The solanine alkaloids in tomato leaves also help protect carrots from pests like carrot flies.

Celery

Celery is another Apiaceae family member that can be grown in the same bed as tomatoes. The celery may enjoy a bit of shade from trellised tomato plants. They don’t necessarily give each other any pest-repellant benefits, but they certainly complement each other with their differing heights and growth habits. 

Onion

Alliums are the most popular companion plants out there thanks to their strong smell and non-competitive nature. Onions are particularly suited for planting with tomatoes because their sulfurous odor deters aphids, thrips, and beetles.

Onions also help reduce the incidence of tomato pathogens. There is evidence that companion planting onion with tomato helps improve the tomato’s resistance to Verticillium wilt. Grow onions in rows alongside tomatoes or circled around the plant. Provide at least 6-8” from the base of tomato plants to the onions.  

Lettuce

All the ingredients of your summer salads could hypothetically be grown in one “salad” bed: tomato, lettuce, basil, and garlic love to be grown and eaten together. I hardly ever plant a tomato crop without tucking in some lettuce beneath the canopy.

Lettuce thrives in the partial shade of trellised tomatoes while simultaneously conserving soil moisture, preventing weeds, and offering a delicious salad-ready harvest. Its low-growing habit and light-feeding fertility requirements make it the perfect compliment to the tall, hungry tomato plants.

You can opt for head lettuce or baby lettuce mixes for growing alongside tomato plants. Just be sure to prune off the lower tomato leaves so that they don’t rub up against the lettuce.

Beans

Known for their nitrogen-fixing capacity, both bush beans and pole beans are eager to please alongside tomatoes. Beans are members of the Fabaceae, or Legume, family. They form symbiotic relationships with beneficial bacteria in the soil called Rhizobium. These bacteria create nodules on the leguminous roots and work their magic by taking nitrogen from the atmosphere and synthesizing or “fixing” it into a plant-available form. As a result, more nitrogen is released into the root zone for companions like tomatoes to uptake and use.

Beans enhance the growth of heavy-feeding tomatoes while also maximizing yields from unused spaces in the garden. Low-growing bush beans can be grown about 12-18” from the base of tomato plants. Pole beans can wind up tomato trellises or grow up a nearby pole in the same bed.

Peas

Similar to beans, peas are nitrogen-fixers that are glad to share their nutrient abundance with tomatoes. Sugar snap peas, cowpeas, and snow peas are particularly delicious additions to any garden.

But the benefits of peas don’t stop with nitrogen! Studies have shown that cowpeas help suppress root-knot nematodes when interplanted or cover cropped in tomato beds. Cowpea also significantly reduces infestations of leafhoppers and other pests.

Peas and tomatoes both benefit from increased yields when grown alongside each other. Just be sure to position your pea a trellis to the north so that it doesn’t shade out sun-loving tomatoes.

Radishes

One of the only brassicas I’d recommend growing near tomatoes, radishes are an ultra fast-growing crop that can yield some delicious spring snacks before the tomatoes fully grow up. If you sow radishes at the same time as you transplant tomatoes, they will be ready to harvest within a month, just as the tomatoes are starting to grow tall.

Radishes don’t require much space or fertility, so you don’t have to worry about them competing with your tomatoes.

Dandelion Greens

While most of us think of dandelions as weeds, they are in fact ultra nutritious and delicious additions to spring and summer salads. New varieties of domesticated dandelion greens (like the tangy red-veined dandelion) are bred to be more tender and less bitter than their wild counterparts. They are best grown as baby greens sown about 6” from the base of tomatoes. 

Best of all, researchers have found that dandelions can protect tomato plants from a disease called Fusarium wilt that often attacks tomato plant roots. This is because dandelions have naturally allelopathic properties against pathogens via compounds they release into the soil.

If you don’t want a bed full of dandelions, be sure to harvest your dandelion greens before they start flowering.

Chickweed

Another commonly dismissed weed, chickweed (Stellaria media) is in fact ultra-nutritious and quite beneficial for tomato plants. This tender lemony salad green is a nutrient accumulator. This means that it pulls potassium and phosphorus from the soil to make them available to your tomato plants. When it flowers, the delicate white blossoms of chickweed provide nectar to attract early spring pollinators that can also pollinate your first tomato flowers. Chickweed is not very aggressive and can easily be harvested or pulled from the garden at any time.

Chard

Last but not least, rainbow chard is a beautiful and versatile companion plant for tomatoes. As long as it is given enough space (at least 8-12” in each direction), you can grow chard in the same bed as spring tomatoes. You can harvest vibrant rainbow leaves and pair them with early tomato fruits in early summer salads. The chard may dwindle off once tomatoes get too big and start shading it out, at which point you may want to tuck in some cilantro or basil.  

Preventing Negative Crop Interactions

One of the risks of companion plantings is inadvertently reducing crop growth by causing too much competition for water, nutrients, and sunlight. Tomatoes are inherently very vigorous, tall-growing plants, however, if they are too crowded by their companions, the result could be reduced growth rather than a symbiosis.

What Not to Plant with Tomatoes

While tomatoes are fairly easygoing, there are a few crops that you should avoid planting in the same bed: