20 Best Companion Planting For Tomatoes
Companion planting is one of the oldest and most effective gardening strategy for healthier tomatoes, bigger harvests and fewer pests. By placing certain plants together, gardeners can create natural support systems where plants protect, nourish and enhance each other. Tomatoes (Solanum lycopersicum) respond exceptionally well to companion planting because their vigorous growth, deep root system and heavy feeding habits make them sensitive to pest pressure, soil deficiencies and environmental stress.
Some plants help tomatoes by enriching the soil with nutrients, releasing pest-repelling compounds, attracting pollinators, or acting as living mulch to cool the soil and suppress weeds. Others work as trap crops, drawing harmful pests away from tomatoes so the main crop remains protected. A few companions even produce biochemical compounds that directly benefit tomato health.
However, not all plants pair well with tomatoes. Some compete for nutrients, attract the diseases and compromise tomatoes growth.
In this complete guide, you’ll learn the 20 best companion plants for tomatoes, the 8 worst plants you should never grow nearby. You’ll also find recommendations on what to plant under tomatoes, vegetables companion plants and container-specific combinations.
Let’s explore the plants that help tomatoes truly thrive.
20 Best Companion Plants for Tomatoes
I have categorized for ease.
Best Herbs for Companion Planting For Tomatoes
Basil (Ocimum Basilicum)
Basil is a herb plant and it is the best tomato companion because it releases aromatic essential oils that repel aphids, whiteflies, thrips, mosquitoes and tomato hornworms. These volatile oils mask the scent of tomato foliage, making it harder for pests to locate the plant. Research also shows that basil planted near tomatoes can help reduce fungal pressure by improving airflow and preventing pest-incited damage.
Beyond pest control, basil improves tomato growth and yield by enhancing root vigor and promoting stronger fruit set. It acts as a living mulch in hot weather, helping maintain soil moisture and cool temperatures. Many gardeners also believe basil enhances tomato flavor. Basil’s compact growth makes it ideal for planting directly under or beside tomatoes.
Parsley (Petroselinum Crispum)
Parsley attracts beneficial predators such as ladybugs, hoverflies and parasitic wasps. These are the natural enemies for insects on tomatoes like aphids, hornworm eggs and mites. Its deep taproot also improves soil texture by breaking compacted layers and improving water infiltration.
As a cool-season plant, parsley thrives in the partial shade created by taller tomato plants. This mutually beneficial partnership keeps parsley from bolting too early in summer heat while allowing tomatoes to enjoy pest protection throughout the season. The plant works well as an underplanting living mulch in both garden beds and pots.
Cilantro (Coriandrum Sativum)
Cilantro is excellent for attracting predatory insects such as tachinid flies and tiny parasitic wasps that lay their eggs inside tomato hornworms. These insects hatch inside the pests, controlling them effectively. The small flowers of cilantro are especially attractive to beneficial insects because of their rich nectar and easily accessible pollen.
Cilantro also helps repel spider mites and Colorado potato beetles—two serious threats in warm climates. While cilantro prefers cooler temperatures, allowing it to bolt and flower near tomatoes during summer maximizes its companion benefits. Even after bolting, the plant continues to attract helpful insects until it dries out.
Chives (Allium Schoenoprasum)
Chives produce natural sulfur compounds that deter aphids, spider mites and leafhoppers—pests that often attack tomatoes in mid-summer. Chives also have mild antifungal qualities that help curb fungal diseases when planted nearby.
When chives flower, their purple blooms attract bees and beneficial wasps that improve tomato pollination. They have shallow root system, so, they don’t compete heavily with tomatoes for nutrients. They are also perennial, making them useful for long-term garden planning.
Thyme (Thymus Vulgaris)
Thyme contains thymol and other aromatic oils that repel hornworms, whiteflies, armyworms, and cabbage loopers. These compounds release into the air and help protect tomato foliage from pest chewing. Thyme’s low-growing nature makes it an effective living mulch that helps regulate soil temperature and retain moisture.
The plant thrives in dry conditions, so when paired with tomatoes in containers, it is best placed at the pot edges where soil drains faster. The flowers attract tiny beneficial insects such as hoverflies, which are major predators of aphids.
Oregano (Origanum Vulgare)
Oregano is a hardy, drought-tolerant herb that provides valuable ground cover around tomatoes. Its thick mat of foliage suppresses weeds, conserves moisture and reduces soil splash. The aroma of oregano repels several harmful insects, including cucumber beetles and whiteflies.
When allowed to bloom, oregano becomes a habitat for ladybugs and green lacewings. These predators play a crucial role in controlling aphids and spider mites. Plant oregano in pots around tomatoes to prevent soil competition.
Best Flowers for Companion Planting For Tomatoes
Marigolds (Tagetes Patula / Tagetes Tenuifolia)
French marigolds are one of the most scientifically proven tomato companions. They release alpha-terthienyl from their roots, a compound that kills root-knot nematodes—microscopic pests that damage tomato roots. This natural nematicide effect can last years if marigolds are grown and worked into the soil.
Above ground, marigolds repel whiteflies, aphids and thrips while serving as a trap crop for tomato hornworms. Their bright blooms also attract pollinators and small beneficial insects. Marigolds grow well in containers with tomatoes, providing colorful, edible flowers.
Nasturtiums (Tropaeolum Majus)
Nasturtiums are exceptional trap crops that lure aphids, whiteflies and beetles away from tomatoes. These pests prefer nasturtium leaves, sparing nearby tomato plants from damage. Their trailing habit also creates natural ground cover, which cools the soil and reduces evaporation.
Their flowers attract pollinators and predatory insects such as hoverflies. Nasturtium leaves and flowers are edible, add value to the garden. Because they grow quickly, they can be replanted throughout the season for continuous pest protection.
Read: Tips For Tomatoes Growing
Calendula (Calendula officinalis)
Calendula produces a scent that repels hornworms, armyworms and flea beetles. Its sticky, resinous stems also trap small insects before they reach tomatoes. The plant grows well in cooler weather, making it a productive companion early in the season.
Calendula flowers attract beneficial insects such as ladybugs, lacewings and predatory beetles.
Sweet Alyssum (Lobularia Maritima)
Sweet alyssum is a great plant to grow next to tomatoes. It brings in helpful insects that eat common tomato pests, like hornworms and aphids. Its tiny flowers give these good bugs nectar to feed on. Because sweet alyssum grows low to the ground, it also works like a natural mulch, helping to keep weeds down and the soil cool and moist.
Zinnias (Zinnia Elegans)
Zinnias attract pollinators like bees, butterflies and hoverflies that help improve tomato pollination. More pollinators mean more fruit set, especially in large tomato plants with dense foliage.
Zinnias also help lure beneficial predators that eat pests like aphids and whiteflies. Their tall blooms add beauty and biodiversity to the garden. They are heat-tolerant and thrive in the same conditions as tomatoes.
Sunflowers (Helianthus Annuus)
Sunflowers attract native bees and bumblebees, which are excellent at shaking tomato flowers to release pollen. This natural “buzz pollination” improves fruit size and quantity. Sunflowers also provide natural shade for crops like lettuce grown under tomatoes.
However, sunflowers should be planted a little distance away because their large roots can compete with tomatoes. Their ability to attract predatory birds is an added advantage.
Best Vegetables Companion Planting For Tomatoes
Carrots (Daucus Carota subsp. Sativus)
Carrots help aerate the soil around tomatoes with their slender taproots, improving drainage and root penetration. They grow well in the filtered shade beneath full tomato plants during summer.
Carrots grow smaller and their presence improves overall soil texture. Always plant short carrot varieties for best results. The shallow root competition is minimal, making this combination ideal for raised beds.
Bush Beans (Phaseolus Vulgaris)
Bush beans are nitrogen-fixing plants that enrich the soil with nitrogen—a nutrient tomatoes heavily consume. As beans grow, they host beneficial bacteria on their roots which convert atmospheric nitrogen into usable forms for tomatoes.
The combination improves tomato vigor and reduces the need for synthetic fertilizers. Beans also help suppress weeds around tomato bases due to their dense foliage.
Lettuce (Lactuca Sativa)
Lettuce thrives in the shade created by tomato plants. As temperatures rise, tomato foliage protects lettuce from bolting too quickly. Lettuce’s shallow roots do not interfere with tomatoes, making it a perfect living mulch.
This pairing maximizes garden space while reducing weed growth. Lettuce also helps maintain soil moisture during hot months.
Spinach (Spinacia Oleracea)
Spinach grows quickly and can be harvested repeatedly while tomatoes mature. Its low-growing structure cools soil and supports moisture retention. Spinach also improves calcium availability in soil when left to decompose, reducing blossom-end rot concerns.
As an early-season crop, spinach matures before tomatoes need full garden space, making them good succession companions.
Radishes (Raphanus Sativus)
Radishes act as a trap crop for flea beetles and leaf miners, which prefer radish leaves over tomatoes. This helps prevent early-season pest damage. Radishes also grow well in the cooler soil beneath young tomato plants.
Their quick growth means they can be replanted multiple times throughout the season to provide ongoing pest protection.
Best Soil-Improving Companion Plants For Tomatoes
Borage (Borago officinalis)
Borage is a mineral accumulator that draws calcium and potassium from deep soil layers and deposits them near the surface as its leaves decompose. These nutrients benefit tomatoes—which are heavy potassium feeders—through improved fruit quality and disease resistance.
Borage also repels tomato hornworms and attracts pollinators with its star-shaped flowers. It grows vigorously, so one or two plants per garden bed are enough.
Asparagus (Asparagus Officinalis)
Asparagus produces natural compounds that repel root-knot nematodes, one of the biggest threats to tomato roots. In return, tomatoes release solanine, a natural alkaloid that deters asparagus beetles. This creates a mutually beneficial relationship.
Both plants occupy different soil levels—tomatoes have deep taproots, while asparagus spreads horizontally—reducing competition. This makes them compatible long-term garden companions.
Crimson Clover (Trifolium incarnatum)
Crimson clover is an excellent nitrogen fixer that enriches soil throughout the growing season. When used as a living mulch, it prevents weeds, keeps soil cool and supports beneficial insect life.
Its dense flowers attract pollinators and predatory insects. Clover can also be tilled into the soil as green manure to replenish nitrogen after heavy-feeding tomato crops.
What Not To Plant with Tomatoes (8 Worst Plants)
Potatoes (Solanum Tuberosum)
Potatoes belong to the same nightshade family as tomatoes and share identical diseases, including early blight, late blight and verticillium wilt. One infected plant can spread disease rapidly to the other. Their heavy feeding requirements also compete with tomatoes for nutrients.
Both crops attract tomato hornworms, creating a concentrated pest zone when planted close together. Potatoes also need hilling, which disturbs soil around tomato roots. Avoid planting potatoes with tomatoes.
Eggplant (Solanum Melongena)
Eggplants attract flea beetles, hornworms and spider mites, increasing pest pressure on tomatoes. Their susceptibility to blight makes them dangerous neighbors for tomatoes.
Eggplants and tomatoes have similar nutrient needs, they compete heavily for nitrogen and potassium. Growing them together drains soil fertility quickly and increases the risk of nutrient deficiencies.
Peppers (Capsicum Annuum)
Peppers are nightshades like tomatoes and attract the same pests: hornworms, aphids and spider mites. They also share susceptibility to blight and mosaic viruses, making disease transfer likely.
Peppers and tomatoes both require high nutrients and moisture, meaning they compete intensely in close proximity. This results in reduced fruit size and slower growth for both.
Corn (Zea Mays)
Corn attracts corn earworm, which is the same pest as tomato fruitworm. Once these caterpillars infest one crop, they easily spread to the other. Corn also casts heavy shade, which tomatoes do not tolerate.
Additionally, corn’s deep, aggressive root system competes with tomatoes for nitrogen and water. This combination significantly weakens tomato growth.
Fennel (Foeniculum Vulgare)
Fennel exudes allelopathic chemicals from its roots that inhibit the growth of many vegetable crops, including tomatoes. These compounds slow root expansion and interfere with nutrient uptake, causing stunted tomato plants.
Because fennel attracts swallowtail caterpillars, it can increase leaf damage in nearby crops. It is best planted far from vegetable beds.
Dill – Mature (Anethum Graveolens)
Young dill helps tomatoes, but once dill matures, its roots release chemicals that stunt tomato root development. Mature dill also attracts hornworms and aphids.
Dill tends to bolt quickly, creating tall, unstable stalks that can shade tomatoes or collapse onto them. The safest approach is to keep dill away from tomatoes entirely.
Brassicas (Brassica oleracea family)
Cabbage, cauliflower, broccoli, kale, and Brussels sprouts compete heavily with tomatoes due to their nutrient-demanding roots. They absorb nitrogen quickly, leaving tomatoes deficient.
Brassicas also attract cabbage loopers and aphids that may migrate to tomatoes.
Rosemary (Salvia Rosmarinus)
Rosemary prefers dry, sandy soil—opposite of the consistent moisture tomatoes require. When grown together, one plant always suffers from improper watering conditions.
Its roots release compounds that inhibit the growth of certain vegetables, potentially affecting tomato root vigor. Rosemary is best kept in a separate pot away from tomatoes.
Conclusion
With careful companion planting, tomatoes can grow healthier, produce more fruit, resist pests naturally and benefit from improved soil conditions. Using the right plant combinations and avoiding harmful ones—creates a thriving, balanced garden ecosystem.
Happy Gardening!
