Companion planting for tomatoes involves growing complementary species nearby to enhance growth, deter pests, or improve garden efficiency. Certain plants can create a balanced ecosystem, supporting tomatoes by attracting beneficial insects or improving soil conditions. These companions work best when they share similar sunlight, water, and soil needs, ensuring harmony in the garden.
Some companions act as natural pest repellents, emitting scents that discourage common tomato pests like aphids or hornworms. Others serve as trap crops, luring harmful insects away from tomatoes. This reduces the need for chemical pesticides, promoting a healthier, organic garden environment.
Certain companions attract pollinators, such as bees, which boost tomato fruit production by aiding pollination. They can also draw predatory insects that feed on pests, creating a natural defense system. This synergy enhances tomato yields and plant vigor.
Other plants improve soil health by fixing nutrients or loosening soil structure, benefiting tomatoes’ root systems. Some act as living mulch, retaining moisture and suppressing weeds, which helps tomatoes thrive in hot or dry conditions.
Companion Plants for Tomatoes
Basil
- Benefits: Basil repels pests like aphids, whiteflies, and tomato hornworms through its strong aroma. It may also enhance tomato flavor and attract pollinators when flowering.
- Planting Tips: Plant basil 12–18 inches from tomato plants to avoid competition for nutrients. It thrives in similar sunny, well-drained conditions as tomatoes.
- Considerations: Pinch back basil to prevent flowering if you want to focus on leaf production, but allow some to bloom for pollinators.
Marigolds (French or African)
- Benefits: Marigolds release chemicals from their roots that deter nematodes, which can damage tomato roots. Their bright flowers also repel aphids and whiteflies.
- Planting Tips: Plant marigolds around the base of tomatoes or in rows between them. French marigolds are particularly effective against nematodes.
- Considerations: Deadhead spent flowers to encourage continuous blooming and pest-repelling effects.
Nasturtiums
- Benefits: Nasturtiums act as a trap crop, luring aphids and whiteflies away from tomatoes. Their flowers attract beneficial insects like hoverflies, which eat pests.
- Planting Tips: Sow nasturtiums 1–2 feet from tomatoes, as they can sprawl. They prefer slightly poorer soil, so avoid over-fertilizing.
- Considerations: Nasturtiums are edible, adding value to your garden, but monitor their spread to prevent overcrowding.
Borage
- Benefits: Borage attracts pollinators like bees, boosting tomato fruit set. It also deters tomato hornworms and improves soil by adding trace minerals.
- Planting Tips: Plant borage 2–3 feet from tomatoes to give both plants space. It tolerates partial shade but prefers full sun like tomatoes.
- Considerations: Borage self-seeds readily, so remove spent flowers if you want to control its spread.
Garlic
- Benefits: Garlic’s pungent smell repels spider mites and aphids. It also has antifungal properties that may reduce tomato fungal diseases.
- Planting Tips: Plant garlic cloves in fall or early spring around tomato beds. Space them 6 inches apart to avoid competition.
- Considerations: Harvest garlic bulbs in late summer, which aligns well with tomato season, freeing up space.
Onions
- Benefits: Onions deter pests like aphids and slugs with their strong odor. They also take up minimal space, making them ideal for interplanting.
- Planting Tips: Plant onions in rows between tomatoes, spacing them 4–6 inches apart. They need similar well-drained soil conditions.
- Considerations: Onions mature faster than tomatoes, so you can harvest them mid-season without disturbing tomato roots.
Chives
- Benefits: Chives repel aphids and spider mites and may improve tomato flavor. Their small size makes them easy to tuck into garden beds.
- Planting Tips: Plant chives in clusters around tomato plants, 6–12 inches apart. They thrive in full sun and tolerate poor soil.
- Considerations: Cut back chives regularly to encourage fresh growth and prevent them from spreading too much.
Parsley
- Benefits: Parsley attracts predatory insects like ladybugs and lacewings, which feed on tomato pests. It also improves soil health as it decomposes.
- Planting Tips: Plant parsley at the edges of tomato beds, 12 inches from tomato stems, to avoid shading smaller plants.
- Considerations: Parsley is biennial, so it may return the next year, but replace it if it starts to bolt.
Carrots
- Benefits: Carrots loosen soil with their deep roots, improving drainage for tomatoes. They also attract beneficial insects when allowed to flower.
- Planting Tips: Sow carrot seeds in rows between tomatoes, thinning to 2–3 inches apart. They prefer loose, sandy soil.
- Considerations: Harvest carrots carefully to avoid disturbing tomato roots, or leave some to flower for pest control.
Lettuce
- Benefits: Lettuce acts as a living mulch, shading the soil to retain moisture and suppress weeds. It also uses space efficiently under taller tomato plants.
- Planting Tips: Plant lettuce 6–12 inches from tomato bases in early spring or late summer to avoid heat stress.
- Considerations: Choose heat-tolerant varieties for summer planting, as lettuce can bolt in high temperatures.
Alyssum
- Benefits: Sweet alyssum attracts hoverflies and parasitic wasps, which prey on tomato pests. Its low-growing habit makes it a great ground cover.
- Planting Tips: Sow alyssum seeds around tomato plants or in borders, spacing 6–8 inches apart. It thrives in full sun to partial shade.
- Considerations: Alyssum is low-maintenance but may need trimming to keep it tidy and encourage blooming.
Amaranth
- Benefits: Amaranth attracts beneficial insects and acts as a trap crop for leaf-eating pests, diverting them from tomatoes. It also adds visual height to gardens.
- Planting Tips: Plant amaranth 2–3 feet from tomatoes to avoid shading. It grows well in warm, sunny conditions.
- Considerations: Choose dwarf varieties if space is limited, as some amaranth can grow tall and compete for light.
Oregano
- Benefits: Oregano’s strong scent repels pests like aphids and tomato hornworms. It also attracts pollinators when flowering, boosting tomato fruit production.
- Planting Tips: Plant oregano 12–18 inches from tomatoes in well-drained soil. It thrives in full sun, matching tomato needs.
- Considerations: Oregano is a perennial, so it can return yearly but may need pruning to prevent it from spreading too much.
Thyme
- Benefits: Thyme deters whiteflies and cabbage worms, which can affect tomatoes. Its low-growing habit makes it an excellent ground cover to reduce weeds.
- Planting Tips: Sow thyme around tomato bases or in borders, spacing 6–12 inches apart. It prefers slightly drier soil than tomatoes.
- Considerations: Harvest thyme regularly to keep it compact and avoid woody growth.
Mint
- Benefits: Mint’s potent aroma repels ants, aphids, and flea beetles. It also attracts beneficial insects when allowed to flower.
- Planting Tips: Plant mint in pots near tomatoes to control its invasive roots, placing them 1–2 feet away. It tolerates partial shade.
- Considerations: Mint spreads aggressively, so containers are essential to prevent it from overtaking the garden.
Cilantro (Coriander)
- Benefits: Cilantro attracts predatory insects like lacewings and ladybugs, which eat tomato pests. Its flowers also draw pollinators.
- Planting Tips: Sow cilantro seeds 6–12 inches from tomatoes in early spring or fall, as it bolts in hot weather.
- Considerations: Succession plant every 2–3 weeks for a continuous supply, as cilantro has a short lifecycle.
Dill
- Benefits: Dill attracts beneficial insects like parasitic wasps and hoverflies, which control tomato pests. It also repels spider mites.
- Planting Tips: Plant dill 1–2 feet from tomatoes to avoid shading. It prefers full sun and well-drained soil.
- Considerations: Dill can grow tall, so stake it if needed, and harvest before it sets seed to control spread.
Spinach
- Benefits: Spinach acts as a living mulch, keeping soil cool and moist for tomatoes. It also maximizes space in small gardens.
- Planting Tips: Plant spinach 6–10 inches from tomato bases in early spring or late summer to avoid heat stress.
- Considerations: Choose heat-tolerant varieties for summer planting, as spinach bolts in warm weather.
Radishes
- Benefits: Radishes deter spider mites and loosen soil with their roots, improving drainage for tomatoes. They mature quickly, freeing up space.
- Planting Tips: Sow radish seeds in rows between tomatoes, thinning to 2–4 inches apart. They grow well in similar soil conditions.
- Considerations: Harvest radishes within 3–4 weeks to avoid competition with tomato roots.
Catnip
- Benefits: Catnip repels aphids, flea beetles, and ants with its strong scent. It also attracts pollinators when flowering.
- Planting Tips: Plant catnip in pots or contained areas 1–2 feet from tomatoes to prevent spreading. It thrives in full sun.
- Considerations: Like mint, catnip can be invasive, so control its growth with barriers or containers.
Yarrow
- Benefits: Yarrow attracts beneficial insects like ladybugs and predatory wasps, which prey on tomato pests. Its deep roots improve soil structure.
- Planting Tips: Plant yarrow 2–3 feet from tomatoes, as it can grow tall. It tolerates poor soil and drought.
- Considerations: Cut back yarrow after flowering to prevent self-seeding and maintain a tidy garden.
Lovage
- Benefits: Lovage attracts beneficial insects and improves soil health with its deep roots. Its tall structure can provide light shade for young tomato plants.
- Planting Tips: Plant lovage 2–3 feet from tomatoes to avoid competition. It prefers rich, well-drained soil.
- Considerations: Lovage is a large perennial, so plan for its space needs in future seasons.
Cosmos
- Benefits: Cosmos attract pollinators and beneficial insects like lacewings, which control tomato pests. Their feathery foliage adds aesthetic appeal.
- Planting Tips: Sow cosmos seeds 1–2 feet from tomatoes in full sun. Space plants 12–18 inches apart to avoid crowding.
- Considerations: Choose dwarf varieties for smaller gardens to prevent shading tomatoes.
Asparagus
- Benefits: Asparagus repels nematodes through its root secretions, protecting tomato roots. It’s a long-term companion as a perennial.
- Planting Tips: Plant asparagus crowns in a separate bed or row near tomatoes, as they need space and remain for years.
- Considerations: Asparagus takes 2–3 years to establish, so plan for long-term garden layout.
Sage
- Benefits: Sage’s strong aroma repels pests like cabbage moths and carrot flies, which can affect tomatoes. It also attracts pollinators when flowering.
- Planting Tips: Plant sage 12–18 inches from tomatoes in well-drained soil. It thrives in full sun, aligning with tomato needs.
- Considerations: Sage is a perennial, so plan for its long-term space needs and prune to prevent woodiness.
Rosemary
- Benefits: Rosemary deters beetles and aphids with its scent. Its woody structure can act as a windbreak for young tomato plants.
- Planting Tips: Place rosemary 2–3 feet from tomatoes to avoid competition. It prefers slightly drier soil than tomatoes.
- Considerations: Rosemary is a perennial, so choose a permanent spot or grow it in pots for flexibility.
Zinnias
- Benefits: Zinnias attract pollinators like bees and butterflies, boosting tomato fruit set. They also draw predatory insects that eat tomato pests.
- Planting Tips: Sow zinnias 1–2 feet from tomatoes in full sun, spacing 6–12 inches apart. They tolerate similar soil conditions.
- Considerations: Deadhead zinnias to prolong blooming and prevent self-seeding in small gardens.
Sunflowers
- Benefits: Sunflowers attract pollinators and beneficial insects. They can provide light shade or act as a windbreak for tomato plants in hot climates.
- Planting Tips: Plant sunflowers 3–4 feet from tomatoes to avoid shading. Choose dwarf varieties for smaller gardens.
- Considerations: Sunflowers have deep roots, so ensure they don’t compete with tomatoes for water.
Lemon Balm
- Benefits: Lemon balm repels mosquitoes and aphids with its citrusy scent. It also attracts bees, aiding tomato pollination.
- Planting Tips: Grow lemon balm in pots or 1–2 feet from tomatoes to control its spread. It tolerates partial shade.
- Considerations: Like mint, lemon balm can be invasive, so contain it to avoid overtaking the garden.
Bush Beans
- Benefits: Bush beans fix nitrogen in the soil, enriching it for nutrient-hungry tomatoes. They also deter pests like beetles.
- Planting Tips: Plant bush beans 12–18 inches from tomatoes in rows. They need similar sunny, well-drained conditions.
- Considerations: Harvest beans regularly to avoid competition and ensure continuous production.
Beets
- Benefits: Beets loosen soil with their roots, improving drainage for tomatoes. They also take up little space, maximizing garden efficiency.
- Planting Tips: Sow beets 6–10 inches from tomatoes in early spring or fall. They tolerate partial shade from tomato plants.
- Considerations: Harvest beets early (8–10 weeks) to avoid disturbing tomato roots later in the season.
Feverfew
- Benefits: Feverfew repels pests like aphids and attracts beneficial insects. Its small, daisy-like flowers add aesthetic value.
- Planting Tips: Plant feverfew 12–18 inches from tomatoes in full sun to partial shade. It’s low-maintenance and drought-tolerant.
- Considerations: Feverfew self-seeds, so remove spent flowers to control its spread if desired.
Calendula
- Benefits: Calendula attracts pollinators and predatory insects like ladybugs, which control tomato pests. It also repels nematodes.
- Planting Tips: Sow calendula seeds around tomato bases or in borders, spacing 8–12 inches apart. It thrives in sunny conditions.
- Considerations: Deadhead calendula to encourage continuous blooms and prevent excessive self-seeding.
Tansy
- Benefits: Tansy repels pests like ants, flies, and tomato hornworms. It also attracts beneficial insects when flowering.
- Planting Tips: Plant tansy 2–3 feet from tomatoes, as it can grow tall. It prefers well-drained soil and full sun.
- Considerations: Tansy is toxic to some animals and can spread aggressively, so contain it in small gardens.
Sweet Potatoes
- Benefits: Sweet potatoes act as a ground cover, suppressing weeds and retaining soil moisture for tomatoes. Their roots deter nematodes.
- Planting Tips: Plant sweet potato slips 12–18 inches from tomatoes in warm, loose soil. They need full sun.
- Considerations: Sweet potatoes spread widely, so ensure enough space or use trellises to manage vines.
Chamomile
- Benefits: Chamomile attracts hoverflies and wasps that prey on tomato pests. It also improves soil health as it decomposes.
- Planting Tips: Sow chamomile 6–12 inches from tomatoes in full sun. It’s low-growing and complements tomato beds.
- Considerations: Chamomile self-seeds, so harvest flowers or trim to control spread if needed.
Worst Companion Plants for Tomatoes
Potatoes
- Why It’s Bad: Potatoes and tomatoes are both in the nightshade family (Solanaceae), making them susceptible to the same pests and diseases, like late blight and potato beetles. Planting them together increases disease risk and competition for nutrients.
- Considerations: Keep potatoes in a separate garden bed or rotate them in different seasons to avoid disease buildup in the soil.
Corn
- Why It’s Bad: Corn attracts pests like corn earworms (also called tomato fruitworms), which can devastate tomato crops. Both plants are heavy feeders, competing for nutrients and water.
- Considerations: Plant corn far from tomatoes, ideally in a different section of the garden, to minimize pest crossover.
Cabbage (and Other Brassicas, e.g., Broccoli, Cauliflower, Kale)
- Why It’s Bad: Brassicas compete with tomatoes for nutrients, particularly calcium, and can stunt their growth. They also attract pests like cabbage worms, which may spread to tomatoes.
- Considerations: Grow brassicas in a separate bed or at a different time of year to avoid resource competition.
Fennel
- Why It’s Bad: Fennel releases allelopathic chemicals that inhibit the growth of nearby plants, including tomatoes. It can reduce tomato vigor and yield.
- Considerations: If you want to grow fennel, keep it in a pot or isolated area far from tomatoes to prevent chemical interference.
Kohlrabi
- Why It’s Bad: Like other brassicas, kohlrabi competes with tomatoes for nutrients and attracts similar pests, such as cabbage worms, increasing pest pressure on tomatoes.
- Considerations: Plant kohlrabi in a separate plot or use crop rotation to avoid overlapping with tomatoes.
Eggplant
- Why It’s Bad: As another nightshade, eggplant shares pests (e.g., Colorado potato beetles) and diseases (e.g., verticillium wilt) with tomatoes. Planting them together can amplify these issues.
- Considerations: Space eggplants and tomatoes far apart or grow them in different seasons to reduce disease and pest risks.
Walnut Trees (Black Walnut)
- Why It’s Bad: Black walnut trees produce juglone, a chemical toxic to tomatoes and many other plants, causing wilting or death. Their roots and fallen leaves spread this toxin into the soil.
- Considerations: Avoid planting tomatoes within 50–60 feet of black walnut trees, and remove any walnut debris from garden beds.
Dill (Mature Plants)
- Why It’s Bad: While young dill can benefit tomatoes by attracting predatory insects, mature dill competes for space and nutrients and may attract pests like cutworms when flowering excessively.
- Considerations: Use dill sparingly and harvest it before it sets seed, or plant it far enough from tomatoes to avoid competition
General Care Tips
- Planting: Space companions appropriately to avoid competition with tomatoes for nutrients and light.
- Watering: Match watering needs; most prefer well-drained soil and moderate moisture, similar to tomatoes.
- Pest Monitoring: Regularly check for pests to ensure trap crops or repellents are effective.
- Soil: Amend soil with compost to support both tomatoes and companions, ensuring good drainage.
- Sunlight: Most companions thrive in full sun, aligning with tomato requirements.
- Check USDA hardiness zones for perennials (most are hardy in zones 4-9; annuals suit most regions).
- These companions enhance tomato health and yield while attracting pollinators, improving garden biodiversity.
- Avoid planting tomatoes near incompatible plants like potatoes or fennel, which may increase disease risk or compete for resources.