Some plants help tomatoes by drawing pests away or attracting pollinators, while others compete for food or share the same diseases. Pick a plant below to see whether it is a good neighbor for tomatoes and why, or browse the good and avoid lists further down.
Try one:
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What Your Result Means: a good companion draws pests away, attracts helpful insects, or shares space without competing. An avoid pairing usually competes for food or shares a disease or pest. Spacing and rotation still matter more than any single pairing.
What Can You Plant with Tomatoes?
Plenty of herbs, flowers, and vegetables make good tomato neighbors, while a few are best kept apart. Choose a plant from the list and the tool tells you whether it is a good companion, one to use with caution, or one to avoid, with the reason.
- Pick a Plant, the one you are thinking of growing near your tomatoes.
- Read the Verdict, good, caution, or avoid, and the reason behind it.
- Plan Your Bed, keeping avoid plants well away and giving everything room and airflow.
What Each Result Means
| Verdict | What It Tells You |
|---|---|
| Good companion | Helps tomatoes or shares space without competing |
| Use caution | Can work with care, spacing, or timing |
| Avoid | Competes strongly or shares a disease or pest |
Good and Avoid Companions
A quick reference for planting around tomatoes.
| Good Companions | Avoid or Use Caution |
|---|---|
| Basil | Fennel (avoid) |
| Marigold | Potatoes (avoid) |
| Nasturtium | Cabbage, broccoli, kale (avoid) |
| Garlic, onion, chives | Corn (avoid) |
| Lettuce, spinach | Black walnut (avoid) |
| Carrots | Peppers, eggplant (caution: rotate) |
| Borage, parsley | Mature dill (caution) |
| Beans, peas | Cucumber (caution: airflow) |
How Does the Checker Work?
The tool matches your plant to a companion list drawn from horticultural guidance. Good pairings deter pests, attract pollinators and predators, or share space without competing. Avoid pairings compete for nutrients or share a disease or pest with tomatoes.
The strongest reasons to avoid a pairing are practical, not folklore: nightshades such as potatoes share blight, corn and tomatoes share the same fruitworm, and black walnut releases juglone that is toxic to tomatoes.
Worked Example
Check basil and the tool returns a good companion, a classic pairing that shares sun and water needs and may help repel some pests. Check potatoes and it returns avoid, because both are nightshades that share blight and other diseases and should be kept apart and rotated.
Factors That Matter More Than Pairings
- Spacing and airflow: crowding raises disease risk far more than any companion helps.
- Crop rotation: keeping tomatoes off beds that grew nightshades recently prevents soil disease.
- Sun: tall tomatoes can shade neighbors, so place shorter plants where they still get light.
- Water and feeding: heavy feeders planted together compete, so match needs or space them out.
- Pollinator support: flowering companions like borage and marigold bring in helpful insects.
When to Use It
Use it when planning a bed or raised bed, deciding what to tuck between tomato plants, or choosing flowers to attract pollinators and deter pests. Pair it with the plant spacing calculator and the crop rotation planner.
Common Mistakes to Avoid
- Crowding for companionship: planting too close for a pairing raises disease more than it helps.
- Ignoring rotation: a good companion does not fix planting tomatoes where potatoes just grew.
- Planting potatoes beside tomatoes: they share late blight; peppers and eggplant can grow nearby with good airflow but must be rotated with tomatoes as one family.
- Letting dill mature nearby: harvest dill young, since mature plants are traditionally said to stunt tomatoes.
- Expecting miracles: companions help at the margins; sun, soil, and water do the heavy lifting.
Accuracy and Limitations
This tool reflects common horticultural guidance on tomato companions.
What It Tells You Reliably: the well-established reasons to avoid certain pairings, such as shared nightshade diseases, the corn earworm, and walnut juglone.
What Is Less Certain: some pest-repelling and growth-boosting claims are traditional rather than proven. Treat the good pairings as helpful, not guaranteed.
Methodology
Method: each plant is matched to a curated companion list and returned with a verdict and reason. Categories: good companion, use caution, or avoid. Basis: pest and pollinator effects, competition for nutrients and space, and shared diseases or pests. Well-supported reasons: nightshade disease sharing (potatoes, peppers, eggplant), the shared corn earworm and tomato fruitworm, and black walnut juglone toxicity. Note: some repellent and growth claims are traditional; spacing and rotation matter more.
Sources: The Old Farmer’s Almanac – Companion Planting Guide, Iowa State University Extension – Growing Tomatoes, Royal Horticultural Society – Tomatoes. Last reviewed: September 25, 2026 · Reviewed by Aiza Anwar.
Frequently Asked Questions
What can I plant with tomatoes?
Good companions include basil, marigold, nasturtium, borage, garlic and onions, lettuce, carrots, parsley, and beans. They deter pests, attract pollinators, or share space without competing.
What should I not plant near tomatoes?
Avoid fennel, potatoes, brassicas such as cabbage and broccoli, corn, and areas near black walnut trees. They compete strongly or share diseases and pests with tomatoes.
Is basil good to plant with tomatoes?
Yes. Basil is a classic tomato companion that shares similar sun and water needs and may help repel some pests. It is one of the safest and most popular pairings.
Do marigolds help tomatoes?
Yes, mainly by attracting beneficial insects. For root-knot nematodes, French marigolds work best grown densely for a season before tomatoes; a few plants tucked between tomatoes do little against nematodes.
Can I plant peppers next to tomatoes?
Use caution. Peppers are nightshades that share diseases with tomatoes. They can grow nearby, but keep airflow good and keep both off that bed for 3 to 4 years afterward.
Why should I keep potatoes away from tomatoes?
Both are nightshades that share blight and other diseases. Planting them together lets disease spread easily and build up in the soil, so keep them apart and rotate.
Does companion planting really work?
Partly. The strongest effects are practical: avoiding shared diseases and pests. Some pest-repelling claims are traditional rather than proven, so treat companions as a helpful bonus, not a guarantee.
Can tomatoes and cucumbers grow together?
They can, with caution. Both are heavy feeders that can share fungal diseases, so give them their own space, feed well, and keep airflow strong to prevent problems.
What flowers are best to plant with tomatoes?
Marigold, nasturtium, and borage are the top choices. They attract pollinators and beneficial insects, and marigold and nasturtium also help manage pests.
Related Tomato Tools
Set Spacing with the Plant Spacing Calculator
This tool reflects common horticultural companion guidance. Some pest and growth benefits are traditional rather than proven, while disease and pest cautions are well established. Spacing, rotation, sun, and soil matter more than any single pairing. Spotted an error? Tell us here.