Tomato Companion Plants
Solanum lycopersicum · nightshade family · rotation group: nightshade
The best companion plants for tomato are Basil, French marigold, Borage, Nasturtium, and Chives. Avoid planting tomato near Potato, Sweet corn, Fennel, Brassicas (cabbage, broccoli). Of the 12 pairings recorded here, 3 are supported by published research and 8 are traditional practice with no controlled evidence behind them.
What to plant with tomato
| Plant | Claimed benefit | Evidence | What the evidence actually shows |
|---|---|---|---|
| Basil | Interplanted basil reduces thrips pressure on tomatoes and may improve tomato growth. | Research-backed | UMN Extension states a few studies show basil can reduce thrips populations in tomatoes; the separate folk claim that basil improves tomato flavor has never been tested. |
| French marigold | French marigold planted with tomato reduces whitefly settling on the crop. | Research-backed | A controlled PLOS ONE study showed the effect is real and is caused by airborne limonene from the marigold, not by generic 'pest repellence'; the separate root-knot nematode benefit requires marigold grown as a pre-crop, not as an interplant. |
| Borage | Borage deters tomato hornworm and attracts pollinators to the tomato patch. | Traditional | Borage is genuinely a strong pollinator magnet (proven on strawberry), but no controlled study tests the hornworm-deterrence claim, and tomatoes are self-fertile so the pollinator benefit is marginal. |
| Chives | Allium foliage repels aphids and spider mites from nearby tomatoes. | Traditional | Allium volatiles do disrupt host-finding in some documented systems (carrot fly, onion fly), but no study tests chives against tomato aphids or mites. |
| Lettuce | Lettuce is interplanted between young tomatoes and harvested before the tomatoes close canopy. | Traditional | This is sound use of space and season rather than a pest claim; nothing tests any biological interaction between the two. |
| Nasturtium | Nasturtium acts as a trap crop pulling aphids away from tomatoes. | Traditional | Nasturtium's trap-crop value is documented for squash bugs and cabbage pests, but no trial demonstrates aphid diversion away from tomato specifically. |
| Parsley | Flowering parsley and other umbellifers attract parasitoid wasps and hoverflies that attack tomato pests. | Traditional | Insectary value of flowering umbellifers is well established in general, but parsley is usually harvested before it flowers and no trial measures a tomato pest benefit. |
| Carrot | Carrots and tomatoes benefit each other when grown together. | Not supported | This is the title claim of Louise Riotte's 1975 book Carrots Love Tomatoes, which cites no experiments; no controlled trial supports it and extension reviewers class it with untested folklore. |
What not to plant with tomato
| Plant | Claimed problem | Evidence | What the evidence actually shows |
|---|---|---|---|
| Potato | Tomatoes and potatoes planted together intensify early blight, late blight and Colorado potato beetle. | Research-backed | Not folklore: Alternaria solani and Phytophthora infestans infect both crops, and extension disease management for both centres on separating and rotating them on a 3-4 year cycle. |
| Brassicas (cabbage, broccoli) | Brassicas compete with tomatoes and stunt them. | Traditional | Both are heavy feeders so competition for nitrogen and water is real, but this is an agronomic spacing issue, not a documented chemical or pest antagonism. |
| Fennel | Fennel root exudates inhibit tomato growth. | Traditional | Fennel essential oil is allelopathic in laboratory germination bioassays, but no field or garden trial demonstrates suppression of an established tomato plant. |
| Sweet corn | Sweet corn next to tomatoes increases fruitworm damage. | Traditional | The shared-pest premise is factual (corn earworm and tomato fruitworm are the same insect, Helicoverpa zea), but no trial shows that separating the two crops in a garden reduces damage to either. |
The honest verdict
Of everything gardeners recommend planting alongside tomato, 2 pairings have been tested properly: Basil, French marigold. Those are the ones worth planning your bed around.
The remaining 5 pairings on this page are traditional practice. They circulate on every companion planting chart online, but we could not find controlled evidence testing them. They are not wrong so much as unverified — most cost nothing to try, and interplanting flowers and herbs has its own well-documented benefit of pulling pollinators and predatory insects into the garden.
Widely repeated, not supported: Carrot — This is the title claim of Louise Riotte's 1975 book Carrots Love Tomatoes, which cites no experiments; no controlled trial supports it and extension reviewers class it with untested folklore.
Every row above links to the publication it came from. See how we grade evidence.
Growing tomato: the numbers
| Sun | Full sun (6+ hours) |
|---|---|
| Water | High — keep evenly moist |
| Spacing | 24 in apart · 48 in between rows · 1 per square foot |
| Mature size | about 60 in tall |
| Soil pH | 6–6.8 |
| Days to maturity | 55–90 days |
| Frost tolerance | Tender — killed by frost |
| Containers | Yes — 5 gallon minimum |
| Typical yield | 4-5 lbs |
| Common pests | tomato hornworm, aphids, whiteflies, flea beetles, cutworms, stink bugs |
| Common diseases | early blight, late blight, Septoria leaf spot, Fusarium wilt, Verticillium wilt, bacterial spot |
When to plant tomato
Zone 6b shownStart seeds indoors: Feb 20 – Mar 6 — 5–7 weeks before your last frost
Transplant outdoors: Apr 17 – Apr 30 — 1 week after last frost
Expected harvest: Jun 11 – Jul 16 — 55–90 days from planting
Those dates are for zone 6b. Get your own dates by ZIP code →
Varieties worth knowing
seeds- Early Girl — indeterminate early slicer, 52 days
- Celebrity — determinate, disease-resistant all-purpose slicer, 70 days
- Better Boy — indeterminate beefsteak-style slicer, 75 days
- Super Sweet 100 — indeterminate cherry, very heavy trusses, 65 days
Variety names link to seeds on Amazon. As an Amazon Associate we earn from qualifying purchases. These are the varieties named in the extension sources for this crop, not a paid placement — where a source recommended a variety for a specific reason, that reason is the note beside it.
Put it in a bed
The garden planner checks every square against this ledger as you place crops — if you drop tomato next to something recorded as a bad neighbour, the square turns red and tells you why.
Records for the plants named above:
Same rotation group (nightshade) — don't follow one with another:
Tomato companion planting questions
What should not be planted next to tomato?
How far apart should tomato be planted?
Does companion planting with tomato actually work?
When should I plant tomato?
Sources for this record
- Growing tomatoes in home gardens, University of Minnesota Extension
- Georgia Homegrown Tomatoes (B1271), University of Georgia Extension
- Tomato, Home Vegetable Gardening, University of Illinois Extension
- Solanum lycopersicum, NC State Extension Plant Toolbox
- Seed Germination Temperature and Timing, UC Master Gardener Program
Record compiled 2026-07. Spot an error or a study we missed? Tell us and we'll correct the entry.