Tomato Companion Plants — What Grows Well With Tomatoes
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GardenSays
Best companions for tomatoes: Basil, Marigold, Onions, Garlic, Lettuce, Spinach, Asparagus, Nasturtium, Borage, Zinnia, Radish, Leeks.
- Good picks
- 12
- Strong evidence
- 3
- Practical
- 4
Basil (folklore — insufficient evidence): The classic pairing: basil's scent may confuse some flying pests, and the two share water and sun needs so they thrive in the same bed. Claims that basil improves tomato flavor are folklore.
Typical estimate · 2 verified sources · Checked 2026-07-15 · How we decide
Why
Marigold (strong evidence): French marigolds (Tagetes patula) suppress root-knot nematodes in soil — one of the few companion effects with solid research behind it. The effect works through root exudates, strongest when marigolds grow in the spot beforehand.
Onions (folklore — insufficient evidence): Alliums' strong scent is traditionally credited with deterring aphids and some beetles, and onions occupy little root or air space, so there's no competition cost either way.
Garlic (folklore — insufficient evidence): Like onions: compact, non-competing, and traditionally credited with deterring spider mites and aphids. Fall-planted garlic is harvested mid-summer, freeing space just as tomatoes peak.
Lettuce (practical compatibility): Lettuce bolts in summer heat — tomato plants cast exactly the afternoon shade that keeps it going longer, and shallow lettuce roots don't compete.
Spinach (practical compatibility): Same logic as lettuce: a cool-season understory crop that benefits from tomato shade and finishes before the tomato needs the space.
- The strongest evidence tier covers trap crops, pollinator/predator attraction, and documented pest or disease suppression — most other 'good' pairings are really about avoiding competition, not a special boost.
- Folklore-tier pairings (traditional scent/repellent claims) are marked as garden tradition, not established science — they're listed because they're harmless, not because they're proven.
When this doesn't apply
- A healthy, well-spaced garden forgives most 'caution' pairings — disease history in that bed is what makes them matter.
How this was calculated
- 1. Selection rule12 plants
Pairs rated 'good' out of 41 evaluated pairings.
- 2. Strong evidenceSource guidance
Mechanism is supported in extension or peer-reviewed research.
- 3. Practical compatibilityCalculated result
Not formally studied as a pairing, but the reasoning is a real, verifiable resource/timing/ecological fact (shade, root depth, season length, shared needs) — not a claimed pest-repelling magic.
- 4. Possible conflictCalculated result
A real, documented or strongly plausible reason to keep these apart or plant with care — shared disease, allelopathy, competition, or resource mismatch.
- 5. Folklore — insufficient evidenceGardenSays estimate
A long-standing companion-planting story (often a claimed scent/repellent effect) with no established scientific mechanism for this specific pairing. Treat as garden tradition, not proven fact.
Data sources
- University of Minnesota Extension — Companion planting in home gardens — Some companion effects (trap crops, pollinator attraction, nematode suppression by marigolds) are documented; many traditional pairings lack formal evidence. (checked 2026-07-15)
- University of Minnesota Extension — Growing tomatoes in home gardens — Avoid planting tomatoes near potatoes (shared blight) or where related crops grew the previous year. (checked 2026-07-15)
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People also ask
What should not be planted with tomatoes?
Keep away from tomatoes: Potatoes, Corn, Cabbage, Broccoli, Kale, Fennel, Raspberry. Use caution with: Peppers, Eggplant, Strawberries, Mint, Rosemary, Sage, Lavender, Sunflower, Dill, Tomatillo, Jalapeno. Calculate yours →
Can you plant tomatoes with basil?
tomatoes + basil: Yes — plant them together. Calculate yours →
Can you plant tomatoes with peppers?
tomatoes + peppers: You can, but there's a real catch. Calculate yours →
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