What Not to Plant With Tomatoes

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GardenSays

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.

Keep apart
7
Caution
11
Worst offender
Potatoes

Potatoes (documented): The worst tomato neighbor: same species family, and both host early and late blight — spores move freely between them. Extension guidance is explicit about keeping them apart.

Corn (documented): The corn earworm and the tomato fruitworm are the same insect (Helicoverpa zea) — planting them together concentrates its favorite two hosts, and tall corn shades tomatoes.

Cabbage (traditional): Brassicas and tomatoes are a long-standing 'keep apart' pairing: heavy feeders competing for the same nutrients, and tomatoes are traditionally said to inhibit brassica growth.

Broccoli (traditional): Same as cabbage — two heavy feeders with a traditional antagonism; neither does its best crowded by the other.

Kale (traditional): A brassica like cabbage and broccoli — the traditional advice to keep brassicas and tomatoes apart applies, though kale's smaller size makes it the least-bad of the family.

Why

  • The strongest documented effects are trap crops, pollinator/predator attraction, and marigold nematode suppression — most other pairings are about avoiding shared diseases and competition.
  • Confidence labels: 'documented' = mechanism supported in extension/research literature; 'traditional' = long-standing practice with plausible mechanism but thin formal evidence.

When this doesn't apply

  • A healthy, well-spaced garden forgives most 'caution' pairings — disease history is what makes them matter.

How this was calculated

  1. 1. Exclusion rule18 plants

    Pairs rated 'bad' (keep apart) or 'caution' out of 41 evaluated pairings.

  2. 2. Evidence standard

    Confidence labels: 'documented' = mechanism supported in extension/research literature; 'traditional' = long-standing practice with plausible mechanism but thin formal evidence.

Data sources

Community choice

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