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Companion Planting Checker & Friends & Foes

Pairs up tomato & basil

63 plantsBest companionsRelationship mapPair checker

“Your 5-star review is a signal. Your 2-star review is a gift.

See the best companions and the plants to keep apart for any vegetable — or check any two plants to find out if they're a good pair, an antagonist, or neutral, with the reason.

What are you planting?

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Selected plant

🍅 Tomato

Pick any plant from the browser below.

Companion relationships follow traditional practice & observation — helpful guidance, not strict rules.

Your result

🍅

Tomato

18 good companions · 10 to avoid

Plant near 🍅 Tomato

🧅 Onion🧄 Garlic🧅 Shallot🌿 Chives🥕 Carrot🌿 Asparagus🥬 Celery🌿 Basil🌿 Parsley🌿 Cilantro🌿 Mint🌿 Oregano🌿 Thyme🌼 Marigold🌺 Nasturtium💙 Borage🌼 Calendula🌿 Garlic Chives

Keep away from Tomato

🥔 Potato🥬 Kale🥬 Cabbage🥦 Broccoli🥦 Cauliflower🥬 Brussels Sprout🥬 Kohlrabi🌽 Corn🌿 Fennel🌿 Dill

Pick a plant — 63 plants

What this means

Across 63 plants, Tomato has 18 good companions and 10 to avoid. Carrots love tomatoes; basil deters hornworms while fennel and potato share blight and stunt growth.

Next: interplant the good companions in the same bed or adjacent rows, put antagonists in a separate block, and rotate plant families each season to keep soil-borne pests down.

Companion relationships are based on traditional practice and observation — treat them as helpful guidance, not strict rules. Local conditions vary.

Companion planting — key facts

Tomato loves: basil, marigold, carrot, onion
Tomato avoids: potato, cabbage, fennel
Three sisters: corn + beans + squash
Legumes: fix nitrogen for heavy feeders
Onions & beans: do not mix
Marigold: all-round pest deterrent
Fennel: keep on its own
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How companion planting helps

Plants interact below and above ground. Legumes such as beans and peas fix atmospheric nitrogen that nearby heavy feeders can use; strong-smelling alliums and herbs mask the scent pests hunt by; flowers like marigold pull in hoverflies and ladybirds that prey on aphids; and tall crops shelter or support shorter ones. The flip side is competition and shared enemies — tomato and potato both carry blight, sprawling squash crowds out potatoes, and fennel chemically suppresses most neighbours.

This checker turns that knowledge into two quick answers: the companions to group around a crop, and a yes/no verdict for any pair with the reason behind it. Use it to lay out beds so friends sit together and antagonists stay apart, then pair it with crop rotation so the benefits carry across seasons rather than letting pests build up in one spot.

Plan a bed

Pick a crop and group its good companions in the same bed or adjacent rows.

Check a pair fast

Test any two plants for a good/avoid/neutral verdict before you sow.

Deter pests naturally

Use companions like marigold, basil and onion to cut pest pressure without sprays.

Pair with rotation

Combine with the Crop Rotation Planner so beds stay healthy year after year.

Frequently Asked Questions

What is companion planting?+

Companion planting is growing certain crops near each other because they help one another — by deterring pests, attracting beneficial insects, fixing nitrogen, providing shade or support, or simply using space and light efficiently. Some pairs, by contrast, compete or share pests and are best kept apart.

What grows well with tomatoes?+

Tomatoes pair famously with basil and marigold (which repel their pests), along with carrots, onions, garlic and lettuce. Keep them away from potatoes (shared blight), brassicas like cabbage, and fennel. Use the checker to see the full list for tomato or any other crop.

What are the 'three sisters'?+

The three sisters is a classic Native American companion grouping of corn, beans and squash: corn gives the beans a pole to climb, beans fix nitrogen for the corn, and sprawling squash shades the soil to suppress weeds and keep it moist. The checker marks corn–bean and corn–squash as good pairs.

What should you not plant together?+

Avoid pairing crops that compete heavily or share pests and diseases — for example tomato with potato, onions or garlic with peas and beans, and fennel with almost everything (it's allelopathic). The checker flags these as antagonists with the reason.

Why do onions and beans not mix?+

Alliums such as onion and garlic release compounds that inhibit the growth of legumes like peas and beans, so the legumes grow poorly nearby. Plant the onion family in a separate bed from your peas and beans.

Does companion planting really work?+

Some effects are well supported — nitrogen fixing by legumes, pest confusion from strong-smelling alliums and herbs, trap cropping with radish, and habitat for beneficial insects from flowers like marigold. Others are traditional lore with mixed evidence, so treat the guide as a helpful starting point rather than a guarantee.

How does marigold help the garden?+

Marigolds are an all-round helper: their roots release compounds that suppress soil nematodes, and their flowers attract hoverflies and other predators that eat aphids. That's why the checker lists them as good companions for tomato, potato, squash, beans and peppers.

Can I plant the same crop in a block together?+

Yes — growing one crop in a block is fine and often practical. The key companion rule is to rotate that family to a different bed each year, because soil-borne pests and diseases build up where the same crop grows repeatedly.

How far apart should antagonists be?+

There's no exact distance, but keeping antagonistic crops in separate beds or on opposite sides of the plot is usually enough to avoid root competition and reduce shared-pest spread. The more vigorous the plant (like sprawling squash or potato), the more separation helps.

Does this replace crop rotation?+

No — companion planting and rotation work together. Companions optimise who grows beside whom this season; rotation changes what grows in each bed across seasons. Use our Crop Rotation Planner alongside this checker for a complete plan.

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Companion Planting Checker & Friends & Foes

What are you planting?

Tomato

Companion planting — key facts

How companion planting helps

Plan a bed

Check a pair fast

Deter pests naturally

Pair with rotation

Frequently Asked Questions

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