Emily ParkerBy Emily Parker

Updated November 2026

A tomato companion planting chart lays out which plants grow well beside tomatoes, how far apart to set them, and which neighbors to keep away. Used well, it helps you pair tomatoes with herbs and flowers that attract pollinators or deter pests, while steering clear of crops that compete for the same nutrients or share soil diseases. This guide shows you how to build a chart you can actually use in the garden.

Step 1: Sort Companions Into Three Groups

Start by dividing your candidate plants into three columns: helpers, neutral plants and plants to avoid. Helpers are typically basil, marigold, nasturtium, borage, chives, garlic and dill. Basil is widely reported to repel some pests, while marigolds are often planted for their nematode-suppressing reputation, though results vary by variety and soil. Avoid planting tomatoes near potatoes, fennel, brassicas and corn. Potatoes share early and late blight with tomatoes, and fennel is widely considered allelopathic toward many vegetables.

Shopping for one? See our guide: 6 Best Garden Layout Free Printable Printable Companion Planting Charts (2026): Our Picks.

Step 2: Set Spacing for Each Pairing

Companion benefits mean little if plants crowd each other. Tomatoes need room for airflow, so plan for 24 to 36 inches between plants, and 36 inches for indeterminate varieties. Use the table below as a starting point for your own chart.

Companion Spacing from tomato Why it’s listed
Basil 12 to 18 inches Commonly grown near tomatoes for pest deterrence
Marigold 12 to 18 inches Flowers attract beneficial insects
Chives 6 to 12 inches Compact growth, low competition
Carrot 6 to 8 inches Uses different root depths
Potato Avoid Shares blight diseases
Fennel Avoid Widely reported to inhibit growth

Step 3: Account for Sun, Water and Soil Needs

A chart that ignores growing conditions will mislead you. Tomatoes want full sun, at least six to eight hours daily, and consistent moisture. Pair them with plants that share those needs. Basil does well in the same sun and water regime, while lettuce planted on the north side can benefit from the tomato’s shade in midsummer. Group thirsty plants together and keep drought-tolerant herbs like rosemary or thyme on their own edge, where they won’t get soggy.

A Simple Layout Checklist

  1. Measure your bed and mark tomato positions at 24 to 36 inch intervals.
  2. Place basil or marigold within 12 to 18 inches of each tomato.
  3. Keep alliums like garlic or onion at the bed edge, 6 to 12 inches away.
  4. Leave a walking path of at least 18 inches for harvesting.
  5. Rotate the whole layout yearly so tomatoes don’t return to the same soil.

Step 4: Adjust the Chart Over Time

Keep notes each season on which pairings looked healthy and where pests still showed up. Companion planting is not a substitute for crop rotation, drip irrigation or good soil. If aphids or hornworms persist, add more flowering plants, check leaves weekly and hand-pick pests early. The chart is a tool for planning, not a guarantee.

Common Mistakes to Avoid

  • Planting tomatoes next to potatoes, which share blight and can spread it quickly.
  • Crowding basil so tightly that airflow drops and foliage stays damp.
  • Ignoring sun needs, such as planting tomatoes beside tall corn that shades them.
  • Assuming one companion will solve every pest problem.
  • Skipping rotation and planting tomatoes in the same bed year after year.

A soil thermometer helps you time transplanting, since tomatoes usually perform best once soil reaches about 60 degrees Fahrenheit. View on Amazon

A tomato cage or stake keeps plants upright, which improves airflow between neighbors. View on Amazon

A garden journal or planning notebook makes it easier to track which pairings worked each season. View on Amazon

FAQ

Can I plant tomatoes and basil together?

Yes. Basil is one of the most commonly recommended tomato partners and is usually planted 12 to 18 inches away. Give both plants enough sun and water.

Which plants should never go near tomatoes?

Potatoes, fennel, brassicas such as cabbage and broccoli, and corn are the usual ones to keep apart. Potatoes share diseases, and fennel is widely reported to stunt many vegetables.

Do companion planting charts work for container tomatoes?

They can, using the same logic in a larger pot. Choose one or two compact companions like basil or chives, and make sure the container is at least 5 gallons so roots don’t compete.

Conclusion

A tomato companion planting chart works best when you sort plants into helpers, neutrals and plants to avoid, then set spacing and sun needs for each pairing. Keep notes each season and adjust based on what you see. Pairing good neighbors with sound basics like rotation and watering gives your tomatoes the best chance to thrive.

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Emily Parker

About Emily Parker

Emily Parker is part of our editorial team and reviews and edits our vegetable & edible gardening guides, checking product details against manufacturer specifications and owner feedback.