PlantWhy

Companion planting: which vegetables grow well together

Companion planting means placing plants side by side so they help each other: one shades, one climbs, one draws in useful insects. Some pairings are backed by research, others are garden folklore. This guide sorts the practical combinations from the myths and shows how to use them in a small bed.

Companion planting: which vegetables grow well together
Photo: , CC BY-SA 3.0 · Wikimedia Commons
Main benefits
Space use, pollinators, pest confusion
Classic trio
Corn, beans and squash
Easy flower helpers
Marigold, calendula, alyssum
Evidence
Mixed; many effects are small (estimated)

How companion planting works

Good neighbors help each other in a few clear ways:

  • Space: Tall and short, fast and slow plants share a bed without competing much.
  • Physical help: Beans climb corn; low plants shade the soil and keep it cool.
  • Insects: Flowers feed pollinators and predators such as hoverflies and ladybugs, which eat aphids.
  • Confusion: Mixed plantings and strong scents can make it harder for some pests to find their host plant.
Tomatoes pair well with basil and low flowers.
Tomatoes pair well with basil and low flowers. Photo: Softeis, CC BY-SA 3.0 · Wikimedia Commons

Pairings that work in practice

Reliable pairs

  • Tomato + basil: similar needs, easy to tend together.
  • Carrot + onion or leek: different root depths; the idea that their scents hide each other from pests is popular lore with limited evidence.
  • Lettuce under tall crops: shade slows bolting in summer.
  • Corn + pole beans + squash: the classic three sisters.

Flower helpers

  • Marigold and calendula at bed edges add flowers for pollinators and beneficial insects.
  • Sweet alyssum attracts hoverflies and ladybugs.
  • Nasturtium is often called a trap crop for aphids, but evidence is limited.
  • Dill and coriander flowers feed beneficial insects.

Plants to keep apart

  • Fennel: Widely believed to hold back nearby vegetables; scientific evidence is limited, but many gardeners give it its own corner.
  • Tall over sun-lovers: Do not plant corn or pole beans on the south side of peppers or tomatoes, where they would cast shade.
  • Same family side by side: Potatoes and tomatoes share diseases such as blight; separate them.
  • Heavy feeders crowded together: Squash, corn and cabbage all need rich soil and space.
Beans climb supports and suit a mixed bed.
Beans climb supports and suit a mixed bed. Photo: Roger Culos, CC BY-SA 3.0 · Wikimedia Commons

Planning a companion bed, step by step

  1. Start with your main crops: Choose the two or three vegetables you most want to eat.
  2. Check needs: Group plants with similar sun, water and soil needs.
  3. Layer by height: Put tall crops on the north side, medium in the middle, low plants and herbs at the front.
  4. Add flowers: Plant a few marigolds, calendula or alyssum at the corners and edges.
  5. Fill gaps: Sow quick crops like radish or lettuce between slow ones.
  6. Record results: Note what worked and rotate families next year.

The three sisters

Corn gives a stalk for beans to climb, beans add a leafy, climbing layer, and broad squash leaves shade the soil and smother weeds. Sow corn first; add beans when the corn is about 4–6 in tall, and squash around the edge. It needs a block of space, at least 10 × 10 ft, for corn to pollinate well (estimated).

Companions in pots and small beds

In a large pot

  • Tomato with basil and a trailing nasturtium.
  • Pepper with parsley at the base.

In a box

  • Lettuce, radish and chives in rows.
  • Strawberry with thyme on the edge.

On a balcony

  • One flower pot among vegetable pots brings pollinators.
  • Keep strong-smelling herbs near the door.

What the evidence says

Flower strips that feed predators and pollinators, intercropping for space and trap crops are well supported. Many popular charts, however, rest on tradition. A pairing that fails is rarely a disaster, so treat charts as starting ideas and observe your own garden.

⚠️ No companion plant replaces good basics: sun, healthy soil, correct watering and crop rotation matter far more.

Common problems and fixes

One plant smothers the otherSpacing was too tight or a vigorous plant took over. Prune, thin or move it next season.
Pests still appearCompanions reduce pests only a little. Check leaves weekly and remove pests by hand early.
Low yields in a mixed bedPlants may be competing for water and light. Give heavy feeders more room.

Frequently asked questions

Do marigolds really repel pests?

They mainly attract beneficial insects. Some types reduce soil nematodes when grown as a dense cover, but a few plants at the edge will not repel pests on their own.

Is companion planting scientifically proven?

Some parts are, such as flower strips and intercropping. Many specific chart pairings are not well tested.

Can I companion plant in containers?

Yes. Pair a main crop with a small herb or flower in a large pot, making sure both get enough water.

What should I never plant next to tomatoes?

Avoid potatoes (shared diseases), fennel and tall crops that shade them.

Plants for companion beds

TomatoBasilMarigoldCarrotOnionGreen BeanLettuceCucumber

Sources

Last updated: 2 November 2026