Companion Planting Chart

How to use the companion planting chart

Type a plant name or tap it in the list. The chart shows the plants commonly recommended as companions, the plants usually kept apart, and the reason for the best-known pairings. Search also finds common alternative names, so "courgette" brings up zucchini and "pole bean" brings up beans.

The chart covers 30 vegetables, herbs and flowers, and every pairing works both ways. If tomatoes list potatoes as a plant to keep apart, potatoes list tomatoes too. Only pairings that mainstream gardening references commonly publish are included. Where those references disagree, the pair is left out. Dill next to tomatoes and beans next to beets are two examples.

Be clear about what you are reading. Much of companion planting is garden tradition passed from book to book, and only a small share has been tested in trials. The reasons say which claims have a real mechanism behind them and which are traditional.

What actually stands behind the pairings

• Shared pests and diseases. Tomatoes and potatoes are in the same family and both get early and late blight. The corn earworm and the tomato fruitworm are the same insect. Strawberries, tomatoes, potatoes and peppers all host Verticillium wilt. These are the most solid "keep apart" rules on the chart.
• Beneficial insects. Flowering dill feeds hoverflies and parasitic wasps that attack cabbage aphids and caterpillars, so dill pairs with the cabbage family and cucumbers.
• Trap crops. Aphids and flea beetles often settle on nasturtiums before your crop. Nasturtiums attract pests rather than repelling them, so check them and pull infested plants.
• Structure and space. In the Three Sisters planting, the corn holds up the beans and the squash covers the ground. Lettuce grows in the shade under tomatoes, and radishes come out before slow carrots need the room.
• Tradition. Alliums stunting beans and peas, fennel harming everything near it, and cabbage-family crops stunting tomatoes all appear on nearly every chart, but there is little trial evidence behind them.

Companion planting chart

A dash means no pairing is commonly published either way, not that the plant has no neighbors.

Example: planning a tomato bed

Say you have a 4 × 8 ft bed and want tomatoes as the main crop.

1. Look up tomato. The good companions are asparagus, basil, carrot, garlic, lettuce, marigold, nasturtium and onion. The plants to keep apart are broccoli, cabbage, cauliflower, corn, fennel, kale, potato and strawberry.
2. Place the tomatoes. Stake them along the north side so they don't shade the rest of the bed.
3. Fill in with companions. Put basil between the tomato plants, then a row of carrots with a few onions in front. Lettuce goes in the gaps while the tomatoes are small.
4. Check the companions' own lists. Onions list beans and peas as plants to keep apart, so beans don't belong in this bed. Carrots list only dill and fennel, so leave the dill out and grow it with your cucumbers.
5. Edge the bed. Put French marigolds and a nasturtium at the corners for pollinators and as an aphid trap.
6. Move the conflicts. Plant potatoes, the cabbage family and strawberries in other beds, not just at the far end of this one.

Tips

• Rotation beats neighbors. Don't grow tomatoes, potatoes or peppers where any of them grew last year. Rotating crop families does more against blight and wilt than any companion plant.
• Sun and spacing come first. A good companion that shades a crop or crowds its roots does more harm than good. Tall plants go on the north side.
• Let some herbs flower. Dill and cilantro left to bloom bring in hoverflies and parasitic wasps all summer.
• Fennel goes in a pot. It is the one plant almost every chart keeps apart, and it grows well alone.
• Keep the proven tools. Row cover against cabbage worms and insect netting against carrot rust fly work far more reliably than any companion plant.