Companion Planting Chart: What Vegetables Grow Well Together

Companion planting works through several proven mechanisms rather than folklore alone. Some plants release compounds through their roots or foliage that repel or confuse insect pests, some attract beneficial predatory insects and pollinators, some fix atmospheric nitrogen in the soil for their neighbors, and some provide physical structure, shade, or ground cover that other plants benefit from.

Marigolds are one of the best-documented examples: their roots release compounds that suppress root-knot nematodes in the soil, which is why they're so commonly planted alongside tomatoes, peppers, and other nematode-susceptible crops.

Legumes like beans and peas host nitrogen-fixing bacteria in nodules on their roots, pulling nitrogen from the air and converting it into a form plants can use. When those roots break down after harvest, that nitrogen becomes available to whatever is planted nearby or afterward, which is why legumes are so often paired with heavy feeders like corn and leafy greens.

Some pairings work simply through physical space efficiency rather than any chemical interaction. Fast-growing radishes planted between slower carrots, for example, use space that would otherwise sit empty while the carrots mature, and are pulled out of the way before they compete seriously for nutrients.

Tomatoes, basil, and marigolds form one of the most reliable trios in vegetable gardening. Basil is widely believed to improve tomato flavor when grown nearby and its strong scent can help confuse pests like aphids and hornworm moths, while marigolds guard the root zone below against nematodes.

The Three Sisters method, developed by Indigenous farming traditions in North America, plants corn, pole beans, and squash together in the same mound. Corn provides a natural living trellis for the beans to climb, the beans fix nitrogen that feeds the heavy-feeding corn and squash, and squash's broad leaves shade the soil surface, suppressing weeds and helping retain moisture for all three plants.

Carrots and onions make an excellent pair since onions' strong sulfur scent can help mask the smell carrots give off that attracts carrot rust flies, while carrots' growth habit loosens soil that benefits the onion bulbs forming nearby.

Cucumbers grow well alongside beans, corn, and radishes, all of which either provide structure, share space efficiently, or help deter cucumber beetles through scent confusion. Nasturtiums are also a popular cucumber companion, acting as a trap crop that draws aphids away from the main vegetable.

Beans and peas generally don't grow well near onions, garlic, leeks, or other alliums, since compounds released by alliums can inhibit the growth and nitrogen-fixing ability of legume roots. Keep these two families in separate beds or at opposite ends of the garden.

Tomatoes and corn compete for many of the same soil nutrients and can also attract the same damaging pest, the corn earworm, which is the same insect known as the tomato fruitworm in its other host plant. Growing them in different sections reduces the risk of a single pest outbreak affecting both crops.

Fennel is best grown alone, well away from most other vegetables, since it releases allelopathic compounds from its roots that can suppress the growth of many neighboring plants, including tomatoes, beans, and peppers.

Potatoes and tomatoes, both members of the nightshade family, are best kept apart as well, since growing them near each other increases the risk of shared diseases like early and late blight spreading between the two crops.

Trap cropping is a specific companion planting strategy where a highly attractive plant is used to lure pests away from your main crop. Nasturtiums are a classic trap crop for aphids, drawing them away from beans, cucumbers, and brassicas.

Aromatic herbs like dill, cilantro, and fennel, when allowed to flower, attract beneficial predatory insects such as parasitic wasps and hoverflies, which then help control aphid and caterpillar populations throughout the garden, not just near the herb itself.

Interplanting strongly scented herbs like sage, thyme, and rosemary among brassicas such as cabbage and broccoli can help disguise the scent cues that cabbage moths use to locate their host plants.

Sketch your garden beds on paper before planting season begins, grouping compatible vegetables together and noting each group's sun and water requirements so beneficial companions don't end up competing for different resources.

Group plants with similar water and sunlight needs together, even when they're excellent pest-control companions, since a mismatch in basic growing requirements can undermine the benefits of the pairing.

Leave room in your plan to rotate companion groupings each year alongside your regular crop rotation. Repeating the exact same layout in the same spot every season allows pest and disease pressure to build up regardless of how good the companion pairings are.

In containers, choose one main vegetable and one or two compatible companions rather than trying to replicate an entire in-ground pairing system, since root competition is more intense in a confined space.

A large container with a tomato plant, a basil plant, and a few marigolds works particularly well and is one of the most popular container companion combinations for patio gardeners.

For small raised beds, prioritize pairings that save space, like fast-maturing radishes interplanted with slower carrots, or lettuce grown in the partial shade cast by taller trellised crops like pole beans.