Companion Planting Chart: Which Vegetables Grow Best Together
Companion planting is the practice of placing crops next to each other on purpose — for pest control, for shared structure, or just because they use space and nutrients differently. Some of it is well supported. A lot of it is folklore that’s been copied from chart to chart since the 1970s.
This chart tells you which is which. The pairings below are the ones worth acting on, the “keep away from” column is where the real stakes are, and the why column is there so you can judge each claim yourself.
The Companion Planting Chart
| Crop | Plant with | Keep away from | Why |
|---|---|---|---|
| Tomatoes | Basil, lettuce, onions, French marigolds | Potatoes, corn, brassicas, fennel | Potatoes share late blight with tomatoes. Corn shares the corn earworm (same insect as the tomato fruitworm). The basil pairing is mostly about matching water and heat needs. |
| Peppers | Basil, onions, carrots | Fennel, brassicas | Same care profile as tomatoes; interplanted alliums may help mask them from pests. |
| Cucumbers | Beans, peas, radishes, corn | Potatoes | Legumes feed nitrogen into the bed; potatoes compete hard for water and nutrients. |
| Squash & zucchini | Corn, beans, nasturtiums | Potatoes | The Three Sisters trio — corn gives structure, beans fix nitrogen, squash shades soil. Nasturtiums pull aphids and squash bugs away. |
| Carrots | Onions, leeks, lettuce, peas | Dill | Onion scent may throw off the carrot rust fly — one of the better-tested masking claims. Dill is a close relative that competes and draws the same pests. |
| Onions & garlic | Carrots, brassicas, beets, lettuce, tomatoes | Beans, peas | Strong scent makes alliums useful maskers all over the bed. They’re reputed to inhibit the nitrogen-fixing bacteria on legume roots — evidence is thin, but the pairing gains you nothing anyway. |
| Brassicas (broccoli, cabbage, kale) | Onions, dill, nasturtiums, potatoes | Tomatoes, strawberries | Nasturtiums trap cabbage aphids; flowering dill feeds the tiny wasps that parasitize cabbage worms. Tomatoes and brassicas are both heavy feeders fighting over the same nutrients. |
| Beans | Corn, squash, cucumbers, radishes | Onions, garlic, chives | Beans fix nitrogen for hungry neighbors, and a corn stalk is a free trellis for pole varieties. |
| Peas | Carrots, radishes, turnips, cucumbers | Onions, garlic | Same nitrogen deal as beans — and peas finish early, vacating space for summer crops. |
| Lettuce | Carrots, radishes, strawberries, taller crops | Nothing significant | Lettuce tucks into gaps, and taller neighbors shade it past its bolting point in summer heat. |
| Basil | Tomatoes, peppers | Nothing significant | The pest-repellent claims are shaky, but basil thrives on the same watering schedule and its flowers feed pollinators. |
| Corn | Beans, squash, cucumbers | Tomatoes | Corn earworm and tomato fruitworm are the same moth. Plant its two favorite hosts side by side and you’ve set the table for it. |
| Potatoes | Beans, brassicas, marigolds | Tomatoes, squash, cucumbers | Tomatoes share late blight; sprawling cucurbits compete for water and make the harvest dig miserable. |
One way to read this chart: the “keep away from” column is more reliable than the “plant with” column. Shared diseases (potato–tomato blight) and shared pests (corn–tomato earworm) are documented and repeatable. Most of the positive pairings are gentler effects — or just efficient use of space.
What’s Proven and What’s Folklore
Every companion chart on the internet presents its pairings with equal confidence. They don’t deserve it. Here’s the honest tier list.
Solid ground. Legume nitrogen fixation is real biology — beans and peas host bacteria that pull nitrogen from the air. Structural pairings work because physics works: corn really does trellis beans, squash leaves really do shade out weeds, lettuce really does bolt later under a taller neighbor. Disease-overlap warnings are the most reliable entries on any chart. And trap cropping plus flower strips for beneficial insects have genuine field-trial support — more on both below.
Real, but smaller than the legend. Marigolds do suppress root-knot nematodes — but the effect is specific to French marigolds (Tagetes patula), and it comes from growing them densely and turning them into the soil, close to a cover crop. One marigold at the end of a bed is decoration. Fennel’s reputation for inhibiting neighbors has some basis, so it still earns its exile to a container.
Folklore. “Carrots love tomatoes” comes from the 1975 book of the same name, which was built on tradition and intuition, not trials. Claims that one plant improves another’s flavor have no supporting evidence at all. And most “X repels Y” scent claims test out inconsistently — plausible mechanism, mixed results.
None of this means folklore pairings will hurt you. Interplanting basil with tomatoes costs nothing and you get basil. Just don’t skip real pest controls because a chart promised the basil would handle it.
Companion Planting for Aphid Control
Aphids are the pest people most want companion planting to solve, and it’s one of the few cases where it can genuinely help — if you use the right tools in the right order.
Attract the Aphid Eaters
The best-supported tactic. Hoverfly larvae, ladybugs, lacewings, and parasitic wasps eat aphids by the hundreds, and small-flowered plants recruit them:
- Sweet alyssum is the standout — commercial lettuce farms plant alyssum strips specifically to draw hoverflies into the crop. Tuck it into bed corners and edges.
- Dill and yarrow, when flowering, feed ladybugs, lacewings, and the parasitic wasps that turn aphids into mummies. Let a few herbs bolt instead of pulling them.
Trap Crops
Nasturtiums are the classic aphid trap — aphids prefer them to almost anything else. Plant a clump a few feet away from your beds, not in them. Check it weekly. When it loads up, hose the colony off or pull the plant and bin it. Even when a trap crop doesn’t fully protect the bed, it works as an early-warning system: aphids show up there first.
Scent Maskers
Chives, garlic, and other alliums interplanted among vulnerable crops are supposed to hide them from aphids seeking hosts by smell. Trials go both ways on this one. It’s cheap to try and alliums earn their keep regardless, but don’t make maskers your whole plan.
Two non-plant notes that matter more than any pairing: a hard spray of water knocks aphid colonies back effectively, and aphid outbreaks often follow heavy nitrogen feeding — lush soft growth is exactly what they want. Fix the feeding before you blame the plant arrangement.
Companion Planting Layout for a Vegetable Garden
Charts are abstract. Here’s a concrete 4x8 raised bed that applies the rules above — bed running east–west, north edge at the back.
| Position | Planting | Why it’s there |
|---|---|---|
| North edge (back row) | 3 tomatoes about 2.5 ft apart, basil between them | Tallest crop goes on the north side so it shades nothing else; basil shares the same water schedule |
| Second row | 4 peppers alternating with clumps of onions | Alliums woven between the nightshades for scent cover — they take almost no light or root space |
| Third row | Carrots and onions in alternating short rows | The classic carrot-fly pairing, and both stay low under the pepper canopy |
| South edge (front row) | Lettuce and radishes, sweet alyssum in both corners | Short crops get full sun in spring; by July the pepper row shades the lettuce through the worst afternoon heat; alyssum recruits hoverflies |
| Just outside the bed | Nasturtiums a few feet off one corner, dill in a pot or spare edge | The aphid trap stays off the bed so pests move away from your crops; flowering dill feeds beneficials without crowding the carrots |
Just as important is what’s not in this bed: no potatoes (late blight next to tomatoes), no corn (shared earworm), no brassicas (feeder clash with the tomatoes). Those go in a second bed — and next spring the two beds swap, which handles crop rotation at the same time.
If you’re still deciding on bed dimensions and paths, start with our raised bed layout guide. And this layout has a second act: when the lettuce, radishes, and spring carrots come out in mid-summer, backfill the gaps using what to plant in August — the companion rules apply to succession plantings too.
Start Simple
You don’t need to optimize all 100+ possible pairings in a 15-crop garden. Three moves cover most of the value:
- Separate the disease-sharers and pest-sharers — tomatoes from potatoes, corn from tomatoes
- Plant sweet alyssum in your bed corners and let some dill flower
- Put a nasturtium clump a few feet from the beds as an aphid trap
Tracking which pairings work in your garden beats any chart. garden.gg flags problematic pairings when you place crops on your plot map, so you catch the tomato-next-to-potato mistake in the planning stage instead of in June.
Once you know what to plant together, the next question is when. Check our zone-specific planting calendars for exact dates based on your USDA zone.