Companion Planting Guide
Quick-reference chart of what to plant together and what to keep apart — plus the science behind why it works.
| Plant | Good Companions | Bad Companions | Benefits |
|---|---|---|---|
| Tomatoes | BasilBorageCarrotsMarigoldsParsley | BrassicasCornFennelPotatoes | Basil repels thrips & hornworms; marigolds deter nematodes; borage attracts pollinators and confuses hornworm moths |
| Corn | BeansCucumberPumpkinsSquashSunflowers | CeleryTomatoes | Three Sisters: beans fix nitrogen for corn; squash shades soil to hold moisture and suppress weeds |
| Beans | CarrotsCornCucumbersMarigoldsSquash | ChivesFennelGarlicOnions | Nitrogen fixers — improve soil for heavy feeders; marigolds deter bean beetles |
| Squash | BeansCornNasturtiumsRadishes | FennelPotatoes | Broad leaves shade soil and retain moisture; nasturtiums deter squash bugs and vine borers |
| Peppers | BasilCarrotsMarigoldsOreganoTomatoes | ApricotsFennel | Basil repels spider mites; oregano deters aphids; marigolds protect roots from nematodes |
| Carrots | LettuceOnionsRosemarySageTomatoes | DillFennel | Onions and rosemary repel carrot fly; tomatoes provide shade that slows bolting |
| Basil | OreganoPeppersTomatoes | RueSageThyme | Repels thrips, aphids, and whiteflies; improves flavor of nearby tomatoes and peppers |
| Lettuce | CarrotsChivesRadishesStrawberriesTall flowers | CeleryParsley | Radishes loosen soil around roots; chives deter aphids; tall companions provide welcome afternoon shade |
| Cucumbers | BeansCornDillMarigoldsRadishesSunflowers | MelonsPotatoesSage | Radishes deter cucumber beetles; beans fix nitrogen; sunflowers attract predatory insects |
| Garlic | Fruit treesPeppersRosesTomatoes | BeansPeasSage | Natural fungicide and aphid deterrent; repels Japanese beetles and root maggots |
| Onions | BeetsCarrotsChamomileLettuceTomatoes | BeansPeas | Repels carrot fly and aphids; chamomile said to improve onion flavor and growth |
| Potatoes | BeansCabbageHorseradishMarigolds | CucumbersFennelRaspberriesTomatoesSquash | Horseradish deters potato beetles; marigolds repel nematodes; beans fix nitrogen in surrounding soil |
| Cabbage | CeleryDillMarigoldsNasturtiumsOnions | FennelGarlicStrawberriesTomatoes | Dill and nasturtiums repel cabbage worm; onions deter cabbage moth; celery improves overall growth |
| Peas | CarrotsCornMintRadishesTurnips | ChivesGarlicLeeksOnions | Nitrogen fixers that benefit the whole garden bed; mint deters pests and attracts pollinators |
| Strawberries | BorageGarlicLettuceSpinachThyme | CabbageFennelBrassicas | Borage deters worms and attracts pollinators; thyme repels worms; garlic deters gray mold |
| Sunflowers | CornCucumbersMelonsSquashTomatoes | Potatoes | Attract predatory insects that eat aphids; provide vertical support and dappled shade for heat-sensitive neighbors |
Beneficial companionAvoid planting together