Companion planting is the practice of growing certain plants together for mutual benefit. While some combinations are based on tradition and others on research, the underlying principle remains the same: diverse plantings create healthier gardens. To make companion planting practical, it helps to think crop by crop. Each vegetable has allies that support growth, deter pests, and attract pollinators—as well as plants it should avoid. This guide explains companion planting crop by crop, giving you clear direction for your garden planning.
Tomatoes
Good Companions:
- Basil: Repels whiteflies and complements tomato growth.
- Marigolds: Deter nematodes and confuse pests.
- Borage: Attracts pollinators and discourages tomato hornworms.
Plants to Avoid:
- Corn (shares pests like corn earworm).
- Potatoes (increase risk of blight).
Peppers
Good Companions:
- Basil: Repels aphids and beetles.
- Onions and Chives: Confuse pests like spider mites.
- Marigolds: Suppress nematodes and deter aphids.
Plants to Avoid:
- Beans (can compete for space and reduce airflow).
Carrots
Good Companions:
- Onions and Leeks: Repel carrot flies.
- Radishes: Loosen soil for better root growth.
- Lettuce: Benefits from shade provided by carrot foliage.
Plants to Avoid:
- Dill (attracts pests that also target carrots).
Cabbage and Other Brassicas
Good Companions:
- Thyme and Rosemary: Repel cabbage moths and flea beetles.
- Dill and Fennel: Attract parasitic wasps to control caterpillars.
- Nasturtiums: Trap aphids away from brassicas.
Plants to Avoid:
- Strawberries (compete for nutrients and may attract pests).
Cucumbers
Good Companions:
- Radishes: Distract cucumber beetles.
- Nasturtiums: Repel aphids and beetles.
- Sunflowers: Provide shade and support for climbing cucumbers.
Plants to Avoid:
- Potatoes (compete for nutrients and space).
Beans
Good Companions:
- Corn: Provides natural support for climbing beans.
- Squash: Shares space efficiently in the “Three Sisters” system.
- Marigolds: Deter Mexican bean beetles.
Plants to Avoid:
- Onions and Garlic (can inhibit bean growth).
Potatoes
Good Companions:
- Horseradish: Repels Colorado potato beetles.
- Beans: Improve soil nitrogen balance.
- Cilantro: Attracts predatory insects to feed on beetle larvae.
Plants to Avoid:
- Tomatoes and Eggplants (share blight and pests).
Lettuce and Leafy Greens
Good Companions:
- Chives and Garlic: Repel aphids.
- Carrots: Pair well in shared space.
- Radishes: Loosen soil around lettuce roots.
Plants to Avoid:
- Parsley (competes too strongly).
Corn
Good Companions:
- Beans: Add nitrogen and climb corn stalks.
- Squash: Sprawling leaves shade soil and deter weeds.
- Sunflowers: Attract pollinators to improve fertilization.
Plants to Avoid:
- Tomatoes (share corn earworm pest).
Squash and Pumpkins
Good Companions:
- Nasturtiums: Trap squash bugs and repel beetles.
- Corn and Beans: Work together in the Three Sisters method.
- Marigolds: Confuse insect pests.
Plants to Avoid:
- Potatoes (compete heavily for nutrients).
Onions and Garlic
Good Companions:
- Carrots: Repel carrot flies while benefiting from carrot spacing.
- Beets: Compatible and benefit from pest deterrence.
- Chamomile: Improves flavor and attracts pollinators.
Plants to Avoid:
- Beans and Peas (growth may be suppressed).
Strawberries
Good Companions:
- Borage: Attracts pollinators and improves fruit yield.
- Thyme and Chives: Deter aphids and nematodes.
- Spinach or Lettuce: Act as living mulch to cool the soil.
Plants to Avoid:
- Brassicas (compete for nutrients and attract overlapping pests).
Benefits of Companion Planting by Crop
- Natural pest management: Aromatic herbs, trap crops, and flowers reduce the need for sprays.
- Improved pollination: Flowers interplanted with vegetables increase fruit set.
- Balanced nutrient use: Rotating and pairing crops prevents soil exhaustion.
- Efficient space use: Pairing plants with different growth habits maximizes productivity.
- Biodiversity and resilience: Mixed plantings reduce vulnerability to pests and diseases.
Common Mistakes to Avoid
- Overcrowding companions: Even allies need airflow and space.
- Relying only on tradition: Some combinations work better in certain climates or soils than others.
- Neglecting rotation: Companion planting doesn’t replace the need for crop rotation.
- Planting incompatible pairs: Ignoring plant family conflicts can increase pest pressure.
FAQs
Q: Are companion planting charts reliable?
A: They’re a good starting point but often oversimplify. It’s best to combine research with your own observations.
Q: Can companion planting replace fertilizers?
A: No. While legumes enrich soil and some companions balance nutrients, crops still benefit from compost or amendments.
Q: Do flowers really make a difference in vegetable gardens?
A: Yes. Flowers like calendula, marigolds, and cosmos attract pollinators and beneficial insects that directly improve yields.
Q: How close should companions be planted to each other?
A: Ideally within 6–18 inches, depending on plant size. Close enough to share benefits but far enough to avoid overcrowding.
Q: Is companion planting effective in containers?
A: Yes. Many crops and herbs thrive in containers together, such as tomatoes with basil or lettuce with chives.