Companion Planting Guide: Which Vegetables Grow Best Together
Companion planting improves yields, reduces pests, and makes the most of limited garden space. Here's what to plant together — and what to keep apart.
Companion planting is the practice of placing plants near each other based on mutually beneficial relationships — one plant may repel pests that attack another, fix nitrogen that feeds a neighbor, or provide shade that another plant needs. Done well, it improves yields without pesticides or extra fertilizer.
The Classic: The Three Sisters
Corn, beans, and squash is the original companion planting trio, used by Indigenous American farmers for centuries. Corn provides a trellis for beans to climb. Beans fix nitrogen from the air into the soil, feeding the corn and squash. Squash leaves shade the ground, retaining moisture and suppressing weeds.
Tomatoes and Basil
This is the most popular companion pairing in home gardens. Basil is said to repel thrips and aphids and may improve tomato flavor. Even if the benefits are partly anecdotal, they thrive under the same conditions (full sun, warm temperatures) and take up different vertical layers of space.
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Marigolds: The Universal Companion
French marigolds repel whiteflies, aphids, and nematodes. Plant them around the perimeter of vegetable beds or interplanted between susceptible crops like tomatoes, peppers, and brassicas. They also attract pollinators and predatory insects that eat garden pests.
What NOT to Plant Together
- Onions + beans: Onions stunt bean growth
- Fennel + almost everything: Fennel secretes chemicals that inhibit germination and growth of most vegetables
- Brassicas + strawberries: They compete and neither does well
- Tomatoes + fennel or brassicas: Tomatoes are particularly sensitive to both
Quick Companion Planting Reference
- Tomatoes: Basil ✅, Marigolds ✅, Carrots ✅ | Fennel ❌, Brassicas ❌
- Carrots: Onions ✅, Leeks ✅, Rosemary ✅ | Dill ❌
- Beans: Carrots ✅, Squash ✅, Marigolds ✅ | Onions ❌, Garlic ❌
- Peppers: Basil ✅, Carrots ✅, Marigolds ✅ | Fennel ❌
- Cucumbers: Beans ✅, Dill ✅, Marigolds ✅ | Sage ❌