Companion planting is the age-old practice of placing specific plants near each other to achieve a mutual benefit. A well-designed companion planting scheme can help deter pests, attract beneficial insects, improve soil health, and even enhance the flavor and growth of your crops. It's about creating a diverse, resilient garden ecosystem.
How Does Companion Planting Work?
Plants can help each other in several key ways:
1. Pest Deterrence
Some plants release aromatic compounds from their leaves and flowers that can confuse or repel pests. For example, the strong scent of marigolds can mask the smell of tomato plants, making it harder for hornworms to find them.
- Aromatic Herbs: Plants like rosemary, thyme, mint, and basil can deter pests like cabbage moths and carrot rust flies.
- Alliums: Onions, garlic, and chives can repel aphids and spider mites.
2. Attracting Beneficial Insects
Many small-flowered plants provide nectar and pollen that attract beneficial predators like ladybugs, parasitic wasps, and hoverflies. These "good bugs" prey on common garden pests.
- Herbs: Dill, fennel, and cilantro are excellent for attracting parasitic wasps.
- Flowers: Sweet alyssum, cosmos, and zinnias provide a season-long food source for beneficial insects.
3. Improving Soil & Plant Health
Some plants can improve growing conditions for their neighbors.
- Nitrogen Fixers: Legumes like beans and peas have a symbiotic relationship with soil bacteria that allows them to "fix" atmospheric nitrogen, making it available to heavy-feeding plants like corn.
- "Trap Crops": You can plant a crop like nasturtiums to lure aphids away from your more valuable plants. The nasturtiums act as a sacrifice.
- Physical Support: Tall, sturdy plants like corn or sunflowers can provide a natural trellis for vining plants like pole beans or cucumbers (the classic "Three Sisters" method).
Classic Companion Planting Chart
Use this chart as a starting point for planning your garden layout. Remember that observation is key; what works in one garden may work differently in another.
| Main Crop | Good Companions | Notes |
|---|---|---|
| Tomatoes | Basil, Carrots, Marigolds, Onions | Basil is said to repel tomato hornworms and improve flavor. Marigolds deter nematodes. |
| Peppers | Basil, Onions, Spinach, Geraniums | Geraniums can trap Japanese beetles. Basil helps deter aphids and spider mites. |
| Cucumbers | Beans, Corn, Radishes, Dill, Nasturtiums | Nasturtiums are a great trap crop for aphids. Radishes deter cucumber beetles. |
| Lettuce | Carrots, Radishes, Chives, Mint | Chives and mint help repel aphids. Taller carrots can provide some welcome afternoon shade. |
| Carrots | Lettuce, Onions, Rosemary, Sage | Rosemary and sage have strong scents that can deter the carrot rust fly. |
| Beans (Bush & Pole) | Corn, Squash, Carrots, Radishes, Marigolds | The classic "Three Sisters" with corn and squash. Avoid planting near onions or garlic. |
| Broccoli & Cabbage | Onions, Thyme, Rosemary, Dill, Mint | Aromatic herbs help confuse and repel cabbage moths. Avoid planting near strawberries or tomatoes. |