Companion plants will either help a specific crop grow or will grow better beside a specific crop, and can do many support jobs in the garden
- Repel insect pests: Cabbage worms, cucumber beetles, Mexican bean beetles, carrot flies, cabbage moths—all kinds of pests can plague vegetable gardens. Many companion plants (like marigold flowers, catnip, and rue) repel specific pests and should be planted near certain crops to keep them pest-free.
- Attract beneficial insects: Pollinators like bees and ladybugs can use a little encouragement to visit vegetable gardens and pollinate the crops. Gardeners often plant attractive plants like borage flowers to encourage pollinators to visit.
- Improve soil nutrients: When crops grow, they take up valuable nutrients from the soil—leaving the gardener to do a lot of work at the end of the season to renew the soil’s nutrients. However, there are many companion plants (like bush beans and pole beans) that add nutrients like nitrogen back into the soil, helping keep other plants healthy.
- Encourage faster growth and better taste: Many companion plants (like marjoram, chamomile, and summer savory) release specific chemicals that encourage faster growth or better taste in the plants around them.
- Provide ground cover: Plants that spread low across the ground (like oregano) serve as a blanket over the soil, protecting it from the sun and keeping it cooler for plants that benefit from lower temperatures.
- Provide necessary shade: Plants that grow tall and leafy (like zucchini and asparagus) can provide welcome shade for sun-sensitive plants beneath them.
- Serve as markers: When growing slow-growing plants, it can be difficult to tell where the rows will be while you’re waiting for the seeds to sprout. Gardeners often use fast-growing plants (like radishes) interspersed with the slow growers in their rows to delineate where the slow growers will be.