What is the practice of planting different crops together for pest control called?

The practice of planting different crops together for pest control is called companion planting.

The idea is to place plants near one another so their interactions benefit the garden. Some companions can mask a crop’s scent, confuse insects, attract predatory or pollinating insects, or act as trap crops that draw pests away. Others provide shade, ground cover, nitrogen, or physical support.

Companion planting has ancient precedents. The Indigenous peoples of the Americas developed the Three Sisters system, in which maize supports climbing beans while squash shades the soil. Rice growers in China have also used mosquito ferns for centuries. The technique is a form of polyculture, but the terms are not interchangeable: polyculture simply means growing multiple species together, while companion planting emphasizes a purposeful beneficial relationship.

Garden charts often claim that pairings such as carrots and onions repel each other’s pests, but scientific evidence varies widely. Results depend on the crop, pest, spacing, and local conditions, so companion planting works best as one part of integrated pest management.