Companion planting is the act of growing two or more plants together so that they complement and assist the growth of one another. A good example of companion planting is growing Tomatoes and Basil together. Basil may enhance the flavor of the Tomato and also act as an insect repellent. Carrots and Onions complement each other because Onions will keep the carrot flies away. Marigold is also grown around vegetables to assist in reducing pests in the soil. Corn, Beans, and Squash—also known as the Three Sisters—complement and support the growth of one another.