Onions serve as a protective companion for pepper plants, repelling harmful pests such as green peach aphids, slugs, and cabbage worms that can hurt pepper plants.
Carrots and peppers form a mutually beneficial relationship where carrots provide shade for the peppers' roots, and peppers offer sun protection for the carrot tops.
Due to its bold scent, cilantro repels most insects except for beneficial bugs like butterflies. Growing it alongside peppers, onions, and tomatoes can yield more fruit.