Not all brassica varieties work as cover crops, but mustard seeds and radish seeds do have cover crop properties. They help significantly control pests because they contain a higher amount of glucosinolate than other brassica plants, a chemical compound that wards off harmful insects. When the plant cells are ruptured the plant releases the glucosinolate. Brassica Cover Crops are known for their rapid fall growth, which makes them an ideal weed suppressor. They also have deep drilling roots that help break up and aerate soil. Find out about all subcategories.