A type of seed that is produced under strict certification standards in order to maintain varietal purity. Certified seed must pass field inspection, be conditioned by an approved seed conditioning plant and be sampled, and pass lab testing before it can be marked and sold as certified. This type of seed is also completely free of noxious weed seeds. The four classes of certified seed are breeder, foundation, registered seed, and certified seed, each with their own requirements. This type of seed is typically used for crops as opposed to lawn seeding.