Kelp introduction Kelp, one of the seaweeds, is a large marine brown algae growing in cold seawater. It belongs to the group Phaeophyceae and the Laminariaceae family. Named for its growth in seawater and flexible strap-like appearance.Kelp is a highly nutritious vegetable with certain medicinal value as well.There are many ways to cook kelp, such as kelp stewed with pork ribs, kelp stir-fried with meat, shredded meat with kelp, kelp soup, and chilled kelp salad.