Mustard seeds are the small round seeds of various mustard plants. The seeds are usually about 1 to 2mm in diameter and may be colored from yellowish white to black. They belong to the Brassica nigra family Black mustard seeds are those tiny little strong flavored seeds used most commonly in Indian cooking. Mustard Seed has for quite some time been depended upon to improve the stomach related framework and to advance a solid craving. Harvest season February to april.