30 days. This japanese mustard green has dandelion-like jagged edged green leaves with a mild, sweet, earthy flavor. Mizuna grows fast and makes an excellent salad green. It can be harvested a few outside leaves at a time, or cut the whole head near ground. It is also used in stir-fry and soups. Also wonderful as a microgreen. Approx. 17,000 seeds/oz.