Mustard Seeds - Cho Kara. Heirloom, Non-GMO. Brassica juncea. 5 days for microgreens. 45 days to maturity. Year round annual. This mustard variety is bred especially for microgreen production and has a hot flavor. The cotyledons or seed leaves are forest green with ivory stems. It will be overwhelming for most, with the exception of hot mustard lovers. For large sprouts or microgreens, sow seeds in spring to summer in sandy soil in a bright but cool location. ~ 14,000 seeds / oz.