22 to 30 Days to maturity. Raphanus sativus. Shirashime Hatsuka Daikon Radish Heirloom Seeds. Cool Season Annual. A uniquely small daikon radish, Shirashime Hatsuka is hardy, quick to harvest, and mildly flavored. This variety can be harvested 20 days after planting and can grow up to 4 inches long and 1/2 inch in diameter. They look a little bit like small white carrots! If your climate is mild, they can be grown year-round. Otherwise, sow in spring or early fall. Shirashime Hatsuka radishes are mild and excellent for eating raw. ~ 3,800 seeds / oz.