30 to 40 Days to maturity. Raphanus sativus. Saisai Leaf Radish Hybrid Seeds. Annual. Leaf radishes are perfect for the gardener who wants tender, peppery radish greens that can be harvested quickly. Saisai leaf radishes are a Japanese variety that can be used for a variety of dishes, including stir-fries. This variety is also spineless meaning they can be consumed and harvested easily pain-free! Saisai radishes are slow to bolt so they can be planted year-round. ~ 1,300 seeds / oz.