2,500 Sparkler Radish seedsapprox. 1 OunceNon-GMO, Heirloom Sparkler Radish Seeds. This fast cool season crop is a delight with its pretty red skin that changes to white at the tip. Matures in 25 to 30 days. The bright but mild radish flavor is a crowd-pleaser and at 1 – 1 1/2 inches is great on a relish tray or eating out of hand.Sparkler radish microgreens have whitish stem with green leaves. Sparkler radish can also be grown as microgreens. Harvest micros around 8 to 10 days.