Radish - Sparkler 3 This is one of the best well known types. This reliable globe variety has an attractive bright red colour with a white tip. It is high yielding with very crisp texture and peppery flavour. Sow outdoors thinly, from February to September, where they are to crop, 1.5cm deep, directly into finely-prepared, well-drained, fertile soil, which has already been watered. Allow 23cm between rows. Early sowings, especially those in February, will benefit from cloche protection. Seedlings usually appear in 7-10 days. Water well until plants are established. Thin only if plants are overcrowded. Harvest from April to October.