Radish - Scarlet Globe This is an easy and fast growing old favourite which produces crisp, round radishes with good flavour, ideal for poorer soils. 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.