Raphanus sativus This is a cheerful blend of radishes in different hues: red, white, rose, and purple. Great fun to harvest, they enliven salads and plates of crudites with their whimsical colors. Roots are round. Soil conditions for radish are simple; a very well-dug soil to a depth of 15cm (6in) with no stones or fresh compost in it. At the time of digging, add two handfuls of bonemeal per square metre (yard) and work it into the topsoil. The soil preparation should ideally be complete a month before sowing, but it makes very little difference if it is done at sowing time. Sow small amounts of radish seed but often to ensure a continuous supply rather than a glut at one time - radishes do not keep well in the soil once they are mature.