The Seed Savers Exchange, RR3, Box 239, Decorah, Iowa 52101, an organization dedicated to preserving open-pollinated cultivars of plants, publishes a detailed listing of all known available vegetables. For more information contact the Seed Savers Exchange directly. Cultural Requirements Radishes are hardy and prefer cool growing conditions. Time fall plantings so the roots mature during the cooling temperatures of fall. Row covers of spun-bonded polyester and polypropylene fabrics can be draped over crop rows after seeding and anchored with soil to protect the new plants.
Row covers can help extend the growing season in spring and fall.
A wide row 8 to 12 inches across uses garden space more efficiently than a single row. Rows should be spaced 1 to 1.5 feet apart to allow for cultivation. Avoid planting any more spring radishes than can be consumed in a shorticulture period of time. Instead of planting separate rows of radishes, try sprinkling a few radish seeds in as you plant slower germinating seeds such as carrots, beets, lettuce and Swiss chard. The radishes germinate quickly and mark the rows so it is easier to tell where you already planted.