Choose a site that gets at least six hours of sunlight daily.
Loosen the soil at least 8 inches in depth for fast-growing radishes and as much as 2 feet for larger sharp tasting radishes, which are generally slow growing winter varieties.
As a rule of thumb space the seeds ½ inch deep and an inch apart, but this may vary from type to type - so always consult the seed packet.
Cover loosely with soil and water gently. For a continuous harvest, weekly spring sowings are best as soon as the soil is workable. Start weekly plantings again in late summer for a fall harvest.
Try different varieties in order to get a wide array of radishes. Most spring varieties will mature quickly, succession plantings ensure a steady supply of radishes. Longer varieties of radishes will tolerate heat better than the short rounder types.
As with all root crops you should avoid excess organic materials and manure or fertilizers high in nitrogen. Excess nitrogen will encourage lush foliage at the expense of the roots.
Radishes can be sown in scattered empty spaces in a bed, or between rows and hills. Gardeners often sow quick-growing radishes in the same beds as other slower growing vegetables as they are harvested long before the other plants need the space.
Thin radish seedlings to about 2 inches apart, and up to 6 inches for the larger winter varieties.
Light mulch is advisable to suppress weeds. For quick growth and the best flavor, water regularly, not excessively, water gently. If the soil is too dry, radishes tend to bolt to seed and become too pungent to eat. with excessive, the roots will split and sometimes rot. Never let the soil dry out entirely, but don't keep it saturated either. Mulch enriched with wood ashes is best, this will help keeps root maggots away.
Carrots, Peas, lettuce, chives, onions, leeks, rosemary, sage, tomatoes, bush beans, brussels sprouts, cabbage, onions, peppers, are all suitable companion plants. They serve as a general aid in repelling many insects and draw aphids, Flea Beetles, and some other pests away from peppers, squash, and cucumbers.
Don't plant radishes in a bed that hosted a cole crop in the last three years. If you incorporate plenty of wood ashes in the soil the root maggots shouldn't be an issue.
Radishes sown among cucumbers and squash will help to repel Cucumber Beetle. They act as a trap crop to attract leafminers away from other crops.
See Companion Planting
Longer radish varieties occasionally develop a black root that produces dark blemishes at the base of the roots. If this is a persistent problem it is advisable to grow only round radishes.
Harvesting Oversized radishes frequently crack and are generally tough ,woody and taste horrible. Harvest radishes while young and tender by pulling the entire plant from the ground.
Oversized radishes frequently crack and are generally tough ,woody and taste horrible. Harvest radishes while young and tender by pulling the entire plant from the ground.