There are many kinds of radishes you can grow

By Melanie Mathieson
Gardening Guru

The radish is a cool-season, fast-maturing, easy-to-grow vegetable and is one of the first crops from the vegetable garden each year. Radishes grow well in almost any soil that is prepared well, fertilized before planting and has adequate moisture maintained throughout the growing season. Radishes are an easy crop to grow and a great open to try for the beginner gardener or with children.
Slow development, usually caused by hot and dry weather, makes radishes hot in taste and woody in texture. Radishes mature rapidly under favourable conditions and should be checked often for approaching maturity. Harvest should begin as soon as roots reach edible size and crops should be depleted quickly, before the summer heat which can cause pithiness (woody texture) or seed stalks (known as bolting) to develop.
Spring radishes should be planted as early as the soil can be worked until mid-spring. Make successive plantings of short rows every 10 to 14 days. If you are tight on space for successive plantings, plant in spaces between slow-maturing vegetables (such as broccoli, cabbage or corn) or in areas that will be used later for warm-season crops (peppers, tomatoes and squash). Later-maturing varieties of radishes (Icicle or French Breakfast) usually withstand heat better than the early maturing varieties and are recommended for late-spring planting for summer harvest. Winter radishes require a much longer time to mature than spring radishes and are planted at the same time as late turnips (usually midsummer to late summer) and left in the garden over the winter. Sow radish seeds 1/4 to 1/2 inch deep. Thin spring varieties to 1/2 to 1 inch between plants. Winter radishes must be thinned to 2 to 4 inches, or even farther apart to allow for proper development of their larger roots. On wide row beds, radishes may be broadcast lightly and thinned to stand 2 to 3 inches apart in all directions.
Pull radishes when they are of usable size (usually starting when roots are less than 1 inch in diameter) and relatively young. Radishes remain in edible condition for only a short time before they become pithy (spongy) and hot. Proper thinning focuses the harvest and avoids disappointing stragglers that have taken too long to develop. By pulling ready to eat plants randomly across the bed will help to allow adequate space for remaining seedlings to develop. Winter varieties mature more slowly and should be harvested when considerably larger in size. Once they reach maturity, they maintain their high quality for a fairly long time in the garden, especially in cool fall weather. Size continues to increase under favourable fall conditions. The Daikon or Chinese radish, can achieve a particularly large size and still maintain excellent quality. Winter radishes can be pulled before the ground freezes and stored in moist cold storage for up to several months. You may find that you have root maggots that tunnel into your radishes if you leave them in the garden too long. The root maggots tend to be more apparent in wetter conditions. You can apply a soil insecticide in the spring before you plant if you find that the maggots are a big problem.
What causes my radishes to crack and split? The radishes are too old. Pull them when they are younger and smaller. A flush of moisture after a period of relative dryness also may cause mature roots to burst and split. Try to avoid uneven moisture conditions in your garden.
Why do my radishes grow all tops with no root development? There may be several reasons: seed planted too thickly and plants not thinned (though some roots along the outside of the row usually develop fairly well even under extreme crowding), weather too hot for the spring varieties that do best in cool temperatures (planted too late or unseasonable weather) and too much shade (must be really severe to completely discourage root enlargement).
What causes my radishes to be too “hot”? The “hotness” of radishes results from the length of time they have grown and in what growing conditions they have developed. Hot radishes either grew too slowly or are too old. Weather conditions that are hot and dry tend to produce vegetables with a hotter taste as well. The sharp or pungent taste in most radishes comes from the skin. If the taste is too harsh for your taste buds, you might want to peel them.
Recommended varieties to try:
Spring
Burpee White (25 days to harvest; round; smooth white skin)
Champion (28 days, large, round, red)
Cherry Belle (22 days, round, red) – I have had the best success with this variety.
Early Scarlet Globe (23 days; globe-shaped, small taproot, bright red)
Easter Egg (25 days; large, oval; color mix includes reddish purple, lavender, pink, rose, scarlet, white) – I have suggested these before for growing for children
Spring/Summer Varieties
French Breakfast (23 days, oblong red with white tip)
Icicle (25 days, long, slim, tapered white)
Winter Varieties
Chinese White (60 days; large, long, square-shouldered, blunt-tipped, creamy white roots)
Round Black Spanish (55 days; rough, black skin, white flesh) – Recently noted to have cancer fighting properties.