Prepare the site: Radishes grow well in almost any soil that is prepared well, is fertilised before planting, and has adequate moisture maintained.
Sowing: Sow indoors from late winter or sow directly from late spring through to early autumn. Plant in spaces between slow-maturing vegetables (such as broccoli and brussel sprouts) or in areas that will be used later for warm-season crops (peppers, tomatoes and squash).
Sow thinly, 0.5in (1.5cm) deep in rows 9in (25cm) apart. Keep moist and thin as necessary. Proper thinning focuses the harvest and avoids disappointing stragglers that have taken too long to develop. Slow development makes radishes hot in taste and woody in texture. Repeat sowings every two to three weeks to ensure a continuous supply. Remember, it is much more economical to sow little and often rather than have a long row of radishes all coming to maturity at the same time.
Cultivation: If you want good-tasting radishes also pay close attention to the watering regimen you provide. Moisture stress can result in the same woody, hot radishes that poor soil conditioning and lack of fertiliser or humus will result in.
Harvesting: Plants will be ready to harvest when they are of usable size and relatively young from 21 days, starting when roots are less than 1 inch in diameter. Radishes remain in edible condition for only a short time before they become pithy (spongy) and hot. Gently hold the tops twist and lift. Remove the tops by twisting them off with your hands. The tops are very tasty and can be cooked and eaten like spinach.
Save the young thinnings of both summer and winter radishes. They are delicious with tops and bottoms intact. Both summer and winter radishes store well in the refrigerator once the tops have been removed. The radish leaves cause moisture and nutrient loss during storage. Store greens separately for 2 to 3 days. Refrigerate radishes wrapped in plastic bags for 5 to 7 days. Store roots in dry sand, soil, or peat for winter use.
Culinary Use: As with any Brassica member, mustard oils are responsible for the tangy taste of radishes. All varieties are excellent sources of Vitamin C and, ounce for ounce, have about 42% as much as fresh oranges. Just like carrot tops, radish greens can be used in a variety of dishes, including raw in blended drinks or in salads. Radishes are high in Vitamin C, folate and potassium. They are known to relieve indigestion and flatulence, as well as being a good expectorant.