Spring radishes are most common and are grown in the spring. They are the quickest maturing, usually in 20 to 30 days. Summer radishes are long rooted and take longer to mature, normally about 45 days. Winter radishes are grown for storage and require about 60 days. Radishes grow best in full sun but tolerate some shade. They like a soil with a pH near 7. If the soil lacks organic matter the roots may be hot and woody. Winter radishes, grown for storage are usually not planted until mid to late August. The seed is sown 1/2 inch deep with 15 seed used per foot in rows 12 inches apart. Spring radishes are thinned to 1 inch spacing while they are small. Thin summer and winter radishes to 3 inch spacings. For sustained yields, a portion of a row may be planted every 10 days. Use summer and winter varieties beginning in June. If no other fertilizer was applied, use 3 cups of 5-10-10 per 50 feet of row. Excessive nitrogen may give large pithy roots. Summer and winter varieties can be mulched. Poor care may result in soft flavorless roots and slow growth may result in hot, woody roots.
The harvest time varies with the variety. The roots should be harvested when a moderate size. Splitting and pithiness occurs if the roots are allowed to become overmature.