Radishes are cool-season crops that can tolerate temperatures below freezing. They can grow anywhere in the United States. They mature in such a short time that you can get two to three crops in spring alone.
Start planting radishes from seed in the garden two to three weeks before the average date of last frost. Radishes germinate quickly and are often used with seeds of slower-growing plants to mark rows.
Radishes like well-worked, well-drained soil. Sow seeds directly in the garden 1/2-inch deep. Thin spring varieties 1 to 3 inches apart; give winter varieties a little more space. Radishes sometimes bolt (go to seed) in the summer, but this is often a question more of day length than of temperature. Cover the plants in midsummer so they get only an 8-hour day; a 12-hour day produces flowers and seeds but no radishes.
The time from planting to harvest is 20 to 30 days for spring radishes, 50 to 60 days for winter radishes. Pull up the whole plant when the radishes are the right size
Types of Radishes
- Cherry Belle, harvest at 22 days, is an All America Selection producing round, red, 3/4-inch roots.
- White Icicle, harvest at 28 days, gives white, icicle-shaped roots that are 5 inches long.
- French Breakfast, harvest at 23 days, is oblong and red with white on the bottom.
- Summer Cross Hybrid, harvest at 45 days, is an Asian-type, all-season variety that gives white flesh.
- Sparkler, harvest at 25 days, is still popular after 30 years.