COOPERATIVE EXTENSION FACT SHEET
Information about the Kentucky State University Cooperative Extension Program
2020
Radishes
Dr. Leigh Whittinghill, Assistant Professor of Urban Agriculture
Radishes are a member of the mustard family and have been cultivated for hundreds, if not thousands, of years. Other popular crops in this family include broccoli, cabbage and collards. Many people like radishes for their characteristic sharp taste. They can be grown all summer, but may get woody in texture during hot weather.
The range of planting dates for radishes vary depending on what region of Kentucky they are grown in:
March 1 to October 1 for western KY
March 10 to September 15 for central KY
March 15 to September 1 for eastern KY
Plant seeds directly into the soil at a depth of 1/4 inch
The final plant spacing should be 2-to-4 inches, which means that you may need to remove extra seedlings that are growing too close to one another.
If planting in a container, use a container that is 6 inches deep.
Always plant into a weed-free area. Weeds are unlikely to be a problem later on because radishes germinate and grow quickly.
Water about 1 inch per week (including rain), taking special care during root development.
Radishes are ready for harvest 20-to-30 days after planting in the spring and 30-to-40 days after planting in the fall, depending on the variety. If you plant early, the days to harvest may take longer because of colder soil or air temperatures.
Radishes should be 1/2-to-1 inch in diameter when harvested, but the ideal diameter will vary depending on the variety.
Radishes get pithy, or spongy in texture, if left in the ground too long.