How to Grow Radishes
A tip sheet on how to grow and care for radishes.
- Family: Brassicaceae (Mustard)
- Season: Cool
- Ease of growing: Easy
- Nutrient needs: Low
- Water needs: High
- Common propagation: Seed
- Germination temperatures: 45°F to 95°F
- Germination time: 3 to 10 days
- Viability: 5 years
- Direct sow: Any time during season
- Spacing: 3/4” (small) to 4” (Daikon)
- Plants per square foot: 9 to 36
- Succession sow: every 2 to 3 weeks
- Time to harvest: 20 to 60 days
Radishes are classified by their planting time – early, mid or late; by root shape – oblong, flat, round, half-long and long; and by color. Aside from your standard red, round radish, try “Easter Egg” radishes for their multiple colors. “D’Avignon” is an excellent cylindrical 3-inch radish with tender and mild flavor. “Daikon” radishes are long, white radishes from Japan that can reach 16 inches or more while holding their texture and flavor. Daikon is a type of oilseed radish that is becoming increasingly popular as a cover crop, planted after early harvested vegetables. The long roots of oilseed radish act as a “bio-drill,” penetrating compacted soils and creating a nice place for early planted vegetables the following spring.
Preparation and planting
Like most root crops, radishes prefer loose-textured soil. Heavy clay soils tend to produce misshapen roots.
Radishes require little care after planting, but they must have sufficient and consistent water for best quality.
Insects: Flea beetle and cabbage maggot
Diseases: Downy mildew, black root, scab
Harvesting and storage
When radishes are ready to harvest, the top of their pink, swollen stem will often emerge from the soil. Harvest whenever they reach the size you desire. Smaller radishes are more tender and have a stronger flavor. If you wait too long, radishes begin to get pithy. Daikon radishes take longer to mature and can snap off easily during harvest, so it’s a good idea to use a fork to loosen the soil before pulling. When stored at 32°F and high humidity, radishes will keep four weeks or more.
Developed by James Manning, Undergraduate Research Assistant, and Daniel Brainard, Vegetable Extension Specialist; MSU Department of Horticulture; Gary Heilig, MSU Extension educator.