Radish (Raphanus sativa)
Radish is a member of the Brassica family, which includes cabbage and other cole crops. This ancient crop may have been important as early as 5,000 years ago. Today’s radishes include both small European varieties and the large-rooted white daikons, which are enjoyed as food and increasingly used as cover crops due to their long taproots that can penetrate compacted soil.
Radishes are fast-growing, typically maturing in 21 to 28 days under ideal conditions. The roots have a spicy flavor due to glucosinolates, sulfur-containing compounds found in the Brassica family. High temperatures and insufficient moisture increase pungency and bolting. Spring and fall crops generally have better quality than summer ones. Some varieties may become pithy under stress.
Temperature
Radishes thrive in cool conditions. Maintain high soil moisture to reduce stress from heat. Hot, dry weather shortens their prime harvest window and may cause toughness or spiciness. Grow them quickly with sufficient moisture for best quality.
Soil
Radishes prefer a pH of 6.5–6.8 in loose, well-drained muck, sand, or loam soils. These conditions support uniform root development. Avoid repeated planting in the same location to prevent buildup of soil-borne diseases like clubroot and scab. Crop rotation also helps preserve color quality and avoid soil fatigue.
Planting
Plant radish seeds ¼–½ inch deep in moist soil. In spring, sow as soon as soil can be worked. Sow every 10 days for continuous harvest. Raised beds (4' wide) with 6 rows are common. Use floating row covers to reduce pest damage. Keep soil moist throughout the growing period.
Spacing
1" between plants, 9–12" between rows
Harvest
Yield: 2,500 dozen bunches per acre (8–12 radishes/bunch), or 15–20 bags per 30 ft of row (8 oz bags). Daikon yield: 15–20 tons per acre.
Table Radishes: Harvest 3–4 weeks after planting when roots are marble-sized. Bunch or top, hydrocool, and store at 32°F with 95% RH. Topped radishes last 3–4 weeks.
Daikon Radishes: Harvest about 60 days after planting. Market sizes range from 2.5" to 14" long. Can be sold topped or with greens. Store similarly to table radishes—topped daikon lasts 3–4 months at 32°F and 95% RH.
Radishes have a short harvest window—3 days in summer, 5–7 days in cooler weather. Harvest daily near maturity to avoid oversizing or pithiness. Commercially, they are machine harvested and hydrocooled. USDA standards require red radishes be at least 5/8" diameter; the most marketable size is 7/8"–1 1/8". Packed in 6 oz or 1 lb bags, 12–15 lbs per carton. Bunched radishes should contain 18–20 uniform roots.
For more information, please see links below:
- University of Arizona - Radish
- Radish Production in Florida (ResearchGate)
- Oregon State - Radish Guide
Note: This information is summarized. Additional details and expanded guidelines can be found in our production sheets available in the Holmes Seed Grower's Guidebook.
Downloadable Copy: