How to Grow Radish — Croft & Covey

Growing Conditions

Radishes prefer cool temperatures between 50°F and 65°F. They tolerate frost and can be sown very early in spring. Heat causes rapid bolting and hot, pithy roots. Full sun is preferred but light shade is tolerated.

Cold climates: Sow as soon as soil can be worked in spring — radishes are among the very first crops you can plant. For fall, sow 4–6 weeks before first frost. Succession sow every 1–2 weeks for continuous harvest.

Warm climates: Spring and fall only. Summer heat makes radishes impractical except for daikon and other heat-tolerant storage types.

Sowing & Planting

Direct sow ½ inch deep, 1 inch apart, in rows 6 inches apart. Thin to 2–3 inches when seedlings emerge — crowded radishes produce small, misshapen roots. Radishes are always direct sown; they do not transplant well.

Care & Maintenance

Consistent moisture produces the best texture and mildest flavor. Irregular watering causes cracking and intensifies heat. Radishes are light feeders — no additional fertilizing needed in average soil.

Common Problems

Pithy or hollow roots result from leaving radishes in the ground too long or from heat stress. Harvest on time. Flea beetles damage leaves — radishes are sometimes planted as a trap crop to draw flea beetles away from other brassicas. The root crop is unaffected by mild flea beetle pressure. Root maggots tunnel through roots — rotate crops and avoid planting where cabbage family crops grew the prior year.

Harvest

Pull spring radishes when roots reach ½ to 1 inch in diameter — about 3–4 weeks after sowing. Check by brushing soil away from the shoulder. Don’t leave them in the ground after maturity; quality declines quickly. Winter storage types (daikon, Black Spanish) are harvested at 50–70 days and store for months in a cool location.

Varieties

Spring radishes (Cherry Belle, French Breakfast, Easter Egg mix) mature in 22–28 days and are eaten fresh. Daikon radishes are large, mild, slow-maturing types used fresh, pickled, or cooked — harvest at 50–60 days. Winter storage radishes (Black Spanish, Watermelon/Shunkyo) mature in 55–70 days and store well. All spring types grow identically; storage types need more space and a longer season.