in , ,

Radish Seed Starting Tips

Seedling Radish
Radish seedlings seed starting
Radish seedlings

Radish is a cool-season crop. Radishes are best grown in spring and fall.

Direct sow radishes in the garden 6 to 3 weeks before the last frost in spring. Sow succession crops every 3 weeks after.

Growing tip: Shorter and cooler days result in radishes with rounder roots. For mild and tender roots, grow radishes rapidly with plenty of moisture in soil rich in aged compost. When growth is interrupted by lack of soil moisture, radish roots will be hot, tough, and pithy.

Radishes mature in 21 to 35 days depending on the variety.

Radish Sowing and Planting Tips

  • Start radishes from seed sown directly in the garden.
  • Radish seeds are viable for 5 years.
  • Start seeds in the garden about 6 to 4 weeks before you expect the last frost in spring. Radish can be started indoors, but they—like most root crops—are difficult to transplant to the garden with success.
  • If started indoors and transplanted, allow two additional weeks to maturity as a result of root insult at transplanting; nip off the long thread tip of the radish root when transplanting.
  • Sow seed ¼ to ½ (6-12 mm) inch deep and be sure to heel or stamp the soil firmly.
  • Sow seed 1 inch (2.5 cm) apart and later thin to 4 inches (10 cm) in all directions.
  • To improve germination sow seed at dusk or on a cool, cloudy day.
  • Sow seed in loose, fertile soil. Adding aged compost to planting beds in advance of sowing will feed the soil and aid moisture retention.
  • Seeds should germinate in 4 to 10 days at an optimal temperature of 70°F (21C) or greater; germination will take longer in colder soil.
  • The optimum soil temperature to grow radishes is 50° to 75°F (10-24°C).
  • Make additional sowing at 3-week intervals for a continuous harvest, but time sowing so that crop does not mature in hot weather.
  • Radishes prefer a soil pH range of 5.5 to 6.5.
  • Grow radishes in full sun for best yield—tolerates partial shade.
  • Fertilize with an organic fertilizer such as fish emulsion at half strength.
  • Common pest enemies are aphids, flea beetles, cabbage root maggots, cabbage worms, cabbage loopers, and wireworms. Protect the seedlings from pests and cold temperatures for two to three weeks after planting with spun poly row covers.

Interplanting: Plant radish with bush beans, beets, carrots, cucumbers, lettuce, peas, peppers, and spinach.

Container Growing Radish: Grow in a container at least 4 inches (10 cm) deep; plant in concentric circles.

Radish Planting Calendar

For Spring Harvest:

  • 6-4 weeks before the last frost in spring: direct-sow in a plastic tunnel or cold frame.
  • 4 weeks before the last frost in spring: direct-sow in the garden; minimum soil temperature 40°
  • Every 2 to 3 weeks sow succession crops.

For Fall Harvest:

  • 10-8 weeks before the first frost in fall: direct-sow in the garden.
  • 4-2 weeks before the first frost in fall: direct-sow in the garden in a plastic tunnel or cold frame.
  • Cherry Belle’ is classic round and red.
  • ‘Easter Egg’ is multicolored.
  • ‘French Breakfast’ is long and cylindrical.
  • ‘Miyashige’ is an Asian daikon radish with long white roots.

Botanical Name: Raphanus sativus

Radish belongs to the Brassicacea (Cruciferae) or cabbage family; other members include cabbage, kale, collard, broccoli, Brussels sprouts, and turnips.

More tips: How to Grow Radishes.

Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. has more than 10 million visitors each year.

How To Grow Tips

How To Grow Tomatoes

How To Grow Peppers

How To Grow Broccoli

How To Grow Carrots

How To Grow Beans

How To Grow Corn

How To Grow Peas

How To Grow Lettuce

How To Grow Cucumbers

How To Grow Zucchini and Summer Squash

How To Grow Onions

How To Grow Potatoes

Brussels Sprouts Harvest bigstock Brussel sprouts in the copper 328452463 scaled

How to Harvest and Store Brussels Sprouts


How to Harvest and Store Kohlrabi