in , ,

Radicchio Seed Starting Tips

Sharing is caring!

Radicchio is a cool-season crop. It grows best in the cool weather of spring and fall.

Radicchio has a lettuce-like head that colors to a deep rosy red as the weather grows cold in autumn or winter. The slightly bitter taste of radicchio sweetens with cooler day temperatures.

Sow radicchio seeds directly in the garden 2 to 4 weeks before the last frost in spring. To set out transplants start seeds indoors 4 to 5 weeks before transplanting. Set transplants in the garden 4 weeks before to 2 weeks after the last frost. Transplants will give you a head start on the season.

Make succession plantings every 2 to 3 weeks until temperatures begin to warm in late spring then sow again in late summer for harvest in cool autumn weather.

Good Products for Growing Radicchio at Amazon:

Radicchio in garden seed starting

Grow radicchio in moisture-retentive, humus-rich soil. If temperatures warm you can mulch them with aged compost to keep the plants from bolting.

Radicchio matures in about 85 days. Start to harvest outer leaves as soon as they are usable size. This cut-and-come-again method will prolong the harvest. The flavor and texture of leaves are best when leaves are still young and tender.

Radicchio planting details

  • Sowing depth: ¼ inch (.6 cm)
  • Space between plants after thinning: 6 inches (15cm)
  • Days to sprout: 5-7
  • Days to harvest: 40 days or as soon as the leaves are edible
  • Storage period: 1-2 weeks
  • Seeds per 100-row feet:  ¼ ounce (7 grams)
  • Yield per 100-row feet: 100 heads
  • Suggested varieties: Astro, Runway, Rocket, Italian Wild Rustic, Treviso

Radicchio sowing and planting tips

  • Radicchio can be grown from seeds or transplants.
  • The seed is viable for 5 years.
  • Start indoors 12 to 8 weeks before the last frost or sow; transplant maturing seedlings into the garden 2 weeks before the last frost. Or direct-sow seed in late summer for autumn or winter harvest.
  • The optimal growing air temperature for radicchio is 45°-65°F (7-18°C).
  • Sow seed ¼ inch (6 mm) deep.
  • Sow seeds 2 inches (5 cm) apart; later thin seedlings 8 to 10 inches (20-25 cm) apart. Make sure there is good air circulation around maturing plants to avoid disease.
  • For intensive planting space plant 8 inches (20 cm) apart in a staggered pattern.
  • Radicchio grows best in full sun but can tolerate light shade.
  • Prefers a soil pH between 5.0 and 6.8.
  • Seed germinates in 5 to 7 days at or near 60°F (7°C)—but sometimes seed can take up to 2 weeks to germinate if the soil is cold.
  • Keep the soil evenly moist until seeds germinate then keep the soil moist until seedlings are well established.
  • Add aged compost to planting beds in advance of sowing; compost will feed the soil and aid moisture retention.
  • Avoid planting radicchio where endive and escarole have recently grown.
  • Make successive sowings every few weeks for an extended harvest.
  • Fertilize with an organic fertilizer such as fish emulsion at half strength.
  • Aphids, flea beetle, leafhoppers, armyworms, snails, and slugs can attack radicchio.

Interplanting radicchio

  • Interplant radicchio with lettuce.

Container growing radicchio

  • Grow radicchio in a container at least 12 inches (30 cm) wide and deep.
Radicchio in garden seed starting
Radicchio ready for harvest

Radicchio planting calendar

For late spring harvest

  • 8 weeks before the last frost in spring: direct-sow in a plastic tunnel or cold frame.
  • 8 weeks before the last frost in spring: start seed indoors for transplanting later.
  • 2 weeks before the last frost in spring: direct sow in the garden.

For fall and winter harvest

  • 5-6 weeks before the first frost in fall: direct-sow in the garden for a fall crop.
  • 3-5 weeks before the first frost in fall: direct-sow in a plastic tunnel or cold frame for winter harvest.

Radicchio seed sowing dates

(These dates are for the Northern Hemisphere)

Average date of the last frostPlanting dates
Jan. 30Jan. 1-Mar. 1
Feb. 8Jan. 1-Mar. 1
Feb. 18Jan. 15-Mar. 1
Feb. 28Feb. 1-Mar. 1
Mar. 10Feb. 15-Mar. 15
Mar. 20Mar. 1-Apr. 1
Mar. 30Mar. 10-Apr. 10
Apr. 10Mar. 15-Apr. 15
Apr. 20Mar. 25-Apr. 15
Apr. 30Apr. 1-May 1
May 10Apr. 15-May 15
May 20May 1-30
May 30May 1-30
June 10May 15-June 1
  • ‘Rossa di Treviso’ and ‘Rossa de Verona’ are standards.
  • ‘Giulio’ for spring crops.
  • ‘Augusto’ for fall and winter crops.

Botanical name: Cichorium intybus

Radicchio belongs to the Compositae (Asteraceae) or sunflower family.

Also of interest:

How to Grow Chicory and Belgian Endive

How to Cook and Serve Belgian Endive

How to Plant and Grow Radicchio

Radicchio Seed Starting Tips

How to Harvest and Store Radicchio

Four Ways to Cook and Serve Radicchio

How to Plant and Grow Endive and Escarole

Edive and Escarole Seed Starting Tips

How to Harvest and Store Endive and Escarole

Escarole and Curly Endive Serving Tips

Garden Planning Books at Amazon:

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

Spinach leaves

How to Harvest and Store Spinach

Lemon flavored herbs

Lemon Herbs to Grow and Cook