Stephen Albert
Radicchio is a cool-season crop. It can be grown in early spring and in fall.
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.
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 seed sowing dates
(These dates are for the Northern Hemisphere)
| Average date of the last frost | Planting dates |
| Jan. 30 | Jan. 1-Mar. 1 |
| Feb. 8 | Jan. 1-Mar. 1 |
| Feb. 18 | Jan. 15-Mar. 1 |
| Feb. 28 | Feb. 1-Mar. 1 |
| Mar. 10 | Feb. 15-Mar. 15 |
| Mar. 20 | Mar. 1-Apr. 1 |
| Mar. 30 | Mar. 10-Apr. 10 |
| Apr. 10 | Mar. 15-Apr. 15 |
| Apr. 20 | Mar. 25-Apr. 15 |
| Apr. 30 | Apr. 1-May 1 |
| May 10 | Apr. 15-May 15 |
| May 20 | May 1-30 |
| May 30 | May 1-30 |
| June 10 | May 15-June 1 |
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
More about planting radicchio:
