Osborne Quality Seeds recommends purchasing only enough pelleted seed for your current growing season. Conventional pellets are not NOP compliant.
RESOURCE: RADICCHIO CHART
Chicory- Radicchio Growing Information
Transplant: Start around summer solstice for most varieties, in trays at ¼” depth. Soil temperature for germination is 50-70° F. Some varieties are more adaptable to warm weather and can be seeded earlier. Transplant out 3-4 weeks from sowing date or when roots have good structure.
Spacing: 8-10” apart in rows 12-24” apart. Transplant so that soil level is even with the top of the plug.
Growth needs: Radicchio is day-length and temperature sensitive, so make sure to choose the right variety for your climate and time of sowing. Cool-season production is better, but some varieties are adapted to warmer temperatures if evenings are 60° F or lower. See our radicchio chart resource linked above for more information on slotting options.
Harvest: When heads are dense (for Chioggia, Castelfranco, and Treviso types) or well-formed and of desired size (Lusia and specialty types). Cut at base, above stem and peel back outer leaves for sales. All varieties are light-frost tolerant. Later maturing varieties are more tolerant of heavy frost.
Storage: Late-maturing varieties store longer than short-season varieties. Recommended to harvest for storage as soon as heads are mature. Plants will continue to grow if left in the field and can be subject to stem growth or splitting like cabbage, which reduces storability.