CULTURE: For North American production, these are vast improvements over older types, but are still not very uniform or completely predictable. Although bred for specific seasons, it is still best to trial more than one variety, using succession plantings to determine which one suits your conditions. PLANTING/GROWING: Very similar to raising lettuce (See Lettuce). NOTE: Radicchio grows best in cool or mild weather, i.e. fall, winter, and spring. Summer crops can be successful if nights are cool (below 60°F/16°C). DAYS TO MATURITY: From transplanting; add 14-21 days if direct seeding. AVG. DIRECT SEEDING RATE: 1M/220'; 5M/1,100'; 10M/2,200'; 131M/acre at 3 seeds every 8" in rows 18" apart. TRANSPLANTS: Avg. 500 plants/M (2 seeds per cell thinned to one seedling). SEED SPECS: SEEDS/OZ.: See individual varieties. PACKET: 200 seeds unless otherwise indicated.