Published on Organic Gardening (http://www.organicgardening.com)
Sow broccoli seed 8 weeks before the last spring frost to 12 weeks before the first fall frost. Seeds sprout in 3 to 10 days at 70° to 80° F. Grow seedlings at 60° to 70°F.
Links:
[1] http://www.organicgardening.com/seed-starting-broccoli
[2] http://www.organicgardening.com/node/2534