I only ONCE got seeds on a Brassica the same year that I planted it. Usually if I'm hoping for seeds, they just hold through our mild WA coast winter and then burst into bloom and seed the next spring.
Here is a Brassica that went that way:
Spigariello Liscia
Broccolo Spigariello
Brassica oleracea var. 'Spigariello'
