Veggies on the roof – the first round!

It’s about that time of year folks!  I put out the first of my veggies on the roof!  Woohooo!  This will be my first year growing calilfower and brocolli and I can’t wait to see how it turns out.  (and no – I didn’t start these guys from seed.  I totally bought seedlings – I hope to grow some heads from seed this Fall.)  Any seasoned brocolli growers out there?  When should I start them?  Late Summer?  Early Fall?