It is hard here in USDA zone 8ish to start fall/winter veges, cause our summer veges last well into the fall! September and October actually being our warmest months!
I have some lettuce planted in the shade, but the tomatoes are just now starting to produce and I have a couple of months left!
I guess the only way to do winter stuff is to buy starts.
It's WAY too hot to start stuff in the GH!