winter sowing cauli

Not really, things are pretty much static over winter, but you can sow now for the plants to over winter and then grow on in spring.

This is the type I sowed a few weeks back, (this company are out of stock now, but you may find them elsewhere).

http://www.thompson-morgan.com/seeds1/product/942/1.html

Cauliflower is not a greenhouse vegetable, in my opinion, and even in winter it can get too warm for them. They much prefer it on the cooler side.