I didn't exactly winter sow the tomatoes but I have them up and one set is putting out true leaves now. They don't seem to mind the cold sheltered, sunny plant room I sowed them in. I didn't think they would come up so fast but after a cold period and a warm period they popped up and have been doing fine ever since. They will just grow slow during the cold spells and be the right size by the time it's safe to put them out in the garden.