I have found that I do manage to get things to grow here reasonably well in the winter mainly because it is very mild and the light is decent... probably in the same way you did in Greece. I have had decent sprouts and Broccoli by Christmas sowing in early August and planting out mid September but we shall see I suppose got to be worth a try the ground will be lying empty if I don't. I find that trying to grow brassicas in the summer is not worth the effort it get too hot and the wilt badly. I am going to try to get some early spring cabbages before it gets too hot come June.