I sowed a few seed such as Marigold and Antirrhinum a week ago which I suspect is a trifle to late but I thought that the Greenhouse would have been too cold if I had planted them any earlier. Now the Antirrhinums are close to one inch tall but look rather frail so when should one prick them out?

I thought it to cold in the Greenhouse and it would cost to much to heat it it. I wish there was an inexpensive method of heating it.