I've got a couple here but once again an intersting article on the subject.
http://www.motherearthnews.com/orga...h-cold-frames-zmaz07djzgoe.aspx#axzz3DgnmlJTT
http://www.motherearthnews.com/orga...h-cold-frames-zmaz07djzgoe.aspx#axzz3DgnmlJTT