I knew I had read not to expect to raise flowering plants for a while, now I know where I read that. I am in Ky just across the river from Evansville In. I plan to have a pasively heated leanto type greenhouse with one exhaust fan. I have 3 double pane house windows that I can raise with the fan on for cooling.. My back wall will be 2x6 with 5 1/2 inch insilation, and the same with the front and side kick wall. I'm planning on digging down 3 ft and placing the 4" sewer pipe and covering them with 4" limestone, placing the sewer pipe one ft on center verticly and 2' on center horazonily (I may be a rocketscientist, but I cant spell), and use some 12 volt fan to circulate the air powered with a solar cell. I have located the stock tanks at Rual King and I am just waiting on grandpa's day where every thing is 10% off to purchase them. I am probably 2 weeks from starting construction. I have priced hydroton and it is quite expensive, so I may go with river run gravel, as the Ohio river is right here and I hope rather cheap. I value your advice and thank you in advance....John