I currently have a cattle panel greenhouse made from four cattle panels. They are the std 16 ft. by abt 50 inch size.

This yielded a greenhouse almost 7 ft. wide and just over 6 ft. high. (for simplicity/low cost, the ends of the panels are sitting directly on the ground). I need something much larger, and I have a MIG welder machine. So I am thinking I could weld two cattle panels short end-to-short end, so I have 32 ft. long panels. By joining up five of these double-panel arches, I could build a greenhouse that is 20 ft. wide and 20 ft. long....400 sq. ft.! The high point of ceiling is abt 10.5 ft.! I didn't believe it, but I cut two pieces of heavy wire, one 16 in., and the other 32 in. long, bent both into an arch, and this is the result. I could put in an aquaponics system large enough to feed a small family. One possible problem is that with a 10 ft. height, I think it will catch more wind (although the sides would have much more slope), and get knocked around a lot more in high gusts. So I'd probably have to put in a couple of 4 in. wood posts near each end and wire the tops to the peak of the ceiling to stabilize it. Anyone tried doubling cattle panels like this? Could it work? Seems like a cheap, cheap way to build a 400 sq. ft. greenhouse!

One problem with the greenhouse: In the summer it is regularly over 100 deg., and the greenhouse has no shade. The film is a quality 6 mil film, 90% transmission, from Farm-Tek. I had to put in a 20 in. high-velocity fan sucking air in from the vent window on the back end of the greenhouse....this keeps you from getting a heat stroke in 5 minutes, but it is still way too hot for any seedlings to germinate, and many plants to grow. Its way too hot in the summer, and in the winter it re-radiates the daytime heat back out in no time after the sun goes down! How to deal with this....it would be the same situation with a much larger greenhouse, I guess. It is incredible how it traps solar heat during the day!