<<Home Depot the other day and saw some really neat polycarbonate sheets, 46 inches wide by 12 feet long, fellow there said they were available in several widths and lengths.>> George, That's what we used when the earth quake a few years back took out much of the glass in our green house, then a nasty storm finished it off. We used stainless caps to make it water tight. Now we need to figure out a good energy effiecient heating method. Was it you that was investigating heating via steer manure? Suggested that to my husband, NOPE not a possiblity! When we bought the house 22 years back the former owner used gas to heat his orchids in there. He did expieriments for Rod McClellan. Anyway capped the line as it was leaking. Anyone try gas heating to maintain the heat. I think it shouldn't go below 55F, but not sure. We've had many a night below 30F this year and have lost at least a dozen citrus and my prized avocado looks very sad. Guess Spring will tell the story. Mary-Anne