After a few trips to Ace Hardware and some creative misapplication of PVC pipe, the greenhouse stands on it's own. The day after I finished it though, the usual winds kicked up and pulled it almost completely apart. I quickly cut a few more clamps to hold the plastic in place and that has held it together...so far.
I purchased the greenhouse film from http://www.greenhousemegastore.com/Greenhouse-Film/products/1033/.
The piece of film I bought was enough for two houses this size.
Our first crop of lettuce is coming up. It seems pretty cool to be growing lettuce in January. I'm hoping we can grow it all winter next year.
And here is that same lettuce a few weeks later:
Now that I've changed all my boxes to Mittleider, I'll have to re-think the green house plan.