That particular plastic sheeting was from the local home improvement store. You can special order a roll if they don't have the size you want in stock. It is 6 mil. Do not even consider 3 mil b/c it will shred in a breeze. 4 mil could hold up for a season if you are careful. You can also get greenhouse plastic (UV treated) from Gardener's Supply Co.

Took some pix a week ago but didn't get 'em posted yet. Sorry - busy! Of course now things are getting a little bigger.