The exciting first step: laying out the site! The greenhouse will be parallel to the tool shed; its long axis will fall on an ENE - WSW line, which is pretty good, I think. This is the view from the patio:

Our building code requires the top of the footing to be 18" below ground. With an 8" deep footing, this meant a serious excavation project (well, no danger of heaving!):

And here is the poured concrete footing. It really wasn't a pretty baby blue color; I took this photo after getting home in the late afternoon. Some of he shade is cast by an old, overgrown apple tree, which I plan to have trimmed down this winter. The side of the tool shed is seen behind the piles of dirt.