This afternoon the weather was okay for outdoor work, and I had the time to begin the assembly of a greenhouse. My original plan was to make a 12 x 12-foot structure but the pipe and four-way coupler materials were so cheap I got materials for a 12 x 36 one. This is as simple as a greenhouse can get. I never saw one like this one but it seems like a logical way to construct one.
It consists of iron construction rebar, plastic water pipe, plastic four-way connectors, and six mil plastic greenhouse film. After measuring out the site and squaring it up, I hammered into the ground three-foot-long rebar at a slight angle every three feet along the sides. It seemed reasonable to tilt them a little to ease the stress on the plastic and to make a wider greenhouse.
The tubes slip directly onto the rebar sticking out of the ground and form an arch. The rope was strung thru the top connectors previously while it was still lying on the ground. After the arch was in place, rebar was driven into the ground where the tip of the rope is seen and it was tied to that rebar and tightened to similarly buried rebar at the other end. That rope will give the whole structure some stability in the wind.
[The next day I added another arch at both ends and when tensioning the rope discovered that the arches needed vertical supports to prevent them from being pulled down too much. Just visible on the right edge is a red bucket and barely visible going out of the picture is a 1½ inch PVC tube attached to it. That tube was just right for supporting an arch.]
After all of the fussing around getting the materials together, it took only an hour to assemble the greenhouse frame.