So I surveyed my "junk stash" and came up with an old cattle panel that had been on the place when I bought it. A couple of neighbors donated two more panels for which they had no use.
First I laid some black landscaping fabric on the ground and let it lay through the summer months to kill all vegetation on the greenhouse "floor."
In the fall I drove eight steel fence posts in the ground, four on each side of the planned structure. They are placed at the two ends of the structure, and at the places where the panels meet along each side. I calculated that a floorspace of approximately 14 feet long and six feet wide would create an arch that reached just over six feet at its highest point.
Placing one end of each panel at the base of two fence posts, I then arched the panel until its other end was inside two fence posts on the other side of the greenhouse. The panels were tied together using plastic zip strips.
Using scrap lumber and an old storm window, I framed and mounted the storm window in the back end of the greenhouse. I also had a spare lightweight aluminum storm door so I framed it into the front end of the structure.
Some old foam pipe insulation served to protect the ends of the cattle panel so my cover wouldn't get torn by friction.
I purchased a roll of 6 mil. clear plastic and spread it over the entire structure, fastening it to the wooden framework that I had installed for the window and the door.
The greenhouse has only one layer of plastic covering now, and I need to add a second layer and some kind of inflating fan in order to provide a longer "greenhouse season."
Total cost out-of-pocket for this fun little greenhouse was about $10, which was the cost of the plastic for covering. All other materials came from my junk piles or the junk piles of my neighbors. Even if I'd had to buy the materials, this would still have been only a small fraction of the cost of a commercial greenhouse of the same size.
