I put together a 6X8 conventional model I purchased through Harbor Freight, when on sale. The Trust stipulations on the property won't allow any more permanent structures so I build it on 2 8'X4'X6" skids, thus making it movable. I had built a new Chicken house this spring so that the chicken yard is cut in half and I can rotate pasture, on the now idle side I had 8 volunteer tomato plants start growing. Since it was the beginning of October I dug them up and replanted them into my new green house. They whilted a bit but 7 made it trough the shock of transplant and I now have 2 flowering with the others showing signs. I wonder what kinds they will turn out to be and how long I can keep the going in the green house. This is my first stab at growing in a green house so I'll be happy with whatever I get. I consider it practice for next year.
Last year, after the 1st frost, I picked about 12 lbs of green tomatoes and made a large batch of Green Tomato Relish like my grandmother used to make. May do the same with those in the green house if they come on strong or start to fade before getting ripe.