A simple greenhouse design by Urban Farmer Curtis Stone that is fast and cheap to install. Also known as Caterpillar Tunnels. Cost is about $1,000 for a 12’ x 100’ poly tunnel made with 1-3/8” galvanized top rail tubing that’s used on chain link fences. Metal hoops are 4’ apart.
A polytunnel (hoop) greenhouse like this would be faster and easier to build than a dome. This particular polytunnel design is low cost, strong and easy to build. A greenhouse this size would provide more than enough fruit and vegetables for one family. Instead of bending galvanized pipe for the hoop sections, consider using gray plastic pipe or electrical conduit (polybutylene). I’m not sure how durable it is, but I have seen it used on hoop houses and it would be much easier to use.