Gramps had a cool one made of two sheets of clear plastic on a stick frame with fir strapping to help keep it tight. we grew all winter long in Massachusetts when i was a kid.
When I inherited Gramps and Grandma's place this is what i would do.. I used to take long maple saplings about twelve feet or so would get about fourteen or so lay two opposing with the widest branches cut off and set aside. then twist the tops together tie it off with grape vines still green and then stick each bottom end in the ground forming a hoop about 8 feet tall in the center. Repeat till the length of the new shelter is to my liking. Take the side branches and weave to make the vertical structure stable. Tie off with grape vines. Cover in plastics 2 layers add door frame of your choice secure plastic at bottom with sand dirt log etc and ta da gorgeous custom greenhouse, come spring remove plastic and ta da gorgeous vine support. Come August and your peas and squash and tomatoes are all over it and you have a seat or two underneath in the evening, glass of wine a bowl of the one hit wonder and a few friends. Bonus points if you would dig out the floor so it was sunk two or three feet below ground level for extra thermal protection like grandpa and eventually, I, would do. It is very beautiful, environmentally sound and works like a champ. Screw catalogs and that mini Vanderbuilt wanna be stuff get close to the ground man, its our heritage...peace