Has anyone built a greenhouse using discarded sliding glass doors?
Haven't yet, but plan to. A friend did it and it looks and works great. He even used two sets on the roof - replaced the glass with plexiglass - so can open when it gets too hot. He used aluminum framing - like for a carport and spaced the frame so the doors would fit (used a double carport frame that he extended 6 feet) and used clear plastic siding to fill in the spaces above doors and on the ends. It looks really nice.
glass gets to hot and will burn the plants unless you have a temp control