I've seen 2 main different types of greenhouse poly used around here, or that's how it looks. One looks clear and the other opaque, as if made to diffuse light. On the other hand, maybe the opaque one is only translucent because it's double layered. On another thread in coop run and design someone just mentioned greenhouse panels, either a specific form of plexiglass or just plain ol' typical plexiglass, I dunno. Then there's glass itself. I hear it blocks UV plants need, so isn't right for greenhouse use. Indoor "house plants" seem to do fine from behind glass.
It's just that I've to redo an old dilapidated falling apart greenhouse and convert our chicken tractor into a cold frame and wonder if the food plants I want to grow are way better off with a certain poly, plexi or glass cover, or if it makes a difference and I can go with whatever on the cheap? I don't seem to have a pic of the greenhouse, probably cuz it's not pictureworthy, yet