I,ve always gotten along just fine without a greenhouse. Recently I've found the need to wanting a greenhouse, cheap but also large that can at least hold up for a couple years or more.
Ive recently been looking into polyethylene cloth, (plastic with mesh). I was curious if this would last long enough and whether or not there is a spray that is uv protective for this kind of material. If so without damaging it, what brand has a good uv sun protectant?