Greenhouse Kits are a wonderful and easy way to add a small, medium or even large growing space to your veranda, patio or garden. They come in all shapes and sizes and coverings. Polyethylene plastic sheeting, or poly film, keeps the cost down and allows for more portability. Polycarbonate panels, on the other hand, last much longer, are stronger and can retain more heat. Whichever covering you choose make sure its UV protected preferably on both sides.