Double Polyfilm Greenhouse
There are many benefits to polyfilm greenhouses. One thing is that some municipalities will consider this a temporary structure and will not require permits, wind and snow load ratings, etc. They are also less expensive than a rigid polycarbonate covered greenhouse. One disadvantage to this is that most of the greenhouse polyfilm found today has a 4 year UV protection, so you will have to figure on replacing the covering every so often. Double polyfilm greenhouses consist of 2 layers of polyfilm with an air inflation system for greenhouse film blowing air between the 2 layers. This will give you a much better R rating than just a single layer of film. Manufacturers claim that it can save you up to 40% of your energy costs. That is quite a considerable savings. I find that the inflated film is more rigid and less susceptible to damage than a single layer of film. This all happens without lowering the light transmission properties of the polyfilm. This is an excellent choice that has been used by many commercial growers through the years and is totally acceptable for a backyard greenhouse operation. Be sure to use greenhouse polyfilm that is UV protected and has an anti condensate coating on it. If the film is not UV protected you should not expect to get any more than one years use out of it, sometimes even less. The anti condensate coating keeps droplets from forming on the film. This will contribute to the overall health of your plants. Any condensation that does form on the roof will come off in sheets rather than in droplets. If you have water dripping on your plants you will have damage to your leaves, fruits, flowers and overall less healthy plants. So, when considering your first or next greenhouse, take a look at a double polyfilm greenhouse and see what benefits it will give you.