Can anyone tell me their experiences with different plastic coverings for greenhouses. This year we've built the structure (I've got to get a picture for you) with the vegetable garden growing beneath. I am getting cross-eyed looking for information on decent plastic to cover this greenhouse through this next winter. Next year we will use that double layered hard plastic. But just want a good, CLEAR? plastic to last for this winter. We'll be heating this structure...last year in October we got a snowfall that collapsed our 'polytunnel'...any ideas will be helpful.
They make "overwintering film" (4mil, I think) which is supposed to work for 1 season. I have no experience with it.
I have considerable experience (by now) with 4-year, 6 mil, IR-UV-AntiDrip greenhouse poly, which I think has been typically 11 cents a square foot, and it beats the heck out of using 6 mil untreated builders poly (vapor barrier plastic.)
Attachments are key - you need to attach the film in such a way that the loads are spread out so the plastic does not simply tear out the fasteners. Rolling it around a wooden batten and nailing through the batten, special wiggle-wire channels, there are various means. Using a double layer and inflating the space between is helpful if you can afford ~50 watts of blower 24/7/365.
I've had more trouble with wind ripping it off (see, "attachments!!") than snow loads - it's on 4 foot spacing, metal supports and I have at times wondered about the frame taking the load, but the film sure takes it just fine if it's attached.
Window-like clarity and good greenhouse film do not go hand in hand, from what I understand. Some films are even treated for extra diffusion.