A tidbit of info you might find useful if considering a poly covered green house. All the UV stabilized 6mil plastic I've seen for sale is rated at 4 year life span. So was the plastic I put on our hoop house November 2013. This week, I'm putting new plastic on the house, so the old has lasted right at 8 years, and honestly, seems to be in real good shape as I wad it up into trash bags......nothing at ALL like regular poly sheeting that is falling apart in a year or so after exposure to the sun. I've been feeling guilty thinking it was needing replacement a year or so ago, but finally got around to it this fall. My 'guess' is the stuff will likely go 10 years before really needing replacement....and maybe more ! I bought enough for this change and two more changes based on that 4 year thing, but good chance somebody is gonna get a real deal at the estate sale.......ahahhahaaaa.......
I agree with TnAndy as I also have direct experience with the Green House plastic. I also replaced my plastic after 6 years (5 winters and 6 summers, one of which was a record setting heat wave, a real drought in the 100's) of North Idaho weather and as long as you use good quality stuff, keep it away from falling branches, it will hold up. I have two hoop houses and replaced both this year but I truly believe I could have got a few more years out of both of them. I use standard old Home Depot 6mil poly plastic on the front and have had to replace it 4 or 5 times mainly due to the sun.
Use two layers of poly with air inflation. Lasts about 6 to 8 years before losing air if you buy IR resistant greenhouse plastic, it has drip, heat retention, and other choices.Looks good, neighbors grab used poly to use with low tunnels I build them using 1in electrical tubing and a bender from Lost Creek. SALE-SALE-SALE Lost Creek Hoop Bender Inner layer of poly is a toss up, either holes from rubbing or really good. Most people use the low tunnels a year or two and quit, but some others stick with it and expand with more units. Can cover with shade cloth or insect cover if desired. Lots of info on net about low tunnels, good season extenders, put layer of black plastic on dirt in spring and cover on hoop house and ground warms up quick, some protection from frost, milk jugs full of water will also help as well as a layer of frost guard over the top of that. Cloth isn't cheap, but lasts for years as you only use it for a short time, roll up and store out of sun. Gro-Guard Frost Cloth by Atmore is a trusted blanket by Atmore Industries Protect your Crop from FROST, INSECTS, EXTREME CHANGES in Weather and Heavy Rain! Other companies sell consumer amounts, but usually don't give you data, only hype. Concrete people grab used film for vapor barrier under concrete. You can reuse it. Don't throw it away, if you wish to use it around place, can cover wood piles under canvas, keeps from poking holes in canvas and doubles life, make temp sides on open buildings, a water still, etc.
Used a 5 year plastic on the greenhouse and got close to ten years out of it, bought supposed 4 year plastic didn't last a year. called the company and told to send pictures which I did never heard from th SOB's again. Bought 5 year plastic from a different company see how that goes --so far so good
Buy from man I bought greenhouse from and have been very happy. Some fly by nights out there with all the hype on Marijauana growing. Lots of expensive junk out there being sold by companies that supply sh**, go out of business and open up under a new name. Net is full of them. Old story, good quality, cheap price, good service, can only have two out of three.
I'm planning on building a greenhouse, but planning to use plexiglass...it costs more but I won't have to replace it. The plans that I have made are modelled on my house with the same siding, stone trim and shingles. The south facing wall will be plexiglass to take advantage of the winter sun. When not being used as a greenhouse I can remove the plexiglass and siding, install screened panels and have a screened shed. According to my current plans...about 2025.
