Greenhouse plastic - not renewable - alternatives?

Discussion in 'Planting, growing, nurturing Plants' started by NJNative, Dec 21, 2012.

  1. NJNative

    NJNative Junior Member

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    Hey everyone. I live in the cold temperate northeast U.S., and a big thing lately in this area is season extension using agricultural fabrics and mini-greenhouse row covers. This is becoming a crucial way of feeding ourselves year round, but a very depressing thought just dawned on me. These fabrics and plastics are made of petroleum. Also, they take a really long time to break down, releasing toxins in the process. Does anyone know of any non-petroleum based greenhouse plastics and agricultural fabrics, or possibly an alternative to these two. One obvious one that is abundant, although not renewable, is glass. However, this is very bulky and easily breakable. Other than that, I'm stumped. Any suggestions?
     
  2. Terra

    Terra Moderator

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    I think the obvious solution is to make greenhouse glass better , it certainly lasts we can make shatter proof glass for vehicle windows , bullet proof glass , glass that can withstand enormous forces in multi story buildings , so do what humans are good at invent the perfect glass for the job 8)

    But of course glass that lasts forever wont provide neverending economic growth and the plastic roll people will go broke and we will all be rooned .
    Rob
     
  3. NJNative

    NJNative Junior Member

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    This is very true. It seems like no one is using glass around here at all, except maybe this fancy nature conservancy. The main limitation to glass is that it's very expensive. However, the fact that they last 30+ years, vs 3-4 years for polyethylene, makes it worth it I suppose. The problem is coming up with the up front costs, which for a beginning farmer like myself is problematic.

    There is in fact an alternative to black plastic mulch, called Bio-agri, made by biobag. According to one source, up front, it's significantly more expensive than traditional black plastic, but if you factor in labor to remove plastic and disposal fees (which would not have to be done with bio-agri), it ends up being slightly cheaper. Here's a link for some more info:

    https://www.biobagusa.com/compostable-film.html
    https://www.novamont.com/default.asp?id=504

    This was actually not exactly what I was looking for (if I'm going to mulch, it will likely be with natural materials grown on site), but definitely on the right track. If there was a clear, uv transmittable version of this stuff, that lasted longer than one season, this would be ideal.

    In the mean time, I suppose glass is in fact the best bet, and rather than have in field row covers, sowing winter crops in greenhouses would be best. I wonder what the durability rating of a glass greenhouse is vs a plastic one. I recently heard of a grower who lost 7 out of 15 greenhouses in hurricane sandy. The monetary damage that that would equate to if the houses were glass would be monumental I would imagine.

    While we're on the subject, does anyone know the most durable greenhouse designs for storms? Would geodesic domes hold up better than a hoop house? Is there a particular model that holds up better than others?
     
  4. Dzionik

    Dzionik Junior Member

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    Polycarbonate is a better insulator and durable material, but also expensive.
    Type with a solid thermal north (or south :) wall and a sloping clear roof almost to the ground.
     
  5. NJNative

    NJNative Junior Member

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    Hmm...after doing some research, it turns out that polycarbonate is made with BPA, which is made with ethylene, which is made with propene, which is made with fossils fuels. So in addition to being made from a non-renewable source, it's quite a convoluted and energy intensive process to get to the final product. Not quite a recipe for sustainability. Thanks for the suggestion though!!
     
  6. pebble

    pebble Junior Member

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    Location:
    inland Otago, NZ
    Climate:
    Inland maritime/hot/dry/frosty
    How big a greenhouse do you need? People make good glasshouses from secondhand windows, very cheap. Lots of examples on the internet.

    re breakability, we had a glass house when I was growing up, and I think there were maybe two breakages over 15 years. It was more fragile than house glass, but you just take more care around it.

    If you go for new glass, then laminated auto glass is very good. It is two sheets of glass, laminated with a sheet of plastic in the middle. If it gets broken it holds itself together. It doesn't shatter like toughened glass, nor shard like ordinary glass, and you still have the pane reasonably intact in terms of weather, cold etc. Yes there is plastic in it, but it will last a very long time.


    Sharon Astyk has some good low tech ideas on season extension.
     
  7. Dzionik

    Dzionik Junior Member

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    There is really no alternative for now, except glass, everything else is on oil base. Bioplastics that are manufactured today are also unsustainable half oil half corn or sugar cane walking from Brazil to India over the U.S. etc. Polycarbonate is at least durable material and as such is a better choice than regular or "bioplastics."
     

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