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Geodesic greenhouse

topic posted Sat, January 10, 2009 - 7:45 AM by  AMANDA
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I bought a geodesic dome on ebay made of metal tubing. It is quite large and I was planing on covering it with plastic to make it into a green house. Problem is is when I did so the wind was able to get up under it and blow the damn thing over, ripping the plastic and twisting the tubing.ERRRRGH! So, I straighted it out, righted the structure and staked the mother down securely to the ground. Problem is is that it ripped up the plastic and now I have had to remove it all, a total waste of time and money. Now I have something resembling a giant jungle gym rather than a green house behind my house.
Does anyone have any suggestions on covering this monster?
Thanks
posted by:
AMANDA
New York
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  • Unless you can afford to frame and glass in the structure plastic is your best bet.. just how windy is it there?
    I would use a poly weave plastic it's stronger than normal plastic and can be bought in a piece big enough to cover the whole dome or seamed do you have a door? or were you planning on picking up the edge? or step through a section? your going to need a ventilation system when it gets warmer or you will cook your tender plants.
    • yes, I was planning on being able to roll up the sides about three feet or so.
      • yes I saw your photograph you do have a door, because its round you would have a hard time rolling it up so instead have your husband build a frame box to fit near the door and mount a box fan.. or if electric is not available then make the frame a window that can be opened and closed with an opposing one on the other side. If it gets too hot you open the windows and draft it.
        What are you using for tables? you should take into consideration what the drafting windows will do to the tender plants near it. so plan to not place anything near them until later when they are big enough to take a blast of cold. If you can do the box fan it wouldn't matter you will only be blowing out not taking in.
        • I also remembered a really good reason to put the vent doors in.. because the condensation that builds up in a greenhouse turns into drips.. drips are bad , you would think its ok its just rain but the fact is that drip can hold millions of pathogens that will kill your small plants. It causes mold which suffocates roots. etc.
          I did some searching for fasteners for the plastic.. I went to school for ornamental horticulture and worked in several large green houses. We used a number of different ways to hold the plastic on the best one was a tongue and groove metal fasteners that would go over the pipe holding the plastic between. We also used the wiggle wire.. I didnt care for that one as much I pinched my fingers too much trying to install it.. but it worked well. This supply house seemed to have the best information for the do it yourselfer.
          www.gothicarchgreenhouses.com/pol....htm

          ps they have the plastic repair tape you may be able to salvage the plastic you had..
          • I have had arguments for and against using marine shrink wrap. What are your thoughts on it? the plastic I had has turned brittle and useless. It has been a very frustrating waste of time and money so far.
            • never mind , I just scrolled down and saw your post .
              • usually the grade of plastic used in greenhouses will deteriorate within 3 to 4 years.. the sun is brutal.. which is why shrink wrap wont work for very long by shrinking it you already denatured the plastic. If you can afford to replace it yearly It might be more pleasing to the eye.. :)
  • Unsu...
     
    My suggestion is to get weather proofing plastic. Do it in long strips and use zip ties to secure it in place. then blow dry it to make a tighter fit over the dome.

    The problem seems to be that there is too much play in the plastic unless you just have really forceful winds. The more the plastic flaps in the wind, the more likely you are to have pockets of air get trapped and cause the whole thing to get ripped off. If you do it in strips and one gets ripped off, you can replace it much easier.

    If you cant do the glass framing thing, consider possibly plexiglass that is very cheap and can be cut to size. If you use liquid nail or gorilla glue you can secure it prettty tightly!
    • Unsu...
       
      House, has it. That heat shrink poly sheeting they use to winter boats - - if you can get it translucent or clear would be the ticket.

      I'd throw a berm of earth up around the edges to keep is from being blown over and draft free.
      • you should not use heat shrink plastic.. because it wont winter and you would need to replace it yearly.
        • Unsu...
           
          Any polymer that is flexible will "unzip" when exposed to the elements. The only plastic that I know of that can sit out in the sun is MethylMethaculate (acrylic / plexiglass / lucite). The UV from the sun unzips most polymers causing that familiar hazing that you'll see.
          The octal-Thylates in flexible polymers along with other plasticizers will sublime away too leaving it brittle.

          Any poly sheeting will have to be replaced rather often

  • I had the same problem here and I needed to make an extension in the roof that could lift up to let the wind out. The flap was still attached but sewn into place with nylon net sort of like a release valve. I think you're on the right track here by staking it down and all, but you really do need to vent a green house or you'll cook everything. if you can lift this roof flap at will , it will go along way toward venting( even using a long pole can work. If you're in Full sun you may also need to provide some shade during hot days. I've seen people use old bamboo shades for this.
  • That's a common problem at Burning Man. One solution is to reinforce the tubing with internal wire cables or strong nylon rope. To keep the whole structure from flying away, two foot long steel rebar stakes are pounded into the ground and the structure secured to them at every corner. Hope it works out as a geodesic greenhouse sounds really cool...
    • ,<Re: Geodesic greenhouse
      That's a common problem at Burning Man. One solution is to reinforce the tubing with internal wire cables or strong nylon rope. To keep the whole structure from flying away, two foot long steel rebar stakes are pounded into the ground and the structure secured to them at every corner. Hope it works out as a geodesic greenhouse sounds really cool...> ................................................................ .................................................................................. WHAT A GREAT IDEA!!!!.... There is one I know I'll use thanks Timbo
      • Just remember that you can't leave the rebar in the ground when your leave Burning Man. The BRC rangers can help you pull them out if you have problems pulling them out yourself. I seem to recall that we had a jeep with a winch on it to help accomplish the rebar removal for our dome...for the handful of stakes that wouldn't come out easily.

        Also, it helps if you have a candy cane profile to the rebar stakes so that people stumbling around the dome don't get skewered...and the hook in the rebar can be used to hook ropes, the dome, etc to etc, etc.
  • Create some type of wind block, at least on the north side. A hedge row or a block wall, maybe a fence, a wall could help reflect solar radiation if you do it right.

    I'd also consider having a bottom few pieces removable as well as a top one or two for venting. Figure a way to remove the plastic all together easily, if you know in advance of some high winds, just open the thing up, that's what professionals do. I think that if reinforcing the structure with guy wires is a good idea, presuming all your connections are secure and the steaks (rebar!) or forms are well attached to the ground.

    But keep in mind that the more structural components you have in your greenhouse the more light will be shaded from your plants. Different materials have different light transmittance characteristics, obviously you want something that seals well and allows the maximum light in the photosynthetic active radiation (PAR) obviously. I think if you dig with those key words you should get some listings. You will loose light if you double materials too. Plastic sheeting's work very well for sealing in air, glass or plexi-glass is generally more drafty due to the pane-joints. Plastic is cheap and if you replace it every year, you will probably have still spent less money after a few years than if you go with glass.

    So how big is this geo-dome?

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