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#1
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Advice sought on large hoophouse
The neighbor has two 40X40 (all units in feet here and after) sheets
of clear poly that he will give me, since he sees that I have tunnels for my winter vegetables (this year I will get to harvest until end of january at least, he actually told me as I was getting back into the house with a paint bucket full of just picked radicchio). I just love these hot stove projects, but before I embark in it, a question or two for those who have built hoophouses. 1) those sheets are clearly very large. If used without cutting, they will cover a 24X38 area, with a maximum height of 12. That is an unusually wide hoophouse. 2) I think I want to use PVC pipes, glued with plumbing solvent. The question is, can I make them withstand a windstorm or snowstorm. I have seen lots of pages on the web, so I have seen what can be done. Amongst other solutions, I noticed that there were hoophouses with poles supporting the central beam, and of course one can always anchor the hoops to the ground. I guess I am more concerned about the snow than the wind. 3) I am thinking about getting a double layer of poly for extra insulation. Any experience with that? I would need a double hoophouse. 4) I plan to make two trap doors at opposite ends, and have one set of doors with poly and another with chicken wire. Will there be enough ventilation with the chicken wire doors in place? |
#2
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Advice sought on large hoophouse
In article ,
simy1 wrote: The neighbor has two 40X40 (all units in feet here and after) sheets of clear poly that he will give me, since he sees that I have tunnels for my winter vegetables (this year I will get to harvest until end of january at least, he actually told me as I was getting back into the house with a paint bucket full of just picked radicchio). I just love these hot stove projects, but before I embark in it, a question or two for those who have built hoophouses. 1) those sheets are clearly very large. If used without cutting, they will cover a 24X38 area, with a maximum height of 12. That is an unusually wide hoophouse. That is HUGE! 2) I think I want to use PVC pipes, glued with plumbing solvent. The question is, can I make them withstand a windstorm or snowstorm. I have seen lots of pages on the web, so I have seen what can be done. Amongst other solutions, I noticed that there were hoophouses with poles supporting the central beam, and of course one can always anchor the hoops to the ground. I guess I am more concerned about the snow than the wind. PVC works well for smaller units, but I think (guess) that this is too big for snow. Even wind can be tough, though IMHE putting guy lines between the hoops can make a world of difference -- there's just too much tension in the plastic to depend on attaching to the perimeter of the material, even if the tension is distributed by tape over a relatively broad periferal area. You didn't say anything about where you live (e.g. frequency/magnitude of snowfalls) nor how much spacing you might have between hoops. My guess is -- if there's a chance of having 6" or more of wet snow, it will probably be more stress than any reasonable PVC system could withstand. 3) I am thinking about getting a double layer of poly for extra insulation. Any experience with that? I would need a double hoophouse. 4) I plan to make two trap doors at opposite ends, and have one set of doors with poly and another with chicken wire. Will there be enough ventilation with the chicken wire doors in place? Might you get a warm sunny day? It's incredible how much heat you can build up in one of these. Doors might be enough if you could supplement with a fan. How big might these trap doors be? ---- What about cutting the 40x40 into two 40x20's, and make 2 hoop-houses? (Long, not wide). If the snow isn't too heavy, there might be a chance... Good luck! -frank -- |
#4
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Advice sought on large hoophouse
simy1 wrote:
The neighbor has two 40X40 (all units in feet here and after) sheets of clear poly that he will give me, since he sees that I have tunnels for my winter vegetables (this year I will get to harvest until end of january at least, he actually told me as I was getting back into the house with a paint bucket full of just picked radicchio). I just love these hot stove projects, but before I embark in it, a question or two for those who have built hoophouses. 1) those sheets are clearly very large. If used without cutting, they will cover a 24X38 area, with a maximum height of 12. That is an unusually wide hoophouse. 2) I think I want to use PVC pipes, glued with plumbing solvent. The question is, can I make them withstand a windstorm or snowstorm. I have seen lots of pages on the web, so I have seen what can be done. Amongst other solutions, I noticed that there were hoophouses with poles supporting the central beam, and of course one can always anchor the hoops to the ground. I guess I am more concerned about the snow than the wind. 3) I am thinking about getting a double layer of poly for extra insulation. Any experience with that? I would need a double hoophouse. 4) I plan to make two trap doors at opposite ends, and have one set of doors with poly and another with chicken wire. Will there be enough ventilation with the chicken wire doors in place? Before you start building with PVC take a look at this hoophouse: http://www2.moment.net/~wingnut/hoophouse.htm Bill |
#5
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Advice sought on large hoophouse
Bill Bolle wrote in message ...
Before you start building with PVC take a look at this hoophouse: http://www2.moment.net/~wingnut/hoophouse.htm Bill nice site, thank you. Indeed cattle panels could be a better choice. |
#6
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Advice sought on large hoophouse
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#7
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Advice sought on large hoophouse
Bill Bolle wrote in message ...
Before you start building with PVC take a look at this hoophouse: http://www2.moment.net/~wingnut/hoophouse.htm Bill some more considerations that will probably interest only backyard hobbyists: 1) the link above uses cattle panels (basically very strong rebar), and (this is important) they bend them quite a bit, so the hoophouse is taller than a semicylinder. The rebar then provides some tension to push up against the snow, in fact they easily hang pots onto the rebar without having the house sag. But, if you want to use the soil, you have less area underneath. I suppose the tradeoff between tension and surface is inevitable. Incidentally, my 11 feet PVC hoops don't do that. After two years at most the take a permanent hoop shape. They are still strong enough to shed snow without collapse. Rebar also provides excellent support to the poly, effectively preventing pooling of water or accumulation of snow. 2) when using the rebar, they have two problems. The first is that all sorts of of rough spots will scratch and break the plastic. IMHO, this is the perfect place where to use that old hose you have in your garage. Slit it lengthwise and fit it over the ends. The second is that they have trouble clamping onto the rebar. the PVC clamps are great (amongst other things, they are capable of holding the plastic even when the wind is blowing from the inside, such as may happen when one leaves an opening after harvest) but alas, only come in PVC sizes (3/4 and 1). Probably just a matter of clamping a PVC pipe to the rebar on the inside, then clamp the poly on the pipe (that will be a pain when one removes the poly for the summer, but safe until then. Various other issues include anchoring the whole thing (probably enough to bury a few cinder blocks around the perimeter, with hooks at the surface for strapping), double layering (do the second layer inside, it will sag, do it outside, it will sag and touch the first), chicken wiring (when I take off the poly, I still want the rabbits out of my garden), and how to do the ends. Nice clean design overall. |
#8
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Advice sought on large hoophouse
Bill Bolle wrote in message ...
Before you start building with PVC take a look at this hoophouse: http://www2.moment.net/~wingnut/hoophouse.htm Bill I am settled on the cattle panel hoophouse (a PVC one has too many techincal problems which I won't mention here, though I will use PVC pipes at the edges for the clamping of poly). One last question: the hoophouses( two of them, each 38X12, side by side), should be oriented N-S or E-W? Light hitting the poly at an angle below 40 degrees is totally reflected. |
#9
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Advice sought on large hoophouse
simy1 wrote:
Bill Bolle wrote in message ... Before you start building with PVC take a look at this hoophouse: http://www2.moment.net/~wingnut/hoophouse.htm Bill I am settled on the cattle panel hoophouse (a PVC one has too many techincal problems which I won't mention here, though I will use PVC pipes at the edges for the clamping of poly). One last question: the hoophouses( two of them, each 38X12, side by side), should be oriented N-S or E-W? Light hitting the poly at an angle below 40 degrees is totally reflected. I really don't know which way would be the best-----I've seen greenhouses around here pointing in all sorts of directions, based mostly, I guess, on the topography of their land. Logically I would assume that the benefits of a hoophouse would be in its use during the winter and I think that with low sun angles that you would get the best perpendicular angle of the suns rays with a East/West orientation. One problem with E/W would be that the hoophouses would have to be end to end and not side by side. For what it's worth-------Bill |
#10
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Advice sought on large hoophouse
Bill Bolle wrote in message ...
simy1 wrote: Bill Bolle wrote in message ... I really don't know which way would be the best-----I've seen greenhouses around here pointing in all sorts of directions, based mostly, I guess, on the topography of their land. Logically I would assume that the benefits of a hoophouse would be in its use during the winter and I think that with low sun angles that you would get the best perpendicular angle of the suns rays with a East/West orientation. One problem with E/W would be that the hoophouses would have to be end to end and not side by side. For what it's worth-------Bill Yes and no. In Zone 6, one would use a greenhouse for, say, tomatoes, until June 1. At that point in Ann Arbor the sun is 71 degrees over the horizon at noon. Also in the winter one has plants that grow during the growing season (mostly), and are kept alive for consumption through the winter. In winter, a N-S house will have shade near the edges on the N side. In May, it will have shade along most of the edges. Then again this is the kind of midday shade many plants actually want. A E-W house will have little shade in winter but all edges will be shaded in May. not much difference. It seems like one is better off orienting the house so as to have the broad side against the prevailing winds. So I will orient it NE-SW... |
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