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shade cloth question

Discussion in 'Introduce Yourself' started by nightwings, Jun 3, 2016.

  1. nightwings

    nightwings New Member

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    I have a small 6 X10 lean to greenhouse in Sonora, MX and heat control i stay main problem. I have auto vent openers in the roof, a auto vent fan and screen window in the door. Also have installed a misting system on an hourly timer to spray the gravel floor, a circulating fan and an evaporative cooler. I added 60% black shad cloth to the top and 50% on the side facing west on a shade house frame about a foot away from the greenhouse walls. Despite all of this and extra spraying, the heat climbs above 90F in the afternoon. So next I bought a 60% aluminum net shade cloth and placed it in the greenhouse just below the double polycarb walls, but it doesn't seem to be helping a whole lot. it has been a few degrees warmer lately but the inside temps will not stay below 90 in the pm (upper half of GH). Would it be better to place it on the shade house frame to deflect the radiation before it actually enters the greenhouse? Not sure what else I can do to defeat the heat until the humidity jumps up later in the summer.
    Hopefully I can get an affordable solution, other than building an air conditioned dome over my back yard (just kidding).
     
  2. carl

    carl Active Member

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    Make sure your shade cloth is not resting on the roof, but is rather suspended some distance above it.

    That allows for an insulating air layer under the cloth. Resting on the roof, it helps heat the inside.
     
  3. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Put the aluminet on the outside, on top of the black shade cloth. As Carl said, if you can raise all of the shade cloth off of the roof, that would really help.
     
  4. Ray

    Ray Orchid Iconoclast Supporting Member

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    Black shade cloth works by converting the light energy into heat. Aluminet works by reflecting it away.

    Don't forget that stacking shade cloth multiplies the shade: 60% Aluminet allows 40% to pass. The 60% black cloth underneath will allow 40% of that to pass, leaving you with the equivalent of 84% shade.
     
  5. nightwings

    nightwings New Member

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    Thanks for the input! I decided to move the aluminet out of the GH to above the black shade cloth this morning, so I moved all of my plants out of the way and reinstalled the aluminet outside. I already had a shade house frame up over the GH about 8-12", so that did leave an airspace, as you both mentioned. I suspected that might be the case. Other than that, everything else is the same as the last two days (except the outside temperature). Well by noon we hit 108F outside, but the inside temperature was staying in mid-80s so far. It looks like that was a good move. This is unusual weather for this time of year, as usually the humidity is much higher by now and that moderates the max temps more. These hot dry winds are something new.
     
  6. nightwings

    nightwings New Member

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    I was wondering about how much light I would be losing, but the heat issue has much bigger in my mind. I may remove some of the lower side shade cloth to allow more light in in the later afternoon. Once the humidity comes up, I move some of the Cats, Dendrobiums and Vandas out to the shade house with some misting and a fan.
     
  7. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Glad to hear that helped.

    On my intermediate house (the most recently built and the only one where I know exactly what % of shade cloth I have) has a first layer of 40%, a 2nd layer of 40% and a 3rd layer of 50% for effectively 82% shade. It is good for me for the summer. In September I will start removing layers until I get down to just one for the winter. All are aluminet.
     
  8. nightwings

    nightwings New Member

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    That is interesting, so I will see how my mixed house does with what I have. My temperatures right now at 10:00am vary from 77 to 87 degrees F. I moved an extra misting system between the shade cloth and the GH across about mid-point and up both sides, including a little overhang on the south side. That is reducing the amount of micro-managing I had to do yesterday when we had 35-40 kph winds, 15% RH and up to 107 degrees!