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Shade cloth percenage for Green house

Glad to hear it  .
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Originally Posted by snaglpus
I would love to have mine have a max temp inside of 90 degrees on a 90 degree day. Any ideas?


Even 90% shade cloth won't get you the same temp inside as out when you are relying on passive ventillation for cooling. Reason: the only way passive removes any heat is if it's warmer inside than out. Warmer air is lighter so moves out the top while cooler outside air moves in the bottom.

If you want inside temp same as out you need evaporative cooling. The most efficient has large exhaust fans on one end blowing hot air outside. On the opposite end is a wet wall that intake air is pulled thru. This is the system I have and depending on dew point I can keep it cooler inside than out with no shade cloth.

90% shade cloth is only necessary if the cooling system is very inefficient. For passive cooling there needs to be large openings for hot air to move out the top and cool air in the bottom. The pictured greenhouse looks to only have an open door.

90% shade is fine for non producing figs but will limit fruit production. 50-60% is enough shade for a properly ventillated greenhouse. But it will still be 10-15F warmer inside than out, same as 90% shade and poor ventillation.
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Great input Steve!  I like that!  Thanks!!!!
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Dennis, do you think your plants in the potting mix with perlite or dark pots would have done OK with an automated watering system?
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Hey Dennis, Steve is right on. You have no air movement, so you will have a very difficult time finding the correct balance of light/heat without it.

Because the greenhouse doesn't have an end wall louver, maybe get a oscilating fan which you can mount on the back wall and blow the air out through the front door to have some circulation and put in on a basic on / off timer. The Air King wall mount fan on ebay is going the be the best bang for you buck, and very affordable for $44 bucks. In addition, this is the time of year for grey mold. High humidity and very little air flow to dry things out is a breeding ground for fungus and other headaches. Grey mold wiped out almost all of my tomatoes last year due to lack of air movement...lesson learned!

AIR KING 9018 Wall Mount Fan
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Thanks Mike!  You guys are correct.  I just did not have enough air flow inside the GH.  The photos I posted doesn't show the whole picture.  There is a pop-up window and a fan on the floor.  The idea was to pull the cool air in from the door and push out the hot air from the top.  It did not work well at all.  So, I pulled every tree out and presently redesigning the air movement.  

I have 2 Air King pedestal fans for my large GH but not for this one.  Yesterday I purchased 4 - 12 inch shelter logic fans.  These will be mounted on the sides and back of the GH and should give me the air flow needed for this GH.  

Thanks everyone for your comments.  they are very much appreciated!!!

cheers!
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