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10-09-2009, 03:47 AM
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#1 |
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legalize
Join Date: Feb 2007
Location: west coast,canada
Posts: 300
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hoophouse cold at night
my hoop house is cold at night but it only has 3.5 mil poly on it so should i add more layers of poly ? will that keep it warmer at night and i am also getting alot of moisture on the inside of the plastic is that because of the heat loss at night
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10-09-2009, 09:27 AM
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#2 |
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Member
Join Date: Mar 2007
Posts: 233
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Hi Cave
Upgrading the covering to a double poly (inflated) would help. Other options are adding a metallized night curtain and suspending lightweight fleece over the plants. The moisture on the inside of the poly is caused by the relatively humid air cooling to dewpoint when it hits the cold surface. As the air cools the RH increases to 100% the water then condenses out on the poly. It gives up a vast amount of energy in the process (latent heat) which is instantly lost through the glazing. Inflated double poly helps keep the inside layer slightly warmer which makes it harder for the air to drop to dewpoint...generating less condensation 
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10-09-2009, 04:43 PM
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#3 |
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Rancher
Join Date: May 2009
Location: Chasing Hybrid Vigor
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Double 6-mil poly with inflation fan is the only way to go to get true "season extension" and reduce the rampant outbreak of the dreaded bud eating fungus.....
I also employ a small space heater to reduce drastic temp swings in October, heed the words of Me2's post..... Hope things turn out ok for you!
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10-09-2009, 06:24 PM
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#4 |
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Member
Join Date: Mar 2007
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If you use any form of greenhouse heating, a radiant barrier made from mylar,reflectix or similar is a good investment. Clear night skies allow the greenhouse to radiate heat directly into outer space..its pretty cold out there.
After a clear night, it can actually feel warmer outside the greenhouse than inside due to radiant cooling 
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10-10-2009, 02:20 AM
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#5 |
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legalize
Join Date: Feb 2007
Location: west coast,canada
Posts: 300
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thanks everyone
what do you mean by inflated like puting a fan in there or what
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10-10-2009, 04:09 AM
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#6 | |
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Analrapist
Join Date: Mar 2004
Location: ...With the Barkers and the coloured balloons
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Quote:
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"What, then, do they want a government for? Not to regulate commerce; not to educate the people; not to teach religion; not to administer charity; not to make roads and railways; but simply to defend the natural rights of man - to protect person and property - to prevent the aggressions of the powerful upon the weak - in a word, to administer justice. This is the natural, the original, office of a government. It was not intended to do less: it ought not to be allowed to do more " - Herbert Spencer |
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10-10-2009, 10:02 AM
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#7 |
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Join Date: Mar 2007
Posts: 233
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Double poly uses two covers with a small blower to create a still air space between the two sheets. You get a couple of extra bonuses..the air pressure keeps the poly under tension so it doesn`t flap in the wind which will destroy it pretty fast and it will absorb gusts of wind.. a little like a car airbag in reverse..it cushions the hit and then instantly re-inflates
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03-08-2010, 10:38 PM
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#8 |
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Member
Join Date: Mar 2010
Posts: 34
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I was thinking of going bubble wrap too. However I went with 12 mil poly.
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