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Vapour Pressure Deficit or VPD for short !

vpd humidity temp growing environment

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#1 Roy Cropper

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Posted 13 January 2018 - 04:23 PM

had this on the computer for ages now, been meaning to upload it,

 

basically, without all the science (as i don't know science, just cafe's), this is a chart to show the optimum humidity and temp for growing bud !  

 

Attached File  IMG_8509.jpg   330.86KB   0 downloads

 

and heres some science about it !


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#2 Roy Cropper

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Posted 13 January 2018 - 04:27 PM

at the end of the video it says that if your leaf is hotter than the air in the room then your lights are too close ! never thought of that before ! ever ! makes sense tho eh ! 


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#3 Anonymiss

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Posted 13 January 2018 - 05:02 PM

at the end of the video it says that if your leaf is hotter than the air in the room then your lights are too close !

 
That may be true but, it would be very difficult to keep the canopy foliage below the air temperature whilst still providing sufficient illumination.

After all, in nature, anything in direct sunlight, including leaves, is likely get warmer than the surrounding air.
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#4 HanShotFirst

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Posted 13 January 2018 - 05:19 PM

at the end of the video it says that if your leaf is hotter than the air in the room then your lights are too close ! never thought of that before ! ever ! makes sense tho eh ! 

 

Maybe try using a laser thermometer to take temp readings off your leaves Roy. It really helps me dial in my air temps and helps me to not be concerned with some things that can warm up my grow room.

 

My atmospheric controller and wall mount thermometer gives me one air temp reading measured at the canopy level but I can say with certain, depending on the zone I take a reading, there's about 10 variations of temps in my room spanning about a 15-20 degree swing in temps.

 

So by taking my readings off the leaves I can dial in my room almost to perfection. My room may be at 82-90F (27-32c) with an upswing of temps around the lights but as long as the leaf temps are at 77F (25c) I disregard those high number readings off the thermostat and controller and adjust according to the leaf temps


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#5 Scone

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Posted 14 January 2018 - 02:41 AM

"Scone you switched off your thermo-lazarmagadjet, what's wrong"

 

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Nothing. I'm all right.

 

Use the force Luke, visualize that missile plunging into the tight quivering thermal exhaust port of the Death Star as it braces itself in anticipation.  

 

gallery_1415_625_21465.jpg

 

Sweat beads up on Vader's brow as you slide your X-Wing gently up the Maridian Trench inching ever closer to the vulerable exhaust port, your missile throbbing as you grip the control stick.

 

 

Come on Obi Wan, your messing with me, this is serious.

 

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To Obi Wan you must listen, Deep into the exhaust port you must ram your missile.

 

 

Come On Obe Wan, that doesn't even Sound like Yoda.

 

 


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#6 Doublej

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Posted 14 January 2018 - 03:53 AM

I need some of you you got man...
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#7 Scone

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Posted 14 January 2018 - 04:47 AM

The World

 

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needs some of what I've got.

 

If your pot ain't all it should be now
This girl could put it right
I'll show you what it could be now
Just give me one Light
 
 
 

 

 


Edited by Scone, 14 January 2018 - 04:47 AM.

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Also tagged with one or more of these keywords: vpd, humidity, temp, growing environment

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