VPD

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formularacer

Well-Known Member
I have a question, it is an odd ball question as par for the course.

My VPD numbers swing .8 to 1.5 when the circulation fan stops for ten minutes each hour?
It climbs to 1.5 in the span of 7 minutes when fan stops once the fan starts it gets close to 1 and a minute or two after that it is at .8
So my question is will this be bad for the plant?
 
Blue brother

Blue brother

Well-Known Member
The fluctuation is caused by allowing the air to settle in the room (cold dry air sinks, hot humid air rises), for best results keep air mixing constantly.
 
F

formularacer

Well-Known Member
Billy the Mountain said:
Unlikely to cause any issue, but why run the fan 50min on/10min off?
Click to expand...
That is the way the programing is set up on the Vivosun. Think the purpose is to simulate outdoor conditions as it doesn't blow all the time.
I noticed this by going over the data. Just upgraded my humidifier so working on that baseline.
Thank you for your response.
 
Billy the Mountain

Billy the Mountain

Well-Known Member
formularacer said:
That is the way the programing is set up on the Vivosun. Think the purpose is to simulate outdoor conditions as it doesn't blow all the time.
I noticed this by going over the data. Just upgraded my humidifier so working on that baseline.
Thank you for your response.
Click to expand...
If that's the case, I would run it continuously and ignore Vivosun's poor analogy.
 
gooshpoo

gooshpoo

Well-Known Member
I am by no means an expert but i have been cracking out on youtube trying to get caught up on new trends and stuff. Harley stated in one of the many videos ive watched that you dont want more then a .4 swing in vpd or you can see noticeable negative effect. i took that to heart and have dumbed a shit ton of money into my 3x3 but i got it to hold a .8 with only a .05 variance. to do this i needed a new ac unit in the room. i live in high humidity so i needed a dehumidifier for the room aw well to keep it lower then the tent i keep the room at about 40%.

im using 2 6 inch fans inside the tent 6 inch exhaust fan, 4 inch intake fan and respected filters, a humidifier for the growtent. im also doing co2 just using a ac infinity ionframe evo 4 with plans on a uvb sub light for flower burst the 8 port controller from ac infinity is really nice aswell.
anyways i went on a tangent but thats the stuff i can think off im using and im having very little problem reaching my targets although i will say, the ac infinity controller seems a little off for me i have to set a .9 target in order to reach a steady .8 where im not running everything full blast. i have a happy medium fan kick on every 25 min for about 3min,
 
LeastExpectedGrower

LeastExpectedGrower

Well-Known Member
gooshpoo said:
I am by no means an expert but i have been cracking out on youtube trying to get caught up on new trends and stuff. Harley stated in one of the many videos ive watched that you dont want more then a .4 swing in vpd or you can see noticeable negative effect. i took that to heart and have dumbed a shit ton of money into my 3x3 but i got it to hold a .8 with only a .05 variance. to do this i needed a new ac unit in the room. i live in high humidity so i needed a dehumidifier for the room aw well to keep it lower then the tent i keep the room at about 40%.

im using 2 6 inch fans inside the tent 6 inch exhaust fan, 4 inch intake fan and respected filters, a humidifier for the growtent. im also doing co2 just using a ac infinity ionframe evo 4 with plans on a uvb sub light for flower burst the 8 port controller from ac infinity is really nice aswell.
anyways i went on a tangent but thats the stuff i can think off im using and im having very little problem reaching my targets although i will say, the ac infinity controller seems a little off for me i have to set a .9 target in order to reach a steady .8 where im not running everything full blast. i have a happy medium fan kick on every 25 min for about 3min,
Click to expand...
C02 in a tent...with intake...and exhaust...

Hrrrrm.
 
Blue brother

Blue brother

Well-Known Member
gooshpoo said:
I am by no means an expert but i have been cracking out on youtube trying to get caught up on new trends and stuff. Harley stated in one of the many videos ive watched that you dont want more then a .4 swing in vpd or you can see noticeable negative effect. i took that to heart and have dumbed a shit ton of money into my 3x3 but i got it to hold a .8 with only a .05 variance. to do this i needed a new ac unit in the room. i live in high humidity so i needed a dehumidifier for the room aw well to keep it lower then the tent i keep the room at about 40%.

im using 2 6 inch fans inside the tent 6 inch exhaust fan, 4 inch intake fan and respected filters, a humidifier for the growtent. im also doing co2 just using a ac infinity ionframe evo 4 with plans on a uvb sub light for flower burst the 8 port controller from ac infinity is really nice aswell.
anyways i went on a tangent but thats the stuff i can think off im using and im having very little problem reaching my targets although i will say, the ac infinity controller seems a little off for me i have to set a .9 target in order to reach a steady .8 where im not running everything full blast. i have a happy medium fan kick on every 25 min for about 3min,
Click to expand...
3x3 as in feet? If so man that’s a crazy amount of work you’ve put into something that size, I do agree that you will see a change in the plant even with small shifts in pressure. Stomata can close or open up quite quickly.

Just for the sake of science I put my probe right next to a branch around mid canopy and watched how the leaf changed posture as I manipulated vpd with a humidifier.
 
gooshpoo

gooshpoo

Well-Known Member
LeastExpectedGrower said:
C02 in a tent...with intake...and exhaust...

Hrrrrm.
Click to expand...
im really lucky my step father owns a welding company and has tons of co2 canisters, he just lets me exchange them out for free. but im not even sure im going to run the co2 this run im having an issue. its almost like the room itself is making co2. its in a ac room that i have a timer in to cycle fresh air into every 12 hours. the co2 will drop of course when the fan turns on. but as soon as its off the co2 levels are rising back up and leveling off between 1200 and 1500 outside of the tent...... i have put up 3 different co2 sensors and all of them are reading within 100 of each other. and i only have little babies right now so nothing to consume it. i triple checked my tanks aswell and all are well and shut off holding pressure so its not comming from the tanks. so im really at a loss on whats up with the co2 levels but im not gonna worry about itss free haha .
and as for my tent size its really all i have the room for right now. but i got everything i need for an easy upgrade in i find the room in the future XD for now im just having fun
 
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