High Humidity

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plantbased_growva

Member
kod42 said:
I was worrying about this not long ago, but I was told if you have a inline fan sucking air out the amount needed within minute.... And if you have fans pushing air around. You will not have to worry much about humidity use a vpd chart and that will help you!
vpdchart.com

VPD Chart

Vapor pressure deficit (VPD) chart & calculator for horticulture in controlled environment. Cannabis, tomatoes, leafy greens, cucumber.
vpdchart.com vpdchart.com
Here is a vpd chart, make sure you switch it to flower so it's accurate
Click to expand...
Whoa this is something I’ve never seen or hear of!!! Thanks!
 
MissinThe90’sStrains

MissinThe90’sStrains

Well-Known Member
You need to be able to bring fresh air into your grow space, and vent the “old” air out. You need both circulation AND ventilation. Also, what is the RH% of your room outside of the grow space? If you’re in a humid climate, and you’re pulling in humid air to your grow space, you might need a big dehumidifier in the room where your grow space is located.
 
LeastExpectedGrower

LeastExpectedGrower

Well-Known Member
Do you have a window in the room that you can run a duct and vent out of? That's the quick fix. If the room your tent in is enclosed (the door is shut) you're just dumping humidity back into the room and sucking it back into the tent. Ideally, your moisture is going outside of your 'lungroom' and you're managing some of the humidity by drawing in dry air from the room itself.
 
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plantbased_growva

Member
LeastExpectedGrower said:
Do you have a window in the room that you can run a duct and vent out of? That's the quick fix. If the room your tent in is enclosed (the door is shut) you're just dumping humidity back into the room and sucking it back into the tent. Ideally, your moisture is going outside of your 'lungroom' and you're managing some of the humidity by drawing in dry air from the room itself.
Click to expand...
Yeah, I’m trying to figure out the logistics of what I’m gonna do for this, but I can make something work!!
 
LeastExpectedGrower

LeastExpectedGrower

Well-Known Member
HydroKid239 said:
It’s my understanding that the AC infinity controller is set to 67% rh.. I would set it to 40% & exhaust that ducting out a window.
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Yes. Exactly. I set mine for a few % less than I really want it then it has room to ramp up a little if needed. The nice thing about the newest app & controllers is that it also calculates VPD and graphs it, so you can really zero in on a good place.

OP, this is what I have running:
Exhausting out my tent:

IMG_4411.jpg
^ I built a little baffle board that fits the ducting exactly and fits snuggly in the window opening. It has some foam stuffed in the edges where the windows leave a gap so it's sealed. Duct runs are as short as possible (helps with air flow) and as straight as possible.

v Inside the tent I DO have a filter, my AC-I T-6 mounted:
IMG_4413.jpg

I also have an intake fan (AC-I S-6) that's pulling air into the tent from the room as well. That's on the floor outside the tent, with a short duct that's raised so I don't get a ton of floor-dust.

I dehumidify the whole basement level when needed (only summer) to keep the air dry enough for everything including the grow tent. I have a very small humidifier inside the tent should that be needed, but it really only uses about 1l per week or so these days.
 
P

plantbased_growva

Member
LeastExpectedGrower said:
Yes. Exactly. I set mine for a few % less than I really want it then it has room to ramp up a little if needed. The nice thing about the newest app & controllers is that it also calculates VPD and graphs it, so you can really zero in on a good place.

OP, this is what I have running:
Exhausting out my tent:

View attachment 5217935
^ I built a little baffle board that fits the ducting exactly and fits snuggly in the window opening. It has some foam stuffed in the edges where the windows leave a gap so it's sealed. Duct runs are as short as possible (helps with air flow) and as straight as possible.

v Inside the tent I DO have a filter, my AC-I T-6 mounted:
View attachment 5217936

I also have an intake fan (AC-I S-6) that's pulling air into the tent from the room as well. That's on the floor outside the tent, with a short duct that's raised so I don't get a ton of floor-dust.

I dehumidify the whole basement level when needed (only summer) to keep the air dry enough for everything including the grow tent. I have a very small humidifier inside the tent should that be needed, but it really only uses about 1l per week or so these days.
Click to expand...
I’m struggling with being able to vent outside in this room is the problem. I may have to set up my operation in another place.
 
LeastExpectedGrower

LeastExpectedGrower

Well-Known Member
plantbased_growva said:
I’m struggling with being able to vent outside in this room is the problem. I may have to set up my operation in another place.
Click to expand...
Yeah, I picked the room that was warmest in the winter, coolest in the summer and had perfect window access. Then bought the tent to fit the size/shape of the room. For me that's basement level and in my utilities room.
 
Star Dog

Star Dog

Well-Known Member
plantbased_growva said:
Whoa this is something I’ve never seen or hear of!!! Thanks!
Click to expand...
I wouldn't take that too seriously, if you can line up the figures then great, if you can't it's not a make or break scenario.

I can only ever get near vpd in summer and only during veg, during flowering I've not a snowballs chance in hell of reaching suggested vpd figures.

A few pics.

Diary and other stuff.

A couple of days after cutting back that plant I noticed it was a bit wilty. Later that evening I looked again and knew something wasn't right, it had wilted further, it was time to panic! I pulled it out thinking possible root rot with the low temps and frequent feeding but no the roots are...
www.rollitup.org
 
kod42

kod42

Well-Known Member
plantbased_growva said:
Whoa this is something I’ve never seen or hear of!!! Thanks!
Click to expand...
Ofc! I do have to air vents on the bottom with the ducting that comes with the fans so it's sucking air out through the top and with the negative pressure it's sucking fresh air in thru the 2 bottom ductings
 
kod42

kod42

Well-Known Member
Star Dog said:
I wouldn't take that too seriously, if you can line up the figures then great, if you can't it's not a make or break scenario.

I can only ever get near vpd in summer and only during veg, during flowering I've not a snowballs chance in hell of reaching suggested vpd figures.

A few pics.

Diary and other stuff.

A couple of days after cutting back that plant I noticed it was a bit wilty. Later that evening I looked again and knew something wasn't right, it had wilted further, it was time to panic! I pulled it out thinking possible root rot with the low temps and frequent feeding but no the roots are...
www.rollitup.org
Click to expand...
Yes it's pretty hard to keep on track unless early veg but it's kind of a good guideline to show you where you should be if humidity super high etc...
 
Star Dog

Star Dog

Well-Known Member
kod42 said:
Yes it's pretty hard to keep on track unless early veg but it's kind of a good guideline to show you where you should be if humidity super high etc...
Click to expand...
Yeah absolutely, I'd like to be able to keep vpd in the suggested range but it's 85/95% rh pretty much continously here, even with a dehumidifier running 63% is the best figure for the last two crops.
 
bubblescrogs

bubblescrogs

Well-Known Member
plantbased_growva said:
Doh!!! I bought this small one because of humidity issues in my dry tent but then started having issues in my grow. Will be purchasing a new (bigger) one today!! Thanks!
Click to expand...
yeah you need both ideally for different stages. I need a humidifier for the first few weeks of veg and then it flips to needing a dehumidifier once you've got a decent amount of leaves transpiring in there. Mine sits at 50% at the moment but will shoot straight up to 90% a few minutes after the dehuey is switched off
 
weedstoner420

weedstoner420

Well-Known Member
As others have said you probably need a bigger dehumidifier (I think I have a 70-pint one in my unfinished basement). And you can put it outside of the tent to save space. If you're in a basement with a utility sink or sump hole, just hook up a hose and have it drain there so you don't have to empty it every day.

It's fine to exhaust into the same room you're pulling air in from, but keep in mind the RH inside the tent is never gonna be below the RH of the room it's in, like if the RH in the room is 75%, that's the lowest you're gonna see it get in the tent.
 
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