Humidity issue from exhaust fan, any suggestions?

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Username85

Well-Known Member
So I'm just setting up a new grow tent in a new space and I've been battling low humidity. I purchased a small humidifier which works well on its own.
When I turn the exhaust fan on, on lowest setting, the humidity drops down to around 45~40; is that too low to keep the humidity?
 
VincenzioVonHook

VincenzioVonHook

Well-Known Member
What stage of plant? Seedlings and week 1-3 veg like humidity around 50-65%, and during flower 40-50 is perfectly fine, and even strived for, my housemate prefers humidity around 35-40 in late flower. Even if your humidity is 40-50 during veg, just give them some foliar feeding, make sure the medium is moist and you will be fine.

In my opinion that isn't too dry to the point of worry yet. I wish I was in your boat. Its been around 80-100% humidity for the last week, and averaging 70% for the weeks previous. Throw in temps around 33-35c and I have the worst environment inside my tent. Luckily it's 28 now, but is reading 96% here.

Despite being the worst environment, no nutes and hard as hell water, the plant is looking amazing.
 
U

Username85

Well-Known Member
VincenzioVonHook said:
What stage of plant? Seedlings and week 1-3 veg like humidity around 50-65%, and during flower 40-50 is perfectly fine, and even strived for, my housemate prefers humidity around 35-40 in late flower. Even if your humidity is 40-50 during veg, just give them some foliar feeding, make sure the medium is moist and you will be fine.

In my opinion that isn't too dry to the point of worry yet. I wish I was in your boat. Its been around 80-100% humidity for the last week, and averaging 70% for the weeks previous. Throw in temps around 33-35c and I have the worst environment inside my tent. Luckily it's 28 now, but is reading 96% here.

Despite being the worst environment, no nutes and hard as hell water, the plant is looking amazing.
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I'm still in the seedling stage, actually just planted my popped seeds a day ago, which is why I was trying to make sure I wasn't making a mistake so early on.
Last year I was battling with too much humidity, I can say too little is much easier to deal with.
Thanks for the info
 
VincenzioVonHook

VincenzioVonHook

Well-Known Member
Username85 said:
I'm still in the seedling stage, actually just planted my popped seeds a day ago, which is why I was trying to make sure I wasn't making a mistake so early on.
Last year I was battling with too much humidity, I can say too little is much easier to deal with.
Thanks for the info
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That being said, you could always hang a damp towel over all the intake holes and it should give you a few percent increase in humidity, especially if you put damp cloth over the bottom window intakes and exhaust from the top.

My old housemate used to grow smack bang at 50% throughout the whole grow and he had some of the nicest weed i have ever smoked.

I've had really good luck so far with bad humidity, and I'm waiting for it to finally give in and destroy my efforts. This was two bag seed plants that spent the majority of their life in rain, 30-35c days, and averaged humidity of 80% or more for a large portion of their life.
 

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TacoMac

TacoMac

Well-Known Member
Username85 said:
When I turn the exhaust fan on, on lowest setting, the humidity drops down to around 45~40; is that too low to keep the humidity?
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In a word, yes. That's drying level humidity.

Put a baffle over the intake port on the tent. That will slow down the air flow a bit and increase your humidity.
 
Arkos

Arkos

Well-Known Member
Take that household/office humidifier and use it for that, your house.

Get one that's made for growing, more efficient, less likely to get super hot and start a fire...

I had one I thought was doing a splendid job, until the reservoir starting melting...

Edit: Fingers too fat for typing :lol:
 
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nobighurry

Well-Known Member
Put a humidity controller on you exhaust fan, then invest in a larger humidifier, I use a simple 1 gal humidifier, if you really want to maximize seedling & veg growth use the VPD chart..,, yes you absolutely can grow without paying any attention to humidity but wait until you see how healthy mad fast they can grow....
 
U

Username85

Well-Known Member
TacoMac said:
In a word, yes. That's drying level humidity.

Put a baffle over the intake port on the tent. That will slow down the air flow a bit and increase your humidity.
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Is it possible to rig something to partially block the exhaust fan, or is that a hazard in the making?
I was going to try and punch some holes in a piece of cardboard and slip it over the exhaust fan intake making it suck up less air. I don't want to overwork my motor and cause any potential fire hazards though.
 
F

Fast Money

Member
Username85 said:
So I'm just setting up a new grow tent in a new space and I've been battling low humidity. I purchased a small humidifier which works well on its own.
When I turn the exhaust fan on, on lowest setting, the humidity drops down to around 45~40; is that too low to keep the humidity?
Click to expand...
You need a humidity controller. Your exhaust fan doesn’t need to be on 24/7, only when humidity or temp gets too high.
 
TacoMac

TacoMac

Well-Known Member
You don't want to block the exhaust fan.

You baffle the intake as I stated.

If you block the fan the force of the air blowing back against it will overheat it and can cause problems.

If you restrict the intake by, say, putting a rolled up towel in it blocking half of it then you reduce the fresh dry air taken in and the fan tends to recirculate the air already in the tent which will result in the humidity increasing.

You'll just have to play with how much to baffle the intake to achieve the desired humidity level.
 
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