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Grow Tent Low Humidity Indoors - Suggestions?


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#1
RiffsandSpliffs

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Hey guys, thanks for taking the time to inquire!

My problem is humidity. I am consistently running around 30% in the vegetative stage, which is about 35% below where I want to be. I can see signs of humidity stress on the leaves. I even bought a nice humidifier today that runs for 24 hours and it managed to raise the humidity levels in my 4x4x7 tent by 1 percentile.

I have a 4 x 4 x 7ft grow tent indoors. All the air vent have been duct-taped off for an air-tighter seal. I run a Sunblaze T5 4'x8 lamp fluorescent fixture in vegetative, and a 600w HPS (6" air-cooled SunSystems Blazer reflector) during flower.

Currently, temperature is not an issue. I pull in cold winter air for my intake. My intake fan runs at 160cfm. It might run a bit slower, because it's a duct booster fan that I have put a small screen on the intake side to keep dust and bugs out. It runs for 24 hours.

My exhaust fan is a 190cfm inline model with a 4"x12" carbon filter attached to it. I'm assuming it doesn't really pull out 190cfm. The fan is manufactured by MTN Gearsmith. It runs for 24 hours.

What gives? Is there a timer that I can hook up both my intake and exhaust to, that will turn them on for 1 minute, every 5 minutes? Is that even the cause of the low humidity? Or are there other factors I'm not considering. :confused:

#2
tothehead

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humidity stress on the leaves?

my entire setup, veg & flower, pretty much run 35-40% humidity constantly. i personally dont have problems.

do you have some pictures of your plants?

#3
jPinkham

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I thought around 40% humidity was good? My room varies from 48-55 and I try to lower it

#4
RiffsandSpliffs

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I'm pretty sure the standard is 60-70% RH in vegetative and 40-60% during flower.

#5
jPinkham

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Ohh ok thank you I wasn't positive

#6
indic4

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I'm pretty sure the standard is 60-70% RH in vegetative and 40-60% during flower.


Wow, that is begging for mold issues. Keep it under 50% for all stages especially flower. You could creep into 60% tops in veg but 70% is nutty.

#7
RiffsandSpliffs

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Okay, so I'm guessing below 40% is the norm for indoor growers, and I'm comfortable with knowing that.

#8
wittakush

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My humidity is about 64 when lights turn on and about 2 hrs into the lights being on it levels out at about 56 to even 58 sometimes. It's not a problem.

#9
Doc-J

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The reason your humidity is so low is because your pulling in cool intake air from outside. Cold air doesnt have the ability to hold moisture, so you get the lower rh. Humidifiers cant compensate as well in low temps either.

#10
DTM420

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veg 40-60 rh. flower 35-50


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