High Humidity... I need some advice please.

sencinitas · Aug 1, 2011

Hi. I have a 5x10 tent. It currently has a 4x4 table in it. I've been vegging a variety of plants for a bout a month now and I'm just about ready to flower but I can't seem to get my humidity down. :cry:

I'm starting to develop some P.M. My Room stays around 60-65% humidity most of the time but it raises alot at night (up to 80 % :!:

I've put ALOT of time and money and effort into these babies so I don't want to flower them until I've the the RH under complete control.

I live in Coastal So Ca. About 1.5 miles from the beach and the humidity is generally somewhat high anyways. My tent is in a bedroom and the bedroom has a large open window. I think this causes more humidity in the room also because of the temp difference. I have a portable a/c in the tent and that keeps the humidity down to about sixtyish but it's not perfect. It does not have a humidity sensor on it so when the temps dip below what the thermostats set to the a/c shuts off and my humidity goes WAY up.

My Res. is a 100 litre (bout 55 gal or so) res and sits under my table. I do not have it covered and realize that this is contributing to the problem. I am planning on getting a new res with lid today.

I currently have a 4" 172ish (not sure exactly, too stoned to check) cfm Vortex exhasting the tent.

Should I get a bigger exhaust fan, maybe an intake?

Or should I invest in a dehumidifier? I can get one that is WAY MORE than sufficient for about $120 bucks at a local store.

Oh... and what RH should I aim for so I can avoid this PM from spreading any more.

Any help or advice will be much appreciated.

Thanks
:peace:

&

jondamon · Aug 1, 2011

You are probably not exhausting enough air out.

IF you tent is 5x10x6 then you need 300CFM's to exchange the air once a minute.

I am guessing it is 6ft high correct me if i am wrong.

If you then add a carbon filter onto the exhaust this reduces the CFMs by 20% so your 300CFM fan then would only be 240CFM's so you would need 350CFMs for air exchange once a minute.

Is this making sense?

RUN your exhaust 24/7 and uprate your exhaust system and you should find that your humidity will decrease. However an open lid on a res creates evapouration thus making more moisture in your air. (make sure you get the lid)

Keep your oscilating fans on 24/7 too this will help disperse the stagnant air at night and during the day.

J

jondamon · Aug 1, 2011

RH during veg can be between 30%-65% with perfect being 55% during lights on

RH during flower should be ideally low 40%'s.

RH will rise during the dark cycle but you should still try to keep it below 65%.

J

sencinitas · Aug 1, 2011

Hey, wassup Jondamon. Thanks for the info(+rep). My tent's actually 7 ft high but it doesn't make that much of a difference, I get your point. I'm going to grab a 6" can max fan too then and I'll run both fans at the same time. If ventilation is the issue then that should be more than enough. I was originally told to exchange the air in the room once every five minutes so I thought my fan was plenty strong enough. This is my first grow by the way. I plan to post a journal as soon as I switch it to flower.

I'm Off to the hydro store now. I'll be back in the morning (to the forum not from the store...ha) and post how it went in case anyone reading is having the same issue.

tibberous · Aug 1, 2011

I read the title and my first thought was: "Tell your mom to close her legs". I was going to post that, but it seemed a little mean

Do you know what the RH outside the tent is staying at? Fans are the way to go (cheaper and use way less electric), but they aren't going to do anything if the air you are sucking in is as humid as the air you are pulling out, and the fact you already have a fan in a relatively small tent makes me think that a bigger fan probably won't help. You are actually exhausting the air outside, right? Not just outside of the tent?

WeeGogs · Aug 2, 2011

sencinitas said:
Hi. I have a 5x10 tent. It currently has a 4x4 table in it. I've been vegging a variety of plants for a bout a month now and I'm just about ready to flower but I can't seem to get my humidity down. I'm starting to develop some P.M. My Room stays around 60-65% humidity most of the time but it raises alot at night (up to 80 %I've put ALOT of time and money and effort into these babies so I don't want to flower them until I've the the RH under complete control.

I live in Coastal So Ca. About 1.5 miles from the beach and the humidity is generally somewhat high anyways. My tent is in a bedroom and the bedroom has a large open window. I think this causes more humidity in the room also because of the temp difference. I have a portable a/c in the tent and that keeps the humidity down to about sixtyish but it's not perfect. It does not have a humidity sensor on it so when the temps dip below what the thermostats set to the a/c shuts off and my humidity goes WAY up.

My Res. is a 100 litre (bout 55 gal or so) res and sits under my table. I do not have it covered and realize that this is contributing to the problem. I am planning on getting a new res with lid today.

I currently have a 4" 172ish (not sure exactly, too stoned to check) cfm Vortex exhasting the tent.

Should I get a bigger exhaust fan, maybe an intake?

Or should I invest in a dehumidifier? I can get one that is WAY MORE than sufficient for about $120 bucks at a local store.

Oh... and what RH should I aim for so I can avoid this PM from spreading any more.

Any help or advice will be much appreciated.

Thanks
&

raise your plants as high of the floor as possible, in my room at night the rh is 80% on the floor, 60% at central height and only 45 at the ceiling, weird? well water is heavier than air.
then buy a small humidifier.

High Humidity... I need some advice please.

sencinitas

Member

jondamon

Well-Known Member

jondamon

Well-Known Member

sencinitas

Member

tibberous

Well-Known Member

WeeGogs

Active Member

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