Excessive Heat/Low Humidity

[BobSwizzle420]

I am having excessive heat issues and low humidity issues. I started with a 3X3 grow tent with 400W MH so it was easy to vent out heat and open the tent when the lights were on to be able to get some "intake." However, I have recently expanded my grow area and now use my tent for a veg/clone chamber and use the rest of the room for a flowering room. I added a 600W HPS for flowering. I am having issues in the flowering room as temps are getting up as high as 90deg and humidity as low as 30%. Plants are showing signs of heat stress and also showing a little bit of nute burn because they are using up more water. The room is about 720 sq ft. I feel I have enough equipment to be able to deal with this, but it's not setup right? I have a fan that is too big...it pulls 400 and some CFM, I also have a smaller booster fan that pulls about 240 CFM. Originally I was using the booster for just the tent and the big fan for the rest of the room. But it was pulling out just about all of the humidity...so i added a small humidifier, but it's not able to keep up with amount of heat generated. I also tried an air conditioner to keep it cooler, however, it also pulls all the humidity out. There are no windows in the room, and keeping the door open pulls in dry air. I do have a hole in the wall that vents air out, but I don't know how I should set this up...any help would be appreciated.

BobSwizzle420 Reviewed by BobSwizzle420 on 10-02-2012. Excessive Heat/Low Humidity I am having excessive heat issues and low humidity issues. I started with a 3X3 grow tent with 400W MH so it was easy to vent out heat and open the tent when the lights were on to be able to get some "intake." However, I have recently expanded my grow area and now use my tent for a veg/clone chamber and use the rest of the room for a flowering room. I added a 600W HPS for flowering. I am having issues in the flowering room as temps are getting up as high as 90deg and humidity as low as 30%. Rating: 5

[BobSwizzle420]

EDIT....NOT 720 SQ ft...the room is about 720 CUBIC ft.

[drew225]

First off, I am a Newbie grower so I am nowhere near an expert, but I just went through this same problem (my tent is about a 1/3 of your size) so I think I can offer some help. First off let me ask if you have your intake drawing in nice cool air from the outside? Also if your having a temperature problem in a larger room you should have a fan capable of evacuating the room at least 3-5 times a minute for optimal cooling. That means your fan should pull anywhere from 2160-3600 cfm a minute. Most budgets don't allow that, so you should have a fan at least capable of 720 cfm which is 1 time a minute. If your using the booster fan as an active intake that should help your more. Also is you exhaust/intake system ran in a closed loop? Meaning your intake is drawn throuh the vent the goes straight through the cooling tubes on your lights and out the exhaust? That should help cool it down as well and will keep up the humidity. Hooking it up that way along with running your ac at times (if the temp spikes up a bit during the day) should get your temp. to where you want to be and still keep it humid enough. Hope this helps feel free to ask anymore question if I didn't cover enough

[low_rdr]

Personally using a room grow I would use the window air unit. Most newer AC's have a great little tool that hardly anyone notices right in the duct that points into the room, there should be a plastic piece in the middle (if your using 12000BTU's or higher) that can be opened or closed - This actually determines where the AC unit gets the air from to condition.

If its pulled out, your pulling air from the outside, conditioning it, and putting it into the room, if its pushed in (comes stock this way) your pulling the air from the room, cycling it, and distributing it, thus sucking out most of the moisture in the room.

There are other options as well, misting fans for cattle have high air flow, and will keep a light mist on the plants, this can of course make them sweat which we don't want, however, if you place the fan correctly and have it set to minimal misting, you should keep your humidity levels up. Check for the plug on the AC first, that might help.

I am using a 12k BTU Haier which ran about $300 I think (somewhere in that range, I know I paid 550 for 2, and one is 10k btus)
The cattle fans can go for as little as $50 and as much as a few thousand - Beyond that point, you can also use a steamer in the room on a timer, this will also help with your humidity levels (I would say a humidifier, but honestly, a vics vaporizer would do just fine on a timer, 20 minutes every few hours or as needed) Those only run about $15

[drew225]

Personally using a room grow I would use the window air unit. Most newer AC's have a great little tool that hardly anyone notices right in the duct that points into the room, there should be a plastic piece in the middle (if your using 12000BTU's or higher) that can be opened or closed - This actually determines where the AC unit gets the air from to condition.

If its pulled out, your pulling air from the outside, conditioning it, and putting it into the room, if its pushed in (comes stock this way) your pulling the air from the room, cycling it, and distributing it, thus sucking out most of the moisture in the room.

There are other options as well, misting fans for cattle have high air flow, and will keep a light mist on the plants, this can of course make them sweat which we don't want, however, if you place the fan correctly and have it set to minimal misting, you should keep your humidity levels up. Check for the plug on the AC first, that might help.

I am using a 12k BTU Haier which ran about $300 I think (somewhere in that range, I know I paid 550 for 2, and one is 10k btus)
The cattle fans can go for as little as $50 and as much as a few thousand - Beyond that point, you can also use a steamer in the room on a timer, this will also help with your humidity levels (I would say a humidifier, but honestly, a vics vaporizer would do just fine on a timer, 20 minutes every few hours or as needed) Those only run about $15

How would I know if mine has one? Mine is a portable LG rated at 9k btu

[low_rdr]

I looked it up, and it has an auto evap system (at least the newer ones do) - SOL on that one, nice unit though, I might get one myself. If you goto page 10 of the Q&A section, someone asked how they could intake from an alternate source, LG responded that this unit isn't capable of that. (sorry)

Source:

LG LP0910WNR: 9,000 BTU Portable Air Conditioner with remote | LG USA

Not sure if I did that right, if this needs to be moderated to fix the link, please do so.

[low_rdr]

Meant to edit again but it took too long -

If you lower the temps with the air conditioner, won't the humidity balance out after a stable room temp is met???

[drew225]

Meant to edit again but it took too long -

If you lower the temps with the air conditioner, won't the humidity balance out after a stable room temp is met???

Not sure if your talking to me or bswizzel up there but id say yes. At least mine has! I have been now able to keep the humidity beteween 40-70% depending on if it night or daytime. If it gets too high I just turn on the ac and it sucks some of the humidity out.

[low_rdr]

There ya go

See, sometimes we just worry too much

[bedrik]

Well just relax do not take tensions.