my 4x4 grow tent is in my finished basement which is usually cool but we’ve had a few heatwaves where temps in the room got up to 75-78 f which caused temps in my tent to hit upper 80’s. i run quantum boards, 4 inch inline fan vented outside the house and 2 smaller fans for air flow in the tent. i figure i have 3 options to cool it down- 1. a portables ac unit inside the tent. which seems like a bad idea for many reasons. 2. a window ac to cool the basement which would work but would be a large upfront investment as i would need a pretty high btu unit due to the size of the basement as well as an added expense to the utility bill. which brings me to my 3rd option- what if i simply upgrade to a more powerful 6 inch inline fan? i realize i will never be able to make the tent cooler than the room it’s in but i can live with 75 to 78. i just grew out 2 valley kush 1.0 which showed signs of heat stress at anything above 80. the other 2 plants were gelat og and the were much more tolerant... anyways this seems like the least expensive option. will it be enough to keep me below 80 as long as the room the tent is in stays below 80? i’m also considering moving the drivers to the outside of the tent. thanks for any imput!
i understand a bigger fan wont cool the air but would it keep it moving fast enough so that it didn’t heat up inside my tent? if i can keep the temps to within a few degrees of the temperature of the room the tent is in i’ll be content. by small ac i assume you mean one of the portable units that have a hose that you vent out a window? other than not wanting to give up that much real estate inside the tent i’ve read that putting an ac inside the tent really isn’t a great idea. have you tried this with success? thanks for the response!
you are running quantum board light. optimum temps for the plants under the LED lighting mis actually in the 78-82f range. The plants prefer a higher temp under the LED's than under HID which you were better having temps no higher than 78f. if you can keep temps in your tent anywhere from mid-70's to 82f you will be fine and don't need to spend money on ac units and extra money to run ac units. the 4" fan might be a bit small for your 4x4 tent, a 6 might be a bit of a better solution, I bet that 4" has to run max speed to keep up. especially since you said you already can vent outside, you should be able to exhaust the excess heat out and keep your tent pretty close to the basement ambient temp. and yes, moving the drivers outside the tent will definitely help also. my tent is in an upstairs bedroom. ambient room tent already starts around 73-75f. no way to vent outside the house, not even outside the room. my tent never get hotter than 80-81f on the hottest days. usually is around 77-79f in the tent. 2x4 tent with a 4" fan. I also run QB lights
A couple things... Do you think the field crop in Columbia ever have to exist in in the high 80s? Of course it does. I assume your light schedule has things dark during the heat of the day. The only time I veg 18/6 is in the summer and I schedule that 6 when heat is at its peak. Similar in flower...lights on at night. During this time of year I am generally fighting even higher temps than you describe and I have found that keeping my medium always moist is the best deterrent to heat stress. You don't mention your medium but I am in peat/perlite and I up my perlite in the summer also so I can water more often. Lastly, do you have a freezer? I have a cooler set up as a filter box on my intake and when things get really bad I put ice in it (actually 2 frozen, 2 gallon jugs)) and it knocks about 10 degrees off my room. Bottom line though is I wish a few days inn the high 80 was my problem. The filter box: https://forum.grasscity.com/attachments/0126191415-jpg.2563461/
I agree with all. Yes a 6 inch may be better suited to a 4x4, but that is just more watts in your tent. Nothing beats ambient air. I have done about every experiment. The lowest return is blowing more out. The highest return is blowing cool in. Lower ambient solves everything. But I can almost guarantee, when you spend all your money and are finally ready to set all the temps and speeds, it will be unusually cool in your area. And you will be hoping for another heat wave to see for sure if all the stuff you bought works. I hear ya, but I found no better solution than to turn down the a/c and give it to the electricity company. The upper limit for indoor growing is 90f before you risk damage to some components. Autos have saved my ass many times because I can just turn all the lights off and air out anytime it gets serious, and my plants start showing heat stress at 84f indoors under artificial.
If you have the spread, and you can dim your lights, lower them a bit and dial them down 10-20% Your plants won't even notice, in fact might even do better because they are in a more friendly temp zone and still getting roughly the same intensity of light hitting them.
