So I have a 2x4x5 tent in my garage. Two 435 cfm fans, one sucking air from the light & top of the tent & the other blowing fresh air in from outside. I'm currently in week two of flower and my lights run from 18:00-06:00 but still during the peak heat of the day (around 16:00) the tent is getting into the low 90's. I understand I would have to cool the tent internal air and the only way I can think is to get a small ac unit and vent the cool air into the tent from that. During the night time (lights on) the tent drops slowly back down to around 58-62. I've noticed some of the lower fan leaves on my indices are showing the slightest signs of clawing. I'm not sure if it's from the heat, but I think it may be. My question is should I be worried about the tent being in the low 90's for those three peak hours of the day? I live in Nor Cal and the hot summer is on it's way 100's+ on occasion. Help me..?
Use your fan to blow air out of tent instead of sucking air inside. I had a similar issue when I started. Are you sucking and blowing air from outside? Try that
im sucking air from outdoors and blowing it into the bottom of the tent and sucking the hot air from the top of the tent and exhausting outdoors. My garage has two low vents in the wall that are pretty convenient. It's the surrounding room temp and outdoor temp that is screwing me. SHould I worry about cooling the air or is low 90's for 3-6 hours a day no big deal?
your plants will survive in that temperature. my plants are currently in flower and i have had them in 100degree temp before. but i just open up my tent when that occurs. a lot of people freak out because they just take the "generally accepted" answer . there's common sense as well. good luck, but don't sweat it. the more you try to help, the worse it will be. leave the plant be and just sit back and water.
Farout man. I was hoping it wasn't too big a deal. It's reassuring to read that you have been above 100F and still okay. And yes, I read 72-76 in my Cannabible and have been obsessing over the numbers. I'd just like to do everything right the first time although I doubt it will happen. Thanks again! Gonna go smoke a monster bowl now that that's off my shoulders. Peace!
Cannabis is a fairly durable plant, it can sustain temps around 100f, but high temps can stress the plants, lower THC %, and cause negative effects to the plant. If you regularly monitor your plants, you can tell if when they are stressed and when you need to improve their conditions. With every grow, whether your 1st or 1000th, you learn valuable information. At high temps, the plants have a high survival rate, but may not produce the amount or quality it has potential to yield. For best results I would recommend 70-85f for light and @65f for dark. I've worked with A/C's in similar conditions and they end up wasting time and money. You can try ventilating the actual garage, if room temp is causing high temp. My advice is improve your setup with each grow until you gain the perfect combo for your climate/strain. What strains you growing, any pics???
Thanks for the advice Jenkinz. I'm not quite sure where I'd even start with ventilating a whole garage. That seems like it could get a bit expensive. If you know a cheap way please do share. The lower leaves of my plants are beginning to claw a little. I am growing three different strains. Sour Flower, God's Gift, and Blue Diesel. Here are some pics of the girls and my setup (left to right: BD, SF, GG). Also, the green fan is intake and the black fan is exhaust.
That plant looks healthy. Are you using big lights(hps/mh) that produce lots of heat? If so, are they enclosed in a hood or cooling tube? If not, you can get a cooling tube fairly cheap, dedicate one of your fans to sucking the air out of the tube(intake/exhaust outside) and the other fan sucking air to the plants. What is dimensions of your garage? Large rooms are tough to cool, and usually require large exhaust. Since your grow is enclosed, could you open a door or window and use a standard fan to exhaust. Can you adjust your light timer to be off at peak temperatures?
I am using a 600w HPS in a glass enclosed hood. I have one end of the ducting off the hood as you can see in the 6th picture and the black fan is sucking the air from the hood and through the opening on the other end of the hood (being the hot air from the top of the tent). The light is running 12/12 currently and it comes on at 18:15 and shuts off at 06:15, so it is running during non-peak hours. If I moved the schedule any further (i.e 21:00-09:00 it would be hard to maintenance them with my schedule. My garage is roughly 22ft. x 20ft and there is a side door I could open to vent the hot air out of with a floor fan I suppose but I do not feel comfortable leaving the side door open while I am at work. =/ My garage stays pretty dark (thanks to me light proofing) so I suppose I could get a portable ac and open the tent during the day and have that blowing on them in the dark (as the unit will not fit in the tent).
You should attach your exhaust vent directly to the light hood. I have a separate vent running to and out of my sealed hood, and another just air flow in the room. So my suggestion would be to attach exhaust to one side of hood, and intake air with the other fan(intake to lower part of tent). What I did to solve my heat problem was run vent to my hood from outdoors, run vent from my hood to a inline fan that exhausts air outside. So my hood is sealed off from my grow area. I have another fan that filters and exhausts the air in the grow area. This got my temps down to 85f on a 100f+ day. I tried big windows A/C unit, but it made little to no difference and dramatically raised humidity. I think you can get temps down if you rethink how you do the vents.
Hey Cali I'd do exactly what thurgood said, the whole point of a cool tube or air cooled hood is to run vents to them so the heat they produce is pulled directly out as its being generated. That alone should dramatically reduce ur temps, for extra insurance just get a regular box or slim fan and put it directly on the plants on a low setting good luck and tell us how it worked out.
@ Thurgood The setup you are describing is the way I used to have my tent setup aside from the fact that I had my other fan pulling the hot air from the top of the tent and venting it outdoors. That setup was creating a negative pressure environment inside the tent forcing the tent to pull air from inside the garage from small screen vents in the bottom to displace the air being pulled out. From my understanding you are suggesting I revert back to that setup but I simply make my fan suck air from outdoors and blow it into the bottom of the tent, correct? Also, you say your tent stays around 85 on 100+ days. How is it that a tent surrounded by 100+ degree air is remaining at 85 with a fan blowing 100+ degree air into it? Is there a factor I am not considering? Perhaps that speeding up the velocity of the flow cools it down before it enters the tent? IDK. Anyhow, here are some pics of how my tent WAS setup. In tyne picture the black fan is pulling the hot air from the top of the tent and the green fan is blowing air through the hood so that the hot air the light produces never enters the tent.
So I spoke with my dad today and he convinced me that the only way I could efficiently cool my tent was with a window ac unit. I am broke as hell right now and cannot afford one however, before I could tell him he offered to pay for it. I'll repay him with a nice ounce of my (hopefully FIRE!) harvest in the end =] So I went out and bought a 5,000 BTU window AC for $135.00 and performed my best Oakland Engineering skills out and cut a "X" in the lower right side of my tent and duct taped the 4 flaps to the outside of the AC unit. And I did it all in the pitch black oven of a garage. Garage is steady running at 100 degrees while the girls remain in a nice constantly cool 77 degree Oasis. Thanks dad! Pics later, for some reason it's giving me an error right now.. =/
For the tent vent I was suggesting pulling air from outside rather than your garage, which would be hotter. Also actually moving the air can drop it 5f-10f. I'm glad you found something that works. Do you have some kind of drip tray for that a/c unit? Those wires are right beside the a/c on the floor, you may have something setup already, but if not get a drip tray/water line or maybe hang those wires on a nail bout a foot off the ground. Only other thing I can think of is humidity rises because the a/c unit. Update us when you can and good luck!
All pictures were taken immediately after I finished the unit installation and the job wasn't 100% cleaned up but it is now. I had to connect the unit to an extension cord that i ran up and over the rafters to an outlet on the other side of my garage (so I didn't overload one outlet). I have yet to see any condensation production from the unit but I put a small pan under the unit incase any arises. As far as humidity goes in the tent my thermostat is reading 30-40% which is a little low for flowering (from my personal reading), but hopefully the unit will increase the humidity 10-20%. The 26% humidity level you see on my thermometer is of the garages humidity, it doesn't read the outdoor humidity levels. Thanks all for the continued advice on everything, it was much appreciated. So far so good. No more stressing over the girls, for now...
40% isn't bad for flowering, i usually lower mine(dehumidifier) in flowering to help with mold prevention. Those a/cs usually will have a hole on the back underside corner for draining the water they accumulate. My advice is to strive to improve your setup with each grow. Good luck with this and future grows!
Well, that's good to hear. I suppose I'll just let em be for now. I'm sure a new problem will arise soon enough. Ill check out the unit and look for that drain spout and see if I can't get the pan directly under it. As far as constant improvement goes I am always working on that and thinking of the best and most efficient ways to do things, especially when it comes to the repetitive tasks and issues. Thanks again Thurgood! Happy growing! Peace!