Question about grow room temperature

A question from a fellow grower:

One of my tents I can not get the temperature down to 80*. It is at 84*. I have two fans in it. I know the higher temps will slow the grow down.
How bad is 84*? My other two tents are at 75* which I know is good.

84f is a bit high, but the plant can adapt, as long as the RH% is not extremely high.

RH (relative humidity) is going to be hard to keep down at 84°F. Can you get more AC in there?

I just bought a exhaust fan. Should be here on Friday. I am hoping that will bring the temp. down. No way of getting a AC in there and right now with all I have going on my cost is way up there. I have three tents. One for cloning and germinating, the second for the next level and then a 4X4 Tent for flowering.

My humidity is good. 60% I leave the ten open to get air in and with the fans on it I hope it will go down. I am going into the flowering stage and I am concerned with the heat. Can I ask you another question?

Yield. I have read a a lot and on ILGM site they say 4M2 should yield 450 gr,
What has you yield been? I was hoping for 4 Z’s per plant.

Go to your air vents around the house and close them off a bit, building more back pressure to push more air into the tents. I have used the “3 tent method” (with a closet of mothers and clones) for a few years and I end up shoving towels in a couple of vents in other rooms to get the air I needed for the tents.

Yield can vary so much with your environment, not to mention strain. In my 4x4 tents, yields have varied from as low as 18 ounces to as high as 36 ounces because they were different strains. Same tent, same environment, different strains, different yields. If you work with mothers and her clones, it gives you an opportunity to dial in that strain for maximum yields as you repeatedly flower out her clones.

Temperature has nothing to do with RH % control. Do what you have to do. Manually attending to your tent and opening it up to refresh the area is a great idea. 60% Rh is OK, and with plenty of fans and air movement, you can get by. The plants adapt well, and a lot of air movement will proactively balance against Rh issues.

Grassmaster; You are rambling on. Please allow the topic poster to reply to the thread. No reply required. :slight_smile: Peace

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I guess I was, my apologies.

Latewood, I’m not trying to be argumentative but after re-reading this thread, I don’t feel I was rambling on at all. I agree with you that temperature has nothing to do with RH % control, but their complaint was about trying to drop the temperature.

My above statement [I]“RH (relative humidity) is going to be hard to keep down at 84°F.”[/I] was made under the influence (as is this) and my thoughts were obviously all over and I was wrong. What I meant to say (I think…) was "RH (relative humidity) is going to be hard to control (without humidifiers/dehumidifiers). "

But thank you for calling me out on that, latewood. The last thing I want to do is to spread misinformation.

What I really need to do is proof read before I hit the reply button or just not reply at all. Again, my apologies.

I have a room 10 ft wide 14 ft long 8 feet high. I’m running 3-1000’s under the umberalla style hood. I’d like to keep the temp around 78 degrees. What size AC would you recommend

Anything that will cool it off , but you will have to vent that much heat or it can become very challenging , especially in flower .

Depending on the temps in your region; A 5000 btu might work out; However, I would invest ina 7500-10,000 btu AC just to make sure I could protect my crops, and grow denser buds.

Hey @GrassMaster u still on this forum? Is it realy possible to get 36 oz out of a 4x4?

Yeah in a scrogs but you have to have strong lights and great nutrients without over stressing your plants , if you keep it dial in the whole grow with out issues and strong intense lighting with a scrogs you can actually double that in a 4x4 if you skilled enough , I done that with one plant in a 2x2 but it was veg outside in direct sunlight and topped 8 times , it was a monstrous plant .

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Thanx @yoshi im planning on a sog like 36 plants in a 4x4 would that work?

36 plants yeah go for it that would be very interesting or a world genius record , now 3 or 6 might work but to be successful in weight you don’t want to over crowd your tent , air flow around and through your plants is very important for vigorous growth .


As said each to their own :stoned:… I believe 72F-76F is perfection, being able to drop 10-14F at night. Co2 enriched plants should be kept 80F-85F, so they can process and transpire faster.

RH 40%-60%, but dont get too stressed out about it… as long as in this range in veg or flower they will be happy. Cuttings 90%-100% (and heat from underneath with a heating pad so medium is 75F, air 70F - this roots cuttings rapidly)

Root wise… i wouldnt worry about heating the pots or anything.However heating the nute solution 65f-75f makes a huge difference to how effeciently the plants can uptake it. You can do this with fish tank heaters very easily. Dont go above 75 tho as the warmer it is the less oxygen it can hold and also if hits 80-85 roots will be damaged. I also use fish tank bubblers to pack oxygen into the solution. Oxygen works wonders for roots!!