High temp concern

New grower here. I have a grow closet that has a door that opens to the garage. I’ve insulated the closet, added a air-conditioning vent and have a 6" Hyper Fan that exhausts air thru the ceiling to a roof turbine. The closet is air tight otherwise.

I have 150 watt Advanced Platinum LED light and a 600 watt MH/HPS light. I bought the 600 watt light first, decided it generated too much heat while testing, so then started out my grow with the LED.

It’s only be less than two weeks and the 3 plants (the closet is 2’ X 5.5’ and 8’ tall) seem to be doing OK but I just felt like the LED wasn’t producing enough light (very scientific ;)) so I ended putting the 600 watt unit back in the room.

I think I may have not given the LED more time…

Anyway, my daytime temp is around 86 F degrees. I have turned up the speed on the exhaust and I set the ballast at 50% power. Light is about 25" above the plants.

My questions are. Should I worry? is 86 too hot? Should I switch back to the LED? Should I provide another source of fresh air? (right now air is pulled from the A/C vent),

I welcome your comments.

86 is a little warm for hid grows but not ridiculous. That led is too small for the space alone, so I’m not really sure what the decision would be there.


You are right, I misspoke the LED unit I have is 300 watt equivalent…


Based on 3rd party integrated sphere testing of the advanced platinum light, it has roughly the recommended par levels to flower 4-5 square feet. Your space is 11 square feet.

I’ve got three plants. Will I use up all that space once they grow?

Sorry for the misinformation but I was right all along… It’s the 150 watt LED unit that I bought. That’s definitely too small and 300 watts if all the space is needed may be as well (per your research).

I am just hoppin in here to let you know I have mine outside it has been 105F a few times theyre still kickin. If you see heat stress of drooping leaves just give them a cool drink at the base. :slight_smile:

1 Like

WOW. That’s hot. Being my first grow I’m trying my best to meet every single recommendation. This may be one where I’ll have to settle for less than optimum.

Things are actually going well, just wonder if I won’t get the growth or other positive characteristics with a warm room.


They like it for a sweet spot below 80 -70 Degrees mine gets up around 87 I’ve had it up in the 90s before it won’t hurt them but they like it when it’s a little bit cool when you’re growing indoors but it ain’t going to hurt them like @HighDesertFarmer Said my outdoor stuff has been up in the hundreds and they’re still grow You may have to water a little bit more often but even at that I don’t think you’ll have any problems


Thanks all, I will relax. Waiting for a result is killing me!


Do you mean just a duct off of your house a/c? This probably won’t be enough fresh air to cool, nor provide the plants with enough fresh air to keep them happy. How is your fan and light configured? What type of hood is your light in?

There are lots of options to improve the environment. Can you post some pics of your setup? Lots of eyes on the project will solve it in no time!

What strain are your 3 plants? Very generally speaking, you want about 2x2ish per plant…but there are a lot of variables that go into that. Are you training your plants at all? Topping? You would probably do better with just two if they’re photos, but 3 autos would probably fit okay.

Also, welcome to the forum!


As a Hvac mechanic i have to agree with @elheffe702
His assessment is spot on
Since you ducted off the house ac it will only get cool air when the ac is actually calling in the house
I recommend you buy a portable ac or try installing a intake fan to help draw cooler air into the closet


OK here you go …

Yes duct is off AC and is positioned in the ceiling. I’m in Texas so the AC runs often but I agree more fresh air would help.Fan (exhaust) is out of pictures to the left on wall. Circulation fan is out of pictures on the floor on the right. Strain is Amnesia Haze, (mostly sativa), non auto flowering.

the system won’t let me reply. too many replies. geesh! so to answer question below:

The light has glass. the air is being pulled thru the hood and exhausted thru a roof turbine.

1 Like

Silly question, looks like you’re air cooling hood. Is the glass in place on the hood?

1 Like

If you’ve already got a vent in there, it wouldn’t take much up in the attic to install an inline duct fan. Then, instead of the a/c feeding that room, you could run the duct coming to the intake fan, we’ll call it, so it’s pulling from a cool place in the house, possibly just air from the attic if it’s got good ventilation through the soffit or whatever the setup may be. You might even be able to use the warmth to your advantage here, in the winter. Anyway, you could use an a/c register in your house that either stays closed or isn’t very necessary. It would look like a typical a/c vent, only it’d be an intake for your grow space. I’ve considered all this myself regarding my closet setup. I had planned to duct fresh air in there in a similar fashion, but scrapped it since we’ll be moving soon. It works, good enough.

Amnesia Haze will probably stretch out a bit once they get going. Since you have a decent amount of height to work with, I wouldn’t do much, if any topping. This will let the plants grow up instead of out. This way, three of them should fit okay. You might need more lighting when they get spread out a bit, to keep the intensity even across all three. But now that I’m rereading that, I think someone covered this, and I’m not the man to talk to about lighting anyway lol Just an idea!

By the way, happy birthday, @Hogmaster!

1 Like

The air from the attic is out of the question. Very hot and of poor freshness. Pulling from another room inside the house would work. Also thinking about pulling from garage. Door to garage already has a vent (currently closed). I could draw through there.

@buddawg the hood is hooked up to exhaust correct ?

Yes to the exhaust. I’ve bought another fan for intake but have not installed it yet. I also purchased the filter to scrub the exhaust as the day where I’ll need that is approaching. Really wish the intake could come from house but I worry about possible noise and smell. My choices are outside (eave), inside garage or inside house.

2 weeks and 2 days. First nutrient added yesterday (“Grow Big”). What do I use to control ph? Right now ph approx 6.8.

Think I’ve watered these a bit too much. Going to back off a little…

Concerning intake suggestions (not enough fresh air), I decided to add an intake fan to the A/C duct. There was no other good location to pull separately from the house. This should pull enough fresh air. Well maybe not the freshest but close to in-house levels, that plus the small grow should get me to a good place.

Also the pull of air down to the floor has cooled things considerably allowing me to crank up the light to 600w.

As always welcome your thoughts.

85 is OK for veg cycle but once you go into flower, you’ll be burning away the good stuff. I would say 85 in flower is still doable and you’ll get decent bud, but I think it’s generally agreed upon that you want to aim for sub 80s during flower.

I’m surprised that with AC flowing in and pulling heat out directly from the HPS enclosure you’re still above 80. Although having said this, your HPS lamp is awfully close to those plants, that’s likely your issue.