The Best Set-Up With No Vents

A customer has a question and I hope we can get some opinions on it, thanks.

“i have a fe questions on a grow for a buddy of mine . anyways he has a 600 watt hid light a 100 watt ans 2 / 400 watt HPS a grow area is a normal bedroom size closet area is 3X3 feet he was wondering the best set up with no vents he has wants to use his 600 watt HID over 6 plants thay are in seed right now just put in soil this morning but the concern is heat. THE QUESTION i have is do you think with the ac in the house set at around 75 degrees with fans blowing on the plants constant will it still not be able to cool down enough ? would like to get the grow done using the 600 watt HID untill veg is done and use one or two of the 400 watt HPS during flower without ventilating the room using just house ac and fans… what do you think? any suggesions comments concerns anything would be helpful please email me back ( inside:picture of light and closet area can move if needed to find space to promote air flow)”

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if anyone has any tips for me please let me know asap

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You can’t place or post your e-mail in any thread. By the time i got to your post it was gone.
If you do it again you could be suspended for up to 3 days.



get off my page garrigan create your own topic you cant just post anywhere please stay off my page garrigan65


Excuse me, but your thread was flaged and i had every wright to post on your thread. and be careful on how you talk to me. Be nice

Garrigan65 Moderator


Was looking but don’t see how you’re gonna exhaust out your air and smell. Even with a carbon filter the smells pretty strong at times .

Bad move dude…


Thanks @latewood ! Like the new avatar!

Back to the customers question: You are talking about running 600 watts or more of lamps and just using the house ac to cool your room. All watts (light or heat) get converted into heat eventually, so this is like running a heater and offsetting that with your ac. You can do it, but it’s very expensive. Air conditioners are not all that efficient and they degrade by 1-3% per year so you might be doubling or tripling your light’s electric bill.

Fans are VERY cheap to run. You might want to get a fan and use some flexible air duct (Home depot, etc.) to go from the top of your closet to a window to vent the heat outside. That’s also the setup you need if you are going to run a carbon odor filter.

the customer is the guy that responded. I don’t waste my time on people like that!

i run a 600w HPS in a 3x5 closet with NO A/C in my room and with room door closed the room never gets over 100f and that is after hours of lights on and i only have one normal fan blowing the plants and then 1 custom 4in mini fan invention i made to fit my Bat Wing shade and i have no issues with heat so far…if you need ideas on how to build something to help let me know as it should not be to hard to control with only a 600w

What do you yield from that @Canna_duh_EH? I have a sneaky suspicion that without an exhaust and any sort of fresh air intake, you’re starving your plants of co2.

It’s not difficult to grow weed, it will practically grow itself. But if you want to grow it well, it will take a few things. Fresh air supply or co2 is one of them. Temps aren’t everything, but I’d hardly look at 100 F as an example of what’s considered reasonable for an indoor grow. The members here are on point with suggesting this isn’t a great idea.

i just said temps were good with my bedroom door closed and the closet has no door and as for fresh air exchange i run fans that take cold clean air from the next room over which happens to be a concrete floored work room and as for the temps its normally around 85-90f and im not sure of my RH yet cause the gauge has yet to get here, and this is the first grow in 10 yrs so its like starting all over again but i dont just lock them in a 3x5 room under a 600w HPS. and for yield not sure but will know in 6-8 weeks or maybe less

You made no mention of drawing air from a different room in earlier post, which seems to be what op is asking if he can do without. If nothing else, I would assume they wouldn’t be very comfortable in their bedroom at 100 degrees regardless.

Above a certain temperature, useful photosynthesis stops and they go into survival mode. If they have enough water they may survive but not have any useful sugar production. Has to do with stomata closing to prevent dehydration, which cuts off CO2 entering the plant. That critical temperature varies from strain to strain but I get the impression it is about 85 F.

will if you consider having the bedroom door open with a fan just inside the door on the 10x19ft bedroom some special venting im not running any small fans or exhaust systems just 2 normal fans in a 10x19ft room and a SINGLE 600w and the closet is not the type you think and its in a basment with NO AC as you see in the pic and the temps have actually been at 80-82f steady now that i have a digital thermometer and not using some junk analog one and that high reading before was since its on the mylar less then 2ft from the shade i think, but honestly its been 6-10yrs since last time i grew so if its not the best this time around then i will change things to make it better, like i wont let them get root bound early on next time, newbie move i know stupid beer cups and plants that grow super fast…lol…i did NOT LST these but they grew a million branches anyways and are budding alright for the small time they been on 12/12…if i had to guess i would say maybe 2 weeks since i changed time another thing im going to do is WRITE is all down and LOG IT…sorry for the huge post but again no vent/ac just open style closet and open door on the room its in

Well, your basement walls are probably natural temperature control. Just need to get some CO2 into the basement so open the door to the rest of the house every couple of days. All the carbon used by your plants has to come from the atmosphere, unless you use some sort of organic soil or fertilizer.

With the door open to the plants, your whole basement becomes the grow room. Just with lights and plants in one area.

technically there is no door on the closet as you can see but i the bedroom i share with them is BIG like 11ft wide by 20ft long the room has its own door to my living room and with nothing more then just fans i can keep my temps around 78-80f DT with a RH of 42% and 68-70 NT with around the same RH…and in the time since last post i added a second 600w IPOWER kit and im mixing MH and HPS bulbs and rotating the plants under the lights mixing the spectrums.

…there is 2x600w kits and the HPS is rated at 85,000lm and the MH is 55,000 for a total of 140,000lm for 8 plants…i guess we will see how it goes…and OP did you find a way to combat your no venting issues?

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