Grow box heat issue

I made a box using these plans ----> http://420tribune.com/2010/03/diy-stealth-grow-box/

and I ran into a temperature poblem.

After testing it empty and having it run at a constant 27 celcius (80.6 F) I put my clones in it. It moved up to 30C (86 F) which was tollerable for the plants if not slightly warm but now the temperature has shot up to 35 celcius (95F).

Can someone please help me figure out how to drop the temp to a tollerable place.

to me it looks like the box has no intake. i skimmed thru the other site and saw they only mentioned 1 computer fan which looks like u have as an ehxuast. you need fresh air. you need to cut a passive intake into the box on the bottom.

I have a passive intake at the bottom and it's shown in the first picture. Your right about the top fan, it's a 12v exhaust.

I have done everything to specs minus bolt size and fan location.

To explain what I mean by fan location, the original specifications indicate the computer fan on the inside bolted to the roof. I have it placed on the outside bolted to the roof and sealed so there's no loss of suction.

I checked my intake, it's passed the paper sticking test (cover intake with paper and see if it sticks) so I know there's definate air flow.

In the box is a large black plant pot(square) 2 smaller plant pots (on the black one) a pyrex bread pan holding dying clones (soon to be removed)


Is the pyrexy throwing heat, is it the black plant pot, is it over crowding, could it be that the intake only has a few inches of room on the inside to establish air flow. could it be a combination of things.


If at all possible I need to sort this out today as the box has to go into unattended hiding for a week.

Will cutting another passive intake help or hinder

Is adding another fan absolutly nessicary because it's not possible

Is this quick repairable or will I have to shut down, let the plants go and start over.

Please help me, I have very little time to figure this out before the dead line.

oops i missed that.i see the intake now.how long are you runing the lights? do you have them on during the day? personally i think the ehxuast is to weak. you have 6 cfl's rite?

I'm running the lights at 18/6 I only had 5 CFLs in at the moment (lost 3 clones before I cought the temp problem)

You say you think the exhaust is weak, how can I fix it?

Will cutting more passive intakes help or hinder or do nothing at all?

I removed the pyrex bread pan and the dead clones, spread out the remaining plants and took out 2 lights which brought the temp down to 30 which is managable for now as a temp solution for the next week untill my guests leave but a better permanent solution would be appreciated.

Best bet would be to get another fan, identical to the exhaust fan and mount it at your current intake hole. This will change things ALOT !!! It will allow the air to be exchanged alot more than what it is now.

Only way to fix a weak exhaust is to get a stronger fan. Put a fan on the intake first, Im quite confident that another fan will fix your problem.

Can I run 2 computer fans off of one 12v plug?

Kalebaiden said:

Can I run 2 computer fans off of one 12v plug?

Click to expand...

Why not ? wire them together and plug the bitch in.

The intake is cut a bit larger than the 2.5 inch to accomadate the slightly larger fan size and it is no longer passive

Noticed a difference yet ?

I just finished and i'll post an update in a half hour after the temp stabilizes. Thank you smrt for the help (check back in a half and see what the news is)

Just checked the temp for a rough reference and it says 29 C (see you in a half hour)

the temperature is sitting at a solid 28 Celcius, there's only 3 lights so I'm going to add another exhaust fan later but this is working for now

skip the comp fan put a toilet fan in itl solve it more than the comp fan ! ups forgot to say use ya comp fan then as intake n the toilet as extractoin itl get bit neg pressure going mate!

you can try adding both fans as exhuast and having 2 passive intake's.im using a bathroom fan rated at 50cfm and still having problems o reaching 90.

Can't do the bathroom fan, my giveaway is the noise so it's got to be cheap to free stealth fans.

Computer fans and whatnot since I have them

sorry my mistake shud av known it was stealth with it been boxed up like that ! yses just dubble up on ya comp fans then ! also is it in a cool cubby? or is temps going to be warm ther too? just thinking of ware ya placing it might have sommet to do with temps? just babbling on mate good look!

No prob dude, it's in a confined closet right now and will be moved into my bedroom proper in a week. I tarped up the back of the double opening front/back closet to create a back shield from prying eyes, the front of the closet will be made inaccessable for roughly a week to everyone including myself so this has to work for a week solo.