Need to Lower the Temp in my Cab

[WeedNeedy]

i have 4 23wattCFLs and a 15W.....2 fans are goin...i got two 2.5" holes in the bottom for cold air to come in....the heat has to rise through four 2.5"holes in the board the lights are mounted to, and then through anouther four 2.5" holes in the board the fans are sitting on....then they are blowing out two holes in the back....i cant seem to keep my cab under the 30 degrees mark...its usually around 30-32....any suggestions on how to keep it cooler? does it need more air holes in the bottom?

[rimbaegeus]

I'd like to preface this post by saying I don't grow in cabs, but the concepts of airflow should stay consistent. With that out of the way, hopefully my advice will help until someone more experienced in your grow environment can help.

In order to lower the temperature of your cabinet, you need to draw in colder air from outside the cabinet (it wouldn't be practical to install an air conditioner). Since you have passive intakes (without fans) and exhaust fans, you're already drawing in outside air to some extent. Those passive intakes are only going to be as effective as your exhaust capabilities. The most effective way to cool a cabinet is to change the air as quickly as possible.

So here's where the math comes in. Calculate the volume of your grow space and compare it with the combined power of your exhaust fans (in cubic feet per minute). With growrooms, to my understanding you are aiming for the air to be completely replaced at least once every three minutes. Of course, more is better, as it only serves to bring in fresh, CO2 rich air. With a grow cabinet and the limited space it provides, you may want to replace the air in your cabinet quicker. If you're unsatisfied with the current ventilation, make sure you have fans on all your exhaust holes. It's much more efficient to exhaust air than it is to push air into your grow space. Once you have all your exhaust holes hooked up with fans, start mounting intake fans, making sure the power of the intake is lower than your exhaust.

Cannabis growing was explained to me as needing three elements equally to succeed: water, air, and light. It's really easy I find to lean towards putting most of your budget into lights or into nutrients, and forget about air. The more I try to supercharge one aspect of my growroom, the more I find the situation forces me to spend more money to balance it out. When I upgraded lights, the temps got away from me and I was forced to add in ventilation, etc.

Good luck.

Good luck.

[stinkyattic]

Cool.
I was talking to chronisseur about this jsut yesterday. We were trying to figure out if it would be practical to build a seedling/breeding box with the lights totally isolated from the plants by a piece of Lexan (obviously using flouros), and do the exhaust for that section separately. Like a combination air-cooled hood and microgrow in one.
Could be worth a try anyway; heat in small grows is a real killer.

[SMOKEnCHOKE]

Cool.
I was talking to chronisseur about this jsut yesterday. We were trying to figure out if it would be practical to build a seedling/breeding box with the lights totally isolated from the plants by a piece of Lexan (obviously using flouros), and do the exhaust for that section separately. Like a combination air-cooled hood and microgrow in one.
Could be worth a try anyway; heat in small grows is a real killer.

If I can get my phone cam working or some other cam I can get pics of exactly what your talking about.

This one is two different rubber maid containers. Plants in bottom container and lights in the top. In the top there is a piece of 1/8 inch lexan and a 4 inch duct fan for exhaust with passive intake. With 8 CFL's in the top, the bottom stays at room temp with only 1 PC fan for exhaust.

[stinkyattic]

Yeah, sweet. I'd like to see that.