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please help with venting

lowkey786

New Member
I made a growbox with CFL bulbs and am having trouble with heat. I started with 5 nice seedlings under one ob those cheap Wally World grow lights and they were doing very well. Then last night I built a growbox, lined it with foil tape, and started with 4 red spectrum and 2 blue (I'm gonna skip veg) when I woke up 4 were burnt and dried crispy!! I have the lights about 4 inches away. Its really hot and I'm not sure what size fan or hole to use. The box is 3 1/2' tallx18"wx1'deep. Thank you for any help you can provide
I cut the light down to 2 red and 2 blue untill I figure this out. The light is on 24/0 for my first 2 weeks at least.
 

ledtester

On Vacation
I made a growbox with CFL bulbs and am having trouble with heat. I started with 5 nice seedlings under one ob those cheap Wally World grow lights and they were doing very well. Then last night I built a growbox, lined it with foil tape, and started with 4 red spectrum and 2 blue (I'm gonna skip veg) when I woke up 4 were burnt and dried crispy!! I have the lights about 4 inches away. Its really hot and I'm not sure what size fan or hole to use. The box is 3 1/2' tallx18"wx1'deep. Thank you for any help you can provide
I cut the light down to 2 red and 2 blue untill I figure this out. The light is on 24/0 for my first 2 weeks at least.

Chokey, a 4' duct like the one in this picture would do.

DSCN00694.JPG


Just a heads up...your starting plants from seed and there's a maturing process to new plants. You might not get favourable results going straight to flower. height is obviously an issue so take cuttings or LST the plants....here gangs grow should help you out.....420 Magazine ®
 

Diemand Edge

New Member
OK, couple of things to consider...

1. 2700k bulbs put out much more heat than 6500k bulbs. A LOT.
2. Oddly, CFL bulbs have a sort of breaking in period. They tend to run hot for the first 3-10 days of operation. Something that is characteristic of florescent bulbs.
3. Venting is a necessity, and not just for heat. Fresh air helps keep things cool and then the force of wind against the plants creates resistance the plant needs to stimulate growth for thicker stems (that can hold up more bud).

Your grow box is about twice the size of mine. I have two 4" computer fans rigged with USB cords exhausting with passive air intakes (just vents cut on the opposite side of the container.)
I'd do two things in your situation. First rig up a single computer fan (to start) or something of a similar size (approx 4"). You'll want it exhausting out the side or top, and then on the opposite side cut a small hole around the height of the plants for the fresh air coming in so it blows against them.
Second, a few times during the light cycle open up your box for a few minutes to let heat escape.
Your bulbs should cool down within a week or so. I had a similar problem where I doubled my lighting (from 4 to 8 bulbs) and I ended up running 100+F at times and got some crispy leaves. But the plants pushed through and the box cooled down. Yours will too!
 
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