New grow box way too hot for plants...??

MeanGreenFarmingMachine

MeanGreenFarmingMachine

Active Member
Hey, yesterday i just finished my mini grow box. Evreything was working perfectly until i put my clones under the lights... after about 5min...yeah only 5min....they started to fold on themselves and got extremely weak...

My box is 2 feet tall and at first, i had put 3x200w clear white bulbs. After noticing that my plants were basically dead after only a couple min and that my box was 38*C, i decided to put 3x23w energy saver bulb instead, which would equal 100w each...but the same is happening, only slower...

Is this normal??
It gets extremely hot, 31*C, even with 3x23w bulbs and i have 2 fans, why?
Is there anything i can do to cool it down?

Anyways, any help is appreciated.

THX
 

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tattoojoe

tattoojoe

Member
With CFLs you need to keep the bulbs no more than 3 inches above the plants, thats the why they're dying so quick. And the heat is probaby because you have no fresh air going into the box. You probably need to at least install an inline fan on the side of the box for ventilation to keep the heat down.
 
MeanGreenFarmingMachine

MeanGreenFarmingMachine

Active Member
tattoojoe said:
With CFLs you need to keep the bulbs no more than 3 inches above the plants, thats the why they're dying so quick. And the heat is probaby because you have no fresh air going into the box. You probably need to at least install an inline fan on the side of the box for ventilation to keep the heat down.
Click to expand...
I do have a inline fan, its on the bottom left, but its not very strong....
 
NewbGrower^.^

NewbGrower^.^

Active Member
Most cfl heat is from the ballast. Have a fan blowing on the ballasts of the cfls and temps will drop a lot. Make both of your fans blowing exhaust out at the highest point of the box. Start with a couple small intake holes at the bottom and seal up the box with the fans running. If you place your hand or fingers over the intake and feel a lot of air moving you have a decent setup. To keep temps adequate you need to have pressure inside the unit you understand>?
 
MeanGreenFarmingMachine

MeanGreenFarmingMachine

Active Member
NewbGrower^.^ said:
Most cfl heat is from the ballast. Have a fan blowing on the ballasts of the cfls and temps will drop a lot. Make both of your fans blowing exhaust out at the highest point of the box. Start with a couple small intake holes at the bottom and seal up the box with the fans running. If you place your hand or fingers over the intake and feel a lot of air moving you have a decent setup. To keep temps adequate you need to have pressure inside the unit you understand>?
Click to expand...
By pressure you mean, sealing up little holes or bigger fan or..?? could you expand on that?

THX
 
NewbGrower^.^

NewbGrower^.^

Active Member
You want to have negative air pressure so that the exhaust fans blowing out force air to strongly pull into the bottom intakes. Make 2 bottom intake holes monitor temps. Cover a hole and watch temp. If temp rises you need more intake opening. Remember though... having too much intake area is bad since air will not be pulled in fast enough. The key is to have a constant flow and exchange of air from the bottom of the grow area towards the top. Cool air stays lower and when the exhaust fans suck the hot air out that is already on top of the box, they are pulling up the cool air from the bottom. It's like a big cycle. Hope I made it more clear because right now I am blazed:blsmoke:. If I didn't just let me know and feel free to ask any questions.
~Newb

Btw remove the foil/mylar reflective stuff. Can also cause heat problems
 
Tripper420

Tripper420

Member
So does that mean you don't need an intake fan? I have a 48"x33"x24" grow box, I have three fans running....one on my 150 watt HPS remote ballast and the other two as intake and exhaust. I leave my black plastic "door" open for fresh air. And I was going to install an intake and exhaust. But by your rationalization for a box my size an exhaust fan and few intake holes would suffice, thus saving time,money and hassle of making a light box and all the cords.

Am I understanding this?
 
MeanGreenFarmingMachine

MeanGreenFarmingMachine

Active Member
NewbGrower^.^ said:
You want to have negative air pressure so that the exhaust fans blowing out force air to strongly pull into the bottom intakes. Make 2 bottom intake holes monitor temps. Cover a hole and watch temp. If temp rises you need more intake opening. Remember though... having too much intake area is bad since air will not be pulled in fast enough. The key is to have a constant flow and exchange of air from the bottom of the grow area towards the top. Cool air stays lower and when the exhaust fans suck the hot air out that is already on top of the box, they are pulling up the cool air from the bottom. It's like a big cycle. Hope I made it more clear because right now I am blazed:blsmoke:. If I didn't just let me know and feel free to ask any questions.
~Newb


Btw remove the foil/mylar reflective stuff. Can also cause heat problems
Click to expand...

Yeah, that sounds pretty good to me, thx for the "Air flow 101" course...now iv got a better idea of how all this stuff works!
 
NewbGrower^.^

NewbGrower^.^

Active Member
Tripper420: As long as you have a strong exhaust system the intake air will be naturally sucked in from wherever it can.(Intake holes at lowest point)

MeanGreen: No problem ;] Check out my old cardboard grow box pic I included. Gives you an idea of what i am describing This baby stayed 80F in my old room when it was always 80F lol I don;t use Ac much
 

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