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Discussion in 'Growing Marijuana Indoors' started by mr_brady2003, Feb 12, 2009.

  1. Wow has this ever been a learning experience, first not enouph watts, to far away to to right amount of watts close enouph but way to hot. I got a termometer and it was around 100 f. I took 2 of the 42 watt cfls out and still fried more. Now I have one left..down to two bulbs and the temp is around 82F.

    These cfls just get so danm hot its rediculous. I have two fans that are now both sucking in air from the basement into the grow box just wondering if anyone has other cooling tips so I can throw an exrta bulb or two to let this one plant grow to its full potential.

  2. Imagine how hot HPS lights get lol.
    You dont have enough ventilation.You need to take those fans of yours and mount them up high on the box, the top if possible. Then cut intake holes near the bottom of the box so it sucks cool air in.
  3. Well I have two 120mm fans that are both sucking in air located halfway up to box. Would that be sufficeint or do I need an exhaust fan?
  4. You want an intake at the bottom of the box/cab, NOT halfway up. you want the cool air going through the entire distance of the cabinet. Also, CO2 is heavier than oxygen, so there is more CO2 in your room the lower you go. you want as much as possible in your grow, so pulling in fresh cool air from the bottom is important.

    you NEED an exhaust at the top. While a passive intake works, you want to force as much of the hot, oxygenated air as possible OUT of your cabinet. If you are successfully pushing hot air away from the grow, cool air WILL come in the bottom through your passive intake.

    my intake is the same size as my exhaust, but they are both forced with fans, and works great. its a surprising amount of air circulation, I have 150w HPS and 200w+ of CFL light, my temps top out around 80-82. upper 60s in the dark.
  5. Can the exhaust be on the same side of the box...I need it to be hidden so I cant do it directly on the top of the box because light will shine through..same witht he bottom so If i have one as low as I can go and have one as high as I can go will that be okay?? even though they will be located on the same side of the box on top of each other?
  6. Like he said, you want that cool air to travel the whole box, so putting them as far apart, sucking in from the very bottom and exhausting out at the very top.
  7. k thanks...if it wern't for this site I would never had figured out how to grow lol its a lot harder then I thought.
  8. IMO if you can smile, stick your finger in the fan, stop the blade, and still be smiling its GARBAGE. CFM ratings are a joke and quality fans are not as easy to come by as so many growers start out on the wrong foot with ventilation. GOOD luck to you ...

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