Will this work?

Discussion in 'First Time Marijuana Growers' started by Xengo, Sep 29, 2009.

  1. The dimensions of my closet are 40.5"x23"x67"(height is adjustable)
    I plan to start with 6 SOG clones ill get from the club
    600 watt air cooled hood MH-HPS (Digital 600 watt HPS MH GROW LIGHT 600w AIR COOLED HOOD - eBay (item 390086616799 end time Oct-25-09 12:24:14 PDT))
    I was thinking of buying an inline fan like New 6" Inch Inline Exhaust Cooling Duct Fan Vent Blower - eBay (item 280278994464 end time Oct-16-09 12:00:00 PDT) and having it pull the air in and then a hole on top to let it out. Walls lined with mylar. Will this setup work?
  2. Yup, most likely.

    Best to have that fan act as exhaust, though, as the name implies. With a passive exhaust the air will sit and stir in the cab faster than it can get pulled out. With the fan as your exhaust, it will not only push stale air out but it will also pull fresh air in through a passive intake...much more efficient than what you mentioned, I believe.

    Good luck and enjoy! :hello:

  3. Why would the cooling part of the hood be pointless? HIDs throw out a lot of heat, and any cooling you can include is worth it. The exhaust fan will help get rid of heat too, but it's not enough acting alone...

    Grab a few smaller fans for intake as well. It will help with temps/ventilation, and then you can have some air blowing on your plants (which is somewhat necessary) to help cool their leaves down and strengthen the stems.

    I just gave the advice about moving that fan over to exhaust to help with ventilation, not cooling, although it will help that as well. Plants enjoy/need fresh air as much as we do. And with that large of a bulb you will need as much ventilation as you can muster to keep temps down. The better exhaust you have, the more hot air is blown out, the lower your temps get, better ventilation, etc etc.

    That setup you linked will, most likely, only be sufficient for 6 clones/small plants (like autoflowers). A full grown plant needs more room than that for the roots, and it would most likely overshadow the other plants in the container if it's big enough.
  4. Right, when i said cooling part i meant of the exhaust fan. Its supposed to cool the air in it so it blows the cool air on to the plants, then maybe i can put a normal fan to blow the extra air out. Should the CFMs be equal?

    Also, how much yield do you think these 6 clones will yield? After this first grow ill probably get another light for vegging a couple mothers.
  5. #6 dragonsfire1988, Sep 29, 2009
    Last edited by a moderator: Sep 29, 2009

    For CFMs, the exhaust should be higher than the intake. This way the air gets pushed out quicker than it is pulled in...A stronger exhaust gives the air less time to sit around and heat up under that light...it will also refresh the air much faster. The intake will take care of blowing cool air on the plants and pulling some fresh air in.

    The fan itself does not actually make the air it sucks in cooler, like a fridge, for the record. The word "cooling" is in the name just 'cause it will pull warm air out, like any fan. There is no mention of any cooling apparatus in the description on that auction site, either.

    With a stronger exhaust, it will help the intake pull air in at a faster rate, regardless of CFMs, to an extent.

    Yield is completely dependent upon strain and growing conditions. There is no way I could even give you a rough guess at this point. Shoot me a picture in three months and then, maybe, I can give you a number ;)

    Oh, thanks for the rep, too...just noticed that :)
  6. Okay thanks that cleared many things up. So do i necessarily need a fan if i just put a big enough hole for the exhaust to pull out?

  7. Um, well, maybe we're backwards here...or i am. whatever. just read :p

    If you're just using a hole for ventilation instead of a fan, the hole should act as INTAKE. The fan should always be EXHAUST...this will make the overall ventilation much better. The exhaust fan will act as intake by pulling air in through that hole, as it is the only source for the fan to pull air from. Assuming you don't have any other holes in your box, the air will pull through that hole and up to the fan, creating some decent ventilation.
    That follows the CFM 'rule' I mentioned above...Exhaust CFM > Intake CFM (which would be 0 if it's just a hole).

    Also, don't know if we discussed this, but intake should be on the bottom near the plants. The exhaust fan should be up top near the lights, opposite the intake.
  8. Rather than editing that, i'll post another one...

    No, you don't necessarily need an extra fan for that intake if you've got a hole big enough for the exhaust fan to pull air from..

    But, having a fan to blow air over your plants is always a good idea. It will strengthen stems and cool the canopy a bit more than just a passive intake (that is with just a hole and an exhaust fan)
  9. Great so thats probably what ill start with, and move up from there. Thanks for all the help

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