Grow Box too hot...90.8 degrees

Discussion in 'Growing Marijuana Indoors' started by VTjay79, Jun 19, 2009.

  1. Hello,

    I'm a first timer and thought I was doing a standup job....personally.

    But then i went to test the heat and put my heat meter in there and after just an hour and a half it was up to 90.8 degrees.

    4.3.4 (w.l.h)

    600w sodium bulb

    6in vortex fan (drawing air through the hood/bulb>>through fan>>T intersection>50% back in, 50% venting out)

    Since there is negative pressure, its drawing in fresh (basement) air at an amount close to 50%.

    The vent is dumping warm air into the basement, I thought it would warm it up a tad, and boy did it ever, its now 82.2 down there...

    There is no way for me to get in the 68-78 range if the fresh air return is 82.2 degrees in and of itself.

    Should i try to get that warm air to vent out of the house? That seems like a near impossible task where this thing is located. I could maybe tap into some flexi ducting that would blow the warm air into my living room, but that seems a bit much as well, maybe it would be nice for winter.

    Speaking of which, am I just doomed here and need to wait for colder temperatures? I can't see putting an AC in there, as its super cramped already if i had 3 plants in there.

    Any help would be appreciated.
     
  2. 600 watts is certainly a lot of wattage for that space.

    -C
     
  3. i wont let it get no hotter then 80.0
     
  4. I realize i shouldnt let it get above 80, but I'm not sure what else to do?

    Should I buy another fan and separately vent the hood? I originally thought I was supposed to have 2 fans and someone talked me into getting one to do it all.

    I have iris dampers, so maybe i'll try putting it to 20% back into the box and 80% out, leaving fresh air to amount to 80% intake.

    Any suggestions would be helpful
     
  5. Your best bet is an inline fan for intake and another for exhaust. You can pick them up fairly cheap at Lowes.

    I have seen bud grow in 100+ Degrees temps outdoors, so I know it can be done. The only difference is that you have a constant supply of fresh(hot, but fresh) air outside, which is one reason they can handle it.

    Fresh air is key

    -C
     
  6. I currently have 1 inline Vortex 449 CFM fan.

    I'm not sure how much better of a fan I can get?

    If i put another one in there, it might spawn a tornado lol.

    Should I just have as much fresh air as possible and forget about recirculating it back into the box?
     
  7. the only way you can get away with running the temps around 86-90 is if you have C02 enrichment as the plants take in C02 better at those temps. Without Co2 enrichment you should be around 70-75.
     
  8. yes, you shouldnt have air from the box going back into the box, that is not fresh air lol.

    your fan should pull through your light and dump everything out of the box.
     
  9. Ah...Ok...I'm a newb, so i'm getting info from all over the place...and i guess sometimes you get the wrong info!

    To clarify...

    Off the 6in Vortex, i have a T intersection. On the ends of those T's are Iris dampers. I can control the flow of air back to the box as well as out of the box. I was hoping this would allow for better temperature control because i could add back more warm air. Perhaps it will be useful in the winter time?

    I also have a fresh air hole (fanless but filtered) because i thought the negative pressure from the 449cfm would just draw in enough of the cool air needed.

    ALSO...

    I have a 20lb CO2 tank with a pretty nifty plug in regulator and timer. I was told 15 minutes twice a day was all I needed.

    Does this mean my temps can run a little higher than 78?
     
  10. Also just read that my 600 watt HPS is good for flowering...should i consider a different bulb for vegging?

    Will that lower heat?

    Any suggestions on bulbs? Can i just plug-n-play another bulb into the socket in the hood?
     
  11. your hps is fine for vegging, people do it all the time. if you want to keep temps/costs down try using cfls for veg, the 6500k kind.

    using a different bulb on your hps ballast would probably generate just as much heat
     
  12. thanks for the input growin...glad to see such a nice community here!

    I'm going to try cutting off the warm air coming back into the box and just have non forced cold air returning back into it tonight.

    If temps don't stabalize, i'll try putting a fan in, if that doesnt work, i'll try something else. I feel a 449cfm fan should be doing the trick!

    as for venting, should i be trying my best to get the air to vent to the ouside of my house? obviously dumping warm air in my basement will make the cold air return...warm lol...

    but trying to figure out what to do with this warm air might be a bit of a chore itself...
     
  13. yeah, to really get those temps down, dumping the hot air somewhere else is key.

    something else to consider, it's good to have 2x the passive intake as the exhaust. in my box i have a 4" fan, and two 4" passive intakes.

    also, do you have your box lined with mylar or emergency blankets? these materials can trap heat, especially in a grow box as opposed to a room. when I took my emergency blankets out and used flat white paint instead, temps dropped a good 5 degrees.
     
  14. #14 cody8892000, Jun 19, 2009
    Last edited: Apr 8, 2023
    .
     
  15. Well i've been home for an hour now and i simply shut off the vent coming into the box. I'm going to give it some more time before i declare it a victory, but i'm at 79.1 degrees right now. my meter has not shown a plateau yet, so i'm going to wait till i see a flat.

    But it makes perfect sense, introducing hot air back into it exponentially increases temperatures. I just figured...which may be the case and i'll find out this winter...that i will need SOME warm air to keep the temps up. (its a sub basement w/ raw concrete and cinderblock floor and walls and 0 heating at all)

    No mylar...just bare wood right now. I'm going to paint it a flat matte ultra bright white. Not done with the project and still finishing the box up. I got some feminized white widdows i'm going to try out!

    So hopefully my design was not a complete flop!

    Still waiting and hoping the heat stays around there, I'll let you know if i still have more heat issues, but i think we nailed it!
     
  16. now you just gotta send me some nugs! :wave:
     
  17. haha...perhaps...my friend!

    So it looks like it plateaued around 83 degrees. That is without forced fresh air and just an opening in the box.

    Someone said co2 enrichment requires higher temperatures...is 83 ok for that?

    I have not made a hole yet for the air intake, what should i be looking at? Would a 6in hole with a damper be a bad idea?
     
  18. if you don't have an intake hole yet (aka passive intake) anything will help, 2 6" holes with light baffles would be great, and I wouldn't doubt it would drop the temps a few deg. as well.

    Passive intakes are a must, otherwise the fan will be working too hard to pull air through all the cracks and tiny holes in the box instead of an intake hole.

    if I put my hand up to my intakes on my box, I can feel them sucking in the fresh air, even though I only have a fan on the exhaust.

    I have no experience with co2, so I can't say. co2 will allow you to run higher temps, but if you run co2, you don't want the fan pulling all your co2 out of the box. You would have the a hole in your box with ducting connected to the light then to your fan, then out the box, so that outside air only goes through the light, to cool it, then hot air goes out the box. this way the co2 stays in the box.
     
  19. So I had read that 15 minutes of co2 for 2x a day was about what was needed. If i have it set so that once i wake up in the morning, i can set the dampers so that none of the air is leaving the box...this would make it so temperatures rise (which is what i read was good for co2).

    Then after 30 minutes or so, i can adjust everything back to normal so the air is venting back out and fresh air coming back in, temps stabilizing, and I can go to work and then do the same thing at night time...

    I guess I'll have to cross my fingers on that one!

    I'll have to check out those light dampers now. You think 2 6in's will be good enough? I guess if its 449 cfm, it has to be more than one...
     

Share This Page