Ventilation Question

[nugzilla27]

My growspace is basically a rectangular shaped "crawlspace" underneath my basement stairs. Pretty big, maybe 12 feet long, 5 feet wide and 6' tall tapering down as the stairs reach the bottom. I cut a "door" out of the sheetrock and attached some magnets and a handle. I have a french drain behind the sheetrock so the wall extending to the rest of the basement has a 1.5' gap between the sheetrock and the block foundation. I am using a small fan to blow "fresh" air in from this space, but have no vent going out. Seems like there is plenty of air movement in there. Is this sufficient? The only way to vent out would be to rent a hammer drill and bust out the block foundation. I really don't want to do that. Planted 3 hashberry and 3 speed queens direct in soil 6 days ago. So far all 3 SQs popped and 2 HBs. Looking good so far under CFLs with temps 78-80 F and 68-70% RH. I plan on gettting a 400 W HPS set up in a week or so.

 

[green_grow]

it's more efficient to pull air out, than to push it in . can you turn that fan around ?

 

[Guest]

so the wall extending to the rest of the basement has a 1.5' gap between the sheetrock and the block foundation.

Yup...adding a 400 will definitely kick the heat up but I'd be more concerned about the humidity of 68-70% as that will only get worse later in flower which can easily cause bud rot issues. Ways to deal with that are a dehumidifier or more air flow. As for the venting thing I'm kind of a dork and didn't quite understand something. Is that gap actually a space where air can escape and if so it will be enough. If there is no way to move the air out then it won't matter if you push or pull. You need 2 holes...air in and air out. Another issue will be the odor generated later in flower. I'd be inclined to block off the space under the stairs which will not be used...the space where the angle of the stairs coming down makes it impossible to use. This will help increase the efficiency of any fans you use cause there's less total volume of space of air to exchange.

 

[nugzilla27]

Thanks for the replies. Yes, that 1.5' gap in the wall could be used to vent air out. Turning that fan around is not a bad idea. I could drill some small holes in the stairs and they would be hidden underneath the carpet. I'm hoping that heat won't be too much of a problem as these will likely be vegging until the first week of Oct. and ambient temps will come down as well as humidity. If I'm only planning on growing 2-3 plants max, maybe a 250W HPS with supplemental CFLs would do the job? As far as smell, I plan on getting a 7" carbon scrubber and venting that into the gap in the wall.

 

[Guest]

Maybe a 250W and some T5's. The T5's rock and that 250 could use some support. Maybe just go with T5's and train your canopy flat? As for the venting issue I'd recommend taking a look at using that gap as a passive intake and turn the fan you currently have around. That setup, actually you know the design of the area and what will work best, would open the door to adding a carbon scrubber hooked up to an inline fan.