Ventilation Expert?

My ventilation *should* be ok. I have two basement rooms that are experiencing the same plant problems and always have in this location. When the plants leave, they get happy. Temps and humidity are fine;a wide range of other solutions have meant that everything in the entire grow has changed. I think it's in the air...like the plague...

So I'm vegging in a 10x10 space open to an 800 SF basement / garage area. it can be left open to the large area or closed with plastic. It has no intake but is venting out the light from a squirrel cage fan & 4" ducting to the main basement area.


The flower room has 4" changing to 8" ducting from the outside and an 8" 483 CFM can fan.
It exhausts back outside with a 10" 780 CFM centrifugal fan. It isn't sealed, and is usually closed to the main area with a couple layers of panda plastic. This is a roughly 1400 cubic foot space.

Discuss! I can't change anything else in here! Food/water/dirt...it all works when we're outside but both these rooms suffer from the same problem.

so what's the issue ?

only way tell is fire up lights and check temps
unless u dont that
seems your set up be fine

slowandsteady said:

so what's the issue ?

Click to expand...

what he said^^^

Sorry, the issue is that the plants keep experiencing the same stresses in both rooms for over a year and every other single thing has been changed. They have never been successful in this room. So...air...right? I RO'ed the water, changed dirt, nutes, and bug control. I have multiple strains.

Does anyone know better math to help figure out if they are not getting the correct kind of air? For instance, is the length of ducting killing them? The width? What's the math as to why? Can a pretty "open" air basement (mice could seriously run in there through the garage) HAVE a ventilation problem? If so, how?

How big is the room? What size fan and ducting are you using?

any standing water or places for mold to hide? what are the walls lined with? are they made with Chinese drywall?

Humidity is ok for a basement. Only a wall or two worth of drywall. Haven't had any bud mold since moving in.

Fans as in first post. I guess I could be concerned that the intake ducting is so long and partially just 4" that it's actually not a negative pressure room but it should be fairly even as far as *I* can tell...not a math expert by any means. Just know I have some environment problem.

To break it down again: big room: 1400CF, 483 input fan, 700 outgoing. Front door leaky -- just panda film. Not sealed. I could do that if it'd help but I'd think *not enough* air circulating randomly would be a bigger issue...

700 small room, open to a big basement, just venting out the light. same exact issue.