getting rid of dirt air

I am growing with a friend of mine and we have come across a bit of a disagreement on a issue and i was wondering if some of you could clear this up. I have a 8'x8'x8' grow room with my inline fan at the top of the room and my air intake at the bottom(just a hole no fan). Now i said the inline fan needs to be sucking the dirty air out of the room. But my friend feels that it doesn't matter if you blow clean air into the room it will be explelled by the air intake hole at the bottom of the room. So my question is does it matter if you suck or blow your air with your inline fan into the room?

always suck..

Your friend is wrong

But how do i explain this to him?

if you suck air out it will create a negative pressure and pull air in from any cracks.if you blow air in it will be coming out of all those cracks and not going through the filter (if your using one)

lazyeyelids said:

But how do i explain this to him?

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Ask him to find any pictures or schematics of grow rooms set up the way he suggests and see if he can come up with any.

No not using any type of filter. I'm in growing in a shipping container. There is no one for miles so i'm not worried about smell.

a couple of my plants are stretching. could this be the reason why????

lazyeyelids said:

a couple of my plants are stretching. could this be the reason why????

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no, that wont be why...the reason that plants stretch is that the light is probably too far away or not strong enough

if you can move the light source closer without causing any heat issues


what kind/size light are you using?

got a 100ow mh on a mover about 8 or 9 inches away.

1000 w sorry

lazyeyelids said:

I am growing with a friend of mine and we have come across a bit of a disagreement on a issue and i was wondering if some of you could clear this up. I have a 8'x8'x8' grow room with my inline fan at the top of the room and my air intake at the bottom(just a hole no fan). Now i said the inline fan needs to be sucking the dirty air out of the room. But my friend feels that it doesn't matter if you blow clean air into the room it will be explelled by the air intake hole at the bottom of the room. So my question is does it matter if you suck or blow your air with your inline fan into the room?

Click to expand...

you want to have a negative air pressure in your grow room. with the neg pressure you have less worries of smell leakage. the negative air flow ensures all air will go through your air scrubber befor exiting grow room.

So if i'm not worried about smell leakage does it not matter?

With no worries about smell, I would still say to use the fan to exhaust air out of the room, creating negative pressure that draws air into the room from the passive intake. That way hot air from the lights is exhausted, and replaced with cool, fresh air from the passive intake. I am forced to create negative pressure as I have a stealth operation going on next door to the apartment manager.

But perhaps someone more experienced can tell us about their grows using positive pressure.

Also, what kind of climate are you growing in? Is it a relatively cold climate, or a hot one? The best set up in your case may be determined by this factor, since there are no concerns about smell

ya you want that HOT air OUT, cool air will find its way in. i have never come across a grow on riu that has an intake before an exhaust. i personally only use exhaust

its been about 50 - 60 this past week so not too cold.