I need to make a carbon filter for my closet grow. I am growing 1-2 plants in a 2x3 closet. I am renting the property, so I can't make any holes in walls or anything like that to exhaust the smell outside, so I'm wondering that if I just stick a carbon filter in the closet and open the door a few times a day, will that circulate the air and cover up most of the smell (I have ONA gel too)? If not, can someone give me some suggestions on what to do. Let me reiterate that I CANNOT cut a hole in anything, not the closet, not my wall, not anything. I will have a fan on the carbon filter, drawing air through the carbon. I just won't have the cleaned air being exhausted anywhere, but I will open the closet door pretty frequently anyway (i like checking on my ladies), so i'm just wondering if that'll work. There is a 1/2 inch or so opening at the bottom of the closet that allows air to flow in, btw. Thanks!
If the closet is near a window you could just keep the closet door open just enough to have a duct coming out and run a ducting from an inline fan to the window. You need some way to vent out the warm, stale smelly air. If you cannot then you would have to keep the closet door opened. Also CVS has their own brand of odor absorbers and I have found they work better than ONAs and are way cheaper ^_^
In my experience ONA will just about take care of the smell on its own. Depending on a number of things including how smelly it is and how much space you're talking about, you might not need anything else. Two other things: That gap at the bottom of your door could let light in and stress your ladies during flowering, which would result in you getting hermies which is no good. So you're going to want to block that up somehow or maybe grow an autoflower strain that doesn't care so much about how much light it gets. Also, you can't cut anything the landlord owns. That's all. You could just take the door off the hinges, take it to a hardware store, lumberyard, or pretty much anywhere that sells doors. Preferably somewhere with a door mill, but that might end up costing extra. Basically just get a duplicate door. You can probably save some bucks if you can find one in the scratch and dent bin. It doesn't matter to you what it looks like, only that it fits and belongs to YOU, so YOU can cut whatever holes in it you want. Hang your door on the closet doorframe, stick the landlord's door somewhere out of the way... when it's time to move out you put his door back and everyone's happy!
I agree ona works wonders, I use it in my bedroom as well to mask the smell of bong smoke. It works I would open your closet more during flowering to discourage mold growth. You should be fine with the carbon filter/ona gel combo!
Another option would be pick up a cheap second hand closet door the same size and put it on and drill your ventilation holes in that.
Here's another option you could try. You could try building this should be cheap aswell. Zen Style Carbon Filter Mirco Grow Edit: you could also try any of these. Some just need down sizing to fit in your closet plus some you wouldn't have to cut any holes in the closet. Hope this is helpful. Happy Growing.