New stealth grower. Questions on ventilation and odor proofing.

This is completely my first post ever on here so I understand if I get mostly criticism. But whatever, here's what I got to work with: it's an old cabinet that's about 3.5' tall x 2.5' wide x 1.5' deep. I've already covered the whole thing in reflective material.

I have a few small holes that light shines through because of the doors. I'm still contemplating how to fix this but it's the least of my problems right now.

I am Currently using 4 100 W CFL's that are 6500k on my setup. I'm going to change my lighting situation shortly to put 6 instead. Even with only 4 and leaving it closed for merely 20 mins the temps got up to over 90. I have the doors open because its in my room so it's not a problem.. YET! But I need to figure out what I should do about ventilation and a carbon filter. Also trying to use as little nutes as possible if any. I am just like every micro grower and don't wanna spend an arm and a leg.

I germinated a few randoms and put them in Rockwool last night and this is what I have so far! Any help on the ventilation/odor proofing and nutrients would be awesome! Thanks for any feedback!

Do you have any fans set up for exhaust? What's your intake?
Can you post a pic of your set up?

Ogonzo said:

Do you have any fans set up for exhaust? What's your intake?
Can you post a pic of your set up?

Click to expand...

Ogonzo I just recently made the new box so I haven't cut any holes for ventilation or anything. I just have the doors cracked slightly and a fan to blow a small breeze around until I figure out what to do about ventilation and odor scrubbing. Exhaust I was thinking about a 4" duct fan. But thought it might be too loud. For intake I'm debating between a pc fan or just a light trap with a hole to pull air through.

You can use a pc fan (or multiple) for exhaust, these should be put at light level to pull as much of the air across the lights as possible.
If you're doing a passive intake, keep in mind that the passive opening should be about 4x as big as the exhaust. Since you've got a variable light, put the exhaust at the top and put your intake at the bottom (if passive be sure to build a light trap).
Alternatively, you can build a little shelf for your girls to sit on and drill several holes at the bottom of the box to let air through the bottom. This will provide good airflow, you can build an easy light trap for this and also will give you access to pull in more lights into the cabinet if need be.
If you're not sure, let me know and I can draw this out for you.

Good luck and keep us in the loop!

That's a nice cabinet by the way!!

Ventilation: Assuming there are no convenient large holes in the back or base of the cabinet, you're probably going to have to cut some. You can use a drill with a boring bit to make a rough circle, or you could do it properly if you have the patience and tools. You probably want one large-ish hole near the top, somewhere out of sight (probably on the back of the cabinet). Then you can attach your fan to this hole, either directly or by a duct. It should suck warm air from the top of your grow space and blow it out into the room. Make sure that the cabinet will have an inch or so between the fan outlet and the wall. You also want a passive air inlet - probably somewhere near the bottom. Cooler air in, warmer air out. To stop light leaks, you will want a light labyrinth on these air holes.

Odor control: depending on your situation, you may be okay with a plug-in "air freshener" in the room with the cabinet (NOT in the cabinet itself). I hate these things, so I have a small DIY carbon filter on the fan-driven air outlet. There are various designs around the place if you search a bit.

Here's one: https://www.rollitup.org/stealth-micro-cab-growing/575738-my-pc-cab-non-stealth.html - FlightSchool's "stinky sucker", one of the simplest carbon filters you can put together. The carbon filter can also serve as your light labyrinth. Mine doesn't quite remove 100% of the smell, but it reduces it to the point where my smoking is more of a problem.

Nutrients: I grow in organic soil, so can't help you there sorry! If I had plants in rockwool, I would be feeding them worm casting tea.

Good luck!

Ogonzo said:

You can use a pc fan (or multiple) for exhaust, these should be put at light level to pull as much of the air across the lights as possible.
If you're doing a passive intake, keep in mind that the passive opening should be about 4x as big as the exhaust. Since you've got a variable light, put the exhaust at the top and put your intake at the bottom (if passive be sure to build a light trap).
Alternatively, you can build a little shelf for your girls to sit on and drill several holes at the bottom of the box to let air through the bottom. This will provide good airflow, you can build an easy light trap for this and also will give you access to pull in more lights into the cabinet if need be.
If you're not sure, let me know and I can draw this out for you.

Good luck and keep us in the loop!

That's a nice cabinet by the way!!

Click to expand...

Do you think two larger pc fans for exhaust would be enough to pull out the hot air? And I saw a video on how to make a light trap and it seemed pretty confusing. And what's this underneath of them like under the box or still on the side?? And thanks the cabinet is actually an old radio cab. There actually used to be a crank on the side to power the thing!

As far as large holes on the back you are right. There are none so I already know sadly that I'm gonna have to cut some. I just wanna make sure I have the right fan and know the size before I start cutting. That carbon filter looks really easy to make. How effective are they normally?

Purplepuffer said:

Do you think two larger pc fans for exhaust would be enough to pull out the hot air? And I saw a video on how to make a light trap and it seemed pretty confusing. And what's this underneath of them like under the box or still on the side?? And thanks the cabinet is actually an old radio cab. There actually used to be a crank on the side to power the thing!

Click to expand...

There is actually a formula that you can use to determine what size fan you need.

Making a light trap is pretty simple, it's kinda like a labyrinth. Here's a video, not sure if it's starts on the previous video in the series, but he goes through how to make. https://www.youtube.com/watch?v=s7TfPVVl0_U

Here's a rough drawing of what the underside of your cab could look like:

The black holes are your passive intakes, the Light Killers are peice of cardboard that has been taped to the bottom in kind of a maze fashion to stop the light from going through. You should have two or three inches between the floor of the cabinet. Very simple, and probably the least intrusive way of building passive intake.

Ogonzo said:

There is actually a formula that you can use to determine what size fan you need.

Making a light trap is pretty simple, it's kinda like a labyrinth. Here's a video, not sure if it's starts on the previous video in the series, but he goes through how to make. https://www.youtube.com/watch?v=s7TfPVVl0_U

Here's a rough drawing of what the underside of your cab could look like:
View attachment 2686767
The black holes are your passive intakes, the Light Killers are peice of cardboard that has been taped to the bottom in kind of a maze fashion to stop the light from going through. You should have two or three inches between the floor of the cabinet. Very simple, and probably the least intrusive way of building passive intake.

Click to expand...

Underside of it?! What?! Lol I'm confused now...

The picture is if you flipped the box upside down and looking at it from the bottom.

Yeah there's about two inches under it. But it only goes down to the floor on the corners.. Would i have to make sure the walls go all the way to the floor?

That's an easy fix with cardboard. The key here is that your getting the passive air without having to install fans. Drill,cardboard, and duct tape, and you've got yourself a passive intake

Sounds easy enough.. That would help tremendously because another fan would make it even louder. Do you happen to know that formula for how big of a fan you need for the box?

I think I read it on RIU, let me see if I can find it.

HA! Just found this posted by Bohbo on grasscity. I hope it helps!!

Q: How big of a fan do I need for my room?

Answer: Big Enough to replace the air in the room every 5 min.

Explanation: The air needs to be replaced every 5 minutes if you are not using CO2, the leaves need fresh CO2 and the the roots need oxygen. Use this formuila Take your total cubic feet and divide by 5.

LxWxH / 5 min

10'x10'x10' / 5 Min
=
1000 ft^3 / 5 Min
=
200 ft^3 / Min
= 200 CFM

So my cab is 2x2x3. After doing the math I end up with 2.4. This can't possibly mean I only need a fan with 2.4 cfm right??

Planted these in the Rockwool 2 days ago and they are looking great!!

Purplepuffer said:

So my cab is 2x2x3. After doing the math I end up with 2.4. This can't possibly mean I only need a fan with 2.4 cfm right??

Click to expand...

Yes, but i would at least double that because pc fans are rated in perfect conditions with no restrictions, as soon as a cage or any restriction (like having to passively suck in air from tight spaces) the cfm drops like crazy.
This may be my first post but I'm quite the computer nerd and thinking logically... It makes sense, companies want you to think highly about their products

Of course. I completely understand that now that you're saying something about it. So just throwing it out there would 2 decent sized computer fans be better or a 4" duct booster fan? I'm also going to be putting a DIY carbon filter on it as well.

It all depends on how you want to set it up. If you have the duct fans i bet that would be an easier setup, just make sure you have a fan with good pressure (look for fat fins) to blow air through the carbon and not act as a wall. Your best bet is using two duct fans with the carbon in between... If you can deal with the noise. Adding a second fan only ads about 3dB no matter the original rating