New Girl

[naturegirl92]

Hey Guys!

I'm a first time grower and wanted some feedback on a small grow box I'm trying to build. I was referred to icmag by a friend and have been doing a lot of research.

I wanted to see if anyone could tell me how to set up a PC fan for ventilation. I'm using a cardboard moving box so cutting holes for intake/exhaust should be pretty easy....I just don't know how many I'd need for around a 2 x 2 x 2 space.

Thanks!

 

[Canniwhatsis]

Your friend pointed you in the right direction!

Good luck with the micro cab!

 

[Avinash.miles]

cut a hole, preferably near the top, where hot air will accumulate, arrange the fan so that it is pushing air OUT of your box...
turn fan on when lites are on, off when lites are off

 

[rives]

You do know that you are going to need a DC power supply for it, don't you? The small "wall wart" style, like cellphone chargers, work well and you can find them in different voltages. Don't go over the fan's nominal rating (probably 12 volt), but running them on a lower voltage will slow them down and make them run quieter if they still move enough air for your box. Good luck with your application, you'll find lots of information and help here.

Don't forget about air inlet holes! The rule of thumb is to use double the area of the exhaust hole.

 

[mikeAKAsilas]

hey!

Here's what I built and it worked pretty well. https://www.icmag.com/ic/showthread.php?t=270591

Like Avinash said, you should put the fans at the top because hot air rises and that's what you want to remove. I ran my fan all the time to keep the smells under to control and prevent stagnant air in the box.

From what I've read, for a 2'x2'x2' space, or 8 cubic feet, you'd want a fan (or combination of fans) that can move between 24 and 40 cfm (cubic feet per minute) to replace the entire volume of air in the grow box 3-5 times per minute.

If you end up having heat problems where the temperature is constantly above 85*F, you'd want to increase the cfm of the fans to circulate the air more frequently and cool the temps down, assuming the ambient air outside the box is cooler than inside the box.

Lastly, you want to make sure to have intake hole area that is as large as, up to twice as large as, your exhaust hole area(s). Too small of intake holes will also decrease the functional cfm of the fan due to the increase of static pressure inside the box, and this is especially true for computer fans that aren't that powerful to begin with.

Keep in mind that ducting and/or carbon filters will lower the cfm that the fans move, so it's always better to size up.

Hope this helps!

 

[PetFlora]

Rives made an important comment regarding 'inlet holes'. These go near the bottom. Make sure nothing is in the way of them sucking air in as your fan pulls air out

Also buy a plastic tote large enough to cover most of the bottom to catch any spills. This will prevent the bottom of the box rotting out, and destroying the carpet or flooring underneath

 

[naturegirl92]

Wow, y'all are really helpful! Thanks!!

So for my small space, do you think I should have 2 fans (I pushing air out, I putting air in) or just the inlet holes with 1 fan pushing air out?

Sorry if I sound stupid, I'm just trying to wrap my head around it before I start.

I'll post some pics soon.

 

[naturegirl92]

Also, I forgot to mention I got a computer fan with around 50 cfm...and I have another one with I'm assuming a lot less (it was cheaper)

 

[Dingofriar]

Welcome to IC NG92! Since you've registered with ic mag you may utilize the search toolbar on top of page... It will help ya on your quest of growing and experiencing. It's kinda picky with searches, as an example if you search micro cabs it will display only about 4 treads but if you search micro cab it will bring up dozen or 2 prior threads that you can read and learn about to help ya on your grow style. Best of vibes and stay safe q;-)

 

[PetFlora]

Depends on the CMFs of the fan on top v cubic volume of your cabinet/cardboard box and how often you need to evacuate the warm air in order to keep temps < 85*s

2 smaller fans can equal CFMs of one larger fan, and probably be more efficient at moving the air.

I like my leafs to gently sway. This makes the stems stronger and minimizes humidity which can lead to mold

Wow, y'all are really helpful! Thanks!!

So for my small space, do you think I should have 2 fans (I pushing air out, I putting air in) or just the inlet holes with 1 fan pushing air out?

Sorry if I sound stupid, I'm just trying to wrap my head around it before I start.

I'll post some pics soon.

 

[mikeAKAsilas]

Wow, y'all are really helpful! Thanks!!

So for my small space, do you think I should have 2 fans (I pushing air out, I putting air in) or just the inlet holes with 1 fan pushing air out?

Sorry if I sound stupid, I'm just trying to wrap my head around it before I start.

I'll post some pics soon.

The single 50cfm fan *should* be enough unless you have temperature problems.

If you do have an inlet fan as well, make sure it's not as strong as your outlet fan or it will push smells out all the cracks and unsealed seems in your box, i.e. around the doors.