How Much Ventilation Do I Need in My Grow Room?

you have 112 cubic feet which is roughly 2/3 the volume your fan is rated for. However, the addition of a carbon filter adds resistance, as well as the length of ducting after the fan. If you can increase the diameter of the ducting after the fan, this will add a little help, also venting heated air upwards will also lend towards helping you out. I was able to effectively vent off heat from a 400watt hps with two 112 cam PC fans, but I didn't use my carbon filter. best way to find out is try and see what ya can come up with. maybe after all is said and done you're fan may not be strong enough, but it's better than nothing at all. if you're only growing one or two plants, you might even get away with no filter at all. Ona gel is another viable option for odor treatment.
 
If you run into air movement issues with your carbon filter making too much resistance on the fan, Ona Gel is the way to go. I hear Ozone generators work fantastic as well, but they are pricey, however air moves right through them.
 
Hey im new user but have used this site for information a while now and found some good advice on several topics. Im hoping someone can help me with my situation. I plan on converting my closed small closet area into a grow room. What im finding difficult is how i should go about my ventilation method.
My growroom is
4.5ft L x 3ft W x 5ft H = 67.5cfm
Was also advised to multiply this by 1.33 to make up for the 20% reduction caused by a carbon filter so iv worked it out to 89.7 cfm. (140m3/h)
Now for the noob part. Iv looked up ventilation and i think I have a basic understanding of it, but everywhere I look either have completely different setups (dif lights, more space) and theres so many people saying different things that its actually giving me a headache. I know the informations out there but i cant find the one most suitable for my needs. I planned initially to buy a "budget fan and extraction kit" from greens horticulture that consists of a ruck100a low power fan and carbon filter that moves 230m3/h. Or a ruck125a that moves 295m3/h Also planned on using a silverstar 125mm with maxibright compact with 250w sunmaster lamp
What i want to know is

1- is a ruck100a/ 230m3h adequate to extract the air of a room that is 140m3h? Or should i get the ruck125a/ 295 m3h?
Is renewing.the air twice a minute.enough?

2- will i need a fan to bring air in? Iv read you dont need fans to pull air in if its a small grow area, however you will have to if your area is closed. Is it possible i could use no fan and just use ducting as a vent at the bottom of the closet? Am i right in thinking the outtake extraction will pull the air up from the bottom intake duct? (is this possible?) or will this put too much strain on the ruck100a/125a fan? (should i get a more powerful extraction fan?)
Also take into account a have a 90degree turn in the duct and both intake and.outtake to ducts have to run 5 metres across my room.

3- if the above is not possible and i have to get a fan for the intake, what power fan should i get to extract and what fan should i get to take in? Can they be the same? and should i have different sizes in the ducting?

And an additional question: is carbon filter vital? I live in the attic and my room faces my garden so smell isnt really an issue.

I CANNOT put holes into the side of house and i want to buy all my equipment so please no diy answers.
Many thanks for any help you can give.
 
Thanks for no help people ;/ found the help I needed from another source
 
i use intake 4" fan and 4" vortex exhaust with phresh filter i take in air from outside though and run 3 6" fans for circulation and have 400hps 10 inches above plants and not even close to being hot on them
 
i am planning to build a 48Wx24Dx72H enclosure, with seperate compartments for flower, veg, germ/clones

I am using CFL in the clone, and led in the veg and flower rooms, so i can't imagine there will be alot of heat to deal with..
But what i am concerned about is smell.. i really need 0% smell.

So based on math of overall size is 48 Cu/Ft. + 20% due to carbon filter loss. = 57.6CF

So from this thread, it stated if only doing CO2, then take room divide by 5 and thats how much you need per CFM
57.6/5 = 11.52CFM..

To me that seems low...

What my plan was to get a (Or Even Two)
61gpWhRQT4L_SL1000_.jpg

Rated @ 104CFM @ 24dBA

Have it blow out the top of a box, with a 4x12 Pfresh Filter as the only inlet to that box,

Also have 120mm ports along the back bottom of each chamber for fresh air to come in. and 120mm ports to allow air out of the veg/clone chambers, with light proofing.


My overall goal is to make it as quiet as possible. but still do 100% cleaning of odor of air.


Thoughts?
 
I used 2 single blade fans from the same company each rated for 110 CFM. B/c my grow box consisted of using existing walls (in my closet), the sound spilled out into the living quarters when there was silence in the room, so beef up your walls a bit to dampen any noise that is produced. Judging from your space, I think you're looking to have 2-3 plants, but probably 2 which means there won't be as much smell as maybe anticipated. There will be odor, but just not as much. A grower buddy on this site had good results just pasting ONA gel in the ducting walls of his exhaust fan (BLOG LINK) so there's another possible option. When dialing in your rig, consider (before buying) what possible advances you'd like to make in the near future (if any) and shop accordingly. I now have a single 400 CFM inline fan, but when I got it, I only had a single 400w air cooled hood. However, I have since added 2 more 600 watt tubes to my rig so the 400 CFM fan is more appropriate. So even though you are using LEDs in the above defined space, you might still find a larger space to get more plants into and it might behoove you to shop for a larger fan and a speed controller. Just some thoughts to consider.
 
My flower space was 15"x30"x60", but I mistakenly designed a veg room to be above the flower room and needed to vent through both before finishing. Also, that space prevented me from using the air cooled hood so I DIYed my own to have one of those fans suck the heat right through the top of the makeshift hood and duct it right up into the veg box where it was then sucked out via the other fan. Many mistakes were made that I learned from and from now on will shop for what I intend to use down the road and just deal with the over kill
 
trying to design the ventilation for my grow closet as I'm bringing this all together, and I'm really having trouble. Not with the mathematics of air turnover rate, just more the logistics of stealth...so I thought I'd throw this out and have those of you who have done successful grows critique me to high hell!

My idea is a "box in a box"- grow tent inside a closet, as that gives me the controlled environment of the tent, reflective surfaces, and all the ports and connections I'll want/need. Then, because I'll be placing it within a closet, I can have another layer of security from guests...nothing says welcome to my home like a giant fooking black box in the corner! I don't have a basement for a secured grow area, and if I all of a sudden didn't allow my friends to grab a beer from the basement after doing so for over a year of living here, well, that would raise some eyebrows as to what was going on down there. And I certainly can't lock off my other bedroom, there has to be a way to camoflague/hide the tent within my "private" living space (my bedroom)- aka no visitors.

***now to the nitty gritty***

Originally I had hoped to intake/outtake from the closet into the tent, as I will be doing a 3-4 plant grow with LEDs and my primary concern is smell, much more than heat, assuming that the cracks around the door and frame from the closet will allow the "clean" air to freeflow in and out of the closet to the main house. I've already received advice that this will not be sufficient, and I need to have a way to get air from a larger source "piped in" and then "forced out", rather than just the closet.

Has anyone placed a grow tent in a closet (I'm looking at a 3x3x6, or a 4x2x6, approx.) and then made successful ventilation configurations that remain stealthy? Price isn't too much of a concern...a few bucks now can be recouped by what I'll save by not buying on the black market and what's a few bucks over time in jail^^:yahoo:
 
Lucky you, African Grower (and I) built a closet around his 4x4 grow tent in the beginning of November. The air is passively drawn into the closet from imperfect seems and corners etc and because the outer closet is situated in the corner of a bedroom, it also encompasses an actual closet that has his fan and is ducted straight through the ceiling and ties into the home's ducting. If someone were to enter the room, there might possibly be suspicion, but if his door was left ajar and someone walked by, they wouldn't bat an eyelash. His journal is linked to his name above. Details therein.

Edit - He's got a video update near the end of page 6 that shows the layout.
 
Lucky you, African Grower (and I) built a closet around his 4x4 grow tent in the beginning of November. The air is passively drawn into the closet from imperfect seems and corners etc and because the outer closet is situated in the corner of a bedroom, it also encompasses an actual closet that has his fan and is ducted straight through the ceiling and ties into the home's ducting. If someone were to enter the room, there might possibly be suspicion, but if his door was left ajar and someone walked by, they wouldn't bat an eyelash. His journal is linked to his name above. Details therein.

Edit - He's got a video update near the end of page 6 that shows the layout.

Wow! This is exactly what I was looking for, and the videos are a huge assistance. I need to look at all my options regarding holes in walls, etc. but the concept of grow tent inside a secure area is just what I was thinking of. Thanks for steering me to that journal!
 
Hi guys,

Massive newbie here so apologies in advance for my lack of understanding in this topic. I have been researching for the past few weeks on exactly how I can make a good stealth grow box and I believe I have most things understood. However when it comes to ventilation, I am having real issues.

So I have a box made from 16mm MDF that measures 900Wx450Dx1200mmH and looks like this.
DSC_05449.JPG


The box will have two doors on the front which I will be sealing with some weatherstripping and a latch to keep it closed. The inside of the box will be lined with Mylar and all joins sealed with silicone sealant.

I am looking to purchase a Mars Hydro 300W LED as the main light source
Marshydro 300W LED Grow Light 170W Draw Power 4 5kg VEG Flower Lighting Lamp | eBay

and also using two CFL's to cover any dark spots.

I was looking to use a soiless medium like Coco Coir growing some Northern Lights Feminised or Auto(haven't worked out which yet). 4 plants maximum.


What I need is someone to help me figure out what I need in the way of ventilation. I have access to a bunch of high quality PC fans which I was originally thinking of using but aren't sure if they will be enough.
Stealth is a big thing with this box as I am renting and need it not to be noticed when having inspections and things. It doesn't have to be silent, but the quieter the better.
I will be using a carbon filter to get rid of any smells but the whole process of getting the right equipment, putting it in the right place and making it all work has got me really stuck. If anyone could help me this it would be GREATLY appreciated!!

Also, if there are any growers from Aus it would be great to get in touch. I will need all the help I can get I think hahaha!
 
Some years ago, I designed (but never built) a stealth box and I worked a lot of those problems out. For starters, as you have a very confined space, I suggest NOT using LED lighting as LEDs really do need to stay roughly 18" above the tops to be most effective. I suggest consider using CFLs, or another type of light.

Carbon filtration might be your biggest problem b/c most units are sold as large cylinders which do not work well in that setting. I then redesigned the c/f to be an in-wall type filter that essentially is a length of ducting with plain carbon held in the middle. If air is to be exhausted, it has no choice but to pass through the carbon and be deodorized. I did implement this in my very next grow in a closet by attaching a PVC elbow to my exhaust port and stuffing a netbag full of carbon in that elbow and it worked well. So if you are able to create your own ducting from the wood, simply screen off the inlet and exhaust and fill the middle with activated carbon. I picked 20 lbs of activated carbon on fleabay for around $50, but some thrifty shopping will be needed to find that much at that price. Otherwise, you can put a regular cylindrical carbon filter on the exterior of your box and blow the box air through it. This does add some sound dampening properties which quiets your fan a bit, but obviously will add to the amount of space the overall project box will need to reside in.

If you are into electronics, a micro controller (such as Arduino) would be great to manage the conditions your box creates for your plants. By adding a clock module and a temp/humidity sensor to the arduino, the arduino can manage the run times of your fans to produce the most stable environment possible, but coding knowledge is a must to use Arduino, or other micro controllers.

For veg, getting rid of the heat and humidity is not as big a deal as it is during bloom, which means you can start your grow as soon as you seal the box and get a light in there, then make those needed adjustments at a later time.

Hope this helps. I will add some of my older photos to maybe inspire your creativity. Nice box BTW, nice craftsmanship!

Stealth_Box_Design_1.PNG
Stealth_Box_Design_2.PNG
Box-1.PNG
Box-2.PNG
DSCF11762.JPG
DSCF12704.JPG
DSCF12671.JPG
Activated_Carbon.JPG
Pre_Filters.JPG
4in_elbow.JPG
round_grate.JPG
 
Hi Skybound,

Thanks heaps for your reply, I really appreciate all the info!

LED no good for this box you say? I was thinking it would be a better option to CFL's due to the amount of CFL's I would need and the possible problems I would run in to with mounting and moving them around. Plus I thought the lack of heat generated by the LED would be beneficial in such a small space, I really want to avoid having air conditioning.
Are you able to suggest a way of mounting CFL's or approximately how many globes you think may be needed?

Wow that is a complicated setup, looks like it would work really well though.
I am not the most handy of people when it comes to building things so I was hoping to avoid as much construction and DIY as possible. Do you think I could achieve a similar result without building the inner walls? I can see myself having a hell of a lot of trouble trying to construct something like that.

Thanks also for the props! As i said before I am not very good when it comes to wood/metal work so I am really going out of my comfort zone with this project. However I think it will be totally worth it and a great learning experience if I can actually pull it off
 
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