# My new grow space



## cubby (Jan 16, 2011)

Hi all, 
   Well as the heading says I'm building a new grow space. I've always been an outdoor grower, and will continue to grow outdoors, I love seeing the plants swaying in the wind. 
   But I figgured it's time to try indoor. My only experience indoor is starting my outdoor plants in a 2 x 3 x 7 hydro closet with 4" inline fan and carbon filter combo, wich has worked pretty good so far. 
   My new space will be a dedicated room measuring 6x8x7 for a total of 336 cubic feet. From what I understand, and I may be wrong, I would need to exchange the air in the room 3-5 times per minuet. Wich means on the low side I would need a fan that is rated 1008cfm? Is this right? Would'nt that be a humungous fan? How much does a carbon filter reduce air flow? Would a larger filter offset the difference?
   I don't know if it enters into the equation, but the fresh air will enter the space thru a passive vent and exit the house thru a exhaust vent like those used for dryers.
   Thanks in advance for any advice or insight you may provide.


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## slowmo77 (Jan 16, 2011)

sorry Cubby, i've not been lucky enough to deal with a room that large so i can't offer any help. i would like to see some pics of this room when you get her up and running.. good luck


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## Jericho (Jan 16, 2011)

cubby said:
			
		

> Hi all,
> Well as the heading says I'm building a new grow space. I've always been an outdoor grower, and will continue to grow outdoors, I love seeing the plants swaying in the wind.
> But I figgured it's time to try indoor. My only experience indoor is starting my outdoor plants in a 2 x 3 x 7 hydro closet with 4" inline fan and carbon filter combo, wich has worked pretty good so far.
> My new space will be a dedicated room measuring 6x8x7 for a total of 336 cubic feet. From what I understand, and I may be wrong, I would need to exchange the air in the room 3-5 times per minuet. Wich means on the low side I would need a fan that is rated 1008cfm? Is this right? Would'nt that be a humungous fan? How much does a carbon filter reduce air flow? Would a larger filter offset the difference?
> ...



If you email the Filter company they will be able to tell you what reduction you will get on the filter. 

but yeh you are looking for a big fan hehe.


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## Peter Jennings (Jan 16, 2011)

Going to get some arguments here but I have always designed rooms that cycle one time in three to five minutes. I have read on here people say three to five times per minute which I have never read anywhere else.

I also have a program that does the calculation for you by entering the room size that was designed for the agriculture business. Entering your info it spits out a minimum of 62 cfm which will take five minutes to do it once.

Just keep in mind that this does not take in to account the lights, or any heat, humidity that may need to be removed so that needs to be addressed as well. 

If your plan is to filter and cool the lights be sure to at least filter the total room size with double the cfm of the total room volume, in this case around 780cfm and up.


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## cubby (Jan 16, 2011)

Thanks for the input guys. Peter Jennings especially. After reading your post I went over to HTG supply site and looked up the fan/filter combo I intend to purchase and they have the same info as you, as far as changing the air every five minuets as opposed to five times per minuet. So my 10 inch fan/filter combo at 790 cfm is more than adequet for the job. I don't think heat will be a major problem. the room is in the lower level of my home and stays around 60 degrees even at hieght of summer (it's perfect for cigars, wine, and my homebrew). Humidity is handled by a small dehumidifier that keeps it around 40-45 %.


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## StoneyBud (Jan 16, 2011)

Peter Jennings said:
			
		

> I have always designed rooms that cycle one time in three to five minutes. I have read on here people say three to five times per minute which I have never read anywhere else.


 
I found it in many places, PJ. The bottom line is however many times it takes to bring your growroom odor and heat under control.

*kindgreenbuds.com/marijuana-grow-guide/adding-ventilation-to-grow-area.html
*Your fan should be big enough to move the volume of your area 2 to 3 times every minute.

*420magazine.com/forums/how-grow-marijuana/71083-how-much-ventilation-do-i-need-my-grow-room.html
*And *seedsplaza.com/how-to-determine-number-of-fans-needed-in-a-grow-room.html
*When dealing with above average temperatures you will want your fan to exchange the grow room air 3-5 times in one minute

*howtogrowmarijuana-cannabis.blogspot.com/
*You will need a system that can remove the volume of your grow room 2 or 3 times every minute.


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## cubby (Jan 17, 2011)

Thanks for the input Stoney. As I said this will be my first real growroom so I'm looking at all pertenant info. 
   If in fact I would require a fan off a jubo jet then I guess I'll just have to scale back the size of the room.
   The room will be/would have been, 6x8, but the grow space was/is intended to be 3x8. I was/am going to hang a reflective curtain to concentrate light to the plants, then when I need to get in to work on them just move the curtain so I have room to move around without harming the plants.
   I had also thought there might be a difference when considdering plant count, but probably not. I only intend to grow 6-8 plants, but wether it's six large plants or a hundred short plants I immagine the amount of veggitative matter is the decideing factor for air cleaning. 
   I guess I got more researching to do.


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## StoneyBud (Jan 17, 2011)

cubby said:
			
		

> Thanks for the input Stoney.


 
You're very welcome cubby. The final fan size will depend on several factors.

1. Strain of weed and how much it reeks.

2. Heat in the grow area being ventilated.

3. Ability to cool the air that is cycled.

4. Noise levels you can stand.

I use a 530 CFM to clean 336 cu ft of grow area. The air is run through the filter and into a room that is cooled with a one ton a/c unit. Then the air is pushed back into the two 168 cu ft rooms using another 530 CFM fan that is identical to the exhaust fan.

This results in about 90% of the odor removal. When I come in from outside the house in the fresh air, I can still smell it just a little.

I think I'm going to add another fan. That should eliminate the odor for me with 3.16 times my Cu Ft.

I'm using a CanFilter100 with a single 530 CFM exhaust fan now that is split between two flowering rooms. I don't think the filter is the problem with mine. I think I'm just not pushing enough air through it at 1.58 times the room cu ft.


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## cubby (Jan 17, 2011)

My intended grow space is the same, 336cf. I was looking at a 10 inch fan, 790 cfm, but I can't find a 10 inch carbon filter. I can however find a 8 inch fan/filter combo that's rated at 590cfm. I'll be drawing fresh air from my lower level laundry room and venting it out the side of my house thru a dryer type vent.
High temps should not be a problem. The lower level of my house is below grade and without heat stays cool year round. Any increased heat would probably be bennifitial to the plants.


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## StoneyBud (Jan 17, 2011)

cubby said:
			
		

> I was looking at a 10 inch fan, 790 cfm, but I can't find a 10 inch carbon filter.


 
Would the 10" flange on this page work for your 10" fan?

*canfilters.com/accessories.html*

My CanFilter100 has a 10 inch flange that I had to reduce using one of those flanges to fit my 6 inch fan.


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## Rosebud (Jan 17, 2011)

This is exciting Cubby. fun, keep us up on everything.


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## Peter Jennings (Jan 17, 2011)

StoneyBud said:
			
		

> I found it in many places, PJ.



Like I said on my initial post, I would get some argument.:doh: 

I guess the more than 100 rooms I have professionally built are all wrong then, and because it has been posted on the net on a bunch of MJ sites they are all right. 



			
				StoneyBud said:
			
		

> The bottom line is however many times it takes to bring your growroom odor and heat under control.



I also addressed the fact that my calculation did NOT take in to account any heat issues.

The original question was on Air Exchange, and was not directed at either odor control, or heat.

As big a stickler you are for jumping on people for not giving the correct info or terminology, you ought to practice what your preach a lil brother. I can do a web search for anything I like. Just becuase I find a result does not mean it is the correct info. I'm not sure who the first person that transposed the correct info was, but like I said 3 to 5 times per minute is wrong. We are not building wind tunnels here.    

Got an Ipad? I'll direct you to a professionally designed grow room calculator or anyone else for that matter who wants to see how it's really supposed to be done.

Cubby, If you want to get some real hard info, I suggest you call one of these companies you are thinking about using, and ask to speak with one of the tech guys and report back.

I feel like until this is done and somebody gets back with the correct info this is going to be an ongoing thing here at MP because I have seen so many people posting the wrong info on Air Exchange.


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## Peter Jennings (Jan 17, 2011)

Going to back up my info with some real info. Most places I have seen run a calculation based on times per hour, but I'll try and find both for your viewing pleasure. This where I think someone screwed up and started talking per minute.

PS. Stony, I don't feel like your problem is that you need an additional fan, I think you are overdriving the crap out of your filter and it won't keep up. I'm curious though. If you are in fact using a one ton unit to keep the room cool. Why on earth do you cycle the air that much and not make it a closed loop system with injected CO2?
Maybe your using one of those window type units?

first source - hxxp://www.marijuana-seeds.net/OdorControl.htm - and I quote "The filter size required for you application will depend on the amount of air flow required for your application. Two rules of thumb are to maintain an air flow that is *eight to ten times the total volume of your vented space per hour*, or, for indoor growing applications, 150 CFM per 1000 watt light bulb"

second source - hxxp://hydroponicsdictionary.com/index.php?s=air+exchange - and I quote "General Hydroponics Carbon Air Filters work with any popular inline fan. Calculate the size of your room and choose a fan *that completely exchanges the air in the room eight to ten times per hour.* Then choose the appropriate filter with the correct CFM and flange size to match that fan.

Third source - hxxp://www.atlantishydroponics.com/Carbon-Filters-and-Air-Purification/Carbon-Filters-and-Air-Purification.asp


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## StoneyBud (Jan 17, 2011)

Jeeeez PJ, you've developed a hell of an attitude over nothing but someone not agreeing with you 100%.

Sorry pal.

Relax man. I'm not trying to say that you're wrong about anything. I'm saying that you and I think a little differently.

No offence was intended, but you obviously took offence.


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## The Hemp Goddess (Jan 17, 2011)

Peter Jennings said:
			
		

> ...Like I said on my initial post, I would get some argument....:doh:



Actually, what you said was:  "... I have read on here people say three to five times per minute *which I have never read anywhere else*."

Stoney was just posting other sources that also recommend exchanging air 3-5 times a minute.   Yours is an opinion, just as Stoney's is...


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## Peter Jennings (Jan 17, 2011)

No offence was intended, and I apologize if my post is taken that way.

I am trying to give the correct info which is based on facts, not opinions. 

My apologies.

PJ


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## StoneyBud (Jan 17, 2011)

Peter Jennings said:
			
		

> No offence was intended, and I apologize if my post is taken that way.
> 
> I am trying to give the correct info which is based on facts, not opinions.
> 
> ...


 
No offence was taken PJ. The point I was trying to make is simply:

The amount of CFM needed for any marijuana grow is dependent on the heat, amount of odor present and the conditions desired by the grower when the fan is running.

I'm not trying to argue with you man. Lots of new growers see a stat here and they think that stat is an absolute. I'm trying to explain to them that there are no absolutes really. It depends on the individual conditions and desires of each grower.

My links, (as HG said), were to only show examples of where the information I was giving were available elsewhere, as you said you hadn't seen it anywhere else.

Peace man. As far as I know, you and I have no problems about anything. I respect your experience and you've never shown anything but respect for mine.


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## cubby (Jan 18, 2011)

WOW.....I was'nt looking to get people fighting with each other, just some general info. I appreciate all of your input.
I just came back from my local Hydro store, talked to the owner, they have the 10 inch in stock with the 10 inch carbon filter. From what he said the 8 inch should work fine, but the 10 inch is'nt over kill. Because the more air that can be moved thru the space the better. My concern is solely odor elliminmation, heat and humidity should'nt be a problem, if they become problematic I'll have to address them when it occurs.
Again, thank you for the info and the cited references, it never hurts to have a wide variety data to contrast and compare.


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## starwarz (Jan 19, 2011)

cubby said:
			
		

> Because the more air that can be moved thru the space the better. My concern is solely odor elliminmation, *heat and humidity should'nt be a problem*, if they become problematic *I'll have to address them when it occurs.*
> Again, thank you for the info and the cited references, it never hurts to have a wide variety data to contrast and compare.



Sorry, gotta call ya on this cubby, bad idea..  What's you're light situation gonna look like?  are ya doing 6 1k's vertical in the little area or are you using 150w (480w comparison) big cfls? or MH?  

Get your idea down and working in theory before you start drilling holes and buying things.. last thing you want is to go buy three fans because the first two didn't work, then you decided to cool the lights and carbon scrub with different filters, and that original 4" $100 fan you thought would be enough is collecting dust....

So what kinda lights do you want to put in there, or have you put in there?

Bong#10 is coming quick... I feel I will become incomprehensible fairly soon.. maybe even forget how to use the mouse...


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## nouvellechef (Jan 19, 2011)

If you want my opinion Cubster, just ask. My scenario is completely diff than the ideas above for a 6x8x7 space.


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## cubby (Jan 19, 2011)

I just finnished taking out a wall, the back wall of a closet actualy. The lights I'm using are 2 600watt HPS. I'll start seeds under T5's, then when the seedlings can handle it they'll go under the HPS's. 
If I need to cool the lights I have a 4inch fan and carbon filter that I can dedicate to the lights. Just means punching an extra hole in the side of my house.
I'm growing for myself, I don't need a humongus amount, plus I'll still be growing outdoors (have had great success for 25+years). 
Nouvellechef, I'll PM you and pick your brain.


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## nouvellechef (Jan 19, 2011)

Cool. Heres what I typed out just in case  Since you already have 2, 600's. Thats mega juice the way I thought it out. Sounds good. You need anything, holla.

I would split the rooms. 1 veg and 1 flower. 

So 2, 6 x 4 x 7 rooms

1k air cooled light in flower

2, 40k lumen T-5's for veg

2, 6" CAP fans

6" R6 insulated ducting

2, 6" filters. Unless your ok without one in flower only

Flower is, filter>duct>hood>duct>Fan>Duct>6" flange>Outside

Veg the same, just no hood, filter only then outside. Seperate fans are nice, cause if one goes down, you are not dead in water.

Get the Pro-grips for lowering/raising lights

Thats it for ventilation and lighting.

PS. I know you have company. So for ultra quietness, esp since you are basically remodeling. Go thick on insulation or look into lining walls with eggfoam. Super stealth my friend. I know you like to BBQ like me in summer. Cant hear anything from couple feet away, blasting those fans.


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