How Much Ventilation Do I Need in My Grow Room?

[FiveToMidnight]

Being is Aussie country, keep an eye out for other successful growers on the web and also down under, and make note of their routines, nutrients they use, are they available for questioning or any other supportive element that would apply. Also, if this will be your first grow, you'll be way more in tuned to every little shift or change so take good notes to monitor responses to techniques you try, and also responses to nutrients. Not knowing a lot about coco, I do know that many growers have been using it for quite a long time which is a statement in and of itself. I expect your grow will go very well and I like the veg time you chose, I think it will jive well with the cabinet height. When you start a journal, please PM me the link as this thread is someone else's.

That is good advice, I will do that.
I intend to make quite a detailed journal so it should be a good way of keeping notes. I should start it soon as you make a good point that this is someone else's thread and being about ventilation, my questions have been answered.
I will be sure you PM you the link and thank you soo much again for you all valuable help! It has been greatly appreciated and could not have got this far without you.

 

[Amandisa]

Hello!
I am at the moment building my first grow-tent setup and was wondering if I need to increase the exhaust fan in my tent?

My setup:
Tent: 4x4x6,5
Light: Mars II LED Grow Light 1200W
Exhaust fan: TT160mm at 552 m3/h / 325 CFM
Charcoal Filter: PrimaKlima 650 m3/h / 383 CFM

Will I have any heat problem with this setup?

Thanks!

 

[Skybound]

Unless you're local climate is extremely hot, I think you'll be just fine, especially with just LED lighting. I cool my HIDs with less air movement.

 

[Amandisa]

Unless you're local climate is extremely hot, I think you'll be just fine, especially with just LED lighting. I cool my HIDs with less air movement.

Thanks mate!
I live in a scandinavian country where the summers usually are between 12-22 degrees C and winters are usually -20 to +2.

Thanks for the info once again mate!

 

[Gaffle]

I am, for the first time, going through the motions of building a "under the stairs" room. I have 2 younger kids running around and I would like to keep my crop a little bit of a parent secret. The space under the stairs would be most excellent (I hope) for a small tent. Nothing fancy, just a 2-3 planter. My question is with venting. I really do not want to cut a hole in my brick for an outside vent. I am looking for options to curb the marvelous smell. I would hope that I could run the tent with a LED array minimizing heat. A vent going back into the room would be ok I think. The door to this room is very much not sealed well. There would be plenty of air movement for a carbon filter to suck it all up. Or would there?

Here is to the pros. Is it feasible to vent inside your house as long as the heat isn't an issue? I feel like I would go LED all the way. I really haven't looked into the operating costs as much, but I know how efficient the LED market has become. I would like to keep my electrical footprint as low as possible. So small tent, 1 light setup (LED, HPS, CFL), and carbon filter/scrubber(?).

 

[FiveToMidnight]

Can anyone suggest a way to increase the suction of the outake without getting a bigger fan?

 

[Skybound]

I am, for the first time, going through the motions of building a "under the stairs" room. I have 2 younger kids running around and I would like to keep my crop a little bit of a parent secret. The space under the stairs would be most excellent (I hope) for a small tent. Nothing fancy, just a 2-3 planter. My question is with venting. I really do not want to cut a hole in my brick for an outside vent. I am looking for options to curb the marvelous smell. I would hope that I could run the tent with a LED array minimizing heat. A vent going back into the room would be ok I think. The door to this room is very much not sealed well. There would be plenty of air movement for a carbon filter to suck it all up. Or would there?

Here is to the pros. Is it feasible to vent inside your house as long as the heat isn't an issue? I feel like I would go LED all the way. I really haven't looked into the operating costs as much, but I know how efficient the LED market has become. I would like to keep my electrical footprint as low as possible. So small tent, 1 light setup (LED, HPS, CFL), and carbon filter/scrubber(?).

For the space, you wont be able to consume enough electricity to warrant a concern, especially when considering the benefits. What is of concern is not being able to exhaust the heat as it will accumulate, unless you live in an arctic region. Carbon filtration will suck up the smell, but the fans needed to pull that air will make noise and I've found this to be one of the biggest issues to deal with when trying to maintain stealth. I think it is Marigold flowers that have the scent of a burnt doober so perhaps keeping a few around the house to distract curious noses.

Can anyone suggest a way to increase the suction of the outake without getting a bigger fan?

This is not really possible unless you decrease the space that it is sucking from, ie your grow area. Any time you add a bend, or a bottleneck in your ducting, you decrease the fan's efficiency and CFM rating. Perhaps you can add another equal or lesser rated fan to assist in air movement? Also, increasing ducting diameters will allow the fan to move more air quieter, but there will be less suction, so keeping the draw area constantly filled with air to be suctioned off will help accomplish what you want. Even strategically placed clip on fans will help you get to where you wanna be.

 

[FiveToMidnight]

This is not really possible unless you decrease the space that it is sucking from, ie your grow area. Any time you add a bend, or a bottleneck in your ducting, you decrease the fan's efficiency and CFM rating. Perhaps you can add another equal or lesser rated fan to assist in air movement? Also, increasing ducting diameters will allow the fan to move more air quieter, but there will be less suction, so keeping the draw area constantly filled with air to be suctioned off will help accomplish what you want. Even strategically placed clip on fans will help you get to where you wanna be.

Would it be benificial to keep my ducting as short as possible? At the moment I have quite a but it slack creating a couple of hanging bends, if I made it all straight would that make a difference?
I was planning to put another small oscillating fan inside but was worried that would cause positive pressure if I don't have enough suction. Is this a correct assumption?


[Edit] Here's a couple of pictures I just took so you can see what it looks like. Any comments about any part of it other than what I have already asked are highly appreciated also!

 

[CptGrowman]

Question for someone. Thinking of starting an auto soon. I have ballast and 400 wat hps and 4 NL's coming if they make it! But I do not have a tent or any type of enclosure. Could I just set it up on my work bench in the garage or do you need a tent or enclosure?

 

[Skybound]

@ 5to - If your lights will not be changing heights, than it is best to have the least amount of travel as possible for max efficiency. Also, flex ducting causes a lot of turbulence which further reduces your fan's efficiency so stretch it out as much as possible. Don't overly concern yourself with "suction" as it is very difficult to create a true air lock and an air tight room. Just as long as the CO2 is constantly replenished, you're fine. Also, don't be overly concerned with heat removal unless temps get into the unmanageable range. Sometimes, you may actually want to keep some or all of the heat produced from your equipment, so you'll have to make your own executive decisions in terms od what produces the most stable climate. traditionally, a lot of our knowledge has originated from larger grows with many kilowatts of light the produces a lot more heat than our smaller micro style grows will ever produce. Just try to stay in the medium 70's (Fahrenheit) range, or (C) equivalent. Also pay attention to humidity. Roughly 60% for vegetative growth and 30% range for bloom growth. Sometimes these ranges are difficult to achieve, but your best effort to provide those ranges will result in a monstrous yield.

@ Cpt, an open space will actually work better for you as the climate will be more stable. So long as you don't mind the obvious concerns the rest of us have regarding our grows being open to everyone that can catch a glimpse or wiff, you'll be just fine. Me personally, I am not a fan of the tent except in certain situations. Im a DIY guy and would rather build a room to utilize the most space I have available to me. A tent is a finite dimension that may or may not maximize the space I have to work with. If you're in a legal jurisdiction and have no concern about other knowing, do you're thing my man!

 

[FiveToMidnight]

@ 5to - If your lights will not be changing heights, than it is best to have the least amount of travel as possible for max efficiency. Also, flex ducting causes a lot of turbulence which further reduces your fan's efficiency so stretch it out as much as possible. Don't overly concern yourself with "suction" as it is very difficult to create a true air lock and an air tight room. Just as long as the CO2 is constantly replenished, you're fine. Also, don't be overly concerned with heat removal unless temps get into the unmanageable range. Sometimes, you may actually want to keep some or all of the heat produced from your equipment, so you'll have to make your own executive decisions in terms od what produces the most stable climate. traditionally, a lot of our knowledge has originated from larger grows with many kilowatts of light the produces a lot more heat than our smaller micro style grows will ever produce. Just try to stay in the medium 70's (Fahrenheit) range, or (C) equivalent. Also pay attention to humidity. Roughly 60% for vegetative growth and 30% range for bloom growth. Sometimes these ranges are difficult to achieve, but your best effort to provide those ranges will result in a monstrous yield.

Please excuse my ignorance but are you saying that I should shorten the ducting and stretch it so there is no slack?
I wasn't planning on moving the light but more moving the pots towards or away from it, seems like the easier thing to do. However I have made it so the light can be moved down or up if needed. In the pic it is at its maximum height though.
At this moment the CO2 is being replenished, I'm just wondering if that will still be the case once there are plants in there and an oscillating fan? We will see though I guess.
I ran it for about 6 hours the other night and it sat at around 25-30 degrees Celsius with about 20-30% Humidity. Do you have any suggestions on how best to control those factors?

 

[Skybound]

Yes, I would use as little flex ducting as possible which equates to little to no slack. By stretching it all the way out, the ribs and foil open in such a way to minimize turbulence which will allow your fan to move more air easier. By having all that excess and slack, the air must travel across all those turbulent pockets and past the extra bends which makes the fan work harder to accomplish its intended purpose.

RH percentages mostly mimic that of the surrounding area so you may need to add some humidity while in vegetative (18/6). However, due to bud growth and the plant having much more surface area when in bloom (12/12), you'll see that the plant actually sweats a lot and if this perspiration is not removed, you'll run the risk of powdery mildew or other molds forming in your buds and ruining your harvest. If your plants are still in veg, and your room's RH is 30% range, you might run into Potassium (K) deficiencies. If your RH is 30% range while in bloom, you're in the sweet spot.

 

[FiveToMidnight]

Yes, I would use as little flex ducting as possible which equates to little to no slack. By stretching it all the way out, the ribs and foil open in such a way to minimize turbulence which will allow your fan to move more air easier. By having all that excess and slack, the air must travel across all those turbulent pockets and past the extra bends which makes the fan work harder to accomplish its intended purpose.

RH percentages mostly mimic that of the surrounding area so you may need to add some humidity while in vegetative (18/6). However, due to bud growth and the plant having much more surface area when in bloom (12/12), you'll see that the plant actually sweats a lot and if this perspiration is not removed, you'll run the risk of powdery mildew or other molds forming in your buds and ruining your harvest. If your plants are still in veg, and your room's RH is 30% range, you might run into Potassium (K) deficiencies. If your RH is 30% range while in bloom, you're in the sweet spot.

I understand, I will make the changes today and see the difference it makes, thank you!

How would one add or subtract humidity?

 

[Skybound]

A humidifier in very arid conditions, or a bucket of water with or without a fish tank heater will add RH. An AC unit or dehumidifier to remove some humidity.

 

[FiveToMidnight]

A humidifier in very arid conditions, or a bucket of water with or without a fish tank heater will add RH. An AC unit or dehumidifier to remove some humidity.

Hmmmmm, that may be difficult being such a small space.
Well I have started it anyway and we will see how we go. I think it should be ok

Have a look at my journal and let me know what you think
FiveToMidnight's First Grow - Coco/Perlite - NL - MarsHydro 300W LED - 2015

 

[iBreakAway]

I have an 18x18x8.5 double car garage (roughly 2700 cubic feet). Could someone PLEASE recommend an affordable intake fan and an outtake fan/filter for the space? I'm going to run 9 1000 watt reflectors and cool them with 3 6" fans.

 

[Skybound]

iPower is the cheapo brand I use, but like all else, ya get what ya pay for.

 

[susbb]

After how many times I get buds form this

 

[Yojitoke]

Hello ) don't want to create a new post so I'll post in here )

my room size is 120x120x200cm so Im going for a 187 M3/h fan for the exhaust with carbon filter..( I won't be using all that space for growing and before I update my light id rather get the air sorted first.

So my question is basically::

Would I be able to use the intake vents just as incoming air or would i need a small intake fan? ( ie: 2x 120mm fans or should they be used just to move air about the room? ) or what would be the best intake fan to use with this exhaust fan?

 

[Skybound]

Carbon filter won't be needed until roughly half way into bloom. You'll be fine with your 120mm fan on the exhaust side. You can inlet air passively through holes and such. Only reason to bring new air in to begin with is to replenish exhausted CO2 levels. If you can generate enough CO2, you can completely air lock your grow space. If you can only make minimal CO2, than your air system can be designed to also move air in and out much less than normal. If your concern is heat and humidity, I once used a 120mm PC fan to vent a 400w HID and also through a DIY carbon filter which made a lot of resistance against the fan. The fan worked well, though I should preface that it is a 120 volt fan, not a 12 volt.