CO2 versus ventillation

I'm planning on growing using the Deep Water Culture method. The main question I have is I was planning on using CO2 and I heard that proper ventillation is a must for using DWC. So what would be the best way to go about ventillating the room and using CO2?

Side Question: How early should I start using CO2 with my plants? How late?

You may not be able to use co2 in this instance. You know who you might ask is nongreenthumb thou, he may have a different take on this.

You will want to put your exhaust/intake fans on timers so theu are not running when your CO2 generator is. The information I have looked at pretty much says good controls are a must.

getting good controls aren't a problem, but I'm not sure as to what sort of time cycle to set them on. I guess maybe I could run the A/C into the room for a short while before running the CO2. I mean don't you think fresh air would be kind of irrelevant if you're running CO2?

There will be no problems at all using co2 with a carbon filter.

When you use the extractor fan though your going to be sucking it all back out again, so if you want to ideally refill the room with fresh co2 just after you finished venting so that it has the maximum amount of time in there


The formula for working out how much co2 to use is in this thread

https://www.rollitup.org/indoor-growing/4350-blackout.html

Sorry to post on someone else's thread, but nongreenthumb, do you think you could tell me more about cO2 supplements. What do they do? Do they increase the heat in your grow room? Can I not have ventilation and cO2? Sorry, I'm kind of clueless.

There is about 0.03- 0.04% c02 in the air we breath. Rapidly growing marijuana can use up the c02 in a grow room within a few hours.

By increasing the percentage to 0.12 -0.15 % plants will grow upto 2 or 3 times faster providing other factors such as light, water and nutrients are not limiting.

Co2 does not show any significant improvements under fluroscent tubes or low watt cfls as they do not put out sufficient lumens to process the extra.

Co2 does not increase the thc content, but it does increase the amount of foliage, so it will give you a larger volume of thc.

Co2 enriched marijuana demands a higher level of maintenance that normal plants, they can use upto double the amount of nutrients water and space.

A higher temperature of around 85 deg f, will help simulate more rapid metabolism within the enriched plants.

i was thinking about this myself.... My main question is why do you vent a room ??? i thought it was to remove heat mainly!! With that being said what if you have a A/C, De-humidifier, circulating fan and add CO2 in a airtight growroom. You wouldnt need to vent more than twice a day if that much. Because you would have created a perfect enclosed environment. That just my take on the situation.... Purple i think you might be good with vent twice a day if you have a A/C for heat control hence saving alot of CO2... I'm a noob so listen to the pro's just trying to think logical...i

if you did all that and then added an ozone generator to remove the smell and worked it all at the right times you wouldnt need to vent

So venting is basically just to get rid of the old air and the smells right?

and if you havent got an air conditioner in there to tackle the heat from high intensity dishcharge systmes but the air conditioner will raise humidity, so to counteract this use a de-humidifier

I use Bottled CO2 and DO NOT exhaust the room. I have plenty of air circulation but it is a sealed room.

I recommend the CAP PPM-3 CO2 monitor/controller and the CAP regulator/solenoid hooked up to a 50 pound CO2 bottle. CO2 generators give off heat and are great for larger rooms. Same thing with de-humidifiers.

My grow area is 10'x14'x7'. I run CO2 during lights on ONLY during Veg and Flower. I keep the CO2 levels at 1,500 PPM's for the entire lights-on cycle. I also run dual 1k HID sealed and air cooled lights on switchable ballasts. CO2 is the shit. It increased my yields by 30% easily.

okay so say I built a small grow box just big enough to put my set up in (lights, plant, several bottles of ghetto home made shake n' made CO2). So correct me if I'm wrong, but what I would do is make a shaft, sealed to an airtight box around the window, and have it run into an airtight sister shaft towards the bottom of the box with a blower to run the fresh air in, and some sort of odor control. Other than the door, which would be sealed with duct tape when not open, there would be no other openings in the box, would this be an ideal setup for using CO2? And for something like this, what would be the ideal choice for odor control, there'd be about 4 plants in the box all together, so guestimate the amount of space and let me know what I might need to modify.

UPDATE: There'd actually be two boxes, one for flowering, and one for veg. You can imagine how much smaller the veg. box would be. Thanks for the gracious replies!

Purple_Ganja said:

okay so say I built a small grow box just big enough to put my set up in (lights, plant, several bottles of ghetto home made shake n' made CO2). So correct me if I'm wrong, but what I would do is make a shaft, sealed to an airtight box around the window, and have it run into an airtight sister shaft towards the bottom of the box with a blower to run the fresh air in, and some sort of odor control. Other than the door, which would be sealed with duct tape when not open, there would be no other openings in the box, would this be an ideal setup for using CO2? And for something like this, what would be the ideal choice for odor control, there'd be about 4 plants in the box all together, so guestimate the amount of space and let me know what I might need to modify.

UPDATE: There'd actually be two boxes, one for flowering, and one for veg. You can imagine how much smaller the veg. box would be. Thanks for the gracious replies!

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4 plants need a 2x2 if not 3x3 area.

Your set up sounds ok but I am not sure of the details? The CO2 has to be kept around 1500 PPMs. Any CO2 is better than no CO2 but you do not want CO2 levels above 5,000 PPM's or so because it could kill your plants. You can buy CO2 test strips to see what levels you are running and then just tweak it from there.

Alright, as far as the grow room goes, for veg I approximate about 5' X 5' X about 7' tall. For Flower I approximate a room (neither are built yet, but giving the space provided, this is what I can do) about 5' X 10'. Will be using an in/out temp & humidity meter, and a seperate meter for CO2. Will probably be using a CO2 Boost bucket to start out. I'll be using the Dual Spectrum Bubbleponic 6 Planter Complete Kit w/ Duel Spectrum II lights upgrade


I'll be adding more lights later. also I found a pretty good deal online, 4" blower and 4" carbon filter for only $200 man that's a steal right there...

I don't see a reason why DWC needs more ventilation than any other system. The fact is if you don't implement CO2 you have to ventilate to replenish CO2 supply.

But if you do supplement with CO2, the best thing is to seal the room, no ventialtion whatsoever.

At least that's what I do with both my E&F flowers and my bubbler moms.

Now as for when you should use CO2, that is a debate I don't want to get into, most will tell you to supplement only during flowering and during day. Me, I just boost my CO2 to 1500 PPM all day and all night in both my flower room and in my vegetative/cloning room. But this is not really practical for most growers, you might end up wasting a lot of CO2. But my grow is completely sealed, boosting the CO2 all the time is rather cheap for me.

But franckly, I wouldn't use CO2 for a small grow such as yours. CO2 is more for the hardcore growers if you ask me.

edit: Scratch the last sentence. I just saw the size of your grow in your last post ..... sounds to me you got a fair size grow .... enough to bring in the CO2 gods ...... but go easy on spending cash on all the stuff. CO2 boosting only works when all other parameters have been maximized as well.

nongreenthumb said:

if you did all that and then added an ozone generator to remove the smell and worked it all at the right times you wouldnt need to vent

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thanks for your advice before,i have now used the co.2 gen with my new grow,and i have it at about 29 celcius,no venting as i have air con,but when the lights go of i go in open the vent just to get rid of old air,not for long though,and my plants really have grown heaps faster,but i have just dropped the hours to flower,so i have turned the co.2 off,as some have said not to use it in that stage,but they look great,and grew a lot quicker,but as you say higher temps, more use of water,and nutes,but i am not complaining, it is a fucking forest in there.
thank for the help,i do have a ionizer but not for smell,as i dont have next door folk to worry about,just it is supposed to be good for the plants??,but the only fuckers that smell my grow is the skippys,and they have not rang the filth on me so far.

blackout said:

thanks for your advice before,i have now used the co.2 gen with my new grow,and i have it at about 29 celcius,no venting as i have air con,but when the lights go of i go in open the vent just to get rid of old air,not for long though,and my plants really have grown heaps faster,but i have just dropped the hours to flower,so i have turned the co.2 off,as some have said not to use it in that stage,but they look great,and grew a lot quicker,but as you say higher temps, more use of water,and nutes,but i am not complaining, it is a fucking forest in there.
thank for the help,i do have a ionizer but not for smell,as i dont have next door folk to worry about,just it is supposed to be good for the plants??,but the only fuckers that smell my grow is the skippys,and they have not rang the filth on me so far.

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I did read somewhere though that ionizers reduced the smell of the bud not just the smell released.

dsswhiz, I believe you are talking about a sealed system, this is commonly done.

Ionizers don't change anything to a plant's growth. In too large amounts and over time, it can be toxic to humans too ... but many will question this.