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

Ventilation is not just to get rid of bad air in the grow room—keeping the air moving is essential for plants that have complicated respiration processes involving not just CO2 but oxygen and water.

Ventilation is also used to keep the heat down, especially considering the increased heat put out by a CO2 generator. I presume you’re burning propane in order to make CO2.

A cooler method (but also more expensive) is to buy compressed, bottled CO2 and have it released by a timer.

Your postings have yet to touch upon the topic that seems to be concerning everyone these days—carbon emissions.

If you generate CO2 and allow a lot of it to escape via a venting system or cracks under the door or other openings in your grow room, you are actually contributing to global warming.

It is estimated that normal air contains about 300 parts-per-million (ppm) of CO2. Advanced Nutrients Medical, my cannabis specific company of choice, advises to generate as much CO2 as the strength of your nutrient solution.

When generating CO2 your plants require considerably more food than without this additive. So let’s say your solution contains 1,500 ppm of nutrients, then you should be generating 1,500 ppm of CO2 in the room.

If you stop generating this gas, it takes about three hours for the air to go from 1,500 ppm of CO2 back to the 300 ppm CO2 level.

The best solution is to have a totally closed room with A/C to keep the air at the desired temperature (around 75º F). Then you’re not contributing to global warming.

If you adjust your timers to stop venting to the outside while CO2 generation is going on, then you’ll minimize your emissions to the outside.

CO2 does help produce higher yields, but it’s not the only factor. Using cannabis specific base nutrients such as Sensi Grow A & B and Sensi Bloom A & B, along with all the root colonizers and supplements that Advanced Nutrients Medical manufactures, has provided me with huge buds and abundant harvests for a number of years now.

Even though I’ve cut back on my CO2 use, in order to be a better global citizen.

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!

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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...

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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.

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.

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.