# helpful info on co2



## monster kush (Aug 7, 2009)

Plant growth requires a tremendous amount of carbon dioxide (CO2). At the center of every plant cell is an *atom of carbon*, which the plant has absorbed from the surrounding atmosphere. When all other growth influencing factors are kept in their ideal ranges, CO2 becomes the limiting factor. This means as you increase the CO2, you will also increase growth rates and yields.






The ideal level of CO2 supplementation to maximize plant growth in a well maintained garden is generally *1500 ppm*


In one final twist of irony, as you begin to increase carbon dioxide levels to maximize plant growth you will reach a point where *temperature* becomes the limiting factor. In order to benefit from the highest levels of CO2 supplementation (1500-2000 ppm), you actually need to run your garden area *warmer* than normal (80-85 degrees). On average, plants will also require an extra 30 watts of light/sq.ft. (80-100 watts/sq.ft.). Plants will use extra water and nutrients under these conditions, so make sure they are available!


This has one implication which may offer you (the indoor gardener) a very *nice solution* to one of your most difficult problems. If all other factors are perfect in your garden EXCEPT your temperature, you may be able to maximize plant growth AND solve your heat problem at the same time with the addition of CO2.




*When Should CO2 be Used in a Garden?

*

CO2 should not be used in a garden where you have to constantly run your exhaust. CO2 should only be used in a well sealed garden area, and should only be used when there are decent periods of time between exhaust cycles. The most ideal circumstance is to use CO2 supplementation in an area that is cooled by air conditioning.




*The Best Ways to Produce
CO2 for Indoor Gardens

*

There are two good choices for efficiently increasing the CO2 levels inside your garden. The first method is to use a CO2 generator. The second option is to use tanks of compressed CO2.





Generators are more convenient because they hook up directly to your natural gas line or propane tank, eliminating the need to periodically fill your CO2 tanks. They also include a dial to adjust CO2 levels. The drawback is that they produce extra heat as well as CO2. Most of the heat is ducted away, but can sometimes still cause a problem for plant growth.





I prefer the second option, which is to use *tanks* of compressed CO2. My garden is only a little larger than personal size, so my CO2 tank does not need to be refilled that often. Furthermore CO2 is cheap, and compressed CO2 does not add any heat to the environment when released.






The most efficient use of CO2 is with air conditioning, otherwise you end up exhausting a lot of CO2 out of your garden




*The General Setup for a
Tank Based CO2 System

*





The pressure in a CO2 tank is around 1200 psi. In order to run CO2 tanks, you need a *pressure regulator*. The regulator will step down the pressure to about 50 psi, so it can be managed by the solenoid valve. Some regulators have two gauges, in which case one gauge displays the tank pressure while the other displays the release pressure.





Tubing is strung above the tops of the plants and run to the solenoid valve. The tubing has many microscopic holes in it, which allow the CO2 to be evenly distributed through the garden. As carbon dioxide is released, it sinks down into the plant canopy because it is heavier than air. An oscillating fan placed on the ground will help keep circulating the CO2 through the plant growth.




*How to Get CO2 Levels Right
With Your Tank CO2 System

*

There are two ways you can set up your tank system to release the proper amount of CO2. The first way is to figure it out using mathematical calculations and set timers that will control your equipment.


The other way is to use a CO2 controller with a sensor. Today's controllers have easy to use dials and digital display panels that make it very easy to set the desired CO2 level.



*
CO2 Calculations and Setting Timers

*

The normal atmospheric CO2 level is about 300 ppm. The ideal range for maximum plant growth is 1500 ppm. That means we need to increase CO2 levels by 1200 ppm (or *.0012*) in the garden area.


First we need the volume of your garden area. This is length x width x height. For our example we will use a 5 x 5 x 8 foot room with an air volume of 200 cubic feet.


Next, we calculate how much CO2 to add the garden area by multiplying the volume of your garden by .0012. For our example this would be 200 x .0012, which equals .24. So, it will take .24 cubic feet of CO2 to bring the garden in our example up to 1500 ppm.


Now to your CO2 tank regulator. On the tank there is a pressure regulator valve and also a flow control valve. The pressure valve is usually set between 50 and 100 psi, depending on the recommendations for the equipment you have purchased. The flow control valve is adjustable, and cubic feet per hour (CFH) is used for the measurement.


In our example, if you set your flow control to .24 cubic feet per hour, and programmed a timer to leave the solenoid valve open for one full hour, you would slowly bring the room up to 1500 ppm by the end of the hour (assuming you didn't have to exhaust in the meantime to bring your temperature down). The following is a more realistic way to set this up...


Set your exhaust fan to kick on at 95 degrees, and kick back off at the ambient room temperature. This will cause the room to get a little warm for a short time during the cycle, but it should not do any harm. Watch it for a while and determine how long You have in between exhaust cycles (while the fan is off). For maximum plant growth, you want to achieve 1500 ppm in the garden area *at least 2/3* of the way thru this time period. Let's use our example one more time...


Let's say you watch the system and determine you have 30 minutes between the exhaust cycles. You need to release .24 cubic feet of gas to bring the room up to 1500 ppm, and you need to do it in less than 20 minutes (2/3 of the way through 30 minutes). Releasing the neccessary amount of CO2 within 10 minutes would certainly be within these guidelines, and would give your plants a little extra time in the fully enriched environment.


The relationship between time and your flow rate is inversely proportional. That simply means if you take 1/4 the time, you need 4/1 flow rate (that's 4 times). In this example, we want to release the required amount of CO2 in 10 minutes, which is 1/6 of an hour (60 mins x 1/6 = 10 mins). We therefor need to multiply our old flow rate by 6/1, or by 6 in other words. The result is...


*.24 CFH x 6 = 1.44 CFH*
​Now you set your flow rate to 1.44 cubic feet per hour and program the CO2 timer to come on for ten minutes immediately following your exhaust cycle. All done, now you are ready to maximize your plant growth!



*
Advanced Atmospheric Control

*

A controller is used to make all your atmospheric control devices work with each other smoothly. Below is an example of how a controller setup might look.






The controller itself consists of the center piece and the digital display panel, where you can set the desired CO2 level. The panel controls both the exhaust fan and the release of CO2. A built in thermostat will kick your exhaust fan or air conditioner on when needed, it will release CO2 when needed, and it will keep the CO2 turned off whenever the exhaust fan is running. In addition, most controllers have a light sensor that will prevent CO2 from being released at night (if not, a timer can be used).


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## monster kush (Aug 10, 2009)

was this helpful to any of the 46 peeps that viewed it yet?


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## RickWhite (Aug 10, 2009)

Good info. I wasn't aware that a warmer environment increased CO2 uptake. I wonder how much because this is not good for guys using a DWC as it can cause root rot.

Doesn't this make you wonder how the whole "greenhouse gas" argument makes sense. If CO2 levels increase wouldn't all of the vegetation on Earth just grow faster and use it all up?


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## bios (Aug 11, 2009)

I learned a thing or two.



RickWhite said:


> Good info. I wasn't aware that a warmer environment increased CO2 uptake. I wonder how much because this is not good for guys using a DWC as it can cause root rot.
> 
> Doesn't this make you wonder how the whole "greenhouse gas" argument makes sense. If CO2 levels increase wouldn't all of the vegetation on Earth just grow faster and use it all up?


Good point rick, i never thought about it before, but our ecosystem does have a way of balancing things out. just one more reason for me not to believe in global warming.


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## LowEnder (Aug 11, 2009)

good info... I knew most of it, but its laid out better than what most people have tried to do. Should be a sticky in the newbie section or garden design section.


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## RickWhite (Aug 11, 2009)

Just checked The Bible and it does mention 75-80 deg F but that CO2 absorption slows at 90F. Question is, what is the temp under the grow light at an given time? I have to think a room cooled with AC and kept around 75F would be closer to 85F when the light is over head. Especially with a mover and the light being closer.


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## RickWhite (Aug 11, 2009)

bios said:


> I learned a thing or two.
> 
> 
> 
> Good point rick, i never thought about it before, but our ecosystem does have a way of balancing things out. just one more reason for me not to believe in global warming.


MI has had one of the coldest winters on record this year and a couple years ago. Evidently the Earth is now cooling and they are no longer using the term "global warming." Now it's called "man made climate change."

I'm old enough to remember the big "global cooling" scare in the 70s that turned out to be bunk. Not saying climate change doesn't exist, I'm just not one to jump on board with every new "theory" that comes down the pike.

Anyway, sorry for the thread jack.


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## monster kush (Aug 13, 2009)

glad this is helpful i find there are a lot of people that want to use co2 but dont want to buy a controller this post has great info on setting flow rate on tank ............thought this post would bring me some +rep or rated r something


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## fenispingers (Aug 17, 2009)

Rep for you then . I can believe in global worming , if we really are cutting down so much rain forest , then the earth can't "right" it self right ? Make the world a better place grow a plant !


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## monster kush (Aug 31, 2009)

ty right back at cha


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## zuluguy (Sep 21, 2009)

+rep for you... I just purchased a tank and regulator, this will come in handy during setup


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## LacyLePlant (Sep 21, 2009)

Great Thread!


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## shinyboy (Sep 25, 2009)

thank you... i tried to show my friends a Time article from the 70s claiming the end of mankind due to global cooling when all this hype started with global warming. they wouldnt have it. the earth is an organism itself and is constantly changing just as we are. 
and great post on how to control cliamate. thank you.


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## ocgasm (Sep 28, 2009)

shinyboy said:


> thank you... i tried to show my friends a Time article from the 70s claiming the end of mankind due to global cooling when all this hype started with global warming. they wouldnt have it. the earth is an organism itself and is constantly changing just as we are.
> and great post on how to control cliamate. thank you.


 What about using it a small closet 2x2?


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## suTraGrow (Oct 25, 2009)

whats a good controller that monitors your ppms for you and activates the co2 set up when it drops lower then 1800ppms in your room?


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## olscratchy (Oct 25, 2009)

Great info,


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## SaneLawsMake4SaneSociety (Feb 14, 2010)

the mechanisms the earth uses to right itself are the very things we are destroying, while at the same time, increasing the load on those mechanisms, so, whether or not anyone believes something from the 70's or not, we need to change how we live, because we are cutting the branch we sit on, so to speak, and there are people who profit from this.

Those people pay other people to keep the debate alive, while there really is no room left for debate. (google "tobacco global warming lobbyists", for some enlightening facts)

I study ecosystems for a living, and can tell you that the evidence that we are destroying the planets ability to suport life (and to "right itself") is so far beyond debate that dulls the mind when people try to debate it. 

CHECK YOUR FACTS

CHECK YOUR FACTS

CHECK YOUR FACTS

CHECK YOUR FACTS

CHECK YOUR FACTS


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## Danthebull (Mar 24, 2010)

great link on c02 mate. help me big time!!!!


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## stonedplay (Mar 25, 2010)

rick is 1000% right


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## Danthebull (Mar 25, 2010)

I just purchased a c02 controller because of this link. thanks for the great info mate. i was stuck with a 20lb tank of c02 and no controller but now it's happy days again.


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