There's a symbiotic relationship between plants and animals on the planet. Animals breathe in oxygen and exhale carbon dioxide while plants do the exact opposite, they breathe in carbon dioxide and exhale oxygen. So it's a great deal for everyone involved, a deal that has kept everything growing on the planet just fine.
Now if you were to listen to what a lot of today's climatologists have to say about global warming though, you can easily be left with the impression that the system is going out of balance. That the air around us is gradually becoming 'flooded' with excess carbon dioxide.
What's important to understand here though, is just how small a percentage of carbon dioxide is really in the total mix with regards the air that surrounds us. Yes it is increasing to a certain degree and that slight amount of increase is enough to cause global warming but it's not quite enough to do growing green plants any good, so to speak.
Just How Much CO2 is in the Air Plants Breathe?
You see, carbon dioxide only makes up a little over 385 parts per million by mass in the air that you breathe, and that's not a whole heck of a lot. To give you a better picture how much CO2 we're dealing with here, if you were to fill 1000 balloons full of air only 3 of those balloons would be made up of the total carbon dioxide contained in those balloons quantitatively speaking.
So what it all boils down to, is that it doesn't take a whole lot of carbon dioxide injected into a grow room (about 4 balloons full) to effectively double the amount that would normally be present, and yes extra carbon dioxide does make a big difference in plant growth.
Carbon dioxide enrichment isn't just done for increasing the atmospheric level above what is normal though. This is because it can also be used to bring the CO2 level up to normal from below normal concentrations in heavy use situations, situations for instance where adequate venting of fresh air might be a problem.
Venting Can Be Problem in Cold Climates
In colder northern climates where a grower simply can't blow all the air into the room that they need due to the freezing temperatures. A full max growth 'sea of green' grow room also goes through a lot of CO2 as well. So the solution in this case is often to reduce the air transfer volume (venting) and then rely on enrichment equipment.
Now there is catch here though, and that 'catch' comes in the form of 'CO2 toxicity'. What this means is that just like fertilizer, too much of a good thing in this case can in fact work against you to stunt your plants growth. Something else to consider here is just how much CO2 your plants will need depends on their stage of growth.
So there's no one set amount of CO2 that can be added to a room from beginning to end. Rather the enrichment rate has to be adjusted in accordance with the size, growth level and numbers of plants. An adjustment process that goes on throughout the entire plant growth cycle.
All the Gadgets and Gizmos are Readily Available
Now the good news here is that carbon dioxide enrichment equipment has come a long way over the years, so it's a far easier prospect than when growers had to patch together their own systems. So you can now find complete, self contained systems that include everything that's needed to get your room up and going with CO2.
The equipment begins of course with a tank, and by the way the tank will be the major expense here, (about $200 US). Once you own the tank though, finding a place to have it refilled is easy. Businesses like welding supply shops provide this service and it's relatively inexpensive, about $15 or so for a refill that will last about two weeks.
The next component you will need is a regulator. This is a brass devise with a dial and couple of knobs on it that screws onto the tank and it will cost you another $150 or so. After that you have the option of going with a basic electrical timer that you can adjust so your room gets a 15 minute 'blast' every hour or so. Or you can buy and hook up a CO2 sensor that measures the CO2 level in your room and in turn signals your regulator when it's time for a 'blast'.
There's also what are called 'CO2 burners', and they basically function in the same way as a gas heater does. Stoves of sorts that are powered by propane that comes in the very same type of propane tank that you would see with a gas barbecue. When the propane is burned it releases CO2 as its exhaust, and these too can be ran on a timer or be hooked up to sensor.
The Complete $7 “Poor Mans” CO2 System
If you don't have the money to jump in headfirst on a full-blown state-of-the-art CO2 enrichment system though, there is a 'poor man's option', one that only requires a block of dry ice that you can buy locally. Simply wrap the dry ice up 'nice and snug' in a down sleeping bag to keep it from dissipating too quickly, and then stick it in your grow room.
This 'cheapo' dry ice enrichment method works surprisingly well on a room full of lush growth but it's easy to go into toxic levels if you don't have the growth to support this type of uncontrollable dispersion system. Also even with a room in full growth it's easy to get into toxic levels, so it's recommend that you give your room a break (a couple of days) in between blocks of dry ice.
The Bottom Line on CO2 Enrichment
CO2 enrichment is proven to work and when done correctly 'will' drastically increase your rate of growth. So it pays for itself if you can afford the initial cost of the equipment.
Once it's set up and going it's low maintenance because now the monitors and regulators are available to do all the work for you. Information on optimal percentage and toxicity levels is also readily available and easy to understand.
It's also the perfect solution for colder climates where restricted ventilation can be an issue and CO2 burners in particular are also a great way heat a room in a cold climate situation.
After the initial investment in the equipment is made a 10' foot 10' room will require a $15 tank refill about once every two weeks.