Carbonating Nutrient Reservoire

I'm new to the whole game, so bear with me here, ladies and gentlemen.

I'll give an in-depth spec of my setup at the end of this post, in case it becomes relevant.

My question is this; I've been reading up on hydroponics for a little while now, and I believe I'm going to try a single plant bucket bubbler (essentially a DWC setup for a single plant)

Integral to this bubbler system is the notion that air and oxygen is being circulated throughout the nutrient solution with an air-pump. The constant movement of the air-bubbles keeps the water from becoming stagnant, and also dissolved oxygen into the nutrient solution. This in turn delivers a great deal of oxygen to the root-mass, alongside the nutrients themselves.

I understand that the roots of the plant require a certain amount of oxygen to grow and thrive; that being said, would it make sense to use the nutrient solution to supplement carbon dioxide also? The straightforward method for doing this would obviously be carbonating the water, to saturate it with CO2.

As I understand it, the plant absorbs *most* of the CO2 it needs through its leaves,(?) Does it absorb CO2 through the roots also? If it does, would it be beneficial to carbonate the reservoir?

(Here also, I will mention that I've heard through hearsay that carbonation has a certain antiseptic quality, and it might actually combat root-rot, or other nasties that otherwise would love to live in the nute-solution. This makes a certain amount of sense to me, as fermenting beverages was the primary method of preservation in the middles ages, due the the alcohol content, but also I believe the CO2)

Anyone have any thoughts?

---I feel like I'm missing some really obvious information here haha... I'm sure someone will tell me excessive CO2 through the roots will murder my ladies...

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[this is the setup I'm constructing]

I'm starting my very first setup here. Built a cabinet 2ft x 2.5ft x 5ft (tall), using a 250 watt lamp ballast, (going to use MH for veg, and HPS for flower)
Walls are lined with white mylar, and I've installed 2 120mm intake fans for cooling, one squirrel fan / carbon filter for security and air removal. I just got my environmental controllers in the mail.

I'm trying to manage a negative differential for shorter internodes; Night temp 80f, Day temp 75f ... SHOULD be feasible. (Including a ceramic heater for a non-light-emitting heat-source in the night periods)

I'm still working out CO2 supplementation, although I may go the fermentation route, as I have a certain amount of experience in brewing beer and wine.
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NO and NO/.. CO2 In Air O2 in water

Agreed.. C02 + water = carbonic acid ... acid rain = carbonic acid.. not good for plants, especially due to the mass pH flex based on temperature.

Figong said:

Agreed.. C02 + water = carbonic acid ... acid rain = carbonic acid.. not good for plants, especially due to the mass pH flex based on temperature.

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Disclaimer; I'm not a chemist, nor do I claim to be anything resembling proficient in the field of chemistry. That being said >

My understanding was that carbonating water does not produce carbonic acid, rather it produces a solution of water, carbon, and a 'precipitate' of carbonic acid which immediately disperses throughout the water, because it is water soluble. But yes, a solution containing carbonic acid, although very dilute.

Is there anything about carbonic acid which is in-and-of-itself/intrinsically harmful to the plants? Or is it harmful because of its severe impact on PH?

If it's merely a matter of alkalinity or acidity the impact on PH could be offset, easily, and this whole notion of introducing CO2 to the nute solution might not be compromised.


^Now, even if I'm right about all that, the real question has yet to be answered;

Do the plants even absorb any appreciable amount of CO2 through the roots?

If not, my whole idea is bunk anyway,

As it stands I'm under the impression that CO2 is only meaningfully absorbed through the leaves of the plant. Can anyone offer any evidence to the contrary?

Actually, yes.. I can provide a bit of information on roots absorbing, from the mouth of Ed Rosenthal:

Adding CO2 to the water will not help the roots and in fact will hurt them. Plants use CO2 when they photosynthesize, the process which results in the production of sugar. Photosynthesis occurs only in areas of the plant that receive light and contain chlorophyll, the source of plants' green color. It is absorbed through pores called stomata. Roots have no chlorophyll and don't ordinarily come in contact with light so they have no use for CO2.



Plants use the sugars they have manufactured as a source of fuel. Their metabolism is similar to the method used by animals. Sugars, which are hydrocarbons, are chemically "burned" in a controlled reaction that occurs when they are combined with oxygen. Energy is released and the waste product CO2 is created.


Both CO2 and oxygen dissolve in water. When water is saturated with CO2 it cannot absorb oxygen so the roots have no source of the element oxygen, which is needed for their metabolism. This weakens the roots and promotes the growth of anaerobic bacteria, which thrive in oxygen-free environments and attack roots.


When water in a reservoir is circulated, it releases the dissolved CO2 to the air and dissolves oxygen. That's why circulating water in a reservoir using a pump is beneficial to roots: It removes the CO2 and supplies the water with oxygen.

that's a copy/paste from here: http://www.cannabisculture.com/articles/4384.html - link provided to show I didn't just type it, make it up, or have a post from someone who is not well known for mj growing being used as a reference point.

Figong said:

Actually, yes.. I can provide a bit of information on roots absorbing, from the mouth of Ed Rosenthal:

Adding CO2 to the water will not help the roots and in fact will hurt them. Plants use CO2 when they photosynthesize, the process which results in the production of sugar. Photosynthesis occurs only in areas of the plant that receive light and contain chlorophyll, the source of plants' green color. It is absorbed through pores called stomata. Roots have no chlorophyll and don't ordinarily come in contact with light so they have no use for CO2.



Plants use the sugars they have manufactured as a source of fuel. Their metabolism is similar to the method used by animals. Sugars, which are hydrocarbons, are chemically "burned" in a controlled reaction that occurs when they are combined with oxygen. Energy is released and the waste product CO2 is created.


Both CO2 and oxygen dissolve in water. When water is saturated with CO2 it cannot absorb oxygen so the roots have no source of the element oxygen, which is needed for their metabolism. This weakens the roots and promotes the growth of anaerobic bacteria, which thrive in oxygen-free environments and attack roots.


When water in a reservoir is circulated, it releases the dissolved CO2 to the air and dissolves oxygen. That's why circulating water in a reservoir using a pump is beneficial to roots: It removes the CO2 and supplies the water with oxygen.

that's a copy/paste from here: http://www.cannabisculture.com/articles/4384.html - link provided to show I didn't just type it, make it up, or have a post from someone who is not well known for mj growing being used as a reference point.

Click to expand...

Good find, Figon!

That makes a lot of sense... (although my idea is now shot!)

My immediate thought was "Well can you saturate the water partially with carbon, and partially with oxygen?" >But methinks that would be inferior to the benefits of simply saturating fully with oxygen, as is standard procedure with DWC.

Citation was useful and informative. Food for thought, certainly! Thanks again, Figon! Cheers.

Mt.Vedoobious said:

Good find, Figon!

That makes a lot of sense... (although my idea is now shot!)

My immediate thought was "Well can you saturate the water partially with carbon, and partially with oxygen?" >But methinks that would be inferior to the benefits of simply saturating fully with oxygen, as is standard procedure with DWC.

Citation was useful and informative. Food for thought, certainly! Thanks again, Figon! Cheers.

Click to expand...

Quite welcome! =)