CO2

Babbabud

Bodhisattva of the Earth

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• Apr 9, 2005

• #1

I have just been lucky enough to come into a co2 setup ... can someone tell me how many parts per million my meter should read for optimum flowering ? maybe tell me what normal should read and how much it should read when adding co2. Ive pretty much been turned on to a closet full of grow equipment so I broke out the large and heavy tank of co2 and the cellonoid for realease and a ppm by meter. Any basic info would be helpful thanks

 

G

Guest

• Apr 9, 2005

• #2

I read that it has more to do with the light concentration than anything.

Something like 30-40 watts per sq.ft. can handle like 800-1100ppm of co2 concentration and it scales up from there. 70-80 watts per sq.ft. can handle up in the 1800-2200ppm when controlled properly.

The more light and the more the plant is actually having to process light and thus the more co2 it can handle.

I think that's right .

Tex

 

Babbabud

Bodhisattva of the Earth

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Veteran

• Apr 9, 2005

• #3

Thanks Tex .... the meter seems to sit at about 800 just in my house without anything running .... think Ill set it up for about 1200 ppm in the growroom and see how that works ... unless someone else sees this thread and can give me some other info

 

m.steelers

Enlightened

Veteran

• Apr 9, 2005

• #4

In the past I've tried to have it hit 1500ppm as the minimum. I had read that was an average target level for optimum results. Tex is right on about more light allowing for more CO2 uptake though. You can push more than 1500 but I think I also read above 2500 or so provides no additional benefit to the plant. Perhaps that is because people dont push much more than 80wpsf.

MS

 

Babbabud

Bodhisattva of the Earth

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• Apr 9, 2005

• #5

Thanks

Thanks

Thanks much then MSteelers Ill set my sights on 1500ppm then. Just waitin for the light to come on so I can set up my new toy thanks again for the info

 

G

Guest

• Apr 10, 2005

• #6

One of the problems I am running into when trying to figure use and concentration is that I will be using a controller that shuts down the co2 when the exhaust fan kicks on as a result of a temp gauge/setting. The problem is that even at night my fan runs non-stop or it will cook the goods in my flower room.

I was thinking of pulling a sealed dedicated exhaust for my lights that run 24/7 and a seperate exhaust on the room that is tied into the tempeture controlled circut. I think that will work, maybe.... It is about to start hittin the miod 90's to the 100's here real quick like.

From what I have read it also makes the plants more resistant to higher heats and ambiant temps.

Is there any benifit to the co2 when the lights are off?

I was looking at a "Producer" setup and it had two 430 watt bulbs and could handle a co2 saturation of 2500-2800ppm. I thought damn. that's kickin.

Tex

Tex

 

G

Guest

• Apr 10, 2005

• #7

Is there any benifit to the co2 when the lights are off?

Click to expand...

Plants need large amounts of oxygen, especially at the root zone. They need large amounts of carbon dioxide (C02), especially at underside of leaves. Total room C02 should be 1500 parts per million, but natural levels of C02 are approximately 400 ppm, so C02 augmentation is recommended, especially in above average temperatures. C02 emitter should be timed in relation to exhaust fan so that C02 is not sucked out of room.

Cannabis mines the air for CO2 (carbon dioxide) as it uses it, so the plants are very sensitive to the CO2 level during the lighted period. Using light to energize the process, the chloroplasts in the leaf cells combine CO2 and water (H2O) to make sugar and water. This is used to fuel the cells' metabolism and as raw material for tissue building.

Plants have several versions of photosynthesis. Cannabis is considered a "C-3" plant. These plants do not absorb or store CO2 during the dark period. "C-4" plants, mostly grasses, and "CAM" plants, mostly cactus and succulents, save CO2 during the dark. This is why CO2 supplementation is so important in enclosed cannabis gardens. There are about 380 parts per million (ppm) CO2 in the atmosphere. In a garden with no ventilation this is used up quickly. Once the amount of CO2 goes down to 200 ppm, photosynthesis stops until the CO2 is replenished.

Low CO2 is a limiting factor, too. In a brightly lit indoor garden, plants get all the water, nutrients and light they need. When CO2 levels are increased to 2000 ppm, cannabis photosynthesizes at a faster rate. Cell metabolism stays normal so there is a large surplus of sugar produced. Sugar is the basic building block of plant growth.

Venting the room serves several purposes. It replenishes CO2 in spaces where enrichment is not used and removes excess humidity and heat from the space.

During the dark period, cannabis does not use CO2. There is little heat generated but humidity does build up. For this reason you should use the vent fans in the dark period connected to a humidistat.

 

G

Guest

• Apr 10, 2005

• #8

Thanks Fred, I think I am on the right track now.

I am going to get this all setup in the next week or so.

Thanks again

Tex

 

King

Member

• Apr 10, 2005

• #9

Interesting, about to use CO2 for the first time here. I had heard above 1500ppm is toxic. I also read on overgrow of people experimenting with CO2 levels. One person was reporting the same rate of growth at 900ppm as when they're at 1300ppm. I'm gonna start at 1250ppm and experiment from there.

I should be receiving my meter here any day. Don't you take it outside and calibrate to 300ppm for the first use?

 

B

badmf

Active member

• Apr 10, 2005

• #10

Hey Peeps, don't listen to "I've heard" type info. Straight facts, co2 is "required by all plants!" The levels depend on the size and number of plants, a few plants in a larger room will exhaust it slower than a larger number of plants in a smaller space. Larger plants have larger appetites, in a standard 10x20 room for example with 200 plants you will need to get to 2000+ppms as the plants will drop the levels pretty quickly, if you have a more modest 20 plants in a 4x5 or so space 1500ppm is more than enough. Also with larger rooms you need to increase the frenquency of dispertion to every 15 to 30 minutes to even it out unless you have a monitor /controller. Smaller setups can go every hour.
King; toxic levels aren't reached til well over 3k ppm and that is to insects, it will slow plant growth rates though. I think the important thing is to have "balance", if you have loads of light and no co2 you are hurting the yeild, if you have anything that isn't in harmony it will become the weak link.
Texas Kid, you can run an a/c unit with the thermostat at plant top level to 85F, and use less juice and have co2 "contained" w/i the room by running the system(a/c) closed. this is more expensive in the short run but will be far better than any other setup. You can get a used a/c cheap now before "summer" heat comes, This will also dehumidify the air some as well!
Co2 should only be run during lites on, nites is wasted, also don't buy the co2 tablets for rezs either, as mentioned roots only need oxygen never never co2!!! Good luck! and remeber to keep it all in balance for centerfold buds!

 

Babbabud

Bodhisattva of the Earth

ICMag Donor

Veteran

• Apr 10, 2005

• #11

thank you very much badmf

 

King

Member

• Apr 10, 2005

• #12

thanks badmf

 

King

Member

• Apr 10, 2005

• #13

What about calibrating my meter. Isn't outside air right at 300ppm?

 

G

Guest

• Apr 10, 2005

• #14

Thanks Badmf (Pulp Fiction reference ) now everyone be cool.

I am working on a sealed draw thr the air cooled hoods and I think that will pull most of the heat from the fixtures. I am going to fire up the a/c pretty quick but I am going to build a wall unit in and do away with the portable. The portable looses way to much sq.footage of floor space.

Won't low humidity be my problem though? My relative humidity is in the 40's at best and in summer it get pretty damn dry. Shouldn't I have to introduce some kind of humidity back into the space.

My space is 4'x4'x9' and there are two of them side by side with ducting between the two.

Thanks again

Tex

 

B

badmf

Active member

• Apr 10, 2005

• #15

Texas kid;Well I would always rather have "too" low a humidity than too high, its easy to raise, but harder to lower. You can raise low humidity spaces with just a bucket of water open near your circulation fans.
King; outside air or ambient air, varies as much as 450ppm in larger cities to 280ppm in farm open type surrounds. Adding more co2 with more light and higher nute levels adds to much larger and quicker yeilds. Example;>75wpsf, co2 2000ppm, nutes at 1500+. With good temps and ph yeilds usually max out but ppms are strain specific as some don't tolerate high rates, again watch "your" plants! (Tip burn is a noticable indication, as well as very dark green and hard leaves)
As for many closet sized spaces, just breathe, simple , but you produce a great level of co2 with every breath. Just brush yer teeth first, lol! Some inexpensive co2 alternatives are; growing mushrooms,hmmm? brewingbeer or makingwine, keeping small pets like hamsters, rabbits etc, (they're poop is usable too!) dry ice can be placed above the plant area in small quantities, buy at least 5 lbs and crack it, wrap the extra in newspaper tight to keep for a few days in the freezer, adding a lil each day, keep checking with Ebay for a co2 setup, tanks are 75 to 125 and used work just as well. Some are as low as 50 bucks used(160-250 new)h or low dispertion types, low for small rooms, but a high will work there too, so I'd opt for the high as you may wish to expand one day.(The tanks used work well but as always check out any other equipment!!) So anyone needing a workout, just do it in the plant room with the lites on! lol

 

Babbabud

Bodhisattva of the Earth

ICMag Donor

Veteran

• Apr 10, 2005

• #16

up and running ...works great
thanks to all that posted here ...your help was very appreciated

 

G

Guest

• Apr 10, 2005

• #17

My 4x4 space has a 3x3 table in it with a daul 600watt air-cooled fixture above that is ducted into the attic. I should be able to crank it up without to many problems.

Is the brewers yeast setup an alternative only because it is a small space?

Does the co2 rise or fall in the space? should sources of co2 be toward the top or bottom of the space?

Thanks again

Tex

 

Babbabud

Bodhisattva of the Earth

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• Apr 10, 2005

• #18

I believe it falls ... I have mine above and then falling into the path of a circulating fan which just moves it around the room.

 

m.steelers

Enlightened

Veteran

• Apr 10, 2005

• #19

Hey Tex - CO2 is heavier than normal air, it falls to the ground when released. I have a tank setup and I position the distribution tubes above the canopy of the plants so that it falls down on the leaves. You can also have a ground fan kick on to blow any gas that falls all the way to the bottom of the space back up to the canopy level.

MS

 

Babbabud

Bodhisattva of the Earth

ICMag Donor

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• Apr 10, 2005

• #20

I have a tank that is bout 5ft tall .... it only cost like 20 bucks to fill it up ... at this rate it should last a good long time ... my buddy said it should last thru flowering but we shall see