Co2 possibly harming plants?

BigTexan

BigTexan

Well-Known Member
from seed to finish 1500 ppm co2 every hour for 15 mins with exhaust fans off and room sealed, let it sit for another 10-15 minutes total exhaust fan off time (30 mins) can get hot but i have a big intake fan blowing cold air in from the basement and a air conditioner to buffer the heat. never had a problem, Ive heard of being able to suffocate the plants but you cant say its harming unless you buy a co2 meter and actually make sure your levels are right.
 
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Blaze23

Well-Known Member
a mongo frog said:
just real quick i set my dehues to 35 because thats what it takes to keep 50-55%. your room may run different. just want you to check and not think i meant run rh a 35 %
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My humidity has been at 50% both my thermostat and dehumid read the same. Whatever I set my dehumid at is what it'll reach. Why wouldn't I lower the RH in the room if the leaves seem to have trouble transpiring? Im confused lol
 
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Blaze23

Well-Known Member
BigTexan said:
from seed to finish 1500 ppm co2 every hour for 15 mins with exhaust fans off and room sealed, let it sit for another 10-15 minutes total exhaust fan off time (30 mins) can get hot but i have a big intake fan blowing cold air in from the basement and a air conditioner to buffer the heat. never had a problem, Ive heard of being able to suffocate the plants but you cant say its harming unless you buy a co2 meter and actually make sure your levels are right.
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I do have a co2 meter. It controls and reads my co2 levels. I have it set at 1100 ppm but it actually reads 1100-1200. . . . Im not exhausting any air out of the room but I do have an a/c blowing.
 
Dr. Who

Dr. Who

Well-Known Member
SnapsProvolone said:
I've NEVER had co2 below 3000ppm cause issues.
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WHAT? 3kppm is overkill and your wasting the Co2

The available light used, dictates the USEFUL/EFFECTIVE Co2 levels to be used by the plant!
How are you supplying lighting over 7500fc (80,400 lux)? To "effectively" allow the plant to "use" 1500ppm. The lighting must maintain a level of 7500fc/80,400 lux!

Oh hell, here's the science.

From darkness. The rate of photosynthesis has the greatest increase as the Co2 level climbs from 0 - 200ppm. Under low light conditions (150mols or 1150fc [12,330lux]), the rate of photosynthesis increases as Co2 levels rise to 400ppm. Increasing the Co2 concentration beyond that without increasing the light intensity does not result in a higher rate of photosynthesis. The plant cannot take advantage of higher Co2 levels until the light intensity increases.

At a light intensity of 600mol (4600fc / 49,310lux) the photosynthesis increases more as Co2 concentrations are increased to that 400ppm. The rate of increase declines a bit after that, but the photosynthesis rate continues to climb as Co2 levels reach 600ppm. Above 600ppm, the photosynthesis rate continues to climb but at an even slower rate, until the rate levels of at about 1200ppm.

By increasing light intensity, you encourage you plants to absorb even more Co2 which increases growth and yield. When the plants receive between 4500 - 5500fc (48,240lux) of light, they can utilize between 1200 - 1300ppm of Co2. While very few gardens are supplied with more then 7500fc (80,400lux) of light, at that intensity the plants can utilize up to 1500ppm of Co2.

Increasing the ppm levels above 1500 is a waste of Co2 and thus money, in so much as the plant has hit the wall so to speak (the photosynthesis increases over 1500ppm Co2, even with an increase in light intensity is at a rate that makes the use versus cost ratio ineffective) on the available lighting intensity versus effective utilization of available Co2!

Now then, to the OP.

Your problem has NOTHING to do with your Co2 use!
I'm with Snaps on your feed being off.
At the stage of bloom your at. I would say you have a to much P problem or a pH problem or a Mg def or a combination of all.
I do lean towards the high P issue!
You don't list your feeds so I can't be sure. But it's most likely it.
You are NOT under feeding and for sure not low N at this point as the plant is using far less N now.

Overpressure of your area is a FAR reach too. It would be so hard to get that it's not even on my list of possibles.

Now then. You should run the gas from the start of bloom to the last 2 weeks of, and stop there.
2 weeks gas off for proper ripening.
 
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Dr. Who

Dr. Who

Well-Known Member
Hmm, yes it can. But don't you use a controller Snaps? Seems like it should not override that far.....
I thought you were running it that high for a reason. Hence my post.
Anyway, I get your point.
 
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Blaze23

Well-Known Member
Dr. Who said:
Seems like a large rise though........Ah hell, I don't meter mine (ppms) when I use gas, so what do I know other then Co2 levels do increase at night.

Anyway, I think we both just gave the folks some good info.

Peace on man!

Doc
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Thanks, you might be right. It could be the feed or a combination of things but I seemed to notice changes as soon as I started using co2. I follow the General Hydroponics guide (Flora Series) for DTW. I have recently calibrated my ph meter, I use a blue lab combo meter. . . . .What could be the cause of soft, yellowing leaves? Im talking completely yellow. i'll have more pics today. Im gonna go through and clean up all the ladies and pick off all the dead leaves.
 
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Blaze23

Well-Known Member
Right now lights are off and the thermostat is reading 73 degrees with 28% humidity. The high says 82 with 50% humidity (from the last time the lights were on)
 
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Blaze23

Well-Known Member
Co2 ppm levels are reading at 500 ppms. Im not supply that, im pretty sure that the rise in co2 in the basement is caused from my furnace running.
 
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