Why 1500?

[Bobby Smith]

Not sure if this is the right forum or not, but seemed like the best fit to me.

Anyhow, the question is why 1500ppms is the "accepted" rate to run CO2 at - if I understand, plants evolved to be able to use CO2 when the concentration was closer to 2000PPMs in the atmosphere, correct?

So why do we run at 1500?

Curious because I just ran a natural gas line to my garage and now will never have to fill propane or CO2 tanks again (or worry about how much CO2 I'm using), so would it behoove me to run at 2000ppms vs. 1500ppms?

Has anyone compared the two and seen a difference?

My lighting is gonna be ~80 watts/sq foot, so that won't be holding me back (I don't believe).

Just curious if there's a benefit to running at 2000 or if 1500 is basically maxing the plants out.

 

[Lost]

I don't think so. I think the effect drops off pretty fast after a certain PPM. While CO2PPM might have been as high as 2000 ppm in the past, that was millions of years ago and thats also of environmental evolution taking place to be optimally efficient. I run 1500 but many ppm set points come stock at 1250..

 

[Tobor the 8th Man]

The experts say that the maximum amount a pot plant can use is 1500 ppm. And then it has to be at the right temperature and conditions to utilize that much.

 

[Bobby Smith]

Thanks and rep to you both; I'm actually gonna do some more digging on this subject and see what I can find.

Now that I'm free and clear from ever running out of CO2, I wanna run it at 3000PPMs and feed my plants meth and rocket fuel to see what they can do :)

 

[Bobby Smith]

So I found the link below - test germination at different CO2 levels, and go up to 2100PPMs - found no difference in germination levels.



And this chart is pretty cool:

http://www.geocraft.com/WVFossils/Carboniferous_climate.html

For anyone who can understand WTF they're saying, this seems to be the definitive word:

http://www.springerlink.com/content/a3527u6018823x43/

And that's about all I got.

 

[Curb Feeler]

I know at some point there can be CO2 burn, but not sure at what point that happens.

To much of a good thing usually ends badly is how I look at it.

 

[growhard]

At some stage the levels will be wasted, and just because gas is cheap, doesn't mean that running 2000ppm will be negligibly different, because you have forgotten to account for the extra cooling budget that will be required.
Admittedly if your room is perfectly sealed (none are unless you never enter it) it should only be the cost of the initial increase. I like to think my room is sealed, but I have two HI-Blo 80's blowing constantly into it, so there must be leaks somewhere! By this I mean that as there is almost 160 liters/minute of outside air that needs to be charged back up to your desired level.
Do it. I am sure the extra cost will be outweighed by any increases in yield.