CO2 ppm?

[iscrog4food]

I have been in this game for a long time and common wisdom has always been to keep your CO2 levels at 1500 ppm for best results. Recently when doing some research I ran across a thread that says not to go over 1200 ppm and that 1100 was ideal. I have been away from the grow forums for a year or so and a lot has changed in that time so I was wondering what do you guys think about the ppm debate? The linked article below is the one I am referring to and it is one of the few I have seen that actually cites peer reviewed studies. What say you farmers?

https://www.icmag.com/ic/showthread.php?t=221893

 

[Theoneandonly Z]

I have been in this game for a long time and common wisdom has always been to keep your CO2 levels at 1500 ppm for best results. Recently when doing some research I ran across a thread that says not to go over 1200 ppm and that 1100 was ideal. I have been away from the grow forums for a year or so and a lot has changed in that time so I was wondering what do you guys think about the ppm debate? The linked article below is the one I am referring to and it is one of the few I have seen that actually cites peer reviewed studies. What say you farmers?

i feel 1500 ppm was built up on store hype. when i run sealed rooms, i usually stay around 1000 on average. i bump up levels during different stages of growth but never exceed 1200. i have also found that some flavorZ enjoy different levels of co2 compared to others. but ever since i made the change from 1500 to 1000/1200 ppm my plants look better and im saving $ on co2 usage.Z

 

[iscrog4food]

i feel 1500 ppm was built up on store hype. when i run sealed rooms, i usually stay around 1000 on average. i bump up levels during different stages of growth but never exceed 1200. i have also found that some flavorZ enjoy different levels of co2 compared to others. but ever since i made the change from 1500 to 1000/1200 ppm my plants look better and im saving $ on co2 usage.Z

Yeah I changed mine over when I read the article a few days ago and I think the girls are looking much more healthy. I have never run a completely airtight room until recently so setting my controller to 1500 usually was resulting in levels around 1100-1300 so I never had issues. Since I built a completely sealed room I can actually maintain my levels now.

 

[Theoneandonly Z]

Yeah I changed mine over when I read the article a few days ago and I think the girls are looking much more healthy. I have never run a completely airtight room until recently so setting my controller to 1500 usually was resulting in levels around 1100-1300 so I never had issues. Since I built a completely sealed room I can actually maintain my levels now.

nice! Much luck going sealed :cigar: <(thats me burnin one for you) if you havent already, i would check into RH% and VPD for being in sealed rooms. This was a curve ball that was thrown at me when i switched from fresh air xchange to sealed awhile back.

 

[Theoneandonly Z]

Scrog - were u working this morning? i think i passed you on my way in to town?....

haha
Z

 

[iscrog4food]

nice! Much luck going sealed :cigar: <(thats me burnin one for you) if you havent already, i would check into RH% and VPD for being in sealed rooms. This was a curve ball that was thrown at me when i switched from fresh air xchange to sealed awhile back.

Yeah I have looked into VPD but i am still not sure I understand how to calculate it. My room runs about 81-85 deg. and my RH ranges from 35-50% depending on how hard my split is working. I was considering throwing in a humidifier but I am short on funds after buying a bunch of toys for this grow. Sealed certainly is more capital intensive that is for sure!

Scrog - were u working this morning? i think i passed you on my way in to town?....

View attachment 305905
haha
Z

I told you I was short on funds man gotta pay the bills somehow! Only in CA.

 

[squiggly]

Yeah I have looked into VPD but i am still not sure I understand how to calculate it. My room runs about 81-85 deg. and my RH ranges from 35-50% depending on how hard my split is working. I was considering throwing in a humidifier but I am short on funds after buying a bunch of toys for this grow. Sealed certainly is more capital intensive that is for sure!


I told you I was short on funds man gotta pay the bills somehow! Only in CA.

Or, alternatively:

http://cronklab.wikidot.com/calculation-of-vapour-pressure-deficit

(To find Saturate Vapor Pressure use temps in degrees C)



For cannabis, if you stay within the green and white blocks from the table above you should be okay. It is okay to drift into the pink blocks (especially in veg) but you should avoid being in the blue blocks if you can.

Depending on the size of your room I can emphatically recommend this humidifier:

http://www.walmart.com/ip/Sunbeam-Cool-Mist-Humidifier-SCM3755C-WM/21670198?_mm=
The availability is somewhat limited, but if you can find/afford one I suggest you grab it.

 

[iscrog4food]

The availability is somewhat limited, but if you can find/afford one I suggest you grab it.

Damn thanks squig that is exactly what I was looking for for the VPD. How much space would you say that humidifier is good for and also how much do they run because there isn't a price on the site? You are always a wealth of knowledge and I always appreciate your contributions here on the farm! Thanks again! Damn 75% seems really high for the 80s. I knew it was a bit dry but damn I din't know I was that far off the mark. Oh well I guess Ill dig up some old humidifiers in the mean time untill I can get a proper one for my girls.

 

[squiggly]

Damn thanks squig that is exactly what I was looking for for the VPD. How much space would you say that humidifier is good for and also how much do they run because there isn't a price on the site? You are always a wealth of knowledge and I always appreciate your contributions here on the farm! Thanks again!

The unit information claims 2000 sqft.

In my opinion it's good for about 500-1000 (lowest and highest estimates) for our purposes.

It runs about $80 if memory serves but maybe you can find a deal!

Thanks for the vote of confidence. I'm always willing to help out a fellow scrogger!

 

[iscrog4food]

Excellent thanks again for the information!

 

[ttystikk]

Damn thanks squig that is exactly what I was looking for for the VPD. How much space would you say that humidifier is good for and also how much do they run because there isn't a price on the site? You are always a wealth of knowledge and I always appreciate your contributions here on the farm! Thanks again! Damn 75% seems really high for the 80s. I knew it was a bit dry but damn I din't know I was that far off the mark. Oh well I guess Ill dig up some old humidifiers in the mean time untill I can get a proper one for my girls.

I know 75% rh at 80f seems high, but if you're a plant and you're trying to both respire and hold onto the water you already have, it has to be higher. Otherwise, opening your stomata costs you more moisture than the co2 gains you.

I run my rh at 70-75% throughout most of flower. Works great!

 

[iscrog4food]

I know 75% rh at 80f seems high, but if you're a plant and you're trying to both respire and hold onto the water you already have, it has to be higher. Otherwise, opening your stomata costs you more moisture than the co2 gains you.

I run my rh at 70-75% throughout most of flower. Works great!

I just don't know how i will drop it once lights go off. I have 2 70 pint dehumeys but if it is cold out they don't very well. I guess ill need more heaters. Oh well I will figure it out i guess. Experience answers all questions eventually.

 

[ttystikk]

I just don't know how i will drop it once lights go off. I have 2 70 pint dehumeys but if it is cold out they don't very well. I guess ill need more heaters. Oh well I will figure it out i guess. Experience answers all questions eventually.

If your dehueys exhaust hot air, they will work to dehumidify, cold weather or warm.