[Cannabean]

hey Spurr,
I know theres no real way to tell without a fuzzy logic, but I read in Jorge's bible that when co2 is increased to 1500ppm, it takes about 3 hours due to light leaks and photosynthsis for the room to return to ~300ppm co2.

I have my regulator set to inject 800ppm co2 every hour. If his math suggests 400ppm co2 used/lost per hour, am I still overdoing it with co2 saturation?

Since you disproved Jorge on the ppm amount, would you be able to provide any more insight in this area? Does the 400ppm/hour rate seem correct?

[noreason]

I am the source in the cannabis world (AFAIK) who pointed out the problem with high Co2 over ~1,200 ppm is the inhibition of "rubisco activase", that in turn greatly lowers the conversion of "inactive rubisco" into "active rubscio". Rubisco activase is needed to convert inactive rubisco into active rubisco. If you have read about that issue it comes from what I have posted in the past, I can post references if you're interested.

I already known you are the same guy wrote about co2 and rubisco activase.I found some of your posts in a big CO2 thread here on IC.You made me understand a lot of things...so one more thank
You seem to have a great knowledge,so if you have more info about co2 saturation for cannabis feel free to post it.

and there is more then a little proof and evidence showing 1,500 ppm is too much.

Do you have any link to a study,test or whatever?It's an interesting point this.

An evolutionary reason why over ~1,000 ppm co2 is too much, is when C3 terrestrial plants where first evolving the ambient Co2 was ~500-700 ppm, maxing out around ~800-1,000 ppm. Thus, plants evolved to use ~7,00-1,000 ppm.

This make sense,I already read an article on the national geografic that say pretty the same thing...but you know...only scentific proof are trusted and a theory could be wrong also if it seems right.

FWIW, the other environmental factor that reduces rubisco activase, and thus lowers conversion of inactive rubisco into active rubisco, is temps over ~89'F.

If you got something to tell on why over 89°F rubisco activase is in lower concentration,I'm happy to understand.

When using a sealed room with high Co2 an issue to be considered is ethylene. It is produced by the plant and affects maturation, senescence and abscission of leafs and flowers. Ethylene buildup also hinders auxin transport if ethylene is built up too high. Ethylene buildup can also reduce flower size. It's a good idea to vent the room at least once a day, esp. in latter stages of flowering to remove buildup of ethylene.

Didn't know anything about this topic.Thanks for sharing,this is interesting and very helpful for growers running propane burner.

There should be plenty of O2 in a sealed room for light independent reactions such as respiration, mostly because a sealed room isn't really sealed 100%. If you let fresh air in at night, that would be good for two reasons: (1) to vent ethylene and (2) to help drop RH (and thus increase VPD).

I let to replace air at least one time per day however I don't need to drop RH because I have my de-huey running 24\7 on the right value.

Here are a couple of ethylene refs, I can post rubisco and cannabis Co2 refs if you'd like to read more:

1. "Ethylene In The Greenhouse": The authors explain how to detect ethylene, how to take action against it and how to stop problems before they happen.
By W. Roland Leatherwood and Neil S. Mattson
April 2010
https://www.greenhousegrower.com/magazine/?storyid=3153





2. "Ethylene, Plant Senescence and Abscission"
Stanley P. Burg
Plant Physiol. 1968 September; 43(9 Pt B): 1503–1511.
https://www.ncbi.nlm.nih.gov/pmc/arti...00512-0034.pdf

Interesting read spurr.Thanks for sharing and feel free to post references about co2 and rubisco,I'm interested.

Have a nice weekend bro

[growshopfrank]

Originally Posted by spurr

Hey,

I am the source in the cannabis world (AFAIK) who pointed out the problem with high Co2 over ~1,200 ppm is the inhibition of "rubisco activase", that in turn greatly lowers the conversion of "inactive rubisco" into "active rubscio". Rubisco activase is needed to convert inactive rubisco into active rubisco. If you have read about that issue it comes from what I have posted in the past, I can post references if you're interested.

It's the active rubisco that allows for highest rate of photosynthesis, for plants to photosynthesize they need active rubisco. Also, a few studies I have read found Co2 saturation for cananbis is ~1,000 ppm. Using 700-1,000 ppm Co2 is ideal. AFAIK, there is zero scientific proof or evidence that using 1,500 ppm is beneficial; and there is more then a little proof and evidence showing 1,500 ppm is too much.

Using 1,500 ppm of Co2 is yet another false claim based on conjecture by so-called cannabis gurus like Jorge Cervantes, Greg Green, Mel Frank, et al.

An evolutionary reason why over ~1,000 ppm co2 is too much, is when C3 terrestrial plants where first evolving the ambient Co2 was ~500-700 ppm, maxing out around ~800-1,000 ppm. Thus, plants evolved to use ~7,00-1,000 ppm.

FWIW, the other environmental factor that reduces rubisco activase, and thus lowers conversion of inactive rubisco into active rubisco, is temps over ~89'F.

When using a sealed room with high Co2 an issue to be considered is ethylene. It is produced by the plant and affects maturation, senescence and abscission of leafs and flowers. Ethylene buildup also hinders auxin transport if ethylene is built up too high. Ethylene buildup can also reduce flower size. It's a good idea to vent the room at least once a day, esp. in latter stages of flowering to remove buildup of ethylene.

There should be plenty of O2 in a sealed room for light independent reactions such as respiration, mostly because a sealed room isn't really sealed 100%. If you let fresh air in at night, that would be good for two reasons: (1) to vent ethylene and (2) to help drop RH (and thus increase VPD).


Here are a couple of ethylene refs, I can post rubisco and cannabis Co2 refs if you'd like to read more:

1. "Ethylene In The Greenhouse": The authors explain how to detect ethylene, how to take action against it and how to stop problems before they happen.
By W. Roland Leatherwood and Neil S. Mattson
April 2010
https://www.greenhousegrower.com/magazine/?storyid=3153





2. "Ethylene, Plant Senescence and Abscission"
Stanley P. Burg
Plant Physiol. 1968 September; 43(9 Pt B): 1503–1511.
https://www.ncbi.nlm.nih.gov/pmc/arti...00512-0034.pdf

just one question do light levels (higher but low leaf temps) effect rubisco inactivity.

[raphenilweed]

Quantifying the uncontrolled CO2 dynamics of growth chambers
https://jxb.oxfordjournals.org/conten.../1143.abstract.

I don't have access through my university any more so I can't get into all these journals =(.
From the little that I know about the subject, I am assuming that ~1500ppm recomendation is because over the 1.5-3 hours it maybe averages out to ~1000... IDK though.
I learned a lot already without asking any of the questions I had. I was going to post something in here but when i went into the forums bam CO2 right at the top.

My question is regarding airflow inside when CO2 is on...
Should circulating fans be on during this time? I have 4 oscillating fans and just picked up one of those industrial size 20" fans. I was going to mount it on the ceiling and blow down ways onto the plants. Will the air circulation of this big fan be contradicting the CO2?
Also, my friend tells me to mount the hose that supplies the CO2 higher up because it is heavy and sinks. Is this true? Would it be better to string the hose at the base of the plants and have the holes pointing up?

[noreason]

Originally Posted by raphenilweed

My question is regarding airflow inside when CO2 is on...
Should circulating fans be on during this time? I have 4 oscillating fans and just picked up one of those industrial size 20" fans. I was going to mount it on the ceiling and blow down ways onto the plants. Will the air circulation of this big fan be contradicting the CO2?
Also, my friend tells me to mount the hose that supplies the CO2 higher up because it is heavy and sinks. Is this true? Would it be better to string the hose at the base of the plants and have the holes pointing up?

CO2 is heavier then air,so it's common to mount the hose on the ceiling.This way CO2 falls right on the plants.

Having fan\s that blows air from the floor upside is good,not viceversa I think.

However a good air movement in the growroom especially trough the leaves it's ok to keep CO2 mixed with air IMO

Hope it helps

[spurr]

hey all,

I will post some studies on cananbis and Co2 and other Co2 studies and try and answer the Q's put to me in this thread tomorrow. Outta time today.

@ raphinellweed,

I should be able to get you that study in full text tomorrow.

[growshopfrank]

Maybe spurr is onto something here I lowered my PPM from 1550 to 1000 and my plant growth rate seems (so far) to be unaffected. this is in a tight sealed continuous harvest(staggered) room running bottled CO2 w a greenair fuzzy controller