CO2-Is it worth it?

[greyfader]

Apical dominance.

great reply! and if it were not for this paper i would have agreed with you. i think apical dominance has to play a role but it's not the whole story.

Shape Matters: Plant Architecture Affects Chemical Uniformity in Large-Size Medical Cannabis Plants

Since plant organs sense their environment locally, gradients of micro-climates in the plant shoot may induce spatial variability in the physiological state of the plant tissue and hence secondary metabolism. Therefore, plant architecture, which affects micro-climate in the shoot, may...

www.mdpi.com

 

[CharlesU Farley]

great reply! and if it were not for this paper i would have agreed with you. i think apical dominance has to play a role but it's not the whole story.

Shape Matters: Plant Architecture Affects Chemical Uniformity in Large-Size Medical Cannabis Plants

Since plant organs sense their environment locally, gradients of micro-climates in the plant shoot may induce spatial variability in the physiological state of the plant tissue and hence secondary metabolism. Therefore, plant architecture, which affects micro-climate in the shoot, may...

www.mdpi.com

As us medical folks are known to say, it's multifactoral.

 

[Hiddenjems]

i agree with most of what you say here, but i think the 600-700 umol point is a rather low light level to say that light above that point is "wasted" without co2. i know that i have seen gains in flower mass using light up to 1200 ppfd without co2 supplementation but with a high air turnover rate.

but i also know that i get even larger gains with co2 supplementation.

in 28 years i have run both with and without extensively for long periods of time and observed the results.

weighed the results too.

the only times i have run without co2 was when i was in a situation where i could not seal a room because the structure leaked so badly that i couldn't control it.

i greatly prefer co2 and my new room that i am building right now will have co2 supplementation.

i don't think agricultural co2 use harms the environment when using sealed rooms.

In other bugbee vids I’ve seen him state that really high dli show’s benefits without co2 supplementation.

It appears that they are both such strong drivers that while increasing both is optimal, increasing either alone will still show gains.

 

[Crooked8]

i agree with most of what you say here, but i think the 600-700 umol point is a rather low light level to say that light above that point is "wasted" without co2. i know that i have seen gains in flower mass using light up to 1200 ppfd without co2 supplementation but with a high air turnover rate.

but i also know that i get even larger gains with co2 supplementation.

in 28 years i have run both with and without extensively for long periods of time and observed the results.

weighed the results too.

the only times i have run without co2 was when i was in a situation where i could not seal a room because the structure leaked so badly that i couldn't control it.

i greatly prefer co2 and my new room that i am building right now will have co2 supplementation.

i don't think agricultural co2 use harms the environment when using sealed rooms.

It is wasted. The photosynthetic rate possible without co2 vs with cannot match your light intensity. The point where it dramatically changes is in that range. This is measurable at the leaf with bugbees equipment. Again, change nothing and just add co2. If you have happy plants under 1500umol they will be much happier with it. Its not that you cant achieve high yields without it. I ran highly ventilated rooms without co2 most of my career. Even in an unsealed room with a draw you can supplement. I have a low exhaust draw on my current space and i run co2. It does not have to be a sealed room. They supplement ventilated greenhouses with co2.

 

[greyfader]

As us medical folks are known to say, it's multifactoral.

yeah, and there's a lot of stuff involved, too!

It is wasted. The photosynthetic rate possible without co2 vs with cannot match your light intensity. The point where it dramatically changes is in that range. This is measurable at the leaf with bugbees equipment. Again, change nothing and just add co2. If you have happy plants under 1500umol they will be much happier with it. Its not that you cant achieve high yields without it. I ran highly ventilated rooms without co2 most of my career. Even in an unsealed room with a draw you can supplement. I have a low exhaust draw on my current space and i run co2. It does not have to be a sealed room. They supplement ventilated greenhouses with co2.

first of all, i strongly recommend co2 supplementation whenever possible. i know the difference in production that it can make.

as far as supplementing unsealed rooms, yes, it can be done, but at a higher expense.

all i'm saying is that 700 umols is a low light level, even with ambient co2. i just grew a plant in an unsealed room using 1100-1200 umols for 12 hours for a DLI up to 52 mols. i got 2.4 lbs dry, cured flower from it.

i know i would have probably gotten a little more from it with co2.

it seems to me that you are saying that i would have gotten the same yield at 700umols that i got at 1200 because i was co2 limited.

i know from practical experience that this is not true. i used a cheap co2 monitor and got at least the ambient co2 level of 425ppm at all times.

i think there's more to it than leaf photosynthetic rate measured by co2 evolution.

what about plants outdoors in ambient co2 under 45-50 mols/day producing multiple lbs.?

i know the curves show photosynthesis rolling off at 1000-1200 umols because of limited co2.

i know that light and co2 should be balanced to complement one another but we do see examples of large, healthy, high yielding plants grown in conditions that are not so balanced. all the time.

i could not have grown this plant this way at 700umols.

 

[Crooked8]

yeah, and there's a lot of stuff involved, too!

first of all, i strongly recommend co2 supplementation whenever possible. i know the difference in production that it can make.

as far as supplementing unsealed rooms, yes, it can be done, but at a higher expense.

all i'm saying is that 700 umols is a low light level, even with ambient co2. i just grew a plant in an unsealed room using 1100-1200 umols for 12 hours for a DLI up to 52 mols. i got 2.4 lbs dry, cured flower from it.

i know i would have probably gotten a little more from it with co2.

it seems to me that you are saying that i would have gotten the same yield at 700umols that i got at 1200 because i was co2 limited.

i know from practical experience that this is not true. i used a cheap co2 monitor and got at least the ambient co2 level of 425ppm at all times.

i think there's more to it than leaf photosynthetic rate measured by co2 evolution.

what about plants outdoors in ambient co2 under 45-50 mols/day producing multiple lbs.?

i know the curves show photosynthesis rolling off at 1000-1200 umols because of limited co2.

i know that light and co2 should be balanced to complement one another but we do see examples of large, healthy, high yielding plants grown in conditions that are not so balanced. all the time.

i could not have grown this plant this way at 700umols.

In the demonstration i saw, they had their equipment hooked up to a leaf, measuring photosythetic rate. As they increased light intensity at ambient co2 the rate failed to increase above that range until co2 was supplied. So thats all im saying. Ive gotten terrific yields from high lighting at ambient co2 levels. But im certain from my own experience it wouldnt be anything like if id had it. I see the plants, i get what youre saying. But until you do the exact same setup with co2 to compare with, its just a plant you grew at high light levels without co2. What could or could not happen is yet to be seen unless youve done it. You cant say for certain youre incapable of plants like that at 700umol unless youve tried it. And why even compare outdoor? Again, do the same thing but with co2. Those multiple pound plants would yield more. Just because something is possible at ambient doesnt mean it wouldnt dramatically improve with more co2.

 

[Ca++]

We'll have to agree to disagree on that.


Impact of Different Phytohormones on Morphology, Yield and Cannabinoid Content of Cannabis sativa L.

"Above all, the inflorescence yields are decisive, since a higher content of cannabinoids is expected. Stout et al. [46] reported the highest CBD levels in Cannabis flowers, with lower amounts in leaves. Cannabinoids can be extracted from the reproductive plant parts and foliage. Inflorescence has higher concentrations of cannabinoids than foliage material, however foliage parts comprise the lager biomass of the Cannabis plant [47]. The PCR genetics used in the present study showed lower leaf DW compared to inflorescence DW. Leaf DW yield depended on the genotype and treatment, where genotype KANADA showed the highest DW leaf yields and genotypes 0.2x and FED were not that profitable. The use of PGR did not reduce leaf yield for BAP-treated and NAA/BAP-mix-treated plants."

I feel like you answered someone else.

Apical is associated with apex. The idea the top of the plant exerts dominance over the rest. Indeed, the better illuminated parts do get favoured, and there is chemical signalling involved. However, Apical is wrong. It talks of positioning, which is false. You have been on that thread, and seen better buds at the bottom of branches than at their apical tip. You can choose to believe what you read over what you have seen, but pause for a moment to consider that. The real picture isn't far from their observations under the sun. They just didn't have all the facts, to make a more informed decision we can.

 

[greyfader]

In the demonstration i saw, they had their equipment hooked up to a leaf, measuring photosythetic rate. As they increased light intensity at ambient co2 the rate failed to increase above that range until co2 was supplied. So thats all im saying. Ive gotten terrific yields from high lighting at ambient co2 levels. But im certain from my own experience it wouldnt be anything like if id had it. I see the plants, i get what youre saying. But until you do the exact same setup with co2 to compare with, its just a plant you grew at high light levels without co2. What could or could not happen is yet to be seen unless youve done it. You cant say for certain youre incapable of plants like that at 700umol unless youve tried it. And why even compare outdoor? Again, do the same thing but with co2. Those multiple pound plants would yield more. Just because something is possible at ambient doesnt mean it wouldnt dramatically improve with more co2.

i agree! my next grow will be with the same plant in a sealed room with co2. i'll report it.

nice conversation! i have done quite a few experimental grows in the last 2 yrs. low light/high light, playing with 8 hour photoperiods. i got some decent results with 8 hours of 1000 umols for a DLI of 28.8.

we'll see how the next one goes.

 

[JKD]

Where cannabis cultivation is still incurs serious penalties, CO2 is another potential identifier. Those growers may appreciate the advice around air movement etc.

 

[Crooked8]

i agree! my next grow will be with the same plant in a sealed room with co2. i'll report it.

nice conversation! i have done quite a few experimental grows in the last 2 yrs. low light/high light, playing with 8 hour photoperiods. i got some decent results with 8 hours of 1000 umols for a DLI of 28.8.

we'll see how the next one goes.

you always have a great attitude and your plants are admirable to say the least. I used to seriously doubt the need for co2. I tried it in the beginning and then switched to just purely 24/7 ventilated rooms for maybe a decade. It wasnt until (i know i mention the courses a lot) bugbees information that i decided i must go back to it myself on my own room. Several other projects i worked on had supplementation and they did well prior but i could never be certain because it wasnt just my labor. Lets just say ive had my fair share of unreliable and inexperienced laborers. With that added experience under my belt using co2 on my own has been eye opening to say the least. With margins as razor thin as they are, its basically saving me from having to retire. I feel it bumps quality and does ripen things a touch faster too which is nice.

 

[tricloud]

so you stop after 4 weeks? you don't have to run it the whole cycle?

You can use Co2 through the entire cycle and get benefits but if you over feed C02 towards the last 2 to 3 weeks your flower will come out tasting like straw due to carbon build up in the plant. Cut back to 600 ppm the last 3 weeks. If you are running perpetual than just stay at 600 all the time.

 

[Crooked8]

You can use Co2 through the entire cycle and get benefits but if you over feed C02 towards the last 2 to 3 weeks your flower will come out tasting like straw due to carbon build up in the plant. Cut back to 600 ppm the last 3 weeks. If you are running perpetual than just stay at 600 all the time.

This is just simply not true. Do you have a source or anything to back that up? Because from experience i can say 100% that is false information. Nothing we grow tastes like straw, ever. We run 1200ppm all the way, like many others.

 

[CharlesU Farley]

I've been doing a very deep dive into NL history on another forum, concentrating on Nevil's involvement rather than NL Seattle Greg, and came upon something readers in this thread may find interesting. This is from a post from 14 years ago, Nevil Schoenmaker describing his experiences with CO2 supplementation:

"I used CO2 once. It gave me 25% more leaf matter. Using CO2 comes with less frequent air exchange and higher humidity and that leads to mould and mildew problems. Even without mould, stale air can affect the taste of the bud.
I like every leaf in the grow-room to be moving gently and I exhaust as much air as conditions will allow. Plants seem to like fresh air and a light breeze and it's hard to add CO2 to that economically.
If the global warmists are right, your plants should already be enjoying extra CO2, but I can't say that I've seen too much evidence of that. Anyone got CO2 meters? Tell me what the outside reading is.
N."

" "I have grown multistran crops with and without co2, and always found the bud grown with freash air cured and tasted the best."
That's my experience too.
N."

Just posting for historical significance, not debate. But it kind of confirms what I've been posting in this thread, and coming from one of the founding fathers of cannabis development, I feel like I'm in good company.

 

[Rocket Soul]

I've been doing a very deep dive into NL history on another forum, concentrating on Nevil's involvement rather than NL Seattle Greg, and came upon something readers in this thread may find interesting. This is from a post from 14 years ago, Nevil Schoenmaker describing his experiences with CO2 supplementation:

"I used CO2 once. It gave me 25% more leaf matter. Using CO2 comes with less frequent air exchange and higher humidity and that leads to mould and mildew problems. Even without mould, stale air can affect the taste of the bud.
I like every leaf in the grow-room to be moving gently and I exhaust as much air as conditions will allow. Plants seem to like fresh air and a light breeze and it's hard to add CO2 to that economically.
If the global warmists are right, your plants should already be enjoying extra CO2, but I can't say that I've seen too much evidence of that. Anyone got CO2 meters? Tell me what the outside reading is.
N."

" "I have grown multistran crops with and without co2, and always found the bud grown with freash air cured and tasted the best."
That's my experience too.
N."

Just posting for historical significance, not debate. But it kind of confirms what I've been posting in this thread, and coming from one of the founding fathers of cannabis development, I feel like I'm in good company.

From the quotes it seems like he used CO2 tanks in a vented space with low extraction in order to keep CO2 high. Not ideal really, tanks go hand in hand with sealed space.

The extra leaves CO2 is something we havent really seen, infact i look at pics from forums and most people seem to have a more dense foilage than what we get. Our co2 is about 1000-1500.

Not bashing, just discussing, and props to you for a nice answer

 

[Ca++]

In the cooler weather (which is most of the time) I'm generally burning gas to heat properties. At this time, I'm making co2 I'm not even using. This is a wasteful situation I would like to address, but co2 generators all seem to be so big. I recently turned down a gas camping light, which would of been a nice token gesture to my plants, but these things, like other fuel based lights, are not timed items, or particularly safe to leave unmanned.

I have twice found myself looking at the gas valves from old boilers. The type with a pilot light, that has a 'flame out' system. I just need a candle sized flame, but does anything that size exist?

The stories of ill rooms due to a bad burn, play on my mind. Though I would be venting 24/7 still

This idea is probably heading nowhere, but perhaps we have a gas guy in, who can take this to the next level. Automatic ignition. It really can't be that hard. It's all there, in a junk boiler.

 

[Rocket Soul]

The most unconventional CO2 source ive ever heard about was this dude who kept two bunny rabbits in his sealed grow room, all he needed to maintain atmosphere levels. Apparently their high metabolism make them ideal. Not a rec just throwing it out there.

 

[Ca++]

I have used a candle, to aid recovery after a mishap.
A 1sqm tent was vented into the room it stood in. The window and door were open, and a bathroom extractor was running opposite. This ensured a constant air exchange in the same direction through the groom, no matter the winds direction. It wasn't much, but just about enough.
The single tea-light made a useful 800ppm'ish. Two of them took me over my 1000ppm alarm, which I didn't want.
This is coming round to the idea a single flame is useful, and a standing pilot-light costs about 10$ a month.

 

[tricloud]

This is just simply not true. Do you have a source or anything to back that up? Because from experience i can say 100% that is false information. Nothing we grow tastes like straw, ever. We run 1200ppm all the way, like many others.

I don't doubt that you enjoy your product. I don't really have anything to back it up other than my word being that I live in a medical/recreational state, know lots of growers personally and have been in several grows and have tasted lots of smoke. I have an experienced pallet and have been growing indoor and first used CO2 in 1987. I know some guys who refuse to use enhanced CO2 for the last 2 to 3 weeks of flower. I know in my grow when I go over 600 I notice a diminished popcorn or straw like flavor and know others who feel that CO2 affects flavor negatively during the end of the grow. I have tasted it and discussed it with friends who agree.

I know there is literature out there but I didn't bookmark it or anything. I also have to wonder if there is a correlation between using a CO2 generator or using CO2 from a tank. Most of the people I know run CO2 generators.

Maybe we will find that there are actually different results from using "tank CO2" compared to "generator CO2".

I can also testify that using CO2 definitely can increase mold growth. I have seen it in several grows. CO2 makes everything grow faster, including mold.

 

[greyfader]

I don't doubt that you enjoy your product. I don't really have anything to back it up other than my word being that I live in a medical/recreational state, know lots of growers personally and have been in several grows and have tasted lots of smoke. I have an experienced pallet and have been growing indoor and first used CO2 in 1987. I know some guys who refuse to use enhanced CO2 for the last 2 to 3 weeks of flower. I know in my grow when I go over 600 I notice a diminished popcorn or straw like flavor and know others who feel that CO2 affects flavor negatively during the end of the grow. I have tasted it and discussed it with friends who agree.

I know there is literature out there but I didn't bookmark it or anything. I also have to wonder if there is a correlation between using a CO2 generator or using CO2 from a tank. Most of the people I know run CO2 generators.

Maybe we will find that there are actually different results from using "tank CO2" compared to "generator CO2".

I can also testify that using CO2 definitely can increase mold growth. I have seen it in several grows. CO2 makes everything grow faster, including mold.

molds take in oxygen and give off co2 so the co2 can not be directly causing the mold or feeding it. but co2 does put a lot of water vapor in the air that must be compensated for to control mold in the first place.

in flower, i like 55% rh plus or minus 5%. 60% at the higher end lights on and lower end at or slightly below 50% lights off.

with a lot of air movement.

 

[CharlesU Farley]

...but co2 does put a lot of water vapor in the air that must be compensated for to control mold in the first place.

Minor scientific correction: it's not the CO2 _addition_ to ambient air that causes the increase in water vapor, it's the _process_ that the CO2 is produced by, when CO2 is not being supplied by a tank.

The liquid CO2 contained in a tank has zero relative humidity as it sublimates to a gas. There's no water vapor contained in tanks, just liquefied CO2 under pressure. If anything, theotetically the addition of pure CO2 from a tank would _decrease_ the actual relative humidity in a tent.

I used to give supplemental CO2 breathing treatments to patients who had intractable hiccups when I was a Respiratory Therapist.