Proof that co2 increases yield

[Whelm]

Greetings,

This following was posted by me as part of a larger thread in the room design section, but I am very curious about this and it fits better in this section anyway.

My partner has a master's degree in plant science. When I spoke to her about the conventional wisdom that 1500ppm co2 is ideal, she asked what proof I had to back up this claim. I realized that I have no actual proof. I have never used co2 and have only heard anecdotal evidence, though lots of it. Many people claim yield increases but I cannot find any grow logs showing side by side grows where the only variable is co2 added in one space, none added in the other. Everyone claims 1500ppm adds 20-30% to final yield, but non-anecdotal proof seems lacking. I recognize that there is a lot of anecdotal evidence, but how much of this is the placebo effect combined with growers paying extra close attention to all details, thus boosting yield.

My partner has access to all scientific journals and researched the issue. There are numerous studies on the effects of co2 that are not anecdotal. For C3 plants like cannabis, science tells us that adding co2 has a substantial positive vegetative effect, increasing leaf and stalk growth rate and size. In the flowering stage though (once flowers start to form), added co2 has a neutral to negative effect. In other words: great for veg, bad for bloom. In other other words: it is possible that any increase in overall yield has to do with creating bigger, healther plants in veg that then finish bigger, as opposed to co2 having a positive effect in bloom.

A few questions:
1. Do you know of any scientific studies that state adding co2 is beneficial to the flowering stage of C3 plants?
2. Do you know of any grows that have done a side by side study of increased co2 vs no added co2 in bloom?
3. Have you used co2 exclusively in veg (not in bloom)? What were your results?

Thanks!

 

[supermanlives]

i had greenhouses . i know for a fact what it does. 1500 is overkill tho. i dont use co2 in veg as i get plenty free from my heater. old fashioned ng heaters.

 

[mcfly420]

The facts about CO2 ppm: don't use 1,500!
https://www.icmag.com/ic/showthread.php?t=221893

 

[dreadkush]

Co2 for sure helps and increases yield for sure

 

[Weird]

bottom line blow CO2 into your grow until it makes a noticeable difference because CO2 will make a garden noticeable different

unless it is throttled by some other condition

liken CO2 is like nitrous in a car

you dont put nitrous in a hooptie to make it a hot rod, you put nitrous in a hot rod if your looking to raise the bar

 

[Shcrews]

i would be down to check out a side-by-side... seems like most people just run one or the other though.

in my experience co2 definitely speeds up plant growth, which would in turn increase bud growth.

 

[mg75]

amongst other nutrients and additives, co2 will shorten your harvest time from 7-10 days. we use 1500ppm with great results. the fact that the sensor picks up 1500ppm does not mean it is 1500ppm all over the room and plants. with fans blowing, air leaks, plant usage and temperature/humidity variations we feel 1500ppm is a good number.

also...

if you run a sealed room (like we do), you must run co2 supplementation. sealed rooms are the best and most efficient/safe way to run a grow op. the fact that i can control everything in it, is golden. no air-born spores nor pests. zero smell on the outside. complete temperature/humidity control regardless of outside. co2 injection is essential in both veg and flower.

 

[lost in a sea]

everyone knows this its simple biology, co2 + h20 + light >>photosynthesis>> sugar,, which is then used by the by mitochondria to release energy by making ATP from it,, its a big part of why plants have stoma,,

even if your the shittest grower co2 will improve the plants yield,, maybe as a side effect to growth speed but its a subjective call,,

ive been adding co2 for over 10 years and i can say it makes life easier,, plants grow stronger, faster, healthier, the roots are happier that are near the surface, it inhibits pests, thicker stems (imo), but you still have to be able to grow good weed though to get the best from adding co2,,

just using a butane heater kicks out tons of the stuff,, but thats better for cold situations,, like living in the uk,,

it does definitely have a positive effect all the way through growth from day one sprouting till the end,,

1500ppm as metioned. much higher and you wont too much improvement,,

if used just in veg the plants would grow taller than normal and sooner but in my opinion it helps to let cannabis mature genetically for as long as possible before flowering to avoid hermie tendancies as much as possible, but if the veg stage was almost totally stress free you will be fine even if they are ready to go through a week earlier than normal,,

during veg the plants efforts and energy are on roots,, but the flowering time is when the plant needs sugar the most for manufacturing nugs,, so yeah benificial during both stages,,

 

[BigDawg]

isnt outdoor co2 only around 500?

 

[SacredBreh]

Whelm..... here is what you asked for.

Whelm..... here is what you asked for.

http://www.plantphysiol.org/content/94/4/1728.full.pdf

You have to have optimal light saturation and increased temp also... the temp part is not in this article.

Not directly related to C3.
http://www.publish.csiro.au/?paper=PP9840375

Peace

 

[TheCatsMeow]

what would be interesting is if someone ran a room with co2 but only comparable to the outside co2 ppms levels! haha

if you did a side by side grow with fresh air and a sealed room with ppms of say, 400 would the grows be similar?

 

[Booner47]

What is the best recommended method of getting plants the CO2 they need?

 

[Tyga]

Either bottled or burner... Depending on what size of room your using I guess. Seems that people with larger rooms go with co2 burners and people rocking smaller set-ups or tents use bottled.

 

[HUGE]

Ol miss has been growing pot legally for the Feds for the last 60 years and their report states cannabis metabolizes best at 1500ppm. Someone posted their notes here somewhere.

 

[MadMike1337]

Read the Ol' Miss research docs, going to read more. They've been doing this for a long time and have the science to back up the numbers. I have adjusted the temps in my rooms up by 5 degrees to see if that boosts anything.

I have CO2 maintained at 1400-1500 PPM in cycles throughout the daylight hours, Sealed room, water cooled. Everything else in this room is maxed out. If the temps going from 79 up to 83 works out, I will dance a jig.

 

[hddeuce]

Greetings,

This following was posted by me as part of a larger thread in the room design section, but I am very curious about this and it fits better in this section anyway.

My partner has a master's degree in plant science. When I spoke to her about the conventional wisdom that 1500ppm co2 is ideal, she asked what proof I had to back up this claim. I realized that I have no actual proof. I have never used co2 and have only heard anecdotal evidence, though lots of it. Many people claim yield increases but I cannot find any grow logs showing side by side grows where the only variable is co2 added in one space, none added in the other. Everyone claims 1500ppm adds 20-30% to final yield, but non-anecdotal proof seems lacking. I recognize that there is a lot of anecdotal evidence, but how much of this is the placebo effect combined with growers paying extra close attention to all details, thus boosting yield.

My partner has access to all scientific journals and researched the issue. There are numerous studies on the effects of co2 that are not anecdotal. For C3 plants like cannabis, science tells us that adding co2 has a substantial positive vegetative effect, increasing leaf and stalk growth rate and size. In the flowering stage though (once flowers start to form), added co2 has a neutral to negative effect. In other words: great for veg, bad for bloom. In other other words: it is possible that any increase in overall yield has to do with creating bigger, healther plants in veg that then finish bigger, as opposed to co2 having a positive effect in bloom.

A few questions:
1. Do you know of any scientific studies that state adding co2 is beneficial to the flowering stage of C3 plants?
2. Do you know of any grows that have done a side by side study of increased co2 vs no added co2 in bloom?
3. Have you used co2 exclusively in veg (not in bloom)? What were your results?

Thanks!

i talk to a lighting geek ( scientist at phillips for lifting

at higher temps vs lower temps with same co2 ppm


he said the tests they performed showed increase in wet yield for high temps but over all dry yield went to lower temps with co2

he says this was due to high temps cause extra let growth to deal with higher temps

and that nobody had a ever tried a
low temp + co2 grow vs high temp co2 grow

he say co2 should be determined by r/h % not temp

lower rh needs high co2

30% relative humidity is what the test revealed for most plant growth combined with
78 f 4500 ppm c02



at 50 RH% ur co2 ppm is 2000

I'm giving it a go

 

[gorilla ganja]

i would be down to check out a side-by-side... seems like most people just run one or the other though.

in my experience co2 definitely speeds up plant growth, which would in turn increase bud growth.

Like Shcrews said, it speeds up growth.
Therefore you can harvest sooner or you will have bigger plants overall in the same time frame with in turn will give larger yields.

Peace GG

 

[ChaosCatalunya]

isnt outdoor co2 only around 500?

I think the "normal" quoted figure is 400ppm

BUT.. this is an average, and it is rising globally (IIRC, reports)

Also... in rural areas, more plants consume it by day and excrete it at night... so in the countryside it can go from 250 in daytime up to 650ppm at night dependent on the time and a lot of other environmental factors (approx figures)

To really benefit from CO2 enrichment, you need to be running 35C and 85%RH (approx) and run more light to raise the metabolism of the plant

As others said, this is not good later on in flower, obviously the temperature and humidity will fuck your crop, but AFAIK nobody has seriously tested when is best to lower/stop enrichment. If they have, they are keeping quiet about it.

 

[davidw44]

I bought a Co2 burner so it's good for veg but not flowering. I am at eight weeks on a ten week plant. I turn the burner off.