Myth busters - the real truth on CO2 in indoor grows

I used to brew beer, meads, cysers, etc. Same "basic" set of ingredients but the yeast always was specific to the brew.

For example, a brewers yeast would get you to about 9-10% a/v before alc toxicity killed off the yeast Sometimes a little more but it depended on the strain of yeast (we cultured our own strains and had a yeast bank in liq nitrogen).

For higher gravity brews like mead or hard cider, we used champagne yeasts. These will take the brew up to about 14-18% a/v.

So the yeast REALLY matters. If it kicks out, you are left with a lot of residual sugars (which is why meads are sweet).

If you go this route, try champagne yeast. The co2 will generate for a longer period (or maybe just faster over the same period).

Unfortunately, it's not a flat line production. The initial fermentation will be hard and heavy, and then taper off as the alc % increases and the sugars decrease. There is always a LOT of yeast in the mix - inches of it on the bottom. The amount of yeast was never the issue.

Also, oxygen helps. If you cold side aerate the wort (sugar solution) before fermentation it will produce a lot more co2.

Finally, lots of things will grow in a wort. A lot of those things are nasty. If you don't pay attention to sanitation you will grow molds and bacteria. Nobody wants to add that to a grow room.

Invest in some idophor. It's one of the best non-toxic sanitizers there is for brewing and restaurant sanitation.

Record CO2 Coincides With Record-Breaking Crop Yields, 'Greening of Globe'

Ummm scientists have reviled that your thread is GARBAGE for stating that supplimented CO2 isn't worth doing.
So, are you just trying to kill off others increase of yield so you can make more by undermining those in your market area?

Sheep's Blood:
Yes, more CO2 will grow plants faster. The point is, in a reasonably tight home inhabited by mammals there's plenty of CO2 for most grower's purposes. Increases in photosynthesis are most dramatic when CO2 is raised from the 420-ish ppm we currently have in our atmsphere to the 600-ish that desert rat's meter indicated in his home. Those of us who live with our girls and are doing small personal grows won't get much benefit from increasing PPM of CO2 beyond this, and then only with sufficiently bright lighting and temps in the low to mid 80's to facilitate increased CO2 respiration by the plants. Increases in photosynthesis with no other limiting factors are much smaller for CO2 concentrations about 600, and the closer you get to 1250 the smaller the increases become. The attached graph illustrates rates of photosynthesis relative to CO2 ppm. That said, if you have a reasonably airtight room where you can run high temps and the equivalent of 650 watts HID per meter, you would see modest increases at levels higher than 600, and significant increases if your base ppm before enrichment is 400 or below. However, these gains only happen when light, temp, nutes and water are optimized, so you should dial in these other limiting factors thoroughly before considering adding CO2.

Bob Dobelina said:

Sheep's Blood:
Yes, more CO2 will grow plants faster. The point is, in a reasonably tight home inhabited by mammals there's plenty of CO2 for most grower's purposes. Increases in photosynthesis are most dramatic when CO2 is raised from the 420-ish ppm we currently have in our atmsphere to the 600-ish that desert rat's meter indicated in his home. Those of us who live with our girls and are doing small personal grows won't get much benefit from increasing PPM of CO2 beyond this, and then only with sufficiently bright lighting and temps in the low to mid 80's to facilitate increased CO2 respiration by the plants. Increases in photosynthesis with no other limiting factors are much smaller for CO2 concentrations about 600, and the closer you get to 1250 the smaller the increases become. The attached graph illustrates rates of photosynthesis relative to CO2 ppm. That said, if you have a reasonably airtight room where you can run high temps and the equivalent of 650 watts HID per meter, you would see modest increases at levels higher than 600, and significant increases if your base ppm before enrichment is 400 or below. However, these gains only happen when light, temp, nutes and water are optimized, so you should dial in these other limiting factors thoroughly before considering adding CO2.

Click to expand...

I can agree with that.
I started at 500ppm. So I supplement from there. I am pretty well sealed. If I had a split ac, vs a dual hose portable that I use, then I would be solid.

greg nr said:

I used to brew beer, meads, cysers, etc. Same "basic" set of ingredients but the yeast always was specific to the brew.

For example, a brewers yeast would get you to about 9-10% a/v before alc toxicity killed off the yeast Sometimes a little more but it depended on the strain of yeast (we cultured our own strains and had a yeast bank in liq nitrogen).

For higher gravity brews like mead or hard cider, we used champagne yeasts. These will take the brew up to about 14-18% a/v.

So the yeast REALLY matters. If it kicks out, you are left with a lot of residual sugars (which is why meads are sweet).

If you go this route, try champagne yeast. The co2 will generate for a longer period (or maybe just faster over the same period).

Unfortunately, it's not a flat line production. The initial fermentation will be hard and heavy, and then taper off as the alc % increases and the sugars decrease. There is always a LOT of yeast in the mix - inches of it on the bottom. The amount of yeast was never the issue.

Also, oxygen helps. If you cold side aerate the wort (sugar solution) before fermentation it will produce a lot more co2.

Finally, lots of things will grow in a wort. A lot of those things are nasty. If you don't pay attention to sanitation you will grow molds and bacteria. Nobody wants to add that to a grow room.

Invest in some idophor. It's one of the best non-toxic sanitizers there is for brewing and restaurant sanitation.

Click to expand...

What your looking for is "TURBO YEAST"! This yeast is used in preparing mash's for distillation (can have a nasty taste for corn and rum shines) It'll run up to 23% and I've seen mash's at 25% with it's use.....It's available by the pound online.

Bob Dobelina said:

Sheep's Blood:
Yes, more CO2 will grow plants faster. The point is, in a reasonably tight home inhabited by mammals there's plenty of CO2 for most grower's purposes. Increases in photosynthesis are most dramatic when CO2 is raised from the 420-ish ppm we currently have in our atmsphere to the 600-ish that desert rat's meter indicated in his home. Those of us who live with our girls and are doing small personal grows won't get much benefit from increasing PPM of CO2 beyond this, and then only with sufficiently bright lighting and temps in the low to mid 80's to facilitate increased CO2 respiration by the plants. Increases in photosynthesis with no other limiting factors are much smaller for CO2 concentrations about 600, and the closer you get to 1250 the smaller the increases become. The attached graph illustrates rates of photosynthesis relative to CO2 ppm. That said, if you have a reasonably airtight room where you can run high temps and the equivalent of 650 watts HID per meter, you would see modest increases at levels higher than 600, and significant increases if your base ppm before enrichment is 400 or below. However, these gains only happen when light, temp, nutes and water are optimized, so you should dial in these other limiting factors thoroughly before considering adding CO2.

Click to expand...

WOW! somebody who actually understands Co2 use!

I agree! The big laugh fest is the guys who claim huge yield increase's with 1500 and higher ppm's.....That is basically impossible as the plant effective limit is 1500, and it's very hard to supply the amount of light intensity needs to actually make that 1500 work!

Basically speaking. 1300 is about the actual limit of effectiveness for the grower. Light has to be delivered at the proper intensity, temps have to be at about 90 F and 80%+ RH for that to actually work also....

Simple and easy to obtain results, fall into the 800ppm area.

I have the ability to generate as I need in a larger area. I don't (now I question why I did add that ability anyway). I can reach plant potentials by proper feeding and supplementing (note that i said "supplementing" and not "boosting").

Another popular mistake in Co2 use. IS to use it in veg. Sorry to break your bubble.....The cost to return ratio of using Co2 in veg...Is not worth the cost!

Another point is. If you don't like the "stretch" in bloom...LOL, don't gas during it!
Don't forget to shut it off at the last 2 weeks also! It inhibits ethylene gas production by the plant. Ethylene gas is what ripens the buds.....

Welcome @Bob Dobelina! You have knowledge!

@DrWho- CO2 in veg is not worth the cost? Care to elaborate?
Increase temp, increase speed of growth, increase uptake of nutes, increase water cyling......???? What am I missing??

https://www.rollitup.org/t/free-co2-with-living-soil.925973/

Plenty of sources that show how increased CO2 increases photosynthesis rates.
I disagree with just about ALL of your post @DrWho

83.7 degrees has been shown to be the money maker NOT 90. 80% rh to be effective really? Do you have any sources>? No wonder you didn't see an increase!

Opinions are great but too often your posts seem like self generated laws.

http://www.climatecentral.org/news/study-finds-plant-growth-surges-as-co2-levels-rise-16094

http://www.co2science.org/subject/f/summaries/flowers.php

http://www.nature.com/scitable/knowledge/library/effects-of-rising-atmospheric-concentrations-of-carbon-13254108

http://www.sjsu.edu/faculty/watkins/CO2plants.htm

I understand ambient c02 of 400 outdoors, and indoors too , I read the reason for the elevated c02 in indoor growing environments is we cannot move enough air to keep that steady ppm at each plant leaf, but outdoors does with much more air movement/exchange than we can reproduce indoors, thus 400ppm is fine, if thats whats actually under your canopy. I move my meter to check this and sure enough, 180, 120...in the plant bush...this is the issue. even without changing my air movement the addition of 800 ppm in the sealed room increased this number to 500ppm+. I added more air movement, and keep my gen tip top now

will she grow without c02 addition? of course, but if the other controls are spot on......c02 resources are the weakest link, and more will improve outcomes is a sealed room.

if my generator took a shit I'd replace it, in an effort to supply all the necessary resources for full expressions.

CO2 + high humidity during the last few weeks of flower will create Carbonic acid, which will settle on tricomes/sugar leaves and will throw off the flavor of your cannabis and give it a sour taste, but not the sour some are looking for.

I read that somewhere. I set my dehuey years ago and never gave it another thought. seen a few high humidity flowering rooms in my day, smelled like a dirty sock/wet crawl space. weed had that funky pocket pissy smell/taste too. Dehumidifier, ac, heat, ....go big or gtfo!

so i was wondering, if a plant uses approximately 100 ppm of CO2 per hour ( i suppose this means a mature plant), and indoor dwellings can have 600 ppm already in the air, then as long as you don't have more than six plants and you are exchanging the air in the room at least once or twice an hour, the PPM in the AIR should be enough with out a need to add more CO2 into the room, unless you are growing in higher temperatures?

What kind of temp/humidity would one be looking at to take advantage of 6/700 ppm?.

I am vegging in a 120x120x60 tent and for that space the yeast method worked really well. To the mix longer lasting i added gelatin to make it firmly...so the yeast needs to work through it...a 2L bootle with this mix it took about 5-6 weeks before it finished. It bubbled constantly so i knew its working. I also used brown sugar instead of the white one.

Rumor has it desertrat is still running this experiment and using the same yeast to make brownies.

Candle can for small grow tents. Buy unscented 15hr candles in packs of 288 for 100 bucks. Get a lantern and an aluminum can with a lid about 1.5'x1.5'. Cut duct hose holes in the can for an intake and outtake to your closed loop Air system. Hook your hoses up to the can outside your tent. Place your lantern inside the can with about 2 inches of water incase if falls over the water puts it out. Burning 2 of these candles will bump CO2 in a closed loop system to 1200-1600ppm for a 70cf area. 288 candles are about 100 Bucks at 2 burning a day=144 Days of CO2. Don't burn at night. Plants don't use the CO2 when Stomata is closed. No need to burn during Veg unless you burn 1 candle which will bring you to 800ppm. Ensure you use a lantern as well as a can. The air current in the can will put out the candle or burn it quickly if you don't have a lantern. Plus, it's another fire safety measure. Which I don't recommend you doing this due to the fire hazard it creates. But it is cheap and effective.

65 bucks for a tank , 10 bucks locally to refill it. 75
120 bucks co2 controller 195
45 valve 240
time to install 10min 15
Total $255 initial investment.
$15 reoccurring every 3 months
my point here is how much money is it over time to do this yeast crap with mixing it dumping it placing it checking it count your labor because time is money.
and a tank is way more simple and a lot less labor and its safe.