When to Stop co2 Increase During Flowering?

Micobfsb

Micobfsb

Member
Ive been reading alot lately and it seems like many people advocate stoping co2 enrichment durring the last two weeks of the flowering phase. I am wondering, why is this? If co2 helps the plant grow durring all of its other stages, why wouldnt you stop the enrichment right before you harvest the plant?
 
Micobfsb

Micobfsb

Member
While we are at it, ive been reading that one is supposed to increase the temperature of plants while co2 enrichment is taking place, but some have said that this stresses the plants, anyone have any thoughts?
 
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TrichomeTrent

Active Member
Micobfsb said:
While we are at it, ive been reading that one is supposed to increase the temperature of plants while co2 enrichment is taking place, but some have said that this stresses the plants, anyone have any thoughts?
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The reason for this is limiting factors. Co2/oxygen/light/nutrients/temp must essentially be balanced. If given numbers just for the sake of explaining, let's say you run all factors at '2', but then decide to increase co2 to '3'. To simplify the explanation the plants will still grow at '2' or only slightly faster unless you increase everything. Ed Rosenthal explains it in his book I believe ;)
 
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TrichomeTrent

Active Member
Reservoir temperature is actually a pretty trivial detail. I would say as long as its not too cold or warm so it doesn't shock the plants or effect room temperature (if its large enough). Other than that just keep the water moving so it doesn't become stagnant or have nutrients settle on bottom. Will also deter alot of insects from laying eggs in your reservoir. ;)

Happy growin' :)
 
hempknightt

hempknightt

Active Member
Micobfsb said:
While we are at it, ive been reading that one is supposed to increase the temperature of plants while co2 enrichment is taking place, but some have said that this stresses the plants, anyone have any thoughts?
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Basically even if you have more CO2, if you dont have enough light/other factors to match the increase the plant wont make its sugar sandwiches or whatever they make to grow.

Im curious to know why people say to shut it off as well. It seems sortve like a myth, like the one about flushing your plants of nutes when it needs them the most.
(I think growers start these myths so that other people dont grow as good lol)
 
mvoltage24

mvoltage24

Member
i have always shut off my co2 off 2 weeks before but in recent weeks ive been doing research and im not doing that anymore. im letting it run till harvest.
IMO those last 2 weeks are the most important to have co2 cuz thats the "swell" phase. im 6 weeks into flower will try to report back to see if it helps.
 
HerbalPrincess

HerbalPrincess

Member
Temperature is proportional to the root mean square velocity of the molecules, be it the plant or the air. This means at higher temperatures the molecules are moving faster, and therefore chemical processes happen at accelerated rates, especially diffusion driven biological processes. Even the air molecules on the surface of the leaf are being replaced quicker at higher temperatures. Adding CO2 allows the plant to operate at this accelerated rate, transpiring water at a faster rate and therefore is able to cool itself better and handle the increased temperature. Its a process that goes hand-in-hand.

But then again that's all just speculation.
 
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rabidnz

Active Member
and also higher heat = faster growth of any bacteria within the ranges we are using, whether mould on the plants or gunk in the res. Dont just go straight to the upper ranges of suggested temperatures without constant monitoring of plants and of course excellent humidity control.
 
322special

322special

Active Member
i do have the same questions. i was bout to do a post then found this..the guy at my hydro shop told me t run 1000 ppm during veg,switch to 1500 for flowering and right when the buds start to swell lower down to 500ppms. you lower to keep oil productions at it top game. this is what he told me,im trying to find similar search results...this c02 alone is like learning how to grow all over again..ive also read to keep temps higher than you would with out c02..any one else want to chime in?.....
 
HerbalPrincess

HerbalPrincess

Member
After doing some more research, I learned that increased temperatures also allow increased CO2 uptake because at higher temps, the plants need to transpire more water to stay cool, so they open their stomata wider and therefore can get more CO2. Increased humidity also helps because it makes it harder for the plant to transpire, so once again the stomata open wider.
 
stondded

stondded

Well-Known Member
i try to keep my cge setup between 78-82 when the lights r on
and i have always left my co2 run all the way up to harvest but i also run a perpetual setup
i have also heard tho tht when co2 is backed off or stopped the the essential oils for smell and taste r more pronounced
but i have tried to make up for running all the way to harvest by putting plants in dark for 2 days before the chop
 
delatour

delatour

Member
I think you should let it go to the bitter end if all other variables are correct it can only help co2 is never going to harm your plants. CO2 also does allow for higher temperatures but as another poster pointed out, with the increase in temperature you could also increase other problems. If your humidity is proper 40% to 50% relative humidity you should be ok though. Also nutrient solutions are best uptaken at 65 degrees, higher than that and less oxygen is getting to the roots. Co2 does not make plants take longer to flower it actually decreases flowering time while simultaneously increasing yield. It also helps plants thrive which keeps them heathier. Co2 is your friend inspite of what your government tells you.
 
delatour

delatour

Member
322special said:
i do have the same questions. i was bout to do a post then found this..the guy at my hydro shop told me t run 1000 ppm during veg,switch to 1500 for flowering and right when the buds start to swell lower down to 500ppms. you lower to keep oil productions at it top game. this is what he told me,im trying to find similar search results...this c02 alone is like learning how to grow all over again..ive also read to keep temps higher than you would with out c02..any one else want to chime in?.....
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Running co2 only works in a vegetative stage if you are growing under a high intensity lamp. If your using fluorescents it's a waste of money.
 
kona gold

kona gold

Well-Known Member
I think the main reason people have said to stop using co2 the last two weeks of flowering is so the flowers stay dense and dont run or fluff at the end. Mainly i believe if you still have too much available nitrogen your plants will still be processing this, then having the co2 can cause unwanted late term leaf growth especially near the bud tips, which is not what you want to happen at end. If not much nitrogen available at end of cycle( nitrogen can also be stored in plant tissue with eccessive chemical ferts.), then should not be a problem. Good luck and aloha
 
K

kannibis

Active Member
delatour said:
Running co2 only works in a vegetative stage if you are growing under a high intensity lamp. If your using fluorescents it's a waste of money.
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No sir, you are wrong. I am not going to lay it out for you however. Go do some research and chime back in when your up to speed.
 
K

kannibis

Active Member
I personally run all the way up to the end. High nitrogen causes to much foliage (foxtailing). Stopping co2 right at the start of the swell is like making a car that shuts off half its cylinders when you press the accelerator to the floor, not very smart. Instead, stop the nitrogen, give it tons of PK and just a touch of N. If you notice, good growers are much more concerned with proper nutrient feed schedules than hoodoo voodoo techniques.
 
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asilsweater

Active Member
From my own expierences co2,is used heavily in conjunction with humidity and 78 to 85 are ideal for veg and in first phase of flower ur co2 is shot up to 1800,2000 and temp 80,second phase of flower co2 is reduced to 600 ppms and temp reduced to 75 degrees,this helps keep trichomes from being affected by heat and last two weeks i keep co2 at 600 and reduce temp to 70,dis helps my flowers dense up and get sugary since they think winter is here,one thing i must say and dat is co2 will increase ur humidity,in veg its k and in early flower but in mid flower and late bloom u dnt want as much becuz it can lead to bud rot or mildew.dehumidifier is highly recommended!! Key to big flowers is high lumens,co2,good fert schedule and good genetics,
 
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