C02 Question

I just picked up a C02 regulator, Tank and an additional timer. I have a 3' X 3' X 7' tent with a 400w HPS cool tube. I have a fan on the cool tube running whenever the light is on, and a exhaust blower on 24/7. I just hoohed up the C02 yesterday for the first time. The exhaust blower was timed to go off for an hour while the C02 cam on for an hour. Then exhausted for 2 hours and repeated the cycle for the 12 hours the light was on. In the tent i have a digital thermometer / hygrometer, and during the time when the exhaust blower is off the temps went up to 88f (normally it is maintained at about 75f) i know higher temps are best when using C02 so that is fine, but my humidity goes up to 95% (normally its about 65%) while the exhaust blower is off. how concerned should i be with the humidity? I usually run 4 plants at various flowering stages so i have perpetual harvesting. I do not want to end up with rot or mold issues. Do I worry or am I being overly cautious?
 

auldy66

Active Member
hey
your grow nearlly exact same as mine. Only Im just hanging bottles with yeast and sugar mix, until I pick up a co2 emitter.
Something I was worrying about is, do you worry about the co2 getting exhausted out of the grow, with your extractor fan?

be interesting to see what info comes back about your humidity.

good luck ;)
 
i got the C02 tank regulator off amazon for about 80.00 so not too bad. I dont worry about exhausting the C02 as it just goes outside, so i think its safe. i have my exhaust fan off while the C02 is being brought into the tent so the plants can utilize it fully. then exhaust at end of C02 cycle to bring in fresh air. Thats when my humidity climbs through the roof.

Gool luck with you grow!
 

auldy66

Active Member
i got the C02 tank regulator off amazon for about 80.00 so not too bad. I dont worry about exhausting the C02 as it just goes outside, so i think its safe. i have my exhaust fan off while the C02 is being brought into the tent so the plants can utilize it fully. then exhaust at end of C02 cycle to bring in fresh air. Thats when my humidity climbs through the roof.

Gool luck with you grow!
was thinking more of how u r wasting the co2.. just a thought, good luck wth ur grow
auldy66
 

auldy66

Active Member
how do you see wasting?
did I read wrong, I thought I read that u had ur co2 on at the same time as exhaust fan? hey, Im askin not tellin, as I also worried(maybe too strong a word. thought) the same thing, was it worth having c02 in grow while my exhaust fan was on ;)
 
nope i didnt take it as you were telling me at all....I have timers shutting down exhaust fan/s when C02 comes on. The C02 is on for an hour then the girls are left for another 1/2 hour to utilize all or as much as possable C02, then the exhaust fan/s come on and refresh the air for two hours. Then the cycles are repeated fot the entire 12 hour light cycle.

i think the exhaust fans on while C02 is increased is a waste though, plants will not get that much of a C02 increase to be usefull.
 

BCNeil

Active Member
Sounds like a nightmare of a grow. Partial CO2 enrichment for a few hours a day, 95% humidity.
Just scrap your CO2 idea, until you have a proper room to use it.

With a 400 watt grow in a 3x3 tent, you don't really have the light intensity to use CO2 for its full benefits.
I'd say you would get just as much yield and of better quality working on proper environmental conditions throughout your grow.
IE proper temp and humidity 24/7.

Yes 95% humidity could damager your buds
 

auldy66

Active Member
nope i didnt take it as you were telling me at all....I have timers shutting down exhaust fan/s when C02 comes on. The C02 is on for an hour then the girls are left for another 1/2 hour to utilize all or as much as possable C02, then the exhaust fan/s come on and refresh the air for two hours. Then the cycles are repeated fot the entire 12 hour light cycle.

i think the exhaust fans on while C02 is increased is a waste though, plants will not get that much of a C02 increase to be usefull.
so you reckon its a waste of co2, me releasing it into grow while lights are on,? (i have to exhaust while lights are on,,temp issue)

I ask because I am genuinely interested.. ;)
 
From the research here and some other sites i believe that the C02 is suppose to be on during the light cycle and there is no benifet to using it during the dark cycle.
I could easily be wrong maybe someone else might have some input on that thought...
 
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Sounds like a nightmare of a grow. Partial CO2 enrichment for a few hours a day, 95% humidity.
Just scrap your CO2 idea, until you have a proper room to use it.

With a 400 watt grow in a 3x3 tent, you don't really have the light intensity to use CO2 for its full benefits.
I'd say you would get just as much yield and of better quality working on proper environmental conditions throughout your grow.
IE proper temp and humidity 24/7.

Yes 95% humidity could damager your buds​



No not a nightmare grow, the grow has been going great. But from the research on this site i found that the C02 should bot be on full time and most people put it on for short durations followed by exhausting. I only have the high humidity for a shot time during the cycle while the exhaust is off. I do agree that the high humidity is bad and a i worry, but i am unsure if short durations will actually have a major impact. for today it is off, but i am going to connect the cool tube up to an AC unit and see if i can control it that wat. Just looking for some other C02 users to maybe chime in....
 

mike91sr

Well-Known Member
First off, you're right about co2 only during light hours. Plants use it for photosynthesis. Youre also right about not wanting to exhaust when you are supplementing. Which is why its so difficult to add to smaller setups. You're not right about co2 in such short bursts being common. Most people DO exhaust periodically, but its more like 15-30 minutes every 2-4 hours. Not the other way around.

I'm not tryin to get you down or anything, but co2 does seem to be a wasteful and less-than-ideal venture for you, at least right now with the setup you have. Tents don't hold co2 in, so even if you dont exhaust youre still going to use much more than you would with a properly sealed environment.

Besides, only supplementing co2 for 4 hours a day is just not going to allow the plants to maintain an increased metabolic rate, so there's very little benefit to even having it there at all.

Lastly, I'm sure you already realize humidity spikes like that are going to be risky for molds and mildews, especially in a small area. And I'm a fan of higher humidity than most people(70-75% for veg,65% flower,55-60% last couple weeks), only IF you have proper airflow/circulation and complete control of your environment. i.e. no spikes or temperature issues. 88F and 95%RH in a small tent doesn't meet that standard, and it's just NOT worth having co2, IMO.

I'm of the belief that you should focus on having a properly controlled environment with the right conditions at a more conservative level before trying to push things farther than they should be and ending up with more problems than benefits.
 

BeaverHuntr

Well-Known Member
so you reckon its a waste of co2, me releasing it into grow while lights are on,? (i have to exhaust while lights are on,,temp issue)

I ask because I am genuinely interested.. ;)
Yeah its a waste all you are doing is sucking your co2 out. Co2 is heavier than air it falls to the floor but regardless you are just sucking it out.
 

auldy66

Active Member
Yeah its a waste all you are doing is sucking your co2 out. Co2 is heavier than air it falls to the floor but regardless you are just sucking it out.
I exhaust from top of cupboard 8' , I have a dead vent at bottom 2'. Im releasing co2 at around 3'. will this matter or make much diff ??
 

mike91sr

Well-Known Member
I exhaust from top of cupboard 8' , I have a dead vent at bottom 2'. Im releasing co2 at around 3'. will this matter or make much diff ??

It doesnt really matter where you release it if you have proper air circulation. My goal with circulation is to avoid any deadspots and to create a general upward current. So even though co2 is heavier, its getting blown around and upwards towards the exhaust before it really gets the chance to 'sink'.

Just do a smoke test if you can: Turn off all fans except your exhaust, and blow a bunch of smoke underneath or into the canopy, and see how long it takes to get sucked into the exhaust. Lets you see what your airflow patterns are, and you get an excuse to smoke a whole bunch :bigjoint:
 

auldy66

Active Member
It doesnt really matter where you release it if you have proper air circulation. My goal with circulation is to avoid any deadspots and to create a general upward current. So even though co2 is heavier, its getting blown around and upwards towards the exhaust before it really gets the chance to 'sink'.

Just do a smoke test if you can: Turn off all fans except your exhaust, and blow a bunch of smoke underneath or into the canopy, and see how long it takes to get sucked into the exhaust. Lets you see what your airflow patterns are, and you get an excuse to smoke a whole bunch :bigjoint:
aaah, never thought of that. I like easy solutions :) well done that man...
 

flea1

Member
i think using co2 properly is a very advanced technique which is the kinda thing u do when u've really mastered ur craft.. (i haven't)... As mentioned optimum environment is the most important factor for big harvests so the humidity hike is an issue as mentioned due to mould susceptibility. Humidity is water content in air so more water=more mould... Plants would prefer to grow in higher humidity but the lower 50-55 % flowering guideline is to avoid mould really ( 70% at veg)... Also temperature and humidity are hand in hand (look up further) so as temperature increases or decreases it directly affects humidity which is why these humidity hikes happen when the extractors or lights go out mainly.. Other food for thought.. as co2 is increased (presuming its available, not just sucked out or on floor) it accelerates photosynthesis and this can cause nutrient problems much more rapidly so what would take several days to show can happen in two... I watched my nitrogen shortage advance very quick and i didn't know where to turn lol... i think there are easier ways to get bigger buds ... not really experienced in co2 but some say it just makes things go faster and not produce much more so for all the gambling ... on 4 beloveds? all the best,,,,, not trying to lecture btw
 
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