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Sealed Rooms and night time oxygen

Seltzerman

New member
I have just converted my grow room to all climate controlled with CO2 augmentation that seems to work OK.

So, because of this, I have no significant air changes anymore.

But...I just read from Jorge Cervantes and a couple of other sources that during the dark, plants take in O2 at the leaves (independent of oxygen they need at the roots), and that since they do not produce O2 in the dark, they need a supply of O2 at night.

I've seen no discussion anywhere of whether a reasonably well sealed room could deprive the girls of useful O2 during the dark and if so whether there is benefit from some modest level of ventilation (or O2 augmentation) during the dark?

Any thoughts ?
 
S

sparkjumper

Yea heres one,Jorge's real name is Billy or some shit and he's never grown erb in his life!Either there is enough oxygen present for 12 hours,or my pants are on fire!Seriously I run a dehumidifier and window AC during lights off and all is well.I have an 8 by 8 sealed room with 20-25 plants normally
 

Seltzerman

New member
Thanks for the input. I am not basing my question on any recommendation made by Cervantes, only to a statement made multiple sources, of which he is one, that during the dark cycle, plants use more O2 than they create. It is purely my own curiosity and question as to whether that fact leaves room for some night ventilation to improve yield when the room is otherwise sealed. Any replies to THAT question?
 

Mr. Greengenes

Re-incarnated Senior Member
ICMag Donor
Veteran
Well, much more O2 is produced by the plants by photosynthesis during the day than is used back up by them at night, I can tell you that for sure. I think it's on the order of ten times, off the top of my head. The area that nighttime O2 needs pose a problem for plants is in aquaculture. Water has a hard time holding enough O2 for plants to reup at night. While O2 is quite abundant in the atmosphere, CO2 (gonna catch hell from the AGW folks now!) is in short supply. When you consider that a field of corn can use up ALL the available CO2 from the ground up to two meters in about five minutes (without air circulation in midday sun), you can see that cannabis which is also a very high energy 'C4' plant, needs CO2 to grow in sealed rooms.
 

Seltzerman

New member
Actually, from everything I've read, Cannabis is a C3 not a C4 type. C4s actually need less exogenous CO2. But its O2 in the dark, of course which I wonder about. Clearly, there is enough O2 in a sealed room at night to sustain the plants or they would die. For now, I'm going to assume my hypothesis to be incorrect and there is no benefit from any night venting for O2 replacement.
 

Mr. Greengenes

Re-incarnated Senior Member
ICMag Donor
Veteran
I have no scientific explanation for this but our grows improved dramatically when we started exhausting during the dark period. Way healthier, hardier and heavier plants. Much less power consumption keeping humidity levels in check too...
 

Seltzerman

New member
What temps do you run with the lights on and then what temps do you target during the dark? I may need to start exhausting during the dark, too - my plants became so massive so fast that the humidity during the dark won't go below 60% unless I run two dehueys and then my temps stay at 75 and humidity at 50%. My lights on temps are about 81-82 and 60% humidity. If I want the lights on humidity to be lower, then I have to put up with 84F temps which seems high, even with 1300-1600 ppm CO2...or is that OK?
 
S

sparkjumper

I run at 85 F at the canopy(using lazer thermometer) for my flowering plants at 1500PPM.I've been doing this for many years now man and I want you to believe me,you dont need any air exchange whatsoever during the 12 dark hours.I have to believe there is enough oxygen available because I get 2 lbs per 1K vertizontal with medium yielding strains like blockhead.Just make sure to always have the dehumidifier and window AC running during the dark hours.
 

Andyo

Active member
Veteran
what about seedlings

what about seedlings

Seedlings are not going to be producing much O2 compared to your increased co2 levels
atmospheric O2 is about 21%
atmospheric nitrogen about 78%
I like the idea of totally sealed rooms, ive run sealed with timed venting and AC.
I think its worth some thought and effort to find answers for a totaly sealed room with top yields
If only for stealth and ease.A
 
I've often wondered if anyone has raised the Oxygen levels in a sealed room at night. We know roots love it, and in organics soils its a must.
 

Andyo

Active member
Veteran
Andyo,
How much are they? Couldn't find a price. Thanks. -granger
No idea yet ,im looking around at what else is availble just now,will let you know when i do.
I think need email the company,.
I use ebb/flow in hydroton airation of the roots is max ,so im thinking if i get the right C02 O2 monitor ill up the room O2 to 25% and let the pots suck that into the hydroton during drain ebb cycle.
 
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Andyo

Active member
Veteran
blood or automotive O2 sensor

blood or automotive O2 sensor

For $129 you can get an O2 monitor on Amazon.
I looked on amazon only saw blood O2 and exhaust O2 monitor
I guess there will be an affordable one out there that can trigger a solenoid valve.
I suppose you could you could grow oxygen weed in you rez.A
 

Dick Turpin

Member
Have a look at this and the company selling it. It may suite your application.
I haven't got around to looking propperly but after an hour or so came up with this.

http://www.co2meter.com/collections/fixed-wall-mount/products/isense-remote-oxygen-safety-alarm

Im also now looking more thoroughly into sealed rooms, theres certainly a benefit but the only complecation i can see at the moment is making it BIG..
I think what i will do is start with 2 sealed 2.4 m2 tents running 4 lights back to back, so 8 in total.
Once that works properly i will then tripple the room size running 24 in total.
It may sound silly but i have been wondering if you will achieve an even mix of gasses throughout a big room without having to put gas tubing everywhere. ( if you get me )

Also i assume you know who it is lolo :)
_________________
Stand And Deliver ...
 

Andyo

Active member
Veteran
Dick! lol

Dick! lol

Have a look at this and the company selling it. It may suite your application.
I haven't got around to looking propperly but after an hour or so came up with this.

http://www.co2meter.com/collections/fixed-wall-mount/products/isense-remote-oxygen-safety-alarm

Im also now looking more thoroughly into sealed rooms, theres certainly a benefit but the only complecation i can see at the moment is making it BIG..
I think what i will do is start with 2 sealed 2.4 m2 tents running 4 lights back to back, so 8 in total.
Once that works properly i will then tripple the room size running 24 in total.
It may sound silly but i have been wondering if you will achieve an even mix of gasses throughout a big room without having to put gas tubing everywhere. ( if you get me )

Also i assume you know who it is lolo :)
_________________
Stand And Deliver ...

Mate id know it was you even in a field of turnips.
Sealed rooms is the way ahead,just need finite control.
Ive had some blinding results sealed ,dark green ,closer internode spacing ,extreme bud density and potency.
One thing ive been considering was the fact the raise dCO2 levels effect on root zone ,as you know i use ebb/flow ,
So definatley surrounding atmosphere sucked down into root zone
Q: if plants given more Co2 do they give off more O2 in return,sounds likely
my roots end of crop white n super healthy ,yeild just over 1G/W
I recon that O2 meter and the data logging usefull could see exactly whats going on id say O2 level of 25% good normal is 20/21%.A
 
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