Does a closed-room CO2 setup need air exchange? (intake or exhaust)?

I don't know what it is but I've been running complete sealed grow rooms using 5 ton ac's and CO2 burners. For some reason that I can't explain, my experience has shown me that when I exhaust the air in my room twice during a 12 hour light cycle while using c02 the rest of the time my buds grow bigger and keep over 80% of their white pistols by week 7 and when I don't exchange air and just run CO2 I get smaller buds and yield a little bit least weight like 10-15% less.

I don't know why. I grow og kush. And also when I've ran fresh air intake with air cooled hoods and not sealed my room and used an AC system that's always spitting fresh air because it grabs it from the roof, I've gotten the biggest fucking og kush kolas I've seen in my life. The size of Footballs but not as dense as the smaller nugs with CO2. Both these setups have produced 2+ lbs per light on digital ballast hoods. Any thoughts from anyone here? Would love to hear some scientific background of why this may be occurring?

patrickkawi37 said:

bro im 100% positive. if your using co2 and bringing in fresh air, your throwing money out the window. stay as sealed as possible. i dont even vent my hoods anymore, no fresh air coming from anywhere.

Click to expand...

I agree. But also you want to exhaust the co2 dense air. If you have all environmental controllers then no biggie. Like co2, humidifier/dehumidifier. Heat and AC.

Just my personal opinion. i feel like if your building/warehouse/room or whatever is dialed in properly without co2, the ROI of running a dialed in sealed room is not worth it. Again just my personal opinion.

The advantage of having a complete sealed room is that you can really control odor and avoid bugs and run CO2. My room is running CO2 in a sealed environment but twice during the 12 hour light cycle (every 6 hours)I turn off CO2 for 15 minutes and remove the air out from the top with a charcoal filter and bring in fresh air with a hepa filter from the bottom on an opposite corner of the room. If i don't do this then I'm still getting good results 2 a light but the buds don't get as big. When I do this I get bigger buds and hit 2.25-2.5 lbs of og kush per 1000 watts on digital ballast.

And I can't figure out what the logic behind it is. I get it. Plants use CO2 so as long as you scrub your room's air and replenish CO2 you don't have to exchange it. But my results have been as I've explained. Maybe it's my strain? I don't grow anything else but my PR og

I thought of a possible logical reason why when I exchange air twice for 2 15 minute periods during the 12 hour light cycle in a completely sealed grow room enriched with co2, I produce slightly more weight and bigger buds. I think by doing that, I'm providing an alternate air flow that my plants don't get out of the wall fans. Recall that I exhaust with a charcoal filter from the top and I bring in fresh air in through a hepa filter from the bottom in opposite corners of the room causing the air from the bottom to rise through the top of the canopy hitting the stomatas, which maybe be also moving air from stagnant hot spots that are not completely covered by the wall fans. Plus it eliminates any additional biological waste gases like methane which may inhibit optimal bud growth. Research is showing that plants not only emit oxygen as a by product but methane as well. Just like we need to fart ("A typical fart is composed of about 59 percent nitrogen, 21 percent hydrogen, 9 percent carbon dioxide, 7 percent methane and 4 percent oxygen. Only about one percent of a fart contains hydrogen sulfide gas and mercaptans, which contain sulfur, and the sulfur is what makes farts stink.) Plants may do the same to release excess gases.

Also another intereting fact I found, "In the wild, cannabis buds are pollinated by the wind and need light from the sun to power the growth of seeds. A cannabis bud in the wild which is not exposed to "air" and light is unlikely to get pollinated, so the plant tends to not put much effort into the hidden middle and lower buds on the plant. Only buds which are exposed to "air" and bright light will tend to fatten up."

That's why deleafing water leaves to get more light and then running air from the bottom to the top of canopy makes the plant put more effort into those bottom lower nodes that normally don't get much of the air circulation from the wall fans. I deleaf in week 3 to get bigger bottoms and when I exchange air in the sealed room, I'm causing air to hit the bottom of the canopy.

I found an interesting article about plant methane gas:

"There are more natural sources of the greenhouse gas methane than previously known to science. Plants are one of these sources. A German-British team led by researchers of the Max Planck Institute for Chemistry in Mainz and the University of Heidelberg, recently discovered that methane in plants is produced from the amino acid methionine, which all living organisms need for the building of proteins. The scientists also propose a mechanism which could explain the abiotic production of methane, i.e. without the aid of enzymes, in plant cells. Already in 2006, the Max Planck researchers discovered that plants can release the gas. However, it remained unclear how the hydrocarbons were created in the plants. Researchers have now discovered that methane is also released from fungi. Until a few years ago, it was only known that the gas is formed naturally in volcano eruptions, forest fires and by microorganisms which metabolize without oxygen."

https://www.mpg.de/8279621/methane_plants_methionine

bobss said:

[FONT=arial, helvetica, clean, sans-serif]

Plants consume CO2 in the process of photosynthesis and convert it to sugar. Oxygen is a waste product of this reaction, in that water is split to form hydrogen and oxygen. The plant uses the hydrogen to produce ATP. This process is only occurring in the day when there is light. However, at all times, the plant is respiring, just like people. They need oxygen for the metabolic process and produce CO2 as a waste product. Indoor closed grows also produce​

[/FONT]

Ethylene . This is a plant hormone in a gas form that can have ​

[FONT=Arial, Verdana, Helvetica, sans-serif]

negative effects on flowering plants { specially when the plants are closer to finish]. Any dying and decomposing plant mater can produce​

[/FONT]

Ethylene.​

[FONT=Arial, Verdana, Helvetica, sans-serif]

Ethylene damage can be hard to see if you dont know what your looking for and can have very negative effects on your yield .Its nice to shut down the ac at night and flush out all contaminants and start fresh every morning. Some people have good success periodically flushing out there rooms of co2 during the day. There is also some discussion out there regarding stimulating the stomata of the plant to open fully after they have slowly been closing and becoming small from large quantities of co2 in the air. I have no idea if this is true. But there is a certain logic to it. [why open your mouth wide if you only need a small breath]. personal preference is the answer you seek ,theres no one way of doing anything​

[/FONT]

Click to expand...

You make a lot of sense with the statement below. The way I grow my OG kush,

"negative effects on flowering plants { specially when the plants are closer to finish]. Any dying and decomposing plant mater can produce"

I peak my nutes at week 4 and then its downhill from weeks 5-9 making my leaves yellow by the end of harvest. This helps improve taste and quality and the reason why everyone tells me that my hydroponically grown og tastes and smells like it was done organically. I deleaf a little in week 3 after they stop their expansive growth and as I lower the ppm's from weeks 5-9 it cause some of the remaining leaves to yellow and some even die off by weeks 7-8 which helps get more light to the bottoms. I get dying decomposing leaf matter which could be adding those extra gases that I exhaust out by clearing out my room twice for 2 15 minute periods during the light cycle of the flowering stage inside a sealed co2 enriched environment.

Wanted to add to this thread..I know it's old but I found it doing a search for some issues I was having.
Built a new sealed room setup and I mean it was sealed.co2 ppm would hold for hrs without adding more.
Anyway I started my clones like I always have in the past and noticed I was having all kinds of fucked up issues.went on for week and finally decided to cut holes,add dampers and do an air exchange.8 minutes every 3 hrs.
Plants started looking 200 percent better within 12 hrs and after 2 days they've exploded.
I'm convinced a truly 100 percent sealed room needs fresh air added and the old air removed.

Guys that have good luck otherwise I dont think are truly 100 percent sealed.they prob have trickle air leaks present that's why these phantom issues never show up.

psillysimon said:

You DON"T need fresh air at night. but plants DO NOT consume co2 at night. they intake o2 and produce CO2. so if you are confident that your room has enough O2 to get them through their night then brava. as for vegging...i have never used co2 just a proper veg length around 50-60 days maybe i should try to use it during veg. I just really don't think it will increase growth that much.

Click to expand...

psillysimon said:

You DON"T need fresh air at night. but plants DO NOT consume co2 at night. they intake o2 and produce CO2. so if you are confident that your room has enough O2 to get them through their night then brava. as for vegging...i have never used co2 just a proper veg length around 50-60 days maybe i should try to use it during veg. I just really don't think it will increase growth that much.

Click to expand...

Behind 1: a marijuana seed, 2: medium to plant said seed, and 3: light, co2 is the most determinant factor above all else in relation to plant growth at every stage. To think co2 "wouldn't help much in veg" shows a severe misunderstanding of what's going on here.