co2 1500ppm++ with no input...fungi in sealed room?

So I have been growing for a long time. Over a decade I have done all kinds of covert grows and have experimented with a plethora of growing methods and have scanned thru these forums and fellow grower's brains for years... Never have I seen what I'm seeing here.. I have relocated to a state where I have become a medical caregiver and have built out my first grow facility. I'm very untraditional.. I have 5 flower rooms all identically formatted.. To make a long story short I had moved all plants into room #1 about 10 days ago. We run 4 hlg 650r's in a sealed 10x10 framed room. Poly walls, waterproof flooring, dehumidifier, humifier, dedicated 18k btu mini split, airoclean 420 photcatalytic air sanitizer, co2 tank and plenty of oscillating fans... The room had been complete as far as construction for multiple weeks before the plants moved in and the environment was also run for 7 days under monitoring beforehand.. co2 levels were always normal (around 400ish) sometimes higher if I was in there for awhile but never anything of note... Plants entered the room and all necessary environmental adjustments were made. Everything was fine.. INCLUDING co2 levels. A week went by of 12/12 before I did there top dressing as I wanted to make sure the plants were acclimated as well as at a proper pot moisture level before adding my flower transition top dressing amendments and fresh mulch. 3 days ago I did the top dressing and applied fresh mulch that is heavily inoculated and fruiting with blue oyster mushroom fungi... Next day comes and it's really an off day for the girls.. I follow a regiment and have off days where only general inspection and cleanup is done..this was one of those days and I had also an obligation with the family.. I checked early in the day (But after my partner had already gone in and out of the room to maintenance some things) and the level seemed normalish but high like 1700...didn't worry because it wasn't too high... left for the day... Came back later that night and was able to catch the room just as the lights were going off and the co2 was at 2300!!!
So I left the door open for a few minutes and sure enough it started to fall...I waited till it fell down around 1000 and closed it back..I checked for leaks..there were none.. Next morning I check the room and the co2 level is like 2500 ppm!! So I shut the co2 generator off completely and close the tank.. now I air the room out to get down to like 1000 and close it back up... Now I know that the plants respirate co2 at night time which wld have potentially raised things a bit from it already running high..maybe..at least that's what I convinced myself of.. Check throughout the day and it just kept climbing back up to like 2000 WITH THE GENERATOR OFF AND THE PROPANE TANK CLOSED COMPLETELY!!! aired out the room before night time... Woke up this morning and the co2 level on the meter read 4000!!! 4000!!!! I freaked out! How?? The generator isn't even plugged in!! I aired the room out back down to like 1200..... completely detached propane tank and removed propane tank from area altogether (LITERALLY OUTSIDE). This room keeps rising when that door is closed. I even opened a BRAND NEW titan controller and calibrated the sensor outside and confirm side by side they read almost identical... both running now. It's a sealed room running no till organic soil 2nd run with these particular pots but first time in a sealed room. Is the fungi in the mulch breathing that much??!! If so holy shit!!! I'm literally having to consider running a co2 exhaust from my room based on how much it's rasing it.. I dropped it to like 1100 and a few hrs later it was at like 1800 so I let it drop with the door open down to 1000ppm at 3:30 and it's 4:25 as I write this and it's at 1100..but I've gone in and out...

That's crazy. I run Co2 in my lol space but never such an issue.

Curious....hope you get it sorted.

5:33 pm now up to 1285...just keeps building

How much soil are you using? And did you make it yourself or buy it from the store?

You have a 10x10 room, and with your rising CO2, I'm willing to bet you're growing in some big ass pots. 10x10 room can have 100s of gallons of soil in it, if not more. You also say its your "second run with these pots", so if you've done no-till with those pots then they certainly have a large enough of a soil web to produce CO2.

You see, CO2 is a natural waste byproduct of the organic decomposition cycle. 5g pots of living soil will produce significantly less CO2 than 25g pots or 4x8 raised beds. The greater your soil mass, the greater the CO2 output.

This however, assumes that your living soil is filled with life. Clearly it is if you're CO2 is raising so much in just a single day.

You're partially correct about the mulch, the mulch decomposing is in fact producing CO2. However, all the other little microbes and bugs in your soil are also excreting CO2. Combine this with however long you're inside the room and breathing, and CO2 levels start to rise in pretty short order.

Most growers will rarely encounter this issue. This is because, even those that grow in raised beds, most people in here are growing in tents of some sort and not in sealed rooms. However, even in a tent this can happen. My last indoor was an 8x8 tent with ~100g of living soil and my CO2 would get to 600-700 without any supplementing. Would get close to 1000ppm if I'd be in the tent working and breathing for long enough.

So, now that we've answered the question as to how and why this happens. On to what to do about it, which you've already seem to have figured out yourself.

No need to get a co2 exhaust, as you're discovering, leaving the door open is sufficient enough on its own. However, I also get that sometimes it isn't practical to constantly be opening the door to your grow room. Especially on such a large scale.

Either method will work, but only you will be able to decide which is best. In your shoes, I'd opt to just open the door more often. I ran a 10x16 sealed room a few years back and I was in there multiple times a day managing it. Simply leaving the door open for the entire time you're inside the grow room working should be enough to bring CO2 levels back down to appropriate levels.

If you can't open the door enough to vent the CO2, you will have to get an extractor of some sort come flower.

As I'm sure you already know, CO2 also contains ethylene gas which will ripen fruits in very short order. This is why CO2 is often shut off around week 4 of flower, because the ethylene will cause your buds to ripen faster than normal. Obviously, this results in diminished yields and quality, which we definitely don't want.

If you think you can keep your CO2 levels below 500-600ppm in flower, you won't need an extractor. Otherwise, you'll need to have an extractor set up prior to week 4 of flower to avoid any issues with your flowers ripening.

All the best.

Yeah, stuff decomposing releases CO2.

Keep the door open for fresh air. And consider separating your plants into individual rooms again. Spread the decomposition around! That way there will be less CO2 produced per room.

@kratos015
Thanks so much for the response. I would have to agree and really needed someone to confirm my suspicions. With that said other than exhausting my sealed room there will be no way for me to regulate the co2 to any specific level at any time.

@youraveragehorticulturist
The plants are each in 15gal grassroots living soil pots. There are 16 plants in a room.

Its like you've created the perfect Co2 machine,Makes me wonder what my levels are at with 40 gallons in a 5x5?

kratos015 said:

How much soil are you using? And did you make it yourself or buy it from the store?

You have a 10x10 room, and with your rising CO2, I'm willing to bet you're growing in some big ass pots. 10x10 room can have 100s of gallons of soil in it, if not more. You also say its your "second run with these pots", so if you've done no-till with those pots then they certainly have a large enough of a soil web to produce CO2.

You see, CO2 is a natural waste byproduct of the organic decomposition cycle. 5g pots of living soil will produce significantly less CO2 than 25g pots or 4x8 raised beds. The greater your soil mass, the greater the CO2 output.

This however, assumes that your living soil is filled with life. Clearly it is if you're CO2 is raising so much in just a single day.

You're partially correct about the mulch, the mulch decomposing is in fact producing CO2. However, all the other little microbes and bugs in your soil are also excreting CO2. Combine this with however long you're inside the room and breathing, and CO2 levels start to rise in pretty short order.

Most growers will rarely encounter this issue. This is because, even those that grow in raised beds, most people in here are growing in tents of some sort and not in sealed rooms. However, even in a tent this can happen. My last indoor was an 8x8 tent with ~100g of living soil and my CO2 would get to 600-700 without any supplementing. Would get close to 1000ppm if I'd be in the tent working and breathing for long enough.

So, now that we've answered the question as to how and why this happens. On to what to do about it, which you've already seem to have figured out yourself.

No need to get a co2 exhaust, as you're discovering, leaving the door open is sufficient enough on its own. However, I also get that sometimes it isn't practical to constantly be opening the door to your grow room. Especially on such a large scale.

Either method will work, but only you will be able to decide which is best. In your shoes, I'd opt to just open the door more often. I ran a 10x16 sealed room a few years back and I was in there multiple times a day managing it. Simply leaving the door open for the entire time you're inside the grow room working should be enough to bring CO2 levels back down to appropriate levels.

If you can't open the door enough to vent the CO2, you will have to get an extractor of some sort come flower.

As I'm sure you already know, CO2 also contains ethylene gas which will ripen fruits in very short order. This is why CO2 is often shut off around week 4 of flower, because the ethylene will cause your buds to ripen faster than normal. Obviously, this results in diminished yields and quality, which we definitely don't want.

If you think you can keep your CO2 levels below 500-600ppm in flower, you won't need an extractor. Otherwise, you'll need to have an extractor set up prior to week 4 of flower to avoid any issues with your flowers ripening.

All the best.

Click to expand...

This is the first time Ive ever read of shutting off co2 after the 4th week of flower and co2 use results in diminished yield...

kratos015 said:

How much soil are you using? And did you make it yourself or buy it from the store?

You have a 10x10 room, and with your rising CO2, I'm willing to bet you're growing in some big ass pots. 10x10 room can have 100s of gallons of soil in it, if not more. You also say its your "second run with these pots", so if you've done no-till with those pots then they certainly have a large enough of a soil web to produce CO2.

You see, CO2 is a natural waste byproduct of the organic decomposition cycle. 5g pots of living soil will produce significantly less CO2 than 25g pots or 4x8 raised beds. The greater your soil mass, the greater the CO2 output.

This however, assumes that your living soil is filled with life. Clearly it is if you're CO2 is raising so much in just a single day.

You're partially correct about the mulch, the mulch decomposing is in fact producing CO2. However, all the other little microbes and bugs in your soil are also excreting CO2. Combine this with however long you're inside the room and breathing, and CO2 levels start to rise in pretty short order.

Most growers will rarely encounter this issue. This is because, even those that grow in raised beds, most people in here are growing in tents of some sort and not in sealed rooms. However, even in a tent this can happen. My last indoor was an 8x8 tent with ~100g of living soil and my CO2 would get to 600-700 without any supplementing. Would get close to 1000ppm if I'd be in the tent working and breathing for long enough.

So, now that we've answered the question as to how and why this happens. On to what to do about it, which you've already seem to have figured out yourself.

No need to get a co2 exhaust, as you're discovering, leaving the door open is sufficient enough on its own. However, I also get that sometimes it isn't practical to constantly be opening the door to your grow room. Especially on such a large scale.

Either method will work, but only you will be able to decide which is best. In your shoes, I'd opt to just open the door more often. I ran a 10x16 sealed room a few years back and I was in there multiple times a day managing it. Simply leaving the door open for the entire time you're inside the grow room working should be enough to bring CO2 levels back down to appropriate levels.

If you can't open the door enough to vent the CO2, you will have to get an extractor of some sort come flower.

As I'm sure you already know, CO2 also contains ethylene gas which will ripen fruits in very short order. This is why CO2 is often shut off around week 4 of flower, because the ethylene will cause your buds to ripen faster than normal. Obviously, this results in diminished yields and quality, which we definitely don't want.

If you think you can keep your CO2 levels below 500-600ppm in flower, you won't need an extractor. Otherwise, you'll need to have an extractor set up prior to week 4 of flower to avoid any issues with your flowers ripening.

All the best.

Click to expand...

Co2 does not contain ethylene gas. CO2 is exactly what it is. Carbon Dioxide. 1 carbon atom and 2 oxygen atoms make up a CO2 molecule.

Ethylene is used to ripen produce but it has to be introduced. During the ripening process CO2 is produced which will slow the ripening process which is why ripening warehouses have to vent the built up CO2 periodically if the levels get too high.