sealed room, air exchange question

ruwtz said:

Can you elaborate on these toxins you speak of?

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Plants transpire and release their waste or toxins thru the leaves.. if this waste remains it becomes toxic..
some outside growers are putting plastic over their plants to protect them from frost.. when it is removed in the morning
the plant is wilted from not being able to transpire properly..
With the size of your room I don't see a problem.. just something for you to consider!

ttystikk said:

The only time a sealed room needs air exchange is to exhaust the buildup of byproducts of combustion of co2 burners.

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Yes that is one opinion and may be true, but there is also other opinions that differ, figured it won't hurt anything to vent once or twice a day as long as I filter the air properly going in and out. I just want it to remain sealed when not in use.. if air would travel through on its own when the fans are off.

HydoDan said:

Plants transpire and release their waste or toxins thru the leaves.. if this waste remains it becomes toxic..
some outside growers are putting plastic over their plants to protect them from frost.. when it is removed in the morning
the plant is wilted from not being able to transpire properly..
With the size of your room I don't see a problem.. just something for you to consider!

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This is bullshit; plants emit water vapor during transpiration. Not exactly dangerous. Just dehuey and you're good- you can even use the reclaim water!

HydoDan said:

Plants transpire and release their waste or toxins thru the leaves.. if this waste remains it becomes toxic..
some outside growers are putting plastic over their plants to protect them from frost.. when it is removed in the morning
the plant is wilted from not being able to transpire properly..
With the size of your room I don't see a problem.. just something for you to consider!

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I want to hear more about these toxins nobody is talking about!

ruwtz said:

I want to hear more about these toxins nobody is talking about!

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From thread I linked earlier

Ethylene ...

A concern with high Co2, especially over ~1,000 ppm, is ethylene buildup. Even low ppm concentration of ethylene gas can affect flower (inflorescence) size, plant growth rate, seed set (for breeders), senescence, etc. If grow rooms or greenhouses are not vented at least once, ex., at the end of the day, and Co2 is used at 1,000 to 1,500 ppm (esp the latter), ethylene can buildup to levels that will lower yield.

Here are a few good resources:

"Ethylene synthesis and sensitivity in crop plants"
Stephen P. Klassen and Bruce Bugbee
HortScience Vol. 39(7) pp. 1546-1552 (2004)



"Ethylene In The Greenhouse"
The authors explain how to detect ethylene, how to take action against it and how to stop problems before they happen
By W. Roland Leatherwood and Neil S. Mattson
April 2010
<broken link>



"Ethylene, Plant Senescence and Abscission"
Stanley P. Burg
Plant Physiol. 1968 September; 43(9 Pt B): 1503–1511.
http://www.ncbi.nlm.nih.gov/pmc/arti...00512-0034.pdf

Is ethylene a hormone ? Is it present in female flowers? Makes sense it would transpire.
Idk just asking , I think read it somewhere around here (colloidal silver ). Can't remember where though. Peace out bare

Ethylene gas build up is a result of combustion of gases created by the co2 generator (as ttystickk clearly mentioned). Throw away the generator and used bottled co2 and your problem will be solved.

Sounds like you just want a damper to solve your problem (that isn't really a problem).

cocoherd said:

Ethylene gas build up is a result of combustion of gases created by the co2 generator (as ttystickk clearly mentioned). Throw away the generator and used bottled co2 and your problem will be solved.

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I don't see where ttystickk said it was because of co2 generation.
I asked about ethylene the hormone ( pre transpiration) not talking about ethylene gas (post transpiration) . And I would never argue with ttystickk he's way to smart and I value his info . Maybe he will set my questions straight.

I'm not gonna lie, I have run a sealed room for some time now. I haven't run into any issues that are being presented. I did however google this issue, and it's a good question. It's got me questioning some things. I would like to hear @Dr. Who opinion. Maybe the introduction of extra ethylene during the ripening stage could work? Maybe not. It's used in many gardens for just that, but idk about cannabis.

Bareback said:

I don't see where ttystickk said it was because of co2 generation.
I asked about ethylene the hormone ( pre transpiration) not talking about ethylene gas (post transpiration) . And I would never argue with ttystickk he's way to smart and I value his info . Maybe he will set my questions straight.

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He has said it on thcfarmer years ago i believe.

Burners eat up oxygen quickly in small rooms, when that happens you start producing carbon monoxide,sulfer dioxide and ethylene from bad combustion of natural gas due to lack of o2 and this will happen with low oxygen levels way before its even depleted.

SPLFreak808 said:

He has said it on thcfarmer years ago i believe.

Burners eat up oxygen quickly in small rooms, when that happens you start producing carbon monoxide,sulfer dioxide and ethylene from bad combustion of natural gas due to lack of o2 and this will happen with low oxygen levels way before its even depleted.

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Thanks I never been over to thcframer . Wasn't aware about natural gas biproducts but I can see that concentrations of those gases hmmm not good .
Peace out bare

Bareback said:

I don't see where ttystickk said it was because of co2 generation.
I asked about ethylene the hormone ( pre transpiration) not talking about ethylene gas (post transpiration) . And I would never argue with ttystickk he's way to smart and I value his info . Maybe he will set my questions straight.

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Um, ah......Ethylene "the gas" IS Ethylene the "hormone"! It is simply "expressed" by the plant as a gas. Same for every other fruit, veggie or flowering plant!

cocoherd said:

Ethylene gas build up is a result of combustion of gases created by the co2 generator (as ttystickk clearly mentioned). Throw away the generator and used bottled co2 and your problem will be solved.

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Your "is" in your first line should be an "as"!
"Throw away" is NOT a solution, and generators work at far lower costs on larger scale operations! Bottles are a pain for anything bigger then a cpl of 5X5 tents. As far as I'm concerned.

xmatox said:

I'm not gonna lie, I have run a sealed room for some time now. I haven't run into any issues that are being presented. I did however google this issue, and it's a good question. It's got me questioning some things. I would like to hear @Dr. Who opinion. Maybe the introduction of extra ethylene during the ripening stage could work? Maybe not. It's used in many gardens for just that, but idk about cannabis.

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Keeping your "sealed" room that way 24/7 IS bad! I have a timed exhaust - fires 2 times a light cycle. One mid "day". Last one is right at lights out.

No "build up" problems when I use gas.

Dr. Who said:

Um, ah......Ethylene "the gas" IS Ethylene the "hormone"! It is simply "expressed" by the plant as a gas. Same for every other fruit, veggie or flowering plant!



Your "is" in your first line should be an "as"!
"Throw away" is NOT a solution, and generators work at far lower costs on larger scale operations! Bottles are a pain for anything bigger then a cpl of 5X5 tents. As far as I'm concerned.




Keeping your "sealed" room that way 24/7 IS bad! I have a timed exhaust - fires 2 times a light cycle. One mid "day". Last one is right at lights out.

No "build up" problems when I use gas.

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Thanks @Dr Who that's what I was trying to say.
Peace out Bare

Bareback said:

Thanks @Dr Who that's what I was trying to say.
Peace out Bare

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I've been running sealed for several years with no problems. The only time there is an air exchange is when I open the door to enter them. Just bought a new place and I will be building the rooms 95% sealed again too(door=5%lol). I do install an emergency exhaust with a damper that is controlled by temp just in case of ac failure which has never turned on except during sanitizing/cleaning breaks between grows.

+ rep for everyone who posted here. It's a good debate with lots of personal experience expressed. This is bound to help some folks and confuse others.
Peace out Bare

I am also in the middle of trying to figure out how to do an air exchange in the grow room I'm building in a 7x7 outdoor shed. My original thought was to use an inline ventilation fan down low with a chimney on top for exhaust and have that going for much of the day. But when I started adding climate control to the build (humidifier, dehumidifier, AC, heater, circulation fan), I realized I wanted this thing sealed and insulated.

This opens up the problem of getting fresh air into the shed. The single-hose portable A/C I am using will create negative air pressure inside the sealed shed, so I am considering leaving the built-in vent, rather than blocking it up, if we can find a way to damper. Otherwise we will make a dampered 4" vent.

In any event, then plan as of now is to open up the 6x6 doors twice a day for 20 min and let the circulation fan blow things around. Seems like @Dr. Who does something similar, except with a ventilation fan twice a day, and now I am considering that. I am forgoing CO2 for now.

In any event, the shed arrived yesterday, and the build will commence on Monday or Tuesday, depending on when my help can get here. I will start a new thread on this forum to document the build and hopefully help someone else out down the road.

Dr. Who said:

Um, ah......Ethylene "the gas" IS Ethylene the "hormone"! It is simply "expressed" by the plant as a gas. Same for every other fruit, veggie or flowering plant!



Your "is" in your first line should be an "as"!
"Throw away" is NOT a solution, and generators work at far lower costs on larger scale operations! Bottles are a pain for anything bigger then a cpl of 5X5 tents. As far as I'm concerned.




Keeping your "sealed" room that way 24/7 IS bad! I have a timed exhaust - fires 2 times a light cycle. One mid "day". Last one is right at lights out.

No "build up" problems when I use gas.

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What temps do you run and what humidity levels? I am learning about VPD and realize I am having an issue with to low humidity (room is ~2 weeks old in flower at about 50% humidity). I setup a humidifier yesterday to try to get it up to around 65 percent which is the low end of recommended for low to mid 80's canopy temps. I am running co2 in sealed room. In the next few days I will be setting up twice a day air exchange, out through a carbon filter and in through a phresh intake filter.

linky said:

What temps do you run and what humidity levels? I am learning about VPD and realize I am having an issue with to low humidity (room is ~2 weeks old in flower at about 50% humidity). I setup a humidifier yesterday to try to get it up to around 65 percent which is the low end of recommended for low to mid 80's canopy temps. I am running co2 in sealed room. In the next few days I will be setting up twice a day air exchange, out through a carbon filter and in through a phresh intake filter.

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For 1300 - 1500 ppm. 92 F and 86 % RH are my environmental controllers set points to cycle. They flip on the AC and the dehum till it resets and starts over..... Hot and damp for gassing !!