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Sealed room, co2 plant using a lot Less water?

siftedunity

siftedunity

cant re Member
Veteran
Have recently switched from a ventilated room to sealed with co2..

I've had a really good couple of runs leading up to this one where I exchanged the air frequently.
For ease I switched to co2 and sealed.

So I'm set at about 950ppm co2, temps fairly high, 84-86f and humid in line with vpd chart pretty much. But strange thing is, I'm two weeks in flower but they don't seem to be drinking much at all.
Since before each plant would prob need about 1 liter to 1.5 daily. Atm they are probably using half the water or less.

For any experienced co2 users, is that normal?
 
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DemonTrich

Active member
Veteran
I've been running a sealed room for about 3yrs now. In my garden, with my environment settings (can vary by what week in flower I'm in), my plants drink the usual. Every 4th day is either feed or amendment day. I'm normally rocking 1200-1400ppm. 950ppm is only +450ish higher than normal. Imo, run 1200 and see how you like it.

Ill never grow with out it.
 
Lost in a SOG

Lost in a SOG

GrassSnakeGenetics
Co2 raises stomatal conductance and closes stomata so if you notice plants drinking a lot slower,, imvho,, always back it down till you figure out why as they should be going hell for leather growth wise..

technically you dont need to go above atmospheric if you dont want to and the results will be a good as a ventilated grow..

Imo youve got to raise it slow and observe them in that grow and how their genetics are responding because there are so many factors its intertwined with in terms of its effect on the plant its not always just as simple as "im at this temp and ppfd so i run at this ppm co2" you can piss plants off.

Sort of depends how dialed your grow is..:2cents:
 
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DemonTrich

Active member
Veteran
My veg room is ambient, when I move to my flower room, its game on. 1400ppm and feed time. But my grow and strains are dialed in.
 
siftedunity

siftedunity

cant re Member
Veteran
Lost in a SOG said:
Co2 raises stomatal conductance and closes stomata so if you notice plants drinking a lot slower,, imvho,, always back it down till you figure out why as they should be going hell for leather growth wise..

technically you dont need to go above atmospheric if you dont want to and the results will be a good as a ventilated grow..

Imo youve got to raise it slow and observe them in that grow and how their genetics are responding because there are so many factors its intertwined with in terms of its effect on the plant its not always just as simple as "im at this temp and ppfd so i run at this ppm co2" you can piss plants off.

Sort of depends how dialed your grow is..:2cents:
Click to expand...

well basically before this I had a semi-sealed room, with a spit ac..
so basically the air would be exchanged in the room twice an hour. the co2 level remained the same as atmospheric but I had the positive side of being able to control temps and humidity.

results were good so I was expecting the c02 to enhance that.. I did set the co2 at 800 and work up to 950..
basically ive kept everything the same, always tried to keep temps and humidity within a good range vpd wise. so was happy with that, and only shot for 950 ppms co2 because I didn't want to go over board but on the other hand thought id see a positive effect with that level. so that was my starting point I guess. the plants are happy but I don't get why they are using so much less.
 
siftedunity

siftedunity

cant re Member
Veteran
DemonTrich said:
I've been running a sealed room for about 3yrs now. In my garden, with my environment settings (can vary by what week in flower I'm in), my plants drink the usual. Every 4th day is either feed or amendment day. I'm normally rocking 1200-1400ppm. 950ppm is only +450ish higher than normal. Imo, run 1200 and see how you like it.

Ill never grow with out it.
Click to expand...

ok cool, thank you for your reply.. so you say crank it up to say 1200? the other guys says back it down.
do you have a stronger nutrient mix than you would have used before co2? or still the same?
 
W

Wendull C.

Active member
Veteran
Lower your humidity and see if they dont drink more. If they dont check your root health and run off ec.
 
siftedunity

siftedunity

cant re Member
Veteran
hello, yeah i could try lowering humidity. root health is great, so I'm happy with that. ive used the same nute mix for years and tbh don't find run off indicative of much. ive had amazing plants with crazy run offs in the past so i generally take more notice of whats going in.. but yeah for sure can try lowering humidity. atm is high. generally around 70ish or above. but the temps are also high..
 
f-e

f-e

Well-known member
Mentor
Veteran
Lost in a SOG said:
Its common in co2 supplementation to lower RH to account for the increased stomatal conductance.

:tiphat:
Click to expand...


It's somewhat like our breathing. If we are getting enough of what we need from the air, we don't breathe heavily. If we don't get enough, we breathe faster, like when we go for a run. We are like the plant in this way. We breathe faster, opening up our lungs more, to get more air. Plants open up their stomata to get more.

Now picture us on a cold day. A day so cold you can see the moisture on our breath condensate as we breathe out. Just like with the plant, the act of breathing looses moisture.

This is the problem with satisfying their co2 needs. They don't breathe so heavily. So don't loose as much moisture.


You can lower the RH to increase water uptake. Or increase food so they're still getting enough. Or even both.
 
siftedunity

siftedunity

cant re Member
Veteran
OK thank you for both of your insights.. Yes I read that they close the stomata with higher co2 concentrations. I didn't know that people counter this by lowering the rh. I've been reading quite a few vpd threads lately where the op is running co2 plus regular vpd levels but I think those rooms might have been hotter than mine.
 
Lost in a SOG

Lost in a SOG

GrassSnakeGenetics
The amount of blue and red light also has quite a big influence on the plants ability to use co2 and transpire in different amounts of vpd difference.

https://www.plantphysiol.org/content/119/3/809

STOMATAL OPENING INDUCED BY BLUE LIGHT

Both red and blue light stimulate stomatal opening. Because chlorophyll also absorbs these wavelengths, sensitivity to red and blue light is consistent with a role of guard cells in opening stomata under conditions conducive for photosynthesis. Indeed, in most species guard cells are the only epidermal cells that contain chloroplasts, and guard cell chlorophyll is implicated as a photoreceptor in the light responses of stomata. However, the greater quantum efficiency of blue light over red light in stimulating stomatal opening (for review and refs., see*Assmann, 1993;*Zeiger and Zhu, 1998) suggests that guard cells also possess a specific blue-light photoreceptor. A species of orchid (Paphiopedilum harrisianum) that lacks guard cell chlorophyll and therefore has guard cell sensitivity only to blue light, shows significant increases in fresh weight when grown under blue-enriched lighting, possibly illustrating the impact of the specific stomatal response to blue light on plant growth (Zeiger et al., 1985). In less exceptional species, the stomatal response to blue light may be particularly important under the blue-enriched illumination that prevails in early morning light and in sunflecks. As discussed below, fundamental questions still remain concerning the identity of the blue-light photoreceptor in guard cells, the cellular signals linking light perception to downstream regulators of guard cell solute content, and the nature of these downstream regulators.
Click to expand...

:tiphat:
 
siftedunity

siftedunity

cant re Member
Veteran
ok ive been doing a bit more reading. mostly on large crop greenhouses that use co2. for tomatoes they often use 800ppm. and it increases fruit number and overall yield.
they didn't mention much about watering needs but I guess they grow them in hydro systems whereas I'm using coco coir.
but I would have thought that if you increase light intensity and co2, surely they would need more water because they would be photosynthesising more. so would keep needing to open the stomata to replace co2 since they might be using it as a faster rate.

it seems like its gonna take a lot of trial and error to find the sweet spot. and although ive read a lot of threads on co2 prior to using it, Ive not remembered reading much if anything about stomata Ci
 
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palmeezy

Member
how's overall plant health? they can't be growing much if not drinking. pics might help. do you know how to identify mildews that aren't obvious like powdery?
 
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palmeezy

Member
sorry if i missed the answers to these questions but i think they will help with painting a better picture:

are you venting after lights off?

what is your room size?

how many BTU cooling?

what kind of dehumidifier?

what temps/RH did you have on your prior successful runs?

and the most important question, what are your night time temps and RH?

some notes:

shorter rooms are more difficult to control the climate in when sealed

a lot of strains don't turn out too well if you don't get the temps and humidity into the mid-upper 70s and 50% max once budset starts. the greenhouse environment will tend to produce fluffier, blander buds.

though, i think it's entirely possible to grow dank, dense buds in high temps and humidity, it's just a lot trickier as you push all of the limiting factors.

over time i'm finding that , at least in RDWC, sealed rooms and attempting to use lower vs. higher EC results in a dehumidification load that borders on impractical.
 
siftedunity

siftedunity

cant re Member
Veteran
palmeezy said:
sorry if i missed the answers to these questions but i think they will help with painting a better picture:

are you venting after lights off?

what is your room size?

how many BTU cooling?

what kind of dehumidifier?

what temps/RH did you have on your prior successful runs?

and the most important question, what are your night time temps and RH?

some notes:

shorter rooms are more difficult to control the climate in when sealed

a lot of strains don't turn out too well if you don't get the temps and humidity into the mid-upper 70s and 50% max once budset starts. the greenhouse environment will tend to produce fluffier, blander buds.

though, i think it's entirely possible to grow dank, dense buds in high temps and humidity, it's just a lot trickier as you push all of the limiting factors.

over time i'm finding that , at least in RDWC, sealed rooms and attempting to use lower vs. higher EC results in a dehumidification load that borders on impractical.
Click to expand...

I vent every hour for 15 mins during lights off..

the ac unit can keep the temps at whatever I set it at, and I'm running the temp/rh from a regular vpd chart.

temps and rh were the same on previous runs the only thing ive changed is the co2. so seems like it can be the only thing making the difference.
 
Cannaseekr

Cannaseekr

Member
I agree with the others. Personally I would first lower RH and see how the plants respond, then if they respond positively I would start raising my feed ppm.
 
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