Co2 and vpd?

mhalter81

Member
Been growing for about two years now. Just started co2 recently, I understand that my temps need to be 82 to 85ish to take the most advantage of co2 enrichment. Is that room temps or canopy temps? Currently running 79 degrees in room humidity around 58 percent, canopy at 84-85 humidity much lower of course. According to the pulse vpd chart im good for room vpd and very poor considering canopy. Plants are looking very healthy, but im afraid im missing out on potential, or wasting CO2. Can someone please help?
 
I run my canopy at around 83-84 and humidity between 50-60. If you're locked in at growing without supplemental co2, you'll see a big benefit to growth rate and yield.

When I started using co2, I increased my yields by 60%...BUT HOLD ON. I was growing is a sealed room with a ton of biomass growing. I picked up a co2 controller before I got a tank and placed it in the room. I noticed that each day I was dropping below 250ppm at many points. So really I was correcting a problem that I didn't know I had.

But I will never grow without it again.
 

BobThe420Builder

Well-Known Member
I run my canopy at around 83-84 and humidity between 50-60. If you're locked in at growing without supplemental co2, you'll see a big benefit to growth rate and yield.

When I started using co2, I increased my yields by 60%...BUT HOLD ON. I was growing is a sealed room with a ton of biomass growing. I picked up a co2 controller before I got a tank and placed it in the room. I noticed that each day I was dropping below 250ppm at many points. So really I was correcting a problem that I didn't know I had.

But I will never grow without it again.

Pretty hard to believe unless you really sucked at growing prior to adding c02...lol
 

mhalter81

Member
I'd say work on your grow knowledge and process to increase production
You are correct, everyone should do this. Thats why I asked the question. Without co2 my plants were healthy throughout grow, I would average anywhere from .85 to 1 gram per watt cured. I try to strive for perfection. Again, if I can get more yield, denser buds with CO2 at same cost why not try and achieve that. Btw, I get Co2 for free.
 
Pretty hard to believe unless you really sucked at growing prior to adding c02...lol
Great response. And from someone that has no experience using supplemental co2.

Not saying I was the best grower on earth...but I had a ton of foliage for the cubic footage of my grow space. The plants were very healthy...just slow growing and modest yield. They consumed the ambient co2 at a high rate causing the levels to bottom out. And at this point they stall.

Just sharing my personal experience.
 

mhalter81

Member
I run my canopy at around 83-84 and humidity between 50-60. If you're locked in at growing without supplemental co2, you'll see a big benefit to growth rate and yield.

When I started using co2, I increased my yields by 60%...BUT HOLD ON. I was growing is a sealed room with a ton of biomass growing. I picked up a co2 controller before I got a tank and placed it in the room. I noticed that each day I was dropping below 250ppm at many points. So really I was correcting a problem that I didn't know I had.

But I will never grow without it again.
Thanks for your relative input for the question asked above.
 

pahval

Well-Known Member
hey mate, i hope i can help, i just posted about this somewhere else on this forum, ill post my resources again:

[...] well, you have to measure temperature of air around the plants (so in canopy level, it wont help much if you measure temps around your lamp), AND you have to measure your leaves temps, i would suggest handheld IR thermometer for that, because we are measuring difference of air vapor saturation and leaf vapor saturation, and that is the vapor pressure deficit we want to have so that our plants can transpire as much as they can without any stress... a good chart, which takes into account your leaf temp (but it looks ugly), can be found here:


a good info about vpd i have found here:


and good info about temps and other with using co2 i have found here:


especially pdf from fluence, which has recommended temperatures with and without co2 supplementation...
 

mhalter81

Member
hey mate, i hope i can help, i just posted about this somewhere else on this forum, ill post my resources again:

[...] well, you have to measure temperature of air around the plants (so in canopy level, it wont help much if you measure temps around your lamp), AND you have to measure your leaves temps, i would suggest handheld IR thermometer for that, because we are measuring difference of air vapor saturation and leaf vapor saturation, and that is the vapor pressure deficit we want to have so that our plants can transpire as much as they can without any stress... a good chart, which takes into account your leaf temp (but it looks ugly), can be found here:


a good info about vpd i have found here:


and good info about temps and other with using co2 i have found here:


especially pdf from fluence, which has recommended temperatures with and without co2 supplementation...
Thank you so much, the plethora of information that you have given me this day, is very much appreciated. I have quickly skimmed through all of it, and plan on referring back to it over the next several days. Even though I was very unsure of myself attempting what I'd consider next level grow methods, I am within close range of optimal cultivation. I honestly believe this info will help me succeed at the next level. Again, thank you so much!
 

J232

Well-Known Member
You would want to adjust the air temp to reach a desired leaf temp. I skimmed threw and didn’t see your lighting, that will factor in there too. If you are new to co2, as I am, I would grab a IR thermometer. I have no problems growing without, I didn’t want to exhaust my room outdoors in winter as it would look like a power plant stack in my mind. I can only assume the free co2 is food grade as well.
 

pahval

Well-Known Member
You would want to adjust the air temp to reach a desired leaf temp. I skimmed threw and didn’t see your lighting, that will factor in there too. If you are new to co2, as I am, I would grab a IR thermometer. I have no problems growing without, I didn’t want to exhaust my room outdoors in winter as it would look like a power plant stack in my mind. I can only assume the free co2 is food grade as well.
yep, thats also a thing, co2 must be food grade... if you go with co2, you need more of lights and nutes... also, if you go with higher VPD that will mean plant will absorb more water, hence will absorb more nutrients, so be careful about it, maybe you just need to raise vpd (make plant intake more), or you keep same vpd as before co2 and enrich your nutrient solution more... anyway, im glad to help out! <3
 

mhalter81

Member
I attached several pics( don't mind the clutter, cleaning up veg room at the moment). Again everything seems to be healthy, two more days will be the beginning of 4th week of flower. The lower temp/ higher rh is room air, the higher temp/ lower rate is at canopy level. My current leaf temp is anywhere from 76 to 79 degrees. I am running 24 hlg 132qb's @ 1400ma12 hrs a day (par is at its highest 1136umole and 697 at the very far corners) and 4 super b uvb bulbs 3.5 hours a day(also something new for me). 4x8 room, plants veg for approx 6 weeks. Vpd is hard for me to wrap my head around, mostly because all of the resources that I own say to keep humidity levels much lower than what vpd charts claim. Anyway, thanks again to everyone that has helped thus far. Before anyone says anything I know I have a lot of wasted space. Lol
 

Attachments

pahval

Well-Known Member
They look nice... Lower rh recommendation is to prevent having bud mold, but from what ive seen these people also have high temps, mold comes with high temp and hum, ive red somewhere tha user had high temp and hum trough the day and lower (esp. humidity) trough the night and had no problems... And in the end, if it works for you, just follow that, you can experiment on some smaller grow...
 

TintEastwood

Well-Known Member
Good info here...


The above has helped me become a better grower. Co2 supplemented or not.

I keep room in the 80s. W leds/cmh
Leaf surface temps in the low 80s.
Rh 50 avg. no higher than 60.
That's with Co2, between 600ppm in veg, up to 900 max. in flower.
 

NukaKola

Well-Known Member
I attached several pics( don't mind the clutter, cleaning up veg room at the moment). Again everything seems to be healthy, two more days will be the beginning of 4th week of flower. The lower temp/ higher rh is room air, the higher temp/ lower rate is at canopy level. My current leaf temp is anywhere from 76 to 79 degrees. I am running 24 hlg 132qb's @ 1400ma12 hrs a day (par is at its highest 1136umole and 697 at the very far corners) and 4 super b uvb bulbs 3.5 hours a day(also something new for me). 4x8 room, plants veg for approx 6 weeks. Vpd is hard for me to wrap my head around, mostly because all of the resources that I own say to keep humidity levels much lower than what vpd charts claim. Anyway, thanks again to everyone that has helped thus far. Before anyone says anything I know I have a lot of wasted space. Lol
Dig the QB 132's! How are you liking the Autopilot APC8200? Was thinking about picking one up.
 

insomnia65

Well-Known Member
hey mate, i hope i can help, i just posted about this somewhere else on this forum, ill post my resources again:

[...] well, you have to measure temperature of air around the plants (so in canopy level, it wont help much if you measure temps around your lamp), AND you have to measure your leaves temps, i would suggest handheld IR thermometer for that, because we are measuring difference of air vapor saturation and leaf vapor saturation, and that is the vapor pressure deficit we want to have so that our plants can transpire as much as they can without any stress... a good chart, which takes into account your leaf temp (but it looks ugly), can be found here:


a good info about vpd i have found here:


and good info about temps and other with using co2 i have found here:


especially pdf from fluence, which has recommended temperatures with and without co2 supplementation...
The guy on that video could do with breathing only CO2 for a a while grr.
 

Renfro

Well-Known Member
I noticed that each day I was dropping below 250ppm at many points. So really I was correcting a problem that I didn't know I had.
One thing about CO2 enrichment, the plants actually perform better if you have low points and high points. I wish that I could set a larger dead band on my CO2 controller personally but I can use periodic vent cycles on a timer to achieve the same thing.
 
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