What are you running your climate at?

[crizzo]

Hi everyone,
I am in the process of dialing in my climate controller.
I was interested in what people were running there's at.

I run 2 sealed room with a 4x8 drip tables, one under 2 1000 watter and the other under 4 600 watter

I am running at 1500ppm of co2, around 82f, and 45-50 rh during the day.

and 400ppm of co2, about 75-78f and 45-50 rh during the the night.

all opinions are welcome but please remember that these are all just opinions.

 

[Dr.GT]

ive been doing a lot of reading and learning concerning this subject, as i am looking to start using this method myself.
all from what i have researched it seems to be pretty dialed in, but i am wondering if the temps and rh numbers you posted are set on the controller or are those based on what the room is seeing?
and are you running a dehumidifier to keep the moisture down?
also have you had any mildew issues?

 

[Legaldroman]

Are you running Co2 during the night cycle or are you just letting us know the readings? I'm assuming your temps and humidity are read from a temp gauge. Personally I like to run my canopy level at 86 room temp at 83 during the day with a RH of 30%. At night my temps are 75 with RH of 40%. I think everything sounds good, possibly lower humidity, but if your not seeing any signs of PM or mold than you should get by. How far are your lights from the canopy?

 

[foaf]

I think that its pretty well accepted that if you suppliment co2, you get higher growth rates with an air temp of mid 90's and chilled roots, and I like much higher rh in veg and until there are buds that might could rot, then I drop it down a bunch. The only value of low rh is to prevent bud rot, it is otherwise a stress on the plant compare to higher humidity.

 

[Legaldroman]

I think that its pretty well accepted that if you suppliment co2, you get higher growth rates with an air temp of mid 90's and chilled roots, and I like much higher rh in veg and until there are buds that might could rot, then I drop it down a bunch. The only value of low rh is to prevent bud rot, it is otherwise a stress on the plant compare to higher humidity.

Higher growth rates with an air temp of mid 90's??? I think not, that IMO is way to hot even with Co2. 86 is the ideal temp for Co2 consumption in flowering, I think this is pretty much consensus...I'd like to see a room running in the mid 90's with healthy looking plants...

 

[foaf]

I'd like to see a room running in the mid 90's with healthy looking plants...

is 4 lbs in a closet healthy enough for you? then 3 lbs bubba kush next? I ran at about 93 and, cooler for veg just because it was cold outside. 1500 ppm co2.



I couldnt find the university study that showed maximum growth rate (tomatoes) and final yeild was 95 degrees at 1500 ppm and at 75 degrees for 400 ppm, but all the articles below suggest 90 degrees is better than ambient.

there are tons of studies that related co2 to growth rate and discuss temperature. most are not with cannabis however. google co2, plant growth, temperature.

the basic premise is that all chemical reactions proceed faster at higher temperatures, up to the point where some plant regulatory factors set in or some disease or other environmental variable is affected. (obviously more complicated than that - some plants wont grow at high temps at all - but cannabis isnt one such plant - think Columbia/Mexico/Africa -> Hot)

but.... the reaction (photosynthesis) is limited by available reactants in the microenvironment of the chloroplasts, and the limiting nutrient is co2 in both c3 and c4 plants.

so the end result is that you dont get much better growth from raising the temperature if you do not provide adequate co2. it doesnt mean that the inverse is true.

the idea that plants can tolerate higher temps when using co2 is a poorly documented issue that gets repeated over and over and over so it becomes dogma. Tolerate isnt the issue, but risk to benefit is. Risk of root zone issues increases with temperature but without co2 growth doesnt increase significantly.

pot plants can grow just fine at higher temperatures without co2 if you keep the root zone cool, and by the same token, even with co2, if your root zone is hot, you are asking for problems.

http://www.maximumyield.com/article...yearVar=2010&issueVar=January&featureVar=true
http://ag.arizona.edu/pubs/garden/mg/botany/physiology.html
http://www.biologie.uni-hamburg.de/b-online/e24/24b.htm
http://www.tutorvista.com/content/biology/biology-ii/nutrition/factors-affecting-photosynthesis.php

 

[Legaldroman]

is 4 lbs in a closet healthy enough for you? then 3 lbs bubba kush next? I ran at about 93 and, cooler for veg just because it was cold outside. 1500 ppm co2.



I couldnt find the university study that showed maximum growth rate (tomatoes) and final yeild was 95 degrees at 1500 ppm and at 75 degrees for 400 ppm, but all the articles below suggest 90 degrees is better than ambient.

there are tons of studies that related co2 to growth rate and discuss temperature. most are not with cannabis however. google co2, plant growth, temperature.

the basic premise is that all chemical reactions proceed faster at higher temperatures, up to the point where some plant regulatory factors set in or some disease or other environmental variable is affected. (obviously more complicated than that - some plants wont grow at high temps at all - but cannabis isnt one such plant - think Columbia/Mexico/Africa -> Hot)

but.... the reaction (photosynthesis) is limited by available reactants in the microenvironment of the chloroplasts, and the limiting nutrient is co2 in both c3 and c4 plants.

so the end result is that you dont get much better growth from raising the temperature if you do not provide adequate co2. it doesnt mean that the inverse is true.

the idea that plants can tolerate higher temps when using co2 is a poorly documented issue that gets repeated over and over and over so it becomes dogma. Tolerate isnt the issue, but risk to benefit is. Risk of root zone issues increases with temperature but without co2 growth doesnt increase significantly.

pot plants can grow just fine at higher temperatures without co2 if you keep the root zone cool, and by the same token, even with co2, if your root zone is hot, you are asking for problems.

http://www.maximumyield.com/article...yearVar=2010&issueVar=January&featureVar=true
http://ag.arizona.edu/pubs/garden/mg/botany/physiology.html
http://www.biologie.uni-hamburg.de/b-online/e24/24b.htm
http://www.tutorvista.com/content/biology/biology-ii/nutrition/factors-affecting-photosynthesis.php

Very interesting! Thanks for the reply, no doubt you are an educated individual. I run a sealed room with no exhaust, fuzzy logic controlled Co2 at 1500ppm. Personally I don't think running a room with 10K at 96 degrees is a good idea... How do you go about keeping root temps cool?

 

[Legaldroman]

I noticed that your running DWC, maybe that allows for increased temps? I've seen rooms running at 95 with Co2 and it wasn't pretty. Now these weren't closet op's, they were rooms with 12K in them...and they weren't running DWC or areo...I wonder if that has some thing to do with it? Interesting how root temp seems to play a critical role...Thanks again for the info.

 

[crizzo]

those are my settings on my controller,
and yes I do run dehumidifiers, they are a must, for the reason stated above and to help speed up transpiration, plant can't transpire when the humidity is to high which will slow down growth.

there is an article on maximum yields websites that talks about and has a graph that details growth rate by heat, co2, humidity, and light par's. and as long as you have optimum co2, light pars, and humidity growth rate are increased with high temps like in the 90's
here's a link http://www.maximumyield.com/article_sh_db.php?articleID=519&submit=Go

sorry to be so abrupt, but I have to go to worked, but thanks for those of you how have replied so far.

 

[bron2k]

i'm also doing RDWC with co2 levels at 1500ppm. my room temp is 88-91 and my humidity is 53-57%. i got no fresh air coming in and no air going out. just a carbon filter recycle the air in the room. anyone else doing this? i just want to make sure i don't need to draw fresh air in few times a day. from what i read you don't have to if your temperature is on point. also is my humidity level ok? i got a dehumidifier but having a hard time getting it lower. good thread by the way! thanks..

 

[Dr.GT]

i'm also doing RDWC with co2 levels at 1500ppm. my room temp is 88-91 and my humidity is 53-57%. i got no fresh air coming in and no air going out. just a carbon filter recycle the air in the room. anyone else doing this? i just want to make sure i don't need to draw fresh air in few times a day. from what i read you don't have to if your temperature is on point. also is my humidity level ok? i got a dehumidifier but having a hard time getting it lower. good thread by the way! thanks..

what size dehumidifier are you using, and what is the sq ft of the room?

 

[Dr.GT]

those are my settings on my controller,
and yes I do run dehumidifiers, they are a must, for the reason stated above and to help speed up transpiration, plant can't transpire when the humidity is to high which will slow down growth.

there is an article on maximum yields websites that talks about and has a graph that details growth rate by heat, co2, humidity, and light par's. and as long as you have optimum co2, light pars, and humidity growth rate are increased with high temps like in the 90's
here's a link http://www.maximumyield.com/article_sh_db.php?articleID=519&submit=Go

sorry to be so abrupt, but I have to go to worked, but thanks for those of you how have replied so far.

sounds pretty dialed in to me.

 

[Legaldroman]

i'm also doing RDWC with co2 levels at 1500ppm. my room temp is 88-91 and my humidity is 53-57%. i got no fresh air coming in and no air going out. just a carbon filter recycle the air in the room. anyone else doing this? i just want to make sure i don't need to draw fresh air in few times a day. from what i read you don't have to if your temperature is on point. also is my humidity level ok? i got a dehumidifier but having a hard time getting it lower. good thread by the way! thanks..

Yo don't need to draw any fresh air in, I don't and my system is great. What are the room dimensions and size of the dehumidifier? I like my humidity to be around 40% during the day and 45% at night.

Dr GT and Foaf,
Thanks for the interesting articles! After reading these today, I think I'll increase my canopy temp from 85-86 to 88-89 and see if I get better results, thanks again for the info, I'm always up for becoming better educated, peace.

 

[crizzo]

I also run a carbon filter recirculating the are in the room to improve air quantity and help with the smell.

hey foaf, your bho recir sys. is sick. I have been wanting to put one together for awhile now. that for that info. i'll get to it soon.

 

[V1AAA]

i havent got time right now to go into detail, but i will quickly say that

"every strain is different". they could be similar in what temps they like, but not the same.

its the same with nutes. 1 plant might like the ec at 14 the other at 22. also the same with brands. some brands have got more of one thing or another, and certain strains might take more of the other.

 

[Lazyman]

is 4 lbs in a closet healthy enough for you? then 3 lbs bubba kush next? I ran at about 93 and, cooler for veg just because it was cold outside. 1500 ppm co2.



I couldnt find the university study that showed maximum growth rate (tomatoes) and final yeild was 95 degrees at 1500 ppm and at 75 degrees for 400 ppm, but all the articles below suggest 90 degrees is better than ambient.

there are tons of studies that related co2 to growth rate and discuss temperature. most are not with cannabis however. google co2, plant growth, temperature.

the basic premise is that all chemical reactions proceed faster at higher temperatures, up to the point where some plant regulatory factors set in or some disease or other environmental variable is affected. (obviously more complicated than that - some plants wont grow at high temps at all - but cannabis isnt one such plant - think Columbia/Mexico/Africa -> Hot)

but.... the reaction (photosynthesis) is limited by available reactants in the microenvironment of the chloroplasts, and the limiting nutrient is co2 in both c3 and c4 plants.

so the end result is that you dont get much better growth from raising the temperature if you do not provide adequate co2. it doesnt mean that the inverse is true.

the idea that plants can tolerate higher temps when using co2 is a poorly documented issue that gets repeated over and over and over so it becomes dogma. Tolerate isnt the issue, but risk to benefit is. Risk of root zone issues increases with temperature but without co2 growth doesnt increase significantly.

pot plants can grow just fine at higher temperatures without co2 if you keep the root zone cool, and by the same token, even with co2, if your root zone is hot, you are asking for problems.

http://www.maximumyield.com/article...yearVar=2010&issueVar=January&featureVar=true
http://ag.arizona.edu/pubs/garden/mg/botany/physiology.html
http://www.biologie.uni-hamburg.de/b-online/e24/24b.htm
http://www.tutorvista.com/content/biology/biology-ii/nutrition/factors-affecting-photosynthesis.php

Most of the research papers and studies I've read over the years have plotted plant growth rates on a chart, and the accepted norm was that plant stomata started to close in the upper 80's F. The plant is trying to protect itself from drying out with high temps and low RH, which stalls or even stops growth.

Cannabis studies usually show optimal growth rates at 85*F and 50% RH, which keeps stomata open and does not stress the plant. I don't have the links handy, but I've been doing this a long time and have been on pot forums since the early days of Overgrow.

I'm not saying that what you're doing isn't feasible (it clearly is) but what I want to clarify is that what you're doing is not typically recommended, and I certainly don't want any newbs experimenting with those levels as a baseline for their sealed rooms. The odds of things turning out favorably are low for anyone without years of experience.

 

[foaf]

Cannabis studies usually show optimal growth rates at 85*F and 50% RH

can you point to just one such such a study? I pointed to several, and one was specifically related to cannabis, and they all suggest higher temps allow faster growth with co2 supplimentation. and you suggest that low humidity forces stomata to close, that is correct, but I consider 50% to be lower humidity except for in the latest stages with dense rot prone buds when the lower the better is well appreciated. Excessive transpiration is a stressor for plants for sure. Pot plants love hot moist environments in nature. Ive been at this quite a while too, and spent a lot of time on the now defunct kbs forum for big scale commercial tree growers. they all swore by the so called "low stress" growing method, which included high humidity until buds were dense, and higher temps, up to a point, but they did usually stay in the upper 80's since it was all top drip and you cant keep the roots cool with that method easily.

I see what you are saying, but I think that the only risk in higher temps comes if you dont have a chilled root zone, and I tried to make that clear, and it is super important. Yes, a hot room with hot roots is a disaster waiting to happen. I dont think that there are any risks to high humidity in veg and early flower.

 

[Lazyman]

Hey foaf, I did a quick check online and of course can't find a thing now. Figures. I did find a decent study that basically showed that even a small amount of supplemental CO2 causes a good deal of thermal tolerance to higher temps, but most decent studies are on cucumbers and roses.

I do find the chilled root zone interesting, I think in veg/early flower it would be detrimental as low temperatures typically drop metabolic rates. In late flower (and in a hot CO2 room) I can see how the roots would like to be cooler, but I'd think that it's fairly easy to accomplish cold when needed (just water with colder/aerated water.)

Excessive humidity (over 80% in my experience) does slow plant transpiration from the roots, as the plant no longer requires water from the roots when the stomata are unable to purge their water due to high RH. I can find you studies if you'd like.

In extreme cases plants will even sprout roots from exposed stem areas. When you say high RH, roughly what % are you meaning?

In short I think that most indica dominant strains are more likely to thrive in a sub-*90F environment than a sativa, which may tolerate higher temps, especially in a CO2 room.

This is a fun discussion!

 

[bron2k]

thanks everyone for the good info so far. i was wondering when do you guys usually shut off your co2? i usually shut it off in week 6 cuz due to very dense buds. you guys think i'll lose some weight by shutting off my co2 in week 6?? thanks!

 

[Pure.Dope]

Great thread. I'm trying to figure out the best way to setup my tent. It's a 600w closed, with a 1/4hp chiller, icebox, CO2, and dehumidifier. My temps stay at about 85f and rh 40-50. I'm running a drip w/ reservoir inside tent. Wondering if I should switch to some sort of connected bucket system with reservoir outside tent. Also should I be chilling my reservoir water for my rootzone? Would it maybe be better to switch to coco? What do you guys think?