What's new
  • Please note members who been with us for more than 10 years have been upgraded to "Veteran" status and will receive exclusive benefits. If you wish to find out more about this or support IcMag and get same benefits, check this thread here.
  • Important notice: ICMag's T.O.U. has been updated. Please review it here. For your convenience, it is also available in the main forum menu, under 'Quick Links"!

Question for those running sealed flower rooms.

overbudjet

Active member
Veteran
flower week 1-2-3 Day 81 Night 82-84
week 4-5-6 Day 81 Night 75-78
week 7-8 Day 81 Night 70-73
last week Day 81 Night the lowest i can around 60-65

In the first 3 week i set the night temp higher to reduce stretching ,after i slowly turn down the temp for the last one i switch to the lowest temp .
 
flower week 1-2-3 Day 81 Night 82-84
week 4-5-6 Day 81 Night 75-78
week 7-8 Day 81 Night 70-73
last week Day 81 Night the lowest i can around 60-65

In the first 3 week i set the night temp higher to reduce stretching ,after i slowly turn down the temp for the last one i switch to the lowest temp .

This just blew my mind. I’ve always been told that during flower, temps should be in the low 70s daytime and night. Have I been missing out on my co2 by running low temps?!?!
 
flower week 1-2-3 Day 81 Night 82-84
week 4-5-6 Day 81 Night 75-78
week 7-8 Day 81 Night 70-73
last week Day 81 Night the lowest i can around 60-65

In the first 3 week i set the night temp higher to reduce stretching ,after i slowly turn down the temp for the last one i switch to the lowest temp .
Is 81 degrees really the ideal daytime temp for flower with sealed co2?!
 

Fixer

Active member
I'm no expert but I run around 80F at all times. I'm working toward temp changes. I've read that the plants utilize the CO2 more efficiently at high temps as it emulates the Earth's atmosphere from 1000's of years ago when CO2 levels were elevated. :tiphat:
 
Mind blown! Thank you for your input. So then another question..what temperature is too high? Where does the danger zone For temperature begin when it comes to flowering?
 
I would think that healthy plant processes would be better at lower temperatures. Heat is really no good when you look at outdoors. I ditched my tent and I bring in outside air continually. It's not easy to keep plant canopy maximized and at 76F at the same time.
 

RockinRobot

Active member
This just blew my mind. I’ve always been told that during flower, temps should be in the low 70s daytime and night. Have I been missing out on my co2 by running low temps?!?!

When running CO2 you raise the temperatures in order to get the plants to uptake more nutrients so that they can actually utilize the extra CO2. Feed levels usually need to be raised as well.
 

tilopa

Member
It's twofold, at higher VPD plants need to transpire more, thereby taking in more nutrient solution AND causing the Stomata to open which is where the plant intakes the CO2. And with more CO2 they need, or can make available, more nutes.

I keep my lights-on temp at 84 degrees, but my buddy swears that over the years he has seen significant increase in bud growth by keeping temps at 86. General consensus is 83 should be your minimum. However humidity is a significant factor, so if your humidity is low temps should also be lower.
 
It's twofold, at higher VPD plants need to transpire more, thereby taking in more nutrient solution AND causing the Stomata to open which is where the plant intakes the CO2. And with more CO2 they need, or can make available, more nutes.

I keep my lights-on temp at 84 degrees, but my buddy swears that over the years he has seen significant increase in bud growth by keeping temps at 86. General consensus is 83 should be your minimum. However humidity is a significant factor, so if your humidity is low temps should also be lower.

Whattt that’s crazy! Was I the only one with lights on temps of 73-76?! I’m about to bump my temperatures up and save some electricity! Fellas tap in, is everyone else’s lights on temps during flower in the 80’s??
 

tilopa

Member
My night temps are around 73-75.

Whattt that’s crazy! Was I the only one with lights on temps of 73-76?! I’m about to bump my temperatures up and save some electricity! Fellas tap in, is everyone else’s lights on temps during flower in the 80’s??
Keep in mind that I'm talking about when using co2. If not using co2 your temps should be 77-78. I've never heard of anyone targeting 73-76 as the ideal temp, but it is also somewhat strain relevant.
 

Hookahhead

Active member
I don’t run a sealed room, but I’ve seen similar charts to this throughout the years. Basically they show that with CO2 enrichment you can/should run higher temps. Hope it helps.

iu

Source: https://www.edrosenthal.com/the-guru-of-ganja-blog/why-co2-is-critical-for-cannabis

Edit: a really good scientific paper on this subject can be found here:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3550641/pdf/12298_2008_Article_27.pdf


Effect of different photosynthetic photon flux densities (0, 500, 1000, 1500 and 2000 ?mol m-2s-1), temperatures (20, 25, 30, 35 and 40 oC) and CO2 concentrations (250, 350, 450, 550, 650 and 750 ?mol mol-1) on gas and water vapour exchange characteristics of Cannabis sativa L. were studied to determine the suitable and efficient environmental conditions for its indoor mass cultivation for pharmaceutical uses. The rate of photosynthesis (PN) and water use efficiency (WUE) of Cannabis sativa increased with photosynthetic photon flux densities (PPFD) at the lower temperatures (20-25 oC). At 30 oC, PN and WUE increased only up to 1500 ?mol m-2s-1 PPFD and decreased at higher light levels. The maximum rate of photosynthesis (PN max) was observed at 30 oC and under 1500 ?mol m-2s-1 PPFD. The rate of transpiration (E) responded positively to increased PPFD and temperature up to the highest levels tested (2000 ?mol m-2s-1 and 40 0C). Similar to E, leaf stomatal conductance (gs) also increased with PPFD irrespective of temperature. However, gs increased with temperature up to 30 oC only.

Temperature above 30 oC had an adverse effect on gs in this species. Overall, high temperature and high PPFD showed an adverse effect on PN and WUE. A continuous decrease in intercellular CO2 concentration (Ci) and therefore, in the ratio of intercellular CO2 to ambient CO2 concentration (Ci/Ca) was observed with the increase in temperature and PPFD. However,
the decrease was less pronounced at light intensities above 1500 ?mol m s . In view of these results, temperature and light optimal for photosynthesis was concluded to be at 25-30 oC and ~1500 ?mol m-2s-1 respectively. Furthermore, plants were also exposed to different concentrations of CO2 (250, 350, 450, 550, 650 and 750 ?mol mol-1) under optimum PPFD and temperature conditions to assess their photosynthetic response. Rate of photosynthesis, WUE and Ci decreased by 50 %, 53 % and 10 % respectively, and Ci/Ca, E and gs increased by 25 %, 7 % and 3 % respectively when measurements were made at 250 ?mol mol-1 as compared to ambient CO2 (350 ?mol mol-1) level. Elevated CO2 concentration (750 ?mol mol- 1) suppressed E and gs ~ 29% and 42% respectively, and stimulated PN, WUE and Ci by 50 %, 111 % and 115 % respectively as compared to ambient CO2 concentration. The study reveals that this species can be efficiently cultivated in the range of 25 to 30 oC and ~1500 ?mol m-2s-1 PPFD. Furthermore, higher PN, WUE and nearly constant Ci/Ca ratio under elevated CO2 concentrations in C. sativa, reflects its potential for better survival, growth and productivity in drier and CO2 rich environment.
 
Last edited:

Hookahhead

Active member
According to the paper, the benefits start to fall off after 30C (86F). So I would try to keep temps under 90. Again just to reiterate, you will likely need to bump your feed/watering because the plants transpire more. Transpiration is water vapor, so you’ll need to adjust the humidity to hit your VPD target.
 

Douglas.Curtis

Autistic Diplomat in Training
I see a LOT of 'stretched' cannabis around. I wonder if this is where it's coming from.

Those of you running 80F+ temps and co2, do your flowers have a central stem without any branching stems? I'm not talking a branch of flowers, I'm talking an individual flower pulled from the stem it's growing from. I prefer to gently pinch my flowers, breaking it into a thousand frosty bits and pieces, and push it into the bowl before pulling the central stem out. I really don't care for smoking stems or leaf.

How many of you have switched from under 70F (where I flower for max resin/terpene production and retention) to 80F+ temps and co2? How would you describe the physical flower differences between them?

Personally, when I've added co2 I've picked up more stem and leaf while lowering quality. I'm definitely interested in more info which could help change this.
 
I see a LOT of 'stretched' cannabis around. I wonder if this is where it's coming from.

Those of you running 80F+ temps and co2, do your flowers have a central stem without any branching stems? I'm not talking a branch of flowers, I'm talking an individual flower pulled from the stem it's growing from. I prefer to gently pinch my flowers, breaking it into a thousand frosty bits and pieces, and push it into the bowl before pulling the central stem out. I really don't care for smoking stems or leaf.

How many of you have switched from under 70F (where I flower for max resin/terpene production and retention) to 80F+ temps and co2? How would you describe the physical flower differences between them?

Personally, when I've added co2 I've picked up more stem and leaf while lowering quality. I'm definitely interested in more info which could help change this.

Ok so everyone I know that runs temps in the low 70s must be doing it for “max resin/terpene retention? I’ve never personally known anyone to run temps in the 80s. Personally I’m scared to. Not sure if temps in the 80s will produce the high quality flower I’m used to.
 

overbudjet

Active member
Veteran
I.m.h.o. flower temp is related to its genetic ,a indica strain higher altitude strain flowering at low 70 and more uv , a sativa in a hotter climate and also require a longer flower time all hybrid are a mix of those gene.
 

RockinRobot

Active member
Ok so everyone I know that runs temps in the low 70s must be doing it for “max resin/terpene retention? I’ve never personally known anyone to run temps in the 80s. Personally I’m scared to. Not sure if temps in the 80s will produce the high quality flower I’m used to.

It's fine to run temps in the 70's but you may as well not supplement with CO2, as you'll just be wasting the CO2 because the plant won't be able to make use of it. Personally I have run cool and no CO2 and 80's with CO2 and no difference in taste or quality of the buds. only difference ended up being quantity.

That being said I only run a few strains and other than my GDP they are fairly sativa dominant. Some strains may lose out on some terpene production at the higher temps but I don't notice a difference in mine.
 

Latest posts

Latest posts

Top