# Dropping Temps During Flowering.



## ASMALLVOICE (Jan 29, 2013)

Greetings Fellow Growers,

I have a question. I have very tight control over the temps in my grow room. I know that when we go to a 12/12 cycle, it imitates the shorter days of fall. I am curious if slowly lowering the temps both during lights on and lights off would have an effect on the final product.

I have them at 78 during lights on and 68 at lights off. I want to try 74 lights on and 64 lights off and drop each week untill I harvest at 68 on and 58 off. I am starting my 5th week of flowering.

Just curious if anyone has tried this. Seems to me, it imitates the natural cycle a bit closer.

Look forward to your input.

Peace and Great Grows

Asmallvoice


----------



## elkukupanda (Jan 29, 2013)

Colder temp increase plant phytohormone gibberellin... (Helps breaking dormancy of buds)


----------



## ASMALLVOICE (Jan 29, 2013)

elkukupanda said:


> Colder temp increase plant phytohormone gibberellin... (Helps breaking dormancy of buds)


Thank you kindly. I wrote that down and will start doing some research on that, I have not heard that term used before, man, I am such a newb...lol

Peace and Great Grows

Asmallvoice


----------



## elkukupanda (Jan 29, 2013)

ASMALLVOICE said:


> Thank you kindly. I wrote that down and will start doing some research on that, I have not heard that term used before, man, I am such a newb...lol
> 
> Peace and Great Grows
> 
> Asmallvoice


Yes man me too... also some other stuff you can find at UB's thread about carbohydrates and stuff...


----------



## Bakatare666 (Jan 29, 2013)

I'm doing 11/13 now, (like short end of season days too) and it's working nice.


----------



## Muffy (Jan 29, 2013)

elkukupanda said:


> Colder temp increase plant phytohormone gibberellin... (Helps breaking dormancy of buds)


 What is dormancy of buds?


----------



## elkukupanda (Jan 29, 2013)

Muffy said:


> What is dormancy of buds?


in other words, stimulates bud development.


----------



## ASMALLVOICE (Jan 30, 2013)

I set it up to drop setpoints by 4 degrees starting Friday lights on at 10:00am. Going to watch it real close for any signs, good or bad. Then next Friday, drop them again. Will throw updates out over the next 3 weeks or so as that should be the 8+ week mark. I have a 40x scope coming in the mail as the 10x jewelers loupe isn't stirring the koolaid for this blind old man..lol I can see the trichs, but I can't REALLY see them.

Peace and Great Grows

Asmallvoice


----------



## akula (Jan 30, 2013)

I recently heard about this as well from TheGreenHornet in another thread. I really wanted to look more into this because I accidentally stumbled across it in this winters grow. Trying to save money I turned down my heaters in my flower room just a bit. My temps were hitting 50-60 ranges during the coldest of days. I was worried about them but they seemed to do not only fine, but really thrive. Need to do more investigation.


----------



## elkukupanda (Jan 30, 2013)

akula said:


> I recently heard about this as well from TheGreenHornet in another thread. I really wanted to look more into this because I accidentally stumbled across it in this winters grow. Trying to save money I turned down my heaters in my flower room just a bit. My temps were hitting 50-60 ranges during the coldest of days. I was worried about them but they seemed to do not only fine, but really thrive. Need to do more investigation.


Yes, I saw that post and began reading
Seems like between 2c and 10c have very close results... For gibberellin in some annuals before full winter... I been dropping temp down to 10c and they seem to be liking it... My buds are beginning to form.. But that might be because of the flowering time as well... I been keeping a rotating fan 24/7 on upper canopy to promote as much osmosis as possible during night...


----------



## elkukupanda (Jan 30, 2013)

This is another report I'm. Reading about temps between roots and leafs
http://aob.oxfordjournals.org/content/early/2013/01/03/aob.mcs298.full


----------



## BCBuddy420 (Jan 30, 2013)

ASMALLVOICE said:


> Greetings Fellow Growers,
> 
> I have a question. I have very tight control over the temps in my grow room. I know that when we go to a 12/12 cycle, it imitates the shorter days of fall. I am curious if slowly lowering the temps both during lights on and lights off would have an effect on the final product.
> 
> ...


LOVE your thinking!!!  On my first grow I gradually lowered my temps down from 84- 68 to 84-55 and even lower!( I struggled with high temps, they were a lot worse than 84 hehe) my portable AC did this job and I got a good yield with nice purple colors on upper fans and bud leaves ( wasn't a purple strain either). If nature does it then why shouldn't we?? It was ice cold in there for the last two weeks of flowering at dark and they did not show any negative response at all, in any way. I also fed with very cold water too, nothing bad happened.


----------



## bicoastal (Jan 30, 2013)

What I do that I have found to really bring out all the colors and get the densest possible nugs I follow this regimen;
9 week cycle

week 1-6 86 degrees w CO2 78 degrees w/o CO2
night- 78 degree or 70 degrees

week 7- 78 degrees w/CO2 75 degrees w/o CO2
night- 66-68 degrees

week 8- 73 degrees w/CO2(half level CO2) 70 degrees w/o CO2
night- 60 degrees

week 9- 70 degrees no CO2
night- 55 degrees

I have found this to work very well for me, what I also have been taught to do is to raise the lights 6 inches once a week for the last two weeks...

Happy growing!


----------



## ASMALLVOICE (Jan 31, 2013)

Many thanx for the replys.

I have them going to 74 and 64 starting tomorrow and they get a feeding that day as well. Then next Friday 70 and 60-62 and finish with a 68-70 on and 58-60 off. I have kept close to a 10 degree split most of the grow. Did have a spell with a small sensor issue and it ran at about 80-83 (lights on) for about 4 days before my goofy ass caught it, but other than that, been steady.

I hope I do get to see some color changes. I am starting to see some orange hairs here and there, so I feel pretty comfortable so far.

Peace and Great Grows

Asmallvoice


----------



## mushead (Feb 2, 2013)

anyone raise the night time temps? i use to keep mine 80 at night in the summer cuz my days would get warm, then drop them the last few weeks. i was told along time ago that cooler temps made your bud harsher, then again they were super picky stoners. any thoughts? it was a cali grower that told me that, not sure what that means, just thought it might have been a west coast thing, cuz no one on the east has heard that info that i know of..


----------



## Twitch (Feb 3, 2013)

it will also tun ur buds purple-ish color, the low temps at night


----------



## Rancho Cucamonga (Feb 3, 2013)

Agree with OP. 
Without all the technical and scientific BS I can tell you from experience slowly lowering the temps in flower helps tremendously. The last 4-5 harvests I have started flower at about 79 degrees, down from 82 on the previous ones. Around week 4-6(30 days after signs of first white pistils) I lower day temps to about 75, and around the last two weeks I not only drop temps to about 72 but I crank the dehumidifier up in the next room to get about 30-35% RH. I see nothing but better and bigger yields from controlling the heat in this way. 
I do not switch light schedule at all. From what I have read anything under 12 hours of light will hurt yield. I have experimented with dimming all my 600 watts to 400 the last few weeks but no real results. 
If you look at the life of a marijuana plant in nature seedlings usually have to deal with fairly cooler weather early on, veg is mostly the hot months as is early flower. But there is no question that in late flower temperatures are usually the coolest time of this plants life so it stands to reason cooling in late flower would help with indoor growing as well.


----------



## ASMALLVOICE (Feb 8, 2013)

Morning All,

So far so good for the first step down, have it set for 72 lights on and 62 off, going to be a chilly work week for the Ladies.  Had to do a bit more staking and supporting, getting some plant matter on the ends of these sticks...lol The last 2 pics are one of the freebies and I have no idea what they are, but I can say this, from a looks standpoint, these two Ladies here just got it going on. I love the frost and the overall symmetry of the plants ( they are a bit younger at just nearly 4 weeks into flower). 


Will throw another update out next week.

Peace and Great Grows

Asmallvoice


----------



## zack66 (Feb 12, 2013)

Looking good man! Those buds look tasty.


----------



## Guitar Man (Feb 14, 2013)

ASMALLVOICE said:


> Morning All,
> 
> So far so good for the first step down, have it set for 72 lights on and 62 off, going to be a chilly work week for the Ladies.  Had to do a bit more staking and supporting, getting some plant matter on the ends of these sticks...lol The last 2 pics are one of the freebies and I have no idea what they are, but I can say this, from a looks standpoint, these two Ladies here just got it going on. I love the frost and the overall symmetry of the plants ( they are a bit younger at just nearly 4 weeks into flower).
> View attachment 2516347View attachment 2516348View attachment 2516349View attachment 2516350View attachment 2516351View attachment 2516352View attachment 2516353View attachment 2516354View attachment 2516364
> ...


I'm enjoying this Thread, as I have been very curious about temps during flowering. Makes total sense to lower temps as the grow matures.

I do have a question about your grow; I'm not trying to be critical, but your leaves seem to be showing nute problems earlier than they should be. How far into flowering are you?

Here is a picture of 1 of my plants that was 6 weeks into flowering. I do have some leaves turing color, but lots of green still left.
.


----------



## ASMALLVOICE (Feb 14, 2013)

Guitar Man said:


> I'm enjoying this Thread, as I have been very curious about temps during flowering. Makes total sense to lower temps as the grow matures.
> 
> I do have a question about your grow; I'm not trying to be critical, but your leaves seem to be showing nute problems earlier than they should be. How far into flowering are you?
> 
> ...


Yea, I had a bit of a cal/mag issue from going a bit light on the nutes during weeks 2 and 3 of flowering. I have since upped the feeding a bit and it seems to have stabilized so far. Only 2 of the plants seemed to want a bit more than I was feeding. Great learning experience overall. Got a new camera, going to play around a bit with it tomorrow and see if I can get some decent upclose shots.

Peace

Asmallvoice


----------



## ASMALLVOICE (Feb 16, 2013)

Hello all,

After a week at 72 and 62, I dropped it down to 70 and 60 for this week and I may drop it a couple of more depending on the weather over the next few days. So far things are going okay. I was able to take a few pics without the HPS light on. Had to install an upgraded carbon filter, so I did a shut down to relocate the plants out of the room while I did my work. New camera as well, going to get a tripod for it so I can get some knarly pics coming.
View attachment 2527467View attachment 2527472View attachment 2527477View attachment 2527478View attachment 2527482View attachment 2527474View attachment 2527476View attachment 2527469View attachment 2527471

Peace and Great Grows

Asmallvoice


----------



## Guitar Man (Feb 16, 2013)

ASMALLVOICE said:


> Yea, I had a bit of a cal/mag issue from going a bit light on the nutes during weeks 2 and 3 of flowering. I have since upped the feeding a bit and it seems to have stabilized so far. Only 2 of the plants seemed to want a bit more than I was feeding. Great learning experience overall. Got a new camera, going to play around a bit with it tomorrow and see if I can get some decent upclose shots.
> 
> Peace
> 
> Asmallvoice


The reason I brought this up is, your test won't be completely accurate because of nute problems early on. But I still agree, lowering temps should encourage a more natural bud development. BTW, your plants do look good and juicy!!


----------



## nick88 (Feb 16, 2013)

ASMALLVOICE said:


> Hello all,
> 
> After a week at 72 and 62, I dropped it down to 70 and 60 for this week and I may drop it a couple of more depending on the weather over the next few days. So far things are going okay. I was able to take a few pics without the HPS light on. Had to install an upgraded carbon filter, so I did a shut down to relocate the plants out of the room while I did my work. New camera as well, going to get a tripod for it so I can get some knarly pics coming.
> View attachment 2527467View attachment 2527472View attachment 2527477View attachment 2527478View attachment 2527479View attachment 2527482View attachment 2527473View attachment 2527474View attachment 2527475View attachment 2527476View attachment 2527469View attachment 2527471
> ...


 Nice looking ladies.. I always drop my night temmps close to the end of flower, with the last 3dys being total darkness and lower temps. 
And before anyone chimes saying thats bs.. Tell it to Mnistry of cannabis, they're the breeder who recommends to do this.


----------



## ASMALLVOICE (Feb 17, 2013)

Guitar Man said:


> The reason I brought this up is, your test won't be completely accurate because of nute problems early on. But I still agree, lowering temps should encourage a more natural bud development. BTW, your plants do look good and juicy!!


Yea, the two plants, 1-WW and 1-J23 showed a later stage of a cal/mag def. and being my first grow, I eased into upping the nutes over 4 feedings but the rest were okay with the original doses (7 plants total), but to keep things simple, I make one batch and everybody gets the same mix. I know I have a couple that are getting close to done and the rest will hopefully finish up over the next 4 weeks as well. Got the trusty little 40x mag glass with uv/led light that gives this old man some visions...lol  Here is a couple of pics of the freebies (almost 4 weeks flowering), I have been told it's a strain of some type of kush, I honestly have no idea. Care to take a guess?, let me know. The frost build up is getting unreal, going to get my tripod today and see if I can get anything REALLY worth sharing from this camera..lol


Thanx again for the replys folks.

Peace and Chill Grows

Asmallvoice


----------



## Trousers (Feb 17, 2013)

*opinion*

I have found nothing that leads me to believe lowering temps is beneficial.
I do not try to imitate outdoor conditions, why?

Light angles, high heat, low temps at night, humidity, dry periods, rain, hail, wind, dust, dirt pests...

All I got from lowering my temps was some powdery mildew. 
Come to find out that powdery mildew does best in temps between 60 and 70. One week of that was enough. 

I'll just stick to trying to keep my plants as close to 75 at all times as possible.


----------



## Guitar Man (Feb 17, 2013)

Trousers said:


> *opinion*
> 
> I have found nothing that leads me to believe lowering temps is beneficial.
> I do not try to imitate outdoor conditions, why?
> ...


Are you positive the mildew came from lowering your temps? What was/is your humidity? Do you live in an area prone to mold/mildew?


----------



## ASMALLVOICE (Feb 17, 2013)

Trousers said:


> *opinion*
> 
> I have found nothing that leads me to believe lowering temps is beneficial.
> I do not try to imitate outdoor conditions, why?
> ...


Hiya Trousers,

I keep the humidity as close to 50% as I can, being winter tho, it runs a bit lower than that right now. The last few days it has barely hit 40%. I have 2 circulation fans going 24/7 and a bit overkill on the carbon filter scrubbing, but thats me. I must add that when the lights go out, I do not try to slam them to my lower setpoint, it takes roughly 4 hrs to come down to my lights off temp and it helps on the potential spike in humidity.
I am just about as low as I am going to take them as of right now. I will say this as a side note, it sure has been a helluva lot nicer to work in there as of late..lol

Peace and Great Grows

Asmallvoice


----------



## zack66 (Feb 17, 2013)

Nothing wrong with your humidity being 40% this far along in flower. I drop mine down to 25-30% the last couple weeks. It get's them nice and sticky. Plus, you don't have to worry about mold.. Nice grow.


----------



## Trousers (Feb 19, 2013)

Guitar Man said:


> Are you positive the mildew came from lowering your temps? What was/is your humidity? Do you live in an area prone to mold/mildew?


I didn't lower my temps, it was a cold snap we had. I grow in my basement. My humidity is usually between 10% and 35%.
Mold is a completely different thing than mildew. It is possible I brought in mildew from my greenhouse. 

Powdery mildew does best between 60 and 70. It can not grow at 77 or above. 




ASMALLVOICE said:


> Hiya Trousers,
> 
> I keep the humidity as close to 50% as I can, being winter tho, it runs a bit lower than that right now. The last few days it has barely hit 40%. I have 2 circulation fans going 24/7 and a bit overkill on the carbon filter scrubbing, but thats me. I must add that when the lights go out, I do not try to slam them to my lower setpoint, it takes roughly 4 hrs to come down to my lights off temp and it helps on the potential spike in humidity.
> I am just about as low as I am going to take them as of right now. I will say this as a side note, it sure has been a helluva lot nicer to work in there as of late..lol
> ...



I do not bother messing with humidity, it is not that important. I prefer it lower. I do not want my fatty buds getting mold in them. 

I have not found anything to convince me that lowering temps indoors or raising humidity is beneficial, much less worth the effort.


----------



## lbrowdy (Feb 27, 2013)

*gebberellic acid and making femized seeds? *computers baffle me, and am new here. speaking of gibberellic acid. i was on some site and did not save. but the info said spray a solution of 300 to 400 ppm (from recall) on buds 5 days? as i recall it was 300 to 400 parts per million. and if the water and gebberellic acid were to few or to many parts per million bad things would occur. help, or a link to some site? PLEASE AND THANK YOU.

LB


----------



## knotmyself (Mar 4, 2013)

Great thread. Im battling very high heat in my flowering due to a tight space and 600 watts HPS... I just cant seem to get the temps lower then 85 on a good day... Has anyone some factoids or experience flowering in excessive heat such as 85-100F? Any tips (other then "TOO HOT" ) would be appreciated..because I know its hot...but I just really cant lower it...Iv tried....( Day 16 of flower on some pretty good bag seed - 3x3x8 - with AC running during day cycle ) I know... I know... its warm... Watt 2 DEW?


----------



## ASMALLVOICE (Mar 5, 2013)

Hello All,

Been fishin my ass off and watching these Ladies finish up. They are coasting at 68 on and 58 off at roughly 40-50% hum. Been fairly decent here the last couple of weeks on humidity, my dehumidifier is catching a well deserved rest...lol. Here are a few shots, I harvested my oldest WW and have it in the dry room.


Wont be long now.

Peace and Great Grows

Asmallvoice


----------



## Jimmy Luffnan (Mar 25, 2013)

Interesting thread about temps =)
I swear I have been debating forever about colder temps and humidity with my peers forever despite proving my point.
What I have found in my instance, colder temps are generally more beneficial in many ways and outweigh the positives.
I live in an extremely warm & humid climate, so I run an A/C cooled room at 20C for entire operation (clone, veg and flower... even drying)
*The res stays at 20C - no root issues
*Plants grow at the same speed as higher temps

I use a good 20L per day dehumidifier and keep RH at around 25-30%. It makes things a bit harder with low temps (stripping water from the air), but with a good dehumidifier and good circulation it's not a problem. The benefits with end production of buds vs happier veg/growing temps, the buds are much better colder (and yield)
The rooms are divided by light, but the air circulation is the same all round. I spray the clones with 'stop wilt' instead of doming them, works much better for me, better success.

The advice I would offer for anybody wanting to run a colder room, just keep the RH as low as you can, keep the fan blowing around really well and in my case (but not necessary) use a UV-C light in your grow room. Yes they are dangerous if used incorrectly, so if you were thinking about using one, RESEARCH and put your SAFETY FIRST!
But in the final 3-4 weeks of flowering I give all the plants a 'scan' with the light every second day and never ever have a bud rot or PM issue since. I use overalls, gloves and a UV face mask. ( I don't let the light touch my skin)
Even just putting one deep in your intake will do good things, but like I said RESEARCH and SAFETY FIRST!

Sorry if it feels like I pulled off topic a little bit, but the relevance was that when I originally dropped the temps, humidity issues and related diseases increased. But if you can control them, you will end up swearing by lower temps like me =)

Cheers Jimmy.


----------



## #DPP (Sep 23, 2018)

Guitar Man said:


> I'm enjoying this Thread, as I have been very curious about temps during flowering. Makes total sense to lower temps as the grow matures.
> 
> I do have a question about your grow; I'm not trying to be critical, but your leaves seem to be showing nute problems earlier than they should be. How far into flowering are you?
> 
> ...



Mine are down to the low 50's at night and some times high 40's... first night was last night.. and its about to be like that the rest of the season at night 40's to 50's


----------



## JayBio420 (Oct 4, 2018)

#DPP said:


> Mine are down to the low 50's at night and some times high 40's... first night was last night.. and its about to be like that the rest of the season at night 40's to 50's


Do you also practice necromancy in your chilly grow room??


----------



## highflying (Dec 7, 2020)

Totally new to the craft and love reading and learning here. I am in week 9 now. Dropped my temps from 83 daytime, to 78, and the night temps from 78 to 69. The calix were all red prior to the drop and seemed to be stalled out. But a couple days after I dropped my temps, the flowers produced a huge burst of new, white calix. Again, I'm new to this, but with no other changes in the room, it seems evident that temperature drops like this improve growth, and maybe potency and flavor, too.
Thanks to all who post and share here. The love is good.


----------



## highflying (Dec 7, 2020)

ASMALLVOICE said:


> Yea, I had a bit of a cal/mag issue from going a bit light on the nutes during weeks 2 and 3 of flowering. I have since upped the feeding a bit and it seems to have stabilized so far. Only 2 of the plants seemed to want a bit more than I was feeding. Great learning experience overall. Got a new camera, going to play around a bit with it tomorrow and see if I can get some decent upclose shots.
> 
> Peace
> 
> Asmallvoice


Thank you for starting this thread. I just dialed down my thermostat a bit and my wife is wanting me to hold her. Two birds, one stoner.


----------

