Light cycles for reducing mid-day heat

Overgrowtho

Overgrowtho

Well-Known Member
It is the hottest time of year where I live and my trees that have been flowering for 6 weeks are getting as hot as 32C/89.6F during the mid-day heat, even inside with my aircon switched to full power.

To combat the heat, I am thinking of switching the light cycle to be at night and dark cycle during the day. Does this switch in the middle of week 6 somehow stress-out the plant badly?

Also we really wish to have SOME hours lights-on during the day so that we can still get-in-there and work during reasonable daytime hours. Is there some weird, special light cycles for flowering that would aid us in this?
 
jondamon

jondamon

Well-Known Member
Overgrowtho said:
It is the hottest time of year where I live and my trees that have been flowering for 6 weeks are getting as hot as 32C/89.6F during the mid-day heat, even inside with my aircon switched to full power.

To combat the heat, I am thinking of switching the light cycle to be at night and dark cycle during the day. Does this switch in the middle of week 6 somehow stress-out the plant badly?

Also we really wish to have SOME hours lights-on during the day so that we can still get-in-there and work during reasonable daytime hours. Is there some weird, special light cycles for flowering that would aid us in this?
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I run mine 8pm - 8am for flower and use an auto irrigation system.

any work such as training etc is done between 9pm and midnight which allows me enough time to get a good sleep before work.

but I’m only a personal grower (2-4 plants) and don’t know how many you’re growing.
 
Kassiopeija

Kassiopeija

Well-Known Member
Overgrowtho said:
It is the hottest time of year where I live and my trees that have been flowering for 6 weeks are getting as hot as 32C/89.6F during the mid-day heat, even inside with my aircon switched to full power.

To combat the heat, I am thinking of switching the light cycle to be at night and dark cycle during the day. Does this switch in the middle of week 6 somehow stress-out the plant badly?

Also we really wish to have SOME hours lights-on during the day so that we can still get-in-there and work during reasonable daytime hours. Is there some weird, special light cycles for flowering that would aid us in this?
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if you do a switch, do it by prolonging the night
they will need a full week or longer for their biorhythm to freshly align
yes it will stress them
you really think 32°C is too much a stress to them? did you measure leaf surface temps also?
outside leaves can get hot +45°C is nothing special in some places
 
Overgrowtho

Overgrowtho

Well-Known Member
Kassiopeija said:
if you do a switch, do it by prolonging the night
they will need a full week or longer for their biorhythm to freshly align
yes it will stress them
you really think 32°C is too much a stress to them? did you measure leaf surface temps also?
outside leaves can get hot +45°C is nothing special in some places
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does it mean they stop growing for a week when their biorhythm is re-aligning? Might not be the best idea in week 6??

Ive read that above 31 degrees or so, cannabis stops growing.

No I didnt measure leaf surface temps. Those are normally a couple degrees lower right?

So what approach stresses them less? Finish off in high temps or redo the light schedule?
 
Overgrowtho

Overgrowtho

Well-Known Member
oooh sounds like we have dualing reports from the above 2 replies. I tend to think the biorythem would reset quickly with minimal stress (compared to the heat which could harm terp and stuff...).
3rd reply concurred.
So it seems like we are gonna try to stick with that plan and see how it goes.
 
Billy the Mountain

Billy the Mountain

Well-Known Member
Overgrowtho said:
oooh sounds like we have dualing reports from the above 2 replies. I tend to think the biorythem would reset quickly with minimal stress (compared to the heat which could harm terp and stuff...).
3rd reply concurred.
So it seems like we are gonna try to stick with that plan and see how it goes.
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I don't think they're contradictory, just extend the dark cycle as mentioned above
 
Kassiopeija

Kassiopeija

Well-Known Member
Overgrowtho said:
does it mean they stop growing for a week when their biorhythm is re-aligning?
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only a little bit, the way how the plant organizes its own starch reserves will be misaligned for a week or more until the circadian rhythmic has been set anew

Overgrowtho said:
Might not be the best idea in week 6??
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indeed, just control it daily

Overgrowtho said:
Ive read that above 31 degrees or so, cannabis stops growing.
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Totally untrue. Cannabis loves warmth. It will reduce growth at 45°C and come to a critical halt at 55°C leaf surface temps.

Overgrowtho said:
Those are normally a couple degrees lower right?
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it depends on your lamp. under LED, yes lower, HID higher
 
Wastei

Wastei

Well-Known Member
Overgrowtho said:
does it mean they stop growing for a week when their biorhythm is re-aligning? Might not be the best idea in week 6??

Ive read that above 31 degrees or so, cannabis stops growing.

No I didnt measure leaf surface temps. Those are normally a couple degrees lower right?

So what approach stresses them less? Finish off in high temps or redo the light schedule?
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Nothing's gonna happen. Give them a little longer sleep if you want to. They won't skip a beat. It takes more than a day for the plants to react to changes. Did exactly what you ask last run and the plants didn't skip a beat. Can't remember ever having a problem changing light timings and schedules.

They get different amount of light every day in nature so one day won't change anything inside of the plant.

Don't listen to @Kassiopeija. She talk alot of theoretical nonsense, doesn't even grow or smoke weed but somehow still think she knows what she's talking about. 32C is not to bad but anything close to 45C will totally torch a plant to bits.
 
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Overgrowtho

Overgrowtho

Well-Known Member
Kassiopeija said:
Totally untrue. Cannabis loves warmth. It will reduce growth at 45°C and come to a critical halt at 55°C leaf surface temps.
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Interesting. Any citations for this? Seems to contradict what I've read.

And nobody actually WANTS to grow at about 32C+ I think, because reduced growth? 45+ seems like a waaay too high threshold. I thought the benefits of heat peak-out at 29.5 which is why when running CO2 I keep that temp.

I suppose growth slows to a near halt when leaf surface temps are too high (beyond 31C I thought) -- the plant spends much energy trying to cool down and not burn.

I know my plants got burned when an a/c stopped working.... it was not even near 45C and the plants got leaf burn like a mofo.
 
xtsho

xtsho

Well-Known Member
All you have to do is skip a light cycle and switch your lights to be on during what was previously your Night cycle. It won't cause any issues with your plants.
 
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