Light cycles for reducing mid-day heat

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is happy, works

in "Pflanzenphysiologie" from Prof. Dr. Libbert you will find commented experiments involving plant's hyponastic leaf angle measurements in response to a change of the light regiment.

Depicting exactly what your situation is.
 
Overgrowtho said:
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.
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if that guy grows under LED then leaf surface temps should just be about right
but it's also a matter to consider genetic origin, overall status of the plant and where he took the temp measurement, as this can vary greatly.

edit:
just measured leaf surf temp at the top fans between 30-32.5°C under CFL + UVA, so it's healthily transpiring which cools though leaves are darkgreen due to high feed EC
 
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Kassiopeija said:
View attachment 5119283
is happy, works

in "Pflanzenphysiologie" from Prof. Dr. Libbert you will find commented experiments involving plant's hyponastic leaf angle measurements in response to a change of the light regiment.

Depicting exactly what your situation is.
Click to expand...

Any chance he has a pic of his LST with the hygrometer in the picture too, I’m not buying this at all personally
 
Kassiopeija said:
if that guy grows under LED then leaf surface temps should just be about right
but it's also a matter to consider genetic origin, overall status of the plant and where he took the temp measurement, as this can vary greatly.

edit:
just measured leaf surf temp at the top fans between 30-32.5°C under CFL + UVA, so it's healthily transpiring which cools though leaves are darkgreen due to high feed EC
Click to expand...

What exactly is the UVA doing currently in the pic posted?
 
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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My leaf surface temp. is 2 to 2.5f degrees lower than my ambient temperature in the mid 80's, under LEDs with the 'current' regular mix of full spectrum diodes (HLG quantums). Last summer some days my tent ran hot, in the 87-93F range and. my plants didn't seem to have any troubles though.

Get a IR thermometer, they're cheap, even a decent Inkbird is only something like $25 bucks or so.

speedwell68 said:
I go 5pm to 5am.
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In veg I'm running my lights from 5pm to 11am. That gives me time in the morning if I'm motivated to check the tent and do any smaller upkeep...then also I have the opportunity to do any serious stuff (LST, HST, more detailed inspection, water/feed) after I get home from the 9-5 office grind.

In flower I'll do 5pm to 5am lights, and forego the morning visit. I don't think I save any extra $$ on our power, but I'm happy with a few degrees off on the light cycle and the dark cycle won't need any additional heat.
 
Wastei said:
So you're citing a book from 1952 and doesn't even question or reflect about the subject? Come on, are you really on that level of thought?
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My version of the book is from 1999, it's the 4th iteration so it got expanded, corrected over a long time and it's scientific meaning this stuff got taught at the university for several decades.
And I do have half a dozen such books and a huge bibliothek of texts and some of these cross-reference each other because when 1 Prof dies the other takes over his work and that is a process lasting for several hundred years now and is consistent with how knowledge is passed through the generations.

So just because something is old doesnt mean it's wrong?! Are Einstein's 2 big theories wrong? Your argument is more than naive LOL!!! Have plants all of a sudden become totally different the last 2 decades?

You don't even know how science works - science itself is most critical and the scientific method has been established long before you were born (the last paradigm shift was from Karl Popper) to diminish errors.

So your stance is that Cannabis doesnt have a Circadian Rhythm? Or stop growing at 31°C ambient? Go away troll. You don't even know the basics about photobiology yet I study the subject extensively for years. Which puts me into the position of immediately recognizing bullshitters or fake wisdom or broscience crap - which is the reason why you pussies want me leave and gang up on trolling me. Others in the know - like MG - have received death threats to postal addresses from guys I put right into the RIU shill group.

I tell you I am aware how plants generally react to a change in all kinds of light regiments, like putting them in the dark for 72h (leaf movement up & down still occurs which is remniscient of a physiological memory-alike mechanism..)

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Kassiopeija said:
My version of the book is from 1999, it's the 4th iteration so it got expanded, corrected over a long time and it's scientific meaning this stuff got taught at the university for several decades.
And I do have half a dozen such books and a huge bibliothek of texts and some of these cross-reference each other because when 1 Prof dies the other takes over his work and that is a process lasting for several hundred years now and is consistent with how knowledge is passed through the generations.

So just because something is old doesnt mean it's wrong?! Are Einstein's 2 big theories wrong? Your argument is more than naive LOL!!! Have plants all of a sudden become totally different the last 2 decades?

You don't even know how science works - science itself is most critical and the scientific method has been established long before you were born (the last paradigm shift was from Karl Popper) to diminish errors.

So your stance is that Cannabis doesnt have a Circadian Rhythm? Or stop growing at 31°C ambient? Go away troll. You don't even know the basics about photobiology yet I study the subject extensively for years. Which puts me into the position of immediately recognizing bullshitters or fake wisdom or broscience crap - which is the reason why you pussies want me leave and gang up on trolling me. Others in the know - like MG - have received death threats to postal addresses from guys I put right into the RIU shill group.

I tell you I am aware how plants generally react to a change in all kinds of light regiments, like putting them in the dark for 72h (leaf movement up & down still occurs which is remniscient of a physiological memory-alike mechanism..)

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There's a big difference between studying and putting your knowledge into practice, you lack the latter and without it you're still just shooting in the dark.
 
@ the guys who laughed:
Insider question:
How many million or billion years has phyllogenetics put chloroplastide genes conserved/stable in evolution?
(when you think 20y matter lol)

larfybudz said:
What exactly is the UVA doing currently in the pic posted?
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UVA is natural in the sun's spectrum and has a number of different consequences regarding leaf optical properties, fluorescence, stomatal conductance, photosynthesis, and later, terpenoid production.
You will never get a natural phenotypical expression when using a SF or Mars or HPS with all their castrate spectra that are missing about 1/3rd the photobiological plant-usable wavelength
 
Wastei said:
There's a big difference between studying and putting your knowledge into practice, you lack the latter and without it you're still just shooting in the dark.
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hmmm my first few years where just practice without study but that was just shooting in the dark.
mostly leading to broscience or 'anecdotal wisdom' - which is no wisdom at all imo

your assessment is wrong and biased because you don't know me - not at all - ZERO!

And the way you elude, or ignore, any points raised just gives away your ignorance and lack of proper education and basic upbringing/decency.
 
Kassiopeija said:
hmmm my first few years where just practice without study but that was just shooting in the dark.
mostly leading to broscience or 'anecdotal wisdom' - which is no wisdom at all imo

your assessment is wrong and biased because you don't know me - not at all - ZERO!

And the way you elude, or ignore, any points raised just gives away your ignorance and lack of proper education and basic upbringing/decency.
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Well you talk a lot of theoretical nonsense which tells me you lack actual practice and I think we all can agree on that one. Get off your high horse, you're making a fool out of yourself.
 
Wastei said:
Well you talk a lot of theoretical nonsense which tells me you lack actual practice and I think we all can agree on that one. Get off your high horse, you're making a fool out of yourself.
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blablabla you only posts are ad hominem retardism

ok facts
what physiological benefits has it to feed cannabis natrium in vivo?
 
Billy the Mountain said:
No, it's poor advice to tout 40+°C as beneficial for a healthy cannabis plant.

Growth will slow after ~30°C leaf surface temp, a little higher w/ supplemental C02.
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you dont even get what I was talking about -now 3 times in row - <hint> and I just made fun of you as you used "<" for "more"

lack of education
 
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