Which wavelengths to choose

RED:BLUE ratio in flowering?

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Doer

Doer

Well-Known Member
AquariusPanta said:
A discussion can hold an argument/point (or two) from multiple parties/individuals, hence "my discussion point is that the phrase about green penetrating the canopy to benefit the lower leaves is not correct.". That is clearly an argument.

Discussions can be informative like this one when multiple thoughts about a subject, such as light absorbance, take place because discrepancies typically pop up due to misunderstandings. Thankfully for us, someone usually holds the facts needed to bring the audience into a new discussion, therefore paving a way of better understanding for all.
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It is why it was not an argument. It is a fact of science. The idea is not correct and there is no argument about it. So, you saying clearly it is an argument is the only argument here. :)
 
AquariusPanta

AquariusPanta

Well-Known Member
Doer said:
It is why it was not an argument. It is a fact of science. The idea is not correct and there is no argument about it. So, you saying clearly it is an argument is the only argument here. :)
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I believe you and a few others held differing views on page one of this thread, which is the root of my questioning and explaining.
 
Doer

Doer

Well-Known Member
http://pcp.oxfordjournals.org/content/50/4/684.short
Because green light can penetrate further into the leaf than red or blue light, in strong white light, any additional green light absorbed by the lower chloroplasts (In that leaf...doer) would increase leaf photosynthesis to a greater extent than would additional red or blue light.

So, if someone would like to discuss with me the idea of green light penetrating through the leaves would have to show a peer reviewed study to counter this one.

And it is still not an argument. It is still the discussion of Botany.

If you want to throw in unsubstantiated myth and marketing claims then someone else can argue about that. :)
 
C

churchhaze

Well-Known Member
It's somewhat misleading to call the 3 cones "blue, green, and red". They are more appropriately named short, medium, and long. The medium and long wave cones almost completely overlap, sort of like Pr and Pfr, but with some minor differences, allowing us to see a gradient of colors. In fact, I think this analogy is a great way to explain how phytochromes work.

Notice how the peak of the long wave cones is not a red wavelength. In order for the human brain to perceive red, the long cone must be excited without exciting the medium or short cones! 660nm photons appear red because of the low ratio of absorbance of medium to long cones. This is also how the brain can be tricked into thinking a combination of 2 wavelengths is actually the same color as 1 wavelength. (spectral yellow vs red + green).
 
Doer

Doer

Well-Known Member
AquariusPanta said:
I believe you and a few others held differing views on page one of this thread, which is the root of my questioning and explaining.
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I know. Not an argument. The argument was from those that were wrong. We can argue over the meaning of facts. But the facts are the facts.

And I see RIU as Myth Ridden. And that's fine. But, now we have more research. And some of the myths are just plain wrong...not all of them. This Green Penetration is part of the defoliation Myth. Which in turn comes from the most backward idea that the upper leaves are "blocking light" from the lower leaves.

And what happened here, was I refuse to walk eggs shells around Marketing Hype.
And Green Penetration, ie you need green is all mixed up in LED.

This thread is about Red and Blue ratio. And I countered with explaining COBs.
That brought up Green Penetration hype as a benefit to lower leaves.

So. it isn't.

I am for spread spectrum white light not discrete nano-meter emitters for just this reason. HYPE.
 
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stardustsailor

stardustsailor

Well-Known Member
Doer said:
http://pcp.oxfordjournals.org/content/50/4/684.short
Because green light can penetrate further into the leaf than red or blue light, in strong white light, any additional green light absorbed by the lower chloroplasts (In that leaf...doer) would increase leaf photosynthesis to a greater extent than would additional red or blue light.

So, if someone would like to discuss with me the idea of green light penetrating through the leaves would have to show a peer reviewed study to counter this one.

And it is still not an argument. It is still the discussion of Botany.

If you want to throw in unsubstantiated myth and marketing claims then someone else can argue about that. :)
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Look,Doer...
~15 % of the green photons are reflected at the adaxial (upper) side of a leaf .
Thus the rest ~85 % is being absorbeb by the leaf.
From that 85% of photons ,~ 73% (of initial 100% ) is being absorbed by the PS systems ,
while ~ 12 % (of initial 100% ) is being transmitted from the abaxial side of the leaf ,towards deeper /lower leaves.
(Regarding Cannabis Sativa L. a "die-hard" , wild weed .)
That ~12% transmittance is forming the so called "green -window" .

Cheers.
:peace:
 
stardustsailor

stardustsailor

Well-Known Member
Doer said:
I know. Not an argument. The argument was from those that were wrong. We can argue over the meaning of facts. But the facts are the facts.

And I see RIU as Myth Ridden. And that's fine. But, now we have more research. And some of the myths are just plain wrong...not all of them. This Green Penetration is part of the defoliation Myth. Which in turn comes from the most backward idea that the upper leaves are "blocking light" from the lower leaves.

And what happened here, was I refuse to walk eggs shells around Marketing Hype.
And Green Penetration, ie you need green is all mix up in LED.

This thread is about Red and Blue ratio. And I countered with explaining COBs.
That brought up Green Penetration hype as a benefit to lower leaves.

So. it isn't.

I am for spread spectrum white light not discrete nano-meter emitters for just this reason. HYPE.
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No,you 're wrong.
There are plenty more of issues ,regarding monochromatic LED emitters.
Green wls or photons MUST be there ,at least at higher PAR levels.
And better not to be in the form of individual green monochromatic leds,because several issues might arise.
(Local Shade avoidance syndrome is amongst of them .And plenty more.)

PAR spectrum is officially rendered as the wl region of 380-780 nm .
Not 380-500 nm and 600-780 nm .
Reference spectrum for plant biology study and research is always "WHITE LIGHT" ...
Not BLUE & RED ,alone.
GREEN light is always there ,too.
HIgher ,light -needy plants ,CAN NOT reach their MAXIMUM GENETIC POTENTIONAL ,without it .
RED & BLUE LED combos ,work well only in certain plant species and/or with certain cultivating techniques and/or LOW PAR levels.

Cannabis Sativa L. species ,will never reach their max genetic potentional without green photons.
And that is a well proven fact .NOT just a theory.


Cheers.
:peace:
 
C

churchhaze

Well-Known Member
bicit said:
So question. Would it be worth while to add 620nm and 660nm red LED's alongside softly driven cobs? I'm thinking 4000k cobs with a few reds thrown in?
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@Positivity seems to think so. He's been saying that he's noticed better results with 660nm + warm white over warm white alone.

I have a feeling that 660nm would benefit veg more than flowering, but that's based on a guess based on how I understand phytochromes, not experiment.

The reason I think it would be better for veg is because there's less need for transmittance to the lower branches, no need to calibrate shade avoidance, and a higher %Pfr in general would mean less stretch, and more "active state" growth. (contrary to believe that red contributes to stretch, which goes against phytochrome theory)
 
C

churchhaze

Well-Known Member
That's another thing about 500-600nm.. Not only does it feed lower leaves, it also calibrates shade avoidance by causing a lower %Pfr at the lower leaves than those exposed to direct light.

Red light is a signal to the plant that it sees the sun directly. The lower branches don't see the red, so they converge at a lower %Pfr and stretch until they see red.

Without 500-600nm, the plant would have to rely on 730nm alone for shade avoidance calibration.
 
stardustsailor

stardustsailor

Well-Known Member
puffenuff said:
Added reds should aid in biomass and essential oil production.
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Biomass yes,"essential oil " (terpenes ,you mean probably),allow me to think not that much .
(For Cannabis species,always)

Added red photons( high number of photons per rad. W ) -during reproductive period- will enhance quantity of yield.
Quality of yield is enhanced -mainly- by other wls .( UV-violet-blue=high energy photons per rad.W )
 
stardustsailor

stardustsailor

Well-Known Member
churchhaze said:
@Positivity seems to think so. He's been saying that he's noticed better results with 660nm + warm white over warm white alone.

I have a feeling that 660nm would benefit veg more than flowering, but that's based on a guess based on how I understand phytochromes, not experiment.

The reason I think it would be better for veg is because there's less need for transmittance to the lower branches, no need to calibrate shade avoidance, and a higher %Pfr in general would mean less stretch, and more "active state" growth. (contrary to believe that red contributes to stretch, which goes against phytochrome theory)
Click to expand...
Here,I've to disagree with you brother.
660 nm ,ain't the ideal reds for vegetative stage.
The 600-640 nm are far better ones,as they do not induce several things.
(thin stems - thick/waxy narrow bladed leaves,etc )

Cheers.
:peace:
 
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