Can a 730NM far red LED be added to HPS lighting during flower?

[SuperFunker]

Google Robert Emerson and Emerson Effect.

Icemud...

Re the absorbance graph in your earlier post... Would it be accurate to say that plants absorb less green light, because green light is used more efficiently that other wavelengths?

 

[SuperFunker]

The hps already emits in that spectrum no? Half of its wattage goes to far red and ir

Is your source regarding led lighting or HPS?

Hello TheMadDabber...

GREAT QUESTION! The research used LED's.

I am not disputing the reality that HPS typically has a decent amount of far red. Rather, this thread meandered, so I was merely adding to the generalities of the far red conversation.

But specifically referring to far red associated with HPS... does that HPS emit 16%, 30% or other of far red? Just looking at the spectrum, it seems the amount of far red is about 10% of the signature? So would supplemental far red enhance photosynthesis? And, what about the HPS cool-down? Does HPS emit far red during cool-down? If yes, how much and how long? Would a dose of night time far red potentiate flower growth? Difficult to tell and difficult to control, right?

The question still remains, what are the practical/useful limits of far red supplementation? Clearly, more research needs to be done.

 

[Mayne]

Using 730 for nighttime must be used alone, like said above. If ANY other wavelenght interrupts it, it instantly wakes the plant. Said to put plant to sleep, and bypass the 2hour upcharge of ATP, i think it is, lol, not sure.. Green, is used for better CO2 uptake,

I currently use GrowMau730 puck, 15mins at end of day, lights out for 13 hours, (+2=15 hours sleep)
Its said the plant only needs 6 hours of beaming light to get its daily needs.

I can tell you this tho. I have a plant that i started "12/12" from seed, it flowered in 21 days from seed, and gets about 11 hours of light a day. the tall plant is 34 days old, the flowering is 43 days intoflower ( first pistils starts count) took 10days to show sex. Its just about finished. Flushing 1 more time, then copn.

 

[Scientific]

Green light does drive photosynthesis, this is proven.

Interesting discussion. If y'all have good references that you could share, that would be awesome.

(With respect, simply saying "this is proven" kind of reminds me of the religious pronouncement, "It is written." )

 

[TheMadDabber]

Interesting discussion. If y'all have good references that you could share, that would be awesome.

(With respect, simply saying "this is proven" kind of reminds me of the religious pronouncement, "It is written." )

At higher ppfd levels more green light is thought to be absorbed. I attribute it to leaves under the canopy and overlapped by other leaves. The light will be tinted green from the chlorophyll as it passes through the leaf. Maybe I'm stretching but it just seems pretty straightforward

 

[Scientific]

At higher ppfd levels more green light is thought to be absorbed. I attribute it to leaves under the canopy and overlapped by other leaves. The light will be tinted green from the chlorophyll as it passes through the leaf. Maybe I'm stretching but it just seems pretty straightforward

Thanks for the comment. Maybe I wasn't clear. I was asking Icemud to provide some links to more information about the more unusual claims if he had them and had the time to post them. I follow his posts here with interest and have a subscription to his YouTube channel, so I value what he has to say.

 

[TheMadDabber]

Yep I found an interesting little read if your interested sci. Not sure if it's the one icemud is referencing or not...

If you Google it you will find the full pdf

 

[Scientific]

Yep I found an interesting little read if your interested sci. Not sure if it's the one icemud is referencing or not...

If you Google it you will find the full pdf

Thanks Dabber. You know I loves da science!

It looks like there is a lot of interesting info at the heliospectra.com website, so I will be spending some time nosing around in their archive.

 

[Mayne]

Green Light Drives Leaf Photosynthesis More Efficiently than Red Light in Strong White Light

"Abstract

The literature and our present examinations indicate that the intra-leaf light absorption profile is in most cases steeper than the photosynthetic capacity profile. In strong white light, therefore, the quantum yield of photosynthesis would be lower in the upper chloroplasts, located near the illuminated surface, than that in the lower chloroplasts. 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 would increase leaf photosynthesis to a greater extent than would additional red or blue light. Based on the assessment of effects of the additional monochromatic light on leaf photosynthesis, we developed the differential quantum yield method that quantifies efficiency of any monochromatic light in white light. Application of this method to sunflower leaves clearly showed that, in moderate to strong white light, green light drove photosynthesis more effectively than red light. The green leaf should have a considerable volume of chloroplasts to accommodate the inefficient carboxylation enzyme, Rubisco, and deliver appropriate light to all the chloroplasts. By using chlorophylls that absorb green light weakly, modifying mesophyll structure and adjusting the Rubisco/chlorophyll ratio, the leaf appears to satisfy two somewhat conflicting requirements: to increase the absorptance of photosynthetically active radiation, and to drive photosynthesis efficiently in all the chloroplasts. We also discuss some serious problems that are caused by neglecting these intra-leaf profiles when estimating whole leaf electron transport rates and assessing photoinhibition by fluorescence techniques.

Green Light Drives Leaf Photosynthesis More Efficiently than Red Light in Strong White Light: Revisiting the Enigmatic Question of Why Leaves are Green | Plant and Cell Physiology | Oxford Academic

 

[SuperFunker]

Green Light Drives Leaf Photosynthesis More Efficiently than Red Light in Strong White Light

"Abstract

The literature and our present examinations indicate that the intra-leaf light absorption profile is in most cases steeper than the photosynthetic capacity profile. In strong white light, therefore, the quantum yield of photosynthesis would be lower in the upper chloroplasts, located near the illuminated surface, than that in the lower chloroplasts. 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 would increase leaf photosynthesis to a greater extent than would additional red or blue light. Based on the assessment of effects of the additional monochromatic light on leaf photosynthesis, we developed the differential quantum yield method that quantifies efficiency of any monochromatic light in white light. Application of this method to sunflower leaves clearly showed that, in moderate to strong white light, green light drove photosynthesis more effectively than red light. The green leaf should have a considerable volume of chloroplasts to accommodate the inefficient carboxylation enzyme, Rubisco, and deliver appropriate light to all the chloroplasts. By using chlorophylls that absorb green light weakly, modifying mesophyll structure and adjusting the Rubisco/chlorophyll ratio, the leaf appears to satisfy two somewhat conflicting requirements: to increase the absorptance of photosynthetically active radiation, and to drive photosynthesis efficiently in all the chloroplasts. We also discuss some serious problems that are caused by neglecting these intra-leaf profiles when estimating whole leaf electron transport rates and assessing photoinhibition by fluorescence techniques.

Green Light Drives Leaf Photosynthesis More Efficiently than Red Light in Strong White Light: Revisiting the Enigmatic Question of Why Leaves are Green | Plant and Cell Physiology | Oxford Academic

The following link is HoseBomber's response to this exact study (I think). Scroll down 6 posts and note HoseBomber's link at the end of his post.
Green Light Drives Leaf Photosynthesis More Efficiently than Red Light in Strong Whit

Actually, would like to get HoseBomber's input on this thread (the whole thread), but he has been relatively inactive.

 

[Mayne]

interesting,

IDK man. Ive heard Green wavelengths increase CO2 uptake, thus bigger plants, faster growth. I think GrowMau5 and Greengenes actually had a utube on this very subject. We have to also keep in mind, we are not talking about lettuce and pepper plant. This weed has a need of its very own.

I can tell ya, Ive grown under some powerfull LEDs ( Modded Mars300) with 4500K spectrum, with CO2 ( DIY ) and it freakin rocked in veg. Its basically a white light, but it was intense.

 

[SuperFunker]

interesting,

IDK man. Ive heard Green wavelengths increase CO2 uptake, thus bigger plants, faster growth. I think GrowMau5 and Greengenes actually had a utube on this very subject. We have to also keep in mind, we are not talking about lettuce and pepper plant. This weed has a need of its very own.

I can tell ya, Ive grown under some powerfull LEDs ( Modded Mars300) with 4500K spectrum, with CO2 ( DIY ) and it freakin rocked in veg. Its basically a white light, but it was intense.

Would explain why new COB systems (equal combination of 4800K and 3500K) are getting outrageous results.

 

[TheMadDabber]

If you guys wanna see a real cob and Samsung bin build with the far red lights and c02 here on 420 you need to check out my buddy riders thread. His plants are insane, like unreal. 1 month veg and the things are hitting the roof in flower he already took down the tent cause they grew out of it....
Rider509 - Two Thais & G13

 

[Mayne]

If you guys wanna see a real cob and Samsung bin build with the far red lights and c02 here on 420 you need to check out my buddy riders thread. His plants are insane, like unreal. 1 month veg and the things are hitting the roof in flower he already took down the tent cause they grew out of it....
Rider509 - Two Thais & G13

Oh Yeah, Im following Rider. he is rockin it for sure.

 

[SuperFunker]

If you guys wanna see a real cob and Samsung bin build with the far red lights and c02 here on 420 you need to check out my buddy riders thread. His plants are insane, like unreal. 1 month veg and the things are hitting the roof in flower he already took down the tent cause they grew out of it....
Rider509 - Two Thais & G13

Yes, Rider509 is creating magic DIY.

Note, the COB's that are now being employed on new systems are even more powerful.