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

[ayekayy]

I have a single far red light 730 nm I want to add as a small supplement to my 1000w raptor hps. would this be healthy for my girls ??? please help i thought so but people are saying only for a couple of minutes daily!

 

[Canresearcher]

I have a single far red light 730 nm I want to add as a small supplement to my 1000w raptor hps. would this be healthy for my girls ??? please help i thought so but people are saying only for a couple of minutes daily!

There is little to no point in doing this.
a) There is no real benefit with this long a wavelength. 730nm outside of the Chlorophyll A/B absorption rate.
b) You're getting already plenty of longer wave red anyways from the HPS light. HPS isn't all that efficient in terms of useful light anyways.
c) If you want more resin there is plenty of evidence to suggest using supplementary shorter blue - medium UV wavelengths can aid in this point.


If you look below you can see the amount of green and farther red in the spectra.
there's a lot here that isn't absorbable and thus wasted energy.

 

[Icemud]

I have a single far red light 730 nm I want to add as a small supplement to my 1000w raptor hps. would this be healthy for my girls ??? please help i thought so but people are saying only for a couple of minutes daily!

Very unlikely to benefit. Adding far red will increase the ratio of Red:Far Red which will increase stretch. HPS already has enough Far Red for the emerson effect and adding more will not do much.

You would benefit more from exchanging the Far Red for a UV-B reptile bulb which will increase trichomes.

The 730nm far red can be used 15 minutes after lights out during flowering, which will speed up flowering slightly. However, speeding up flowering I found can happen with Far Red by about 2 weeks, however, I also had a reduced yield. The 2 weeks faster harvest was not worth the loss IMO.

 

[taijoo]

I've been playing with the 730 nm night-transition lighting, and I'm finding you have to balance it out. If you just use the 730nm goodnight-light but don't shift the light schedules, yeah, you're gonna get a quicker harvest. But if you add more light to the schedule (which the 730nm should allow you to do), you'll get bigger yields. You gotta play with the leeway that the quicker Pfr->Pr shift gives you.

(But in answer to the OP, yeah, I don't think there's any benefit to constantly supplemental 730nm lighting, and possible drawbacks.)

 

[Icemud]

I've been playing with the 730 nm night-transition lighting, and I'm finding you have to balance it out. If you just use the 730nm goodnight-light but don't shift the light schedules, yeah, you're gonna get a quicker harvest. But if you add more light to the schedule (which the 730nm should allow you to do), you'll get bigger yields. You gotta play with the leeway that the quicker Pfr->Pr shift gives you.

(But in answer to the OP, yeah, I don't think there's any benefit to constantly supplemental 730nm lighting, and possible drawbacks.)

Can you elaborate on "add more light to the schedule". I don't quite understand what you mean.

Are you meaning instead of 12/12 with 15 mins of Far Red, you are doing something more like a 14/10?

I've heard growers use Far Red and love the results, and I definitely agree that there must be some way it can be used where it would be a balance of shorter flowering and no yield loss... but haven't found that light regiment yet. I will be experimenting more with Fr in the near future.

 

[Canresearcher]

Sorry but the far red-end longer than (700nm) of the spectrum is beyond the range of either Chlorophyll a or b. It doesn't do anything for the plant at all. The plant is essentially blind to it. [/I]

Consequently, the quantum yield from these wavelengths drops off markedly below about 425 nm. Beyond 700 nm (infrared band) absorption drops to near zero, and forestalls leaf heating from this source of energy.

Shorter than 700nm but longer than 590nm (590-570nm) is where yellow light exists and is also not used by the plant.
The next big absorption occurs at ~490nm - 400nm with the lower edge at ~350nm (UVA). The peak absorption in the blue range is approximately 450nm (pure blue)

 

[Icemud]

Sorry but the far red-end longer than (700nm) of the spectrum is beyond the range of either Chlorophyll a or b. It doesn't do anything for the plant at all. The plant is essentially blind to it. [/I] Shorter than 700nm but longer than 590nm (590-570nm) is where yellow light exists and is also not used by the plant.
The next big absorption occurs at ~490nm - 400nm with the lower edge at ~350nm (UVA). The peak absorption in the blue range is approximately 450nm (pure blue)

Thats incorrect.

Emerson effect.

Phytochrome manipulation

Has nothing to do with Chlorophyll, and Chlorophyll is just one of many pigments that capture light. Many pigments surround the reaction centers.

Its used mainly for photomorphogenesis,

Far Red light is used by plants to sense other plants proximity

Far Red light and the ratio to red determine stretch and elongation

Far Red light is one of the wavelengths associated with shade avoidance syndrome...

even wavelengths as high as 780nm can have up to a 20% quantum yield.

Also, Yellow light is absolutely used by the plant... The quantum efficiency is not much different from red, blue or green and all visible light wavelengths. Green light is too!

 

[Canresearcher]

The emerson effect occurs from a light of wavelength 670 nm (deep red spectrum) and 700 nm (far red spectrum). Generally not longer than 700nm. Some people have tried 730nm IR diodes and found some success as diodes in this wavelength can shift with temperature from 700-725nm (GaAs). Generally the effect peaks at from a 670nm-700nm, or also far (deep) red.

As for yellow light, it is at the upper band that Chlorophyll can just barely absorb. Technically you are right that some of the longer yellow wavelengths can be absorbed for photosynthesis it is an incredibly small bandwidth. As for Green light, recent research does show for some plants (non green) do infact absorb a very tiny amount of this light. Green leaves on cannabis however are unable to use it.
One thing I can say, and this goes back to the graph you posted is that full spectrum light is healthier for plants than using monochromatic
LEDs.
Lots of research in this area being done. Anyways... thanks for the correction.

 

[Icemud]

The emerson effect occurs from a light of wavelength 670 nm (deep red spectrum) and 700 nm (far red spectrum). Generally not longer than 700nm. Some people have tried 730nm IR diodes and found some success as diodes in this wavelength can shift with temperature from 700-725nm (GaAs). Generally the effect peaks at from a 670nm-700nm, or also far (deep) red.

As for yellow light, it is at the upper band that Chlorophyll can just barely absorb. Technically you are right that some of the longer yellow wavelengths can be absorbed for photosynthesis it is an incredibly small bandwidth. As for Green light, recent research does show for some plants (non green) do infact absorb a very tiny amount of this light. Green leaves on cannabis however are unable to use it.
One thing I can say, and this goes back to the graph you posted is that full spectrum light is healthier for plants than using monochromatic
LEDs.
Lots of research in this area being done. Anyways... thanks for the correction.

Phototsystem 2 uses all light below 680, the electrons are raised to an excited state and slowly passed through the electron transport chain to the photosystem.

Photosystem 1 uses energy from photons above 700nm up to 750nm and some like the article above show up to 780.

The emerson effect is a general symbiosis between both photosystems which yields more efficiency when combined vs their own.


All colors from the sun that are visible drive photosythesis, and this is easily shown on the mcree curve, absorption and action spectrums. Yellow and green included. Green actually has been proven in other plant species to drive photosynthesis harder than other wavelengths at high PPFD and in white light. It penetrates deeper into the mesophyll and hits the lower thylocoid. Because it is slightly more reflected due to green reflecting leaf pigments it also penetrates deeper into the canopy and is the predominant spectrum intracanopy other than Far red.

The different of the photosynthetic efficiency of yellow vs 620nm orange/red is minimal and there may be a 20% difference roughly between efficiency, but both are above 70%. All the colors we as humans see drive photosynthesis. Look up RQE or relative quantum efficiency.

Green is used by plants...... again this myth has been recently flipped. Do you have proof that cannabis doesn't use green light? if so please share because in my years of plant lighting research this would be news to me.

I agree that full spectrum is more useful, but according to your statements of yellow and green being pretty much useless, this would conflict with your statement that full spectrum is best.. because if yellow and green were useless, then your perspective would also say that blue/red lights are the best... which we all know isn't the case.

I do agree with you that there is a ton more research into plant lighting that needs to be done. I mean just within the last 10 years they discovered a photo receptor for UV light (UVR8) and also that green light is actually more efficient at high ppfd than other wavelengths. With LED technology now there is much more that can be done than in previous years with gel filters so I'm sure the rate of emphasis on plant lighting will accelerate fast.

 

[Canresearcher]

Phototsystem 2 uses all light below 680, the electrons are raised to an excited state and slowly passed through the electron transport chain to the photosystem.

Photosystem 1 uses energy from photons above 700nm up to 750nm and some like the article above show up to 780.

The emerson effect is a general symbiosis between both photosystems which yields more efficiency when combined vs their own.


All colors from the sun that are visible drive photosythesis, and this is easily shown on the mcree curve, absorption and action spectrums. Yellow and green included. Green actually has been proven in other plant species to drive photosynthesis harder than other wavelengths at high PPFD and in white light. It penetrates deeper into the mesophyll and hits the lower thylocoid. Because it is slightly more reflected due to green reflecting leaf pigments it also penetrates deeper into the canopy and is the predominant spectrum intracanopy other than Far red.

The different of the photosynthetic efficiency of yellow vs 620nm orange/red is minimal and there may be a 20% difference roughly between efficiency, but both are above 70%. All the colors we as humans see drive photosynthesis. Look up RQE or relative quantum efficiency.

Green is used by plants...... again this myth has been recently flipped. Do you have proof that cannabis doesn't use green light? if so please share because in my years of plant lighting research this would be news to me.

I agree that full spectrum is more useful, but according to your statements of yellow and green being pretty much useless, this would conflict with your statement that full spectrum is best.. because if yellow and green were useless, then your perspective would also say that blue/red lights are the best... which we all know isn't the case.

I do agree with you that there is a ton more research into plant lighting that needs to be done. I mean just within the last 10 years they discovered a photo receptor for UV light (UVR8) and also that green light is actually more efficient at high ppfd than other wavelengths. With LED technology now there is much more that can be done than in previous years with gel filters so I'm sure the rate of emphasis on plant lighting will accelerate fast.

The lower graph clearly illustrates the effect I was getting at. If you look at the absorbed photons the absorption drops sharply after 700nm. While the absorption rate is not 0, it's not significant enough to warrant supplementing LEDs that use longer than ~700nm. That's my point. Yes, full spectrum is best as you get more frequencies to the plant in question, BUT... Green light won't be driving the photosynthesis process. Instead it will be absorbed by Anthocyanins to produce colour in the leaves and stems.


Chlorophyll a/b is sensitive to very specific frequency bands, none are really capable of using green. This is due to the the fact the the chloroplasts are actually green themselves, BUT as mentioned earlier Anthocyanins responsible for pigmentation are able to receive this light. These aren't responsible for photosynthesis.

Oregon state University
CORVALLIS - Some ornamental plants have leaves that aren't green. Rather, they have purple, red, yellow or variegated leaves. Ever wonder how these plants photosynthesize, since they don't have a green color?
"There is no secret here," said Sven Svenson, research horticulturist with Oregon State University. "The chlorophyll needed for photosynthesis is 'hiding' within the leaf color, whether it be purple, yellow or red. Our eyes lack the ability to see that chlorophyll is there."
Plant leaves have three primary classes of pigments: chlorophyll, carotinoids and anthocyanins, explained Svenson.
Chlorophyll absorbs the red and blue light from the sunlight that contacts the leaf. Therefore, the light reflected from or transmitted through the leaf is deficient in red and blue light, so it appears green to our eyes. "Green" is the type of light used the least by chlorophyll. When a leaf has a high concentration of chlorophyll relative to other pigments, the leaf appears green.
Carotinoids absorb the blue-green and blue light from the sunlight that contacts the leaf. Light reflected by carotinoid pigments appears yellow or yellow-orange to our eyes. Generally, carotinoids assist chlorophylls in the process of photosynthesis. Carotinoid pigments are involved in forming the color of carrots. When a leaf has a high concentration of carotinoids relative to other pigments, the leaf usually appears yellow.
A third class of pigments found in leaves is the anthocyanins. Anthocyanins absorb blue, blue-green and green light. When leaves contain high concentrations of anthocyanins relative to other pigments, the leaves appear red or purple to our eyes. Anthocyanin pigments are involved in the red skin of apples, and the purple color of grapes.
Purple leaves usually have high anthocyanin concentrations relative to chlorophyll. Since the anthocyanin absorbs green light (chlorophyll reflects green light), and reflects reds and purples (chlorophyll absorbs these light colors), the leaves "appear" purple to our eyes. The chlorophyll is still there, but it is masked by the higher concentration of anthocyanins.
"If you look at the leaves of a "purple" plant that is growing in the shade, you will see the leaves look muddy-purple or even green," said Svenson. "In the shade, the leaves produce more chlorophyll to assist in photosynthesis, so the purple color is not as strong by comparison. Similarly, many apples are reddish on the 'sun' side, and green on the 'shade side.
"So, plants with leaf color other than green perform photosynthesis just like green-leafed plants (if they did not, they would not live). The chlorophyll needed for photosynthesis is masked among the colorful pigmentation."

 

[Icemud]

The lower graph clearly illustrates the effect I was getting at. If you look at the absorbed photons the absorption drops sharply after 700nm. While the absorption rate is not 0, it's not significant enough to warrant supplementing LEDs that use longer than ~700nm. That's my point. Yes, full spectrum is best as you get more frequencies to the plant in question, BUT... Green light won't be driving the photosynthesis process. Instead it will be absorbed by Anthocyanins to produce colour in the leaves and stems.


Chlorophyll a/b is sensitive to very specific frequency bands, none are really capable of using green. This is due to the the fact the the chloroplasts are actually green themselves, BUT as mentioned earlier Anthocyanins responsible for pigmentation are able to receive this light. These aren't responsible for photosynthesis.

With all due respect.. I think you need to research plant lighting a bit more... you are confusing 2 separate things... there are 2 light type reactions with a plant... photosynthesis and photomorphogenesis...

anthocyanin is like sunblock to a plant, its a photomorphogenic reaction, a protective measure. It has very little to do with photosynthesis, and more to do with blocking the higher energy wavelengths.. This IS NOT a photosynthetic pigment. I know this.

Green light does drive photosynthesis, this is proven.

ALL wavelengths of light in the PAR region drive photosynthesis, this is why is called PAR by definition. (Photo synthetically Active Radiation)

The OP's question was referring to manipulating phytochrome by using Far red light, which speeds up a natural process that occurs over the dark period. This can speed up the flowering cycle...THIS is the original question... and what I was answering. This has NOTHING to do with photosynthesis. This is a photomorphogenic reaction. NOT PHOTOSYNTHESIS

You are confusing things my friend. Chlorophyll is not the only pigment that drives photosynthetic reactions.

I think the best way to explain this is that other pigments than chlorphyll absorb all wavelengths of light, the captured energy (electrons) are then transported to the chlorophyll and then onward... but the chlorophyll is not the only pigment that absorbs light used in photosynthesis. Its just the most abundant. At the point light energy is captured though, wavelength doesn't matter as the electron energy is what is used.

Green Light Drives Leaf Photosynthesis More Efficiently than Red Light in Strong White Light: Revisiting the Enigmatic Question of Why Leaves are Green
Ichiro Terashima
Takashi Fujita
Takeshi Inoue
Wah Soon Chow
Riichi Oguchi
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.


Absorbance spectra of chlorophylls or pigments extracted from green leaves show that green light is absorbed only weakly. Action spectra of photosynthesis for thin algal solutions, transparent thalli of ordinary green algae, and leaves of aquatic angiosperms also show that green light is less effective than red light. As has been pointed out by Nishio (2000), these facts are often confused, and it is frequently argued that green light is inefficient for photosynthesis in green leaves. However, many spectra of absorptance (the absolute value of light absorption) measured with integrating spheres have shown clearly that ordinary, green leaves of land plants absorb a substantial fraction of green light (McCree 1972, Inada 1976, Gates 1980). It is also known that green light, once absorbed by the leaves, drives photosynthesis with high efficiency (Björkmann 1968, Balegh and Biddulph 1970, McCree 1972, Inada 1976). On an absorbed quantum basis, the efficiency or photosynthetic quantum yield of green light is comparable with that of red light, and greater than that of blue light. The difference between the quantum yields of green and blue light is particularly large in woody plants grown outdoors in high light. The question of how much green light is absorbed and used in photosynthesis by the green leaves of land plants has therefore been solved. In this mini-review, however, we aim at further clarifying another important role of green light in photosynthesis, by considering the intra-leaf profiles of light absorption and photosynthetic capacity of chloroplasts. First, we briefly explain light absorption by the leaf. Secondly, we examine the light environment within the leaf. Thirdly, we compare the vertical, intra-leaf profile of photosynthetic capacity with that of light absorption. We also discuss some serious problems with the use of pulse amplitude modulated (PAM) fluorometry in assessing leaf electron transport rate and photoinhibition. Fourthly, we propose a new method to measure the quantum yield of any monochromatic light in white light, and demonstrate the effectiveness of green light in strong white light. Based on these arguments, we finally revisit the enigmatic question of why leaves are green

 

[Canresearcher]

With all due respect.. I think you need to research plant lighting a bit more... you are confusing 2 separate things... there are 2 light type reactions with a plant... photosynthesis and photomorphogenesis...

anthocyanin is like sunblock to a plant, its a photomorphogenic reaction, a protective measure. It has very little to do with photosynthesis, and more to do with blocking the higher energy wavelengths.. This IS NOT a photosynthetic pigment. I know this.

Green light does drive photosynthesis, this is proven.

ALL wavelengths of light in the PAR region drive photosynthesis, this is why is called PAR by definition. (Photo synthetically Active Radiation)

The OP's question was referring to manipulating phytochrome by using Far red light, which speeds up a natural process that occurs over the dark period. This can speed up the flowering cycle...THIS is the original question... and what I was answering. This has NOTHING to do with photosynthesis. This is a photomorphogenic reaction. NOT PHOTOSYNTHESIS

You are confusing things my friend. Chlorophyll is not the only pigment that drives photosynthetic reactions.

I think the best way to explain this is that other pigments than chlorophyll absorb all wavelengths of light, the captured energy (electrons) are then transported to the chlorophyll and then onward... but the chlorophyll is not the only pigment that absorbs light used in photosynthesis. It's just the most abundant. At the point light energy is captured though, wavelength doesn't matter as the electron energy is what is used.

I know my lighting quite well thanks. There are some in this industry who will market the crap out of far-red to drive up the price of their LED lights. We must be very careful to spot this.

This is getting a little confusing... I think we've got our trichomes tangled up.

***Ok, assuming I got the wrong impression about what is trying to be done here.

The Æ’Pa (735-740nm) this accelerates the night time effect if it is on when the rest of the lights are off ONLY, so it makes zero sense - in terms of phytochrome - to include 730+nm LEDs in a regular light.

You may be right about green light being able to drive photosynthesis ( I do see some literature on experimental lighting) , but it is still widely accepted that green light reflects off the chloroplasts.

 

[Icemud]

The ƒPa (735-740nm) this accelerates the night time effect if it is on when the rest of the lights are off ONLY, so it makes zero sense - in terms of phytochrome - to include 730+nm LEDs in a regular light.

I apologize for my condescending remark... you do have a good grasp of things.

I think that you and I were taking the OP's question differently..which is why I think we didn't make sense to each other.

I was thinking he was referring to using far red light for Night Interruption... (he asked the same question in my far red journal which is why I assumed he was talking about far red interruption). I posted here a 2nd time because I wasn't sure he saw it.

I believe you were thinking he was asking about using it during the day with his light... which is why you were talking about photosynthesis...

So I agree with what you say above, as most lights like HPS already have far red.

The one exception is for LED monochromatic grow lights using red and blue chips with minimal white chips or no white chips (old school). These should add far red to add to the emerson effect. Also by adding far red this decreases the ratio of red;far red which increases stretch slightly for better node distance and not too tight of plants.

Whats funny is after all this, we pretty much are back to our original statements, I still say not worth it for flower triggering and you say not worth it for photosynthesis, both which are true... but at least we now understand each other better...LOL

anyhow, both of us probably scared away the OP with all our lighting lingo and stuff... sorry op..but to answer your question OP.. both of us can agree the answer is no..LOL

Happy weekend and blaze one! again sorry for the frustration, it was mutual...LOL better now

 

[Canresearcher]

I apologize for my condescending remark... you do have a good grasp of things.

I think that you and I were taking the OP's question differently..which is why I think we didn't make sense to each other.

I was thinking he was referring to using far red light for Night Interruption... (he asked the same question in my far red journal which is why I assumed he was talking about far red interruption). I posted here a 2nd time because I wasn't sure he saw it.

I believe you were thinking he was asking about using it during the day with his light... which is why you were talking about photosynthesis...

So I agree with what you say above, as most lights like HPS already have far red.

The one exception is for LED monochromatic grow lights using red and blue chips with minimal white chips or no white chips (old school). These should add far red to add to the emerson effect. Also by adding far red this decreases the ratio of red;far red which increases stretch slightly for better node distance and not too tight of plants.

Whats funny is after all this, we pretty much are back to our original statements, I still say not worth it for flower triggering and you say not worth it for photosynthesis, both which are true... but at least we now understand each other better...LOL

anyhow, both of us probably scared away the OP with all our lighting lingo and stuff... sorry op..but to answer your question OP.. both of us can agree the answer is no..LOL

Happy weekend and blaze one! again sorry for the frustration, it was mutual...LOL better now

You too... Sorry for misunderstanding your point initially. I was unclear what the OP wanted to do. But I think we both came to the conclusion that trying to force flower using ƒPa while the plant is undergoing photosynthesis won't work and that this can only be done during its dark period.

 

[taijoo]

Can you elaborate on "add more light to the schedule". I don't quite understand what you mean.

Are you meaning instead of 12/12 with 15 mins of Far Red, you are doing something more like a 14/10?

Yah, that's what I meant. If you just add the far red but don't shift the schedule, you're just giving them more time in the dark to mature (and probably be healthier, etc), but you're ultimately taking away the extra light they would've gotten with a slower flowering process. But you can shift it so that the extra time becomes extra light, and find the balance that gives you the same yields as before, but quicker, or even more yields in the same amount of time.

Right now I'm just on 13/11 with the 15m far-red goodnight, but it's working well. I'm still playing around with it all, though, so who knows where it'll wind up...

 

[SuperFunker]

Phototsystem 2 uses all light below 680, the electrons are raised to an excited state and slowly passed through the electron transport chain to the photosystem.

Photosystem 1 uses energy from photons above 700nm up to 750nm and some like the article above show up to 780.

The emerson effect is a general symbiosis between both photosystems which yields more efficiency when combined vs their own.


All colors from the sun that are visible drive photosythesis, and this is easily shown on the mcree curve, absorption and action spectrums. Yellow and green included. Green actually has been proven in other plant species to drive photosynthesis harder than other wavelengths at high PPFD and in white light. It penetrates deeper into the mesophyll and hits the lower thylocoid. Because it is slightly more reflected due to green reflecting leaf pigments it also penetrates deeper into the canopy and is the predominant spectrum intracanopy other than Far red.

The different of the photosynthetic efficiency of yellow vs 620nm orange/red is minimal and there may be a 20% difference roughly between efficiency, but both are above 70%. All the colors we as humans see drive photosynthesis. Look up RQE or relative quantum efficiency.

Green is used by plants...... again this myth has been recently flipped. Do you have proof that cannabis doesn't use green light? if so please share because in my years of plant lighting research this would be news to me.

I agree that full spectrum is more useful, but according to your statements of yellow and green being pretty much useless, this would conflict with your statement that full spectrum is best.. because if yellow and green were useless, then your perspective would also say that blue/red lights are the best... which we all know isn't the case.

I do agree with you that there is a ton more research into plant lighting that needs to be done. I mean just within the last 10 years they discovered a photo receptor for UV light (UVR8) and also that green light is actually more efficient at high ppfd than other wavelengths. With LED technology now there is much more that can be done than in previous years with gel filters so I'm sure the rate of emphasis on plant lighting will accelerate fast.

Icemud...
A 60nm diff in the 2 photo sys is critical to induce the emerson effect... is this correct? If yes, can you cite the research?

 

[TheMadDabber]

Why? The cooling of the HPS is where the Emerson effect was more or less discovered... far reds are built into the cool down

 

[Icemud]

Icemud...
A 60nm diff in the 2 photo sys is critical to induce the emerson effect... is this correct? If yes, can you cite the research?

Google Robert Emerson and Emerson Effect.

 

[SuperFunker]

Found a summary of relevant research. I am looking for the original, still...
~ Supplemental far red on throughout daylight hours resulted in a 12% increase in photosynthesis.
~ Extending far red into lights out for 30 minutes... at 30 umol (16% of total) resulted in 7% increase in yield... at 55 umol (30% of total) resulted in 17% increase in yield.

Again, this is from a summary, so I suggest caution (could have omitted info, misstated info, etc). However, the results are promising and certainly warrant more studies.

 

[TheMadDabber]

Found a summary of relevant research. I am looking for the original, still...
~ Supplemental far red on throughout daylight hours resulted in a 12% increase in photosynthesis.
~ Extending far red into lights out for 30 minutes... at 30 umol (16% of total) resulted in 7% increase in yield... at 55 umol (30% of total) resulted in 17% increase in yield.

Again, this is from a summary, so I suggest caution (could have omitted info, misstated info, etc). However, the results are promising and certainly warrant more studies.

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?