OneHitDone
Well-Known Member
A lot of folks running 10/14 with HPS.
Have you stumbled on any literature with the science on why 730nm has bee chosen to represent the entire "far red" spectrum?
The far red thread
- Thread starter Rahz
- Start date
Have you stumbled on any literature with the science on why 730nm has bee chosen to represent the entire "far red" spectrum?
ChiefRunningPhist
Well-Known Member
Photoperiod plants are categorized as short day plants or long day plants.
Cannabis is a photoperiod sensative plant and categorized as a short day plant, with sativa liking shorter days & longer nights than indica. Ruderalis plant processes are not regulated by a sensitivity to the photoperiod, it will bloom regardless.
Plants use a few different photoreceptors to help them determine what to do and when (coupled with genetic instruction), and photoceptor groups are stimulated by specific WVs. Out of the photoreceptors present in plants (chyptochrome, phototropin, phytochrome, UVR8, neochrome, aureochrome, Zeitlupes, ect), phytochrome is the photoreceptor responsible for the assimilation of R/FR light for bloom signaling. Furthermore, there's actually 2 forms of phytochrome, the active form (Pfr) or the inactive form (Pr).
Photorecptors
1. phytochrome
i) Pr
ii) Pfr
The ratios of the 2 forms of phytochrome, Pr (inactive), and Pfr (active) are what signal bloom, and are a large part in what determines the classification of a plant being a short day plant or long day plant.
In nature, plants absorb certain colors of the sun during the day (some wavelengths are absorbed more than others as you can see when looking at photoreceptor absorption spectras), and practically no light during the night. During the day, the red light emitted by the sun is absorbed by the photoreceptor phytochrome (amoung other pigments, ie chlorophyll ect), which expresses itself as the active form, Pfr, while during the night the active phytochrome form Pfr, breaks down into the inacitve phytochrome form, Pr.
If the day is long, then more of the active form Pfr has time to build up in the plant. Conversely if the days are long, then the nights are short, so there's less time to naturally break down this accumulated Pfr into the inactive form, Pr. So it's a bit of a double whammy, a longer day makes more Pfr and a shorter night breaks less of it down into Pr, while a shorter day accumulates less Pfr and the longer night allows for greater breakdown of Pfr into Pr.
When days are long:
- more Pfr accumulated during the day
- less Pfr breaks down into Pr at night
When days are short:
- less Pfr accumulated during the day
- more Pfr breaks down into Pr at night
In nature, a short day plant needs a short day (low Pfr) and long nights (high Pr) to stimulate the plant to bloom. It's why we switch to 12/12 for bloom. In the lab they've found that emitting WVs targeting the peak absorption of Pfr (725nm) breaks down the active form of phytochrome Pfr to the inactive form Pr quicker than waiting for "father time" to do his bidding. This is the science behind EOD FR initiators (end-of-day, far-red).
Pfr builds up under R light, Pr builds up under FR light
The sun emits both R & FR, at a ratio close to 6:5. Looking at the absorption spectras compared to the solar spectrum, one can see why Pfr isn't simultaneously broken down into Pr at the same rate, and why it builds up.
I'm wondering if we can mimic long nights by emitting greater FR intensity (725nm), or greater total amounts of "nightly FR," than typically thought of when using an EOD FR initiator. I'm wondering if we can adjust the bloom signaling ratios of Pr: Pfr via lights, specifically 660nm & 725nm, and mitigate our typical need for long nights or days for certain stages of growth. We grow plants under different intensities currently, ie some people blast 1200PPFD for 12hrs a day, while others only use 700 PPFD to bloom. This points to the assumption that increased intensity over a shorter period with the intention of maintaining DLI (daily light integral) could be possible (the plant could handle it). If we can mimic a 12hr day into 8hrs, ie same amount of photons absorbed but in a smaller time frame, then I'm wondering if we could also mimic the necessary long nights of bloom by blasting FR at lights out, or emitting EOD lights for a longer time period. If the plant is signalling bloom instructions based on the ratio of Pr: Pfr, then do we need 12hrs of darkness or can we speed up the natural time quenching process the plant typically uses to break down Pfr into Pr? Can we add a catalyst in the form of 725nm to reduce night time needs to only 8hrs with no detrimental effects?
If you could condense the plant day cycle while maintaining DLI, I think you might be able to realize the same ~yield but shorter grow times?? Finishing a bloom in 6wks compared to 9wks?
In terms of photoperiodsm, 725nm seems to be the most significant WV. I think it's important, but not saying it's the only beneficial FR WV because I have no clue. Bloom signalling is only a portion of the processes a plant undergoes, so maybe other FR or NIR WVs are still beneficial despite photoperiodsm relying heavily upon 660nm & 725nm. I just came across a study showing that phytochrome is not only stimulated by light, but also by temperature too, (so maintaining temps at night rather than dropping might help Pfr breakdown into Pr, I think, but not sure).
Link on phytochrome & temperature:
Science | AAAS
science.sciencemag.org
Link on photoperiodsm:
Photoperiodism | BioNinja
The switch to flowering is a response to the length of light and dark periods in many plants AND Methods used to induce short-day plants to flower out of season
Last edited:
Airwalker16
Well-Known Member
Absolutely SCHOOLED.Photoperiod plants are categorized as short day plants or long day plants.
Cannabis is a photoperiod sensative plant and categorized as a short day plant, with sativa liking shorter days & longer nights than indica. Ruderalis plant processes are not regulated by a sensitivity to the photoperiod, it will bloom regardless.
Plants use a few different photoreceptors to help them determine what to do and when (coupled with genetic instruction), and photoceptor groups are stimulated by specific WVs. Out of the photoreceptors present in plants (chyptochrome, phototropin, phytochrome, UVR8, neochrome, aureochrome, Zeitlupes, ect), phytochrome is the photoreceptor responsible for the assimilation of R/FR light for bloom signaling. Furthermore, there's actually 2 forms of phytochrome, the active form (Pfr) or the inactive form (Pr).
Photorecptors
1. phytochrome
i) Pr
ii) Pfr
The ratios of the 2 forms of phytochrome, Pr (inactive), and Pfr (active) are what signal bloom, and are a large part in what determines the classification of a plant being a short day plant or long day plant.
In nature, plants absorb certain colors of the sun during the day (some wavelengths are absorbed more than others as you can see when looking at photoreceptor absorption spectras), and practically no light during the night. During the day, the red light emitted by the sun is absorbed by the photoreceptor phytochrome (amoung other pigments, ie chlorophyll ect), which expresses itself as the active form, Pfr, while during the night the active phytochrome form Pfr, breaks down into the inacitve phytochrome form, Pr.
If the day is long, then more of the active form Pfr has time to build up in the plant. Conversely if the days are long, then the nights are short, so there's less time to naturally break down this accumulated Pfr into the inactive form, Pr. So it's a bit of a double whammy, a longer day makes more Pfr and a shorter night breaks less of it down into Pr, while a shorter day accumulates less Pfr and the longer night allows for greater breakdown of Pfr into Pr.
When days are long:
- more Pfr accumulated during the day
- less Pfr breaks down into Pr at night
When days are short:
- less Pfr accumulated during the day
- more Pfr breaks down into Pr at night
In nature, a short day plant needs a short day (low Pfr) and long nights (high Pr) to stimulate the plant to bloom. It's why we switch to 12/12 for bloom. In the lab they've found that emitting WVs targeting the peak absorption of Pfr (725nm) breaks down the active form of phytochrome Pfr to the inactive form Pr quicker than waiting for "father time" to do his bidding. This is the science behind EOD FR initiators (end-of-day, far-red).
Pfr builds up under R light, Pr builds up under FR light
View attachment 4433317
The sun emits both R & FR, at a ratio close to 6:5. Looking at the absorption spectras compared to the solar spectrum, one can see why Pfr isn't simultaneously broken down into Pr at the same rate, and why it builds up.
View attachment 4433333
I'm wondering if we can mimic long nights by emitting greater FR intensity (725nm), or greater total amounts of "nightly FR," than typically thought of when using an EOD FR initiator. I'm wondering if we can adjust the bloom signaling ratios of Pr: Pfr via lights, specifically 660nm & 725nm, and mitigate our typical need for long nights or days for certain stages of growth. We grow plants under different intensities currently, ie some people blast 1200PPFD for 12hrs a day, while others only use 700 PPFD to bloom. This points to the assumption that increased intensity over a shorter period with the intention of maintaining DLI (daily light integral) could be possible (the plant could handle it). If we can mimic a 12hr day into 8hrs, ie same amount of photons absorbed but in a smaller time frame, then I'm wondering if we could also mimic the necessary long nights of bloom by blasting FR at lights out, or emitting EOD lights for a longer time period. If the plant is signalling bloom instructions based on the ratio of Pr: Pfr, then do we need 12hrs of darkness or can we speed up the natural time quenching process the plant typically uses to break down Pfr into Pr? Can we add a catalyst in the form of 725nm to reduce night time needs to only 8hrs with no detrimental effects?
If you could condense the plant day cycle while maintaining DLI, I think you might be able to realize the same ~yield but shorter grow times?? Finishing a bloom in 6wks compared to 9wks?
In terms of photoperiodsm, 725nm seems to be the most significant WV. I think it's important, but not saying it's the only beneficial FR WV because I have no clue. Bloom signalling is only a portion of the processes a plant undergoes, so maybe other FR or NIR WVs are still beneficial despite photoperiodsm relying heavily upon 660nm & 725nm. I just came across a study showing that phytochrome is not only stimulated by light, but also by temperature too, (so maintaining temps at night rather than dropping might help Pfr breakdown into Pr, I think, but not sure).
Link on phytochrome & temperature:
Science | AAAS
Link on photoperiodsm:
Photoperiodism | BioNinja
The switch to flowering is a response to the length of light and dark periods in many plants AND Methods used to induce short-day plants to flower out of seasonib.bioninja.com.au
Airwalker16
Well-Known Member
That fixture is a complete and utter rip off. $180 for a single Chinese cob that's probably closer to 680 than 730.
You can customize practically ANY FAR RED setup you want with less than $150.
Airwalker16
Well-Known Member
You mean 14 ON/10 OFF, Right?
OneHitDone
Well-Known Member
Other way around broski
Airwalker16
Well-Known Member
Far red allows the sleeping period of an hour or two to be done in a matter of minutes. Therefore you're days would. Be longer an extra hour.
SSGrower
Well-Known Member
Kinda curious why nobody is working with uv at bod and eod when atmospheric refraction dictates those wv are dominant before fr at bod and after fr at eod.Photoperiod plants are categorized as short day plants or long day plants.
Cannabis is a photoperiod sensative plant and categorized as a short day plant, with sativa liking shorter days & longer nights than indica. Ruderalis plant processes are not regulated by a sensitivity to the photoperiod, it will bloom regardless.
Plants use a few different photoreceptors to help them determine what to do and when (coupled with genetic instruction), and photoceptor groups are stimulated by specific WVs. Out of the photoreceptors present in plants (chyptochrome, phototropin, phytochrome, UVR8, neochrome, aureochrome, Zeitlupes, ect), phytochrome is the photoreceptor responsible for the assimilation of R/FR light for bloom signaling. Furthermore, there's actually 2 forms of phytochrome, the active form (Pfr) or the inactive form (Pr).
Photorecptors
1. phytochrome
i) Pr
ii) Pfr
The ratios of the 2 forms of phytochrome, Pr (inactive), and Pfr (active) are what signal bloom, and are a large part in what determines the classification of a plant being a short day plant or long day plant.
In nature, plants absorb certain colors of the sun during the day (some wavelengths are absorbed more than others as you can see when looking at photoreceptor absorption spectras), and practically no light during the night. During the day, the red light emitted by the sun is absorbed by the photoreceptor phytochrome (amoung other pigments, ie chlorophyll ect), which expresses itself as the active form, Pfr, while during the night the active phytochrome form Pfr, breaks down into the inacitve phytochrome form, Pr.
If the day is long, then more of the active form Pfr has time to build up in the plant. Conversely if the days are long, then the nights are short, so there's less time to naturally break down this accumulated Pfr into the inactive form, Pr. So it's a bit of a double whammy, a longer day makes more Pfr and a shorter night breaks less of it down into Pr, while a shorter day accumulates less Pfr and the longer night allows for greater breakdown of Pfr into Pr.
When days are long:
- more Pfr accumulated during the day
- less Pfr breaks down into Pr at night
When days are short:
- less Pfr accumulated during the day
- more Pfr breaks down into Pr at night
In nature, a short day plant needs a short day (low Pfr) and long nights (high Pr) to stimulate the plant to bloom. It's why we switch to 12/12 for bloom. In the lab they've found that emitting WVs targeting the peak absorption of Pfr (725nm) breaks down the active form of phytochrome Pfr to the inactive form Pr quicker than waiting for "father time" to do his bidding. This is the science behind EOD FR initiators (end-of-day, far-red).
Pfr builds up under R light, Pr builds up under FR light
View attachment 4433317
The sun emits both R & FR, at a ratio close to 6:5. Looking at the absorption spectras compared to the solar spectrum, one can see why Pfr isn't simultaneously broken down into Pr at the same rate, and why it builds up.
View attachment 4433333
I'm wondering if we can mimic long nights by emitting greater FR intensity (725nm), or greater total amounts of "nightly FR," than typically thought of when using an EOD FR initiator. I'm wondering if we can adjust the bloom signaling ratios of Pr: Pfr via lights, specifically 660nm & 725nm, and mitigate our typical need for long nights or days for certain stages of growth. We grow plants under different intensities currently, ie some people blast 1200PPFD for 12hrs a day, while others only use 700 PPFD to bloom. This points to the assumption that increased intensity over a shorter period with the intention of maintaining DLI (daily light integral) could be possible (the plant could handle it). If we can mimic a 12hr day into 8hrs, ie same amount of photons absorbed but in a smaller time frame, then I'm wondering if we could also mimic the necessary long nights of bloom by blasting FR at lights out, or emitting EOD lights for a longer time period. If the plant is signalling bloom instructions based on the ratio of Pr: Pfr, then do we need 12hrs of darkness or can we speed up the natural time quenching process the plant typically uses to break down Pfr into Pr? Can we add a catalyst in the form of 725nm to reduce night time needs to only 8hrs with no detrimental effects?
If you could condense the plant day cycle while maintaining DLI, I think you might be able to realize the same ~yield but shorter grow times?? Finishing a bloom in 6wks compared to 9wks?
In terms of photoperiodsm, 725nm seems to be the most significant WV. I think it's important, but not saying it's the only beneficial FR WV because I have no clue. Bloom signalling is only a portion of the processes a plant undergoes, so maybe other FR or NIR WVs are still beneficial despite photoperiodsm relying heavily upon 660nm & 725nm. I just came across a study showing that phytochrome is not only stimulated by light, but also by temperature too, (so maintaining temps at night rather than dropping might help Pfr breakdown into Pr, I think, but not sure).
Link on phytochrome & temperature:
Science | AAAS
Link on photoperiodsm:
Photoperiodism | BioNinja
The switch to flowering is a response to the length of light and dark periods in many plants AND Methods used to induce short-day plants to flower out of season
wietefras
Well-Known Member
It is not supposed to represent the entire "far red"spectrum at all. It's been specifically chosen for regulating photoperiodism because around 730nm is only absorbed by the active version of the Phytochrome (Pfr).
OneHitDone
Well-Known Member
Kinda like Red / Blue is all you need to grow plants?
Led is is clearly still about shorting the plant either certain wavelengths or entire parts of the spectrum in the name of chasing "efficiency"
Will be interesting when Bugbee actually starts releasing legit studies on these other portions of the spectrum and the true effect on plant growth.
ChiefRunningPhist
Well-Known Member
After looking into it a bit, it very well could be. Plants really don't absorb again till NIR of about 1.4μm.
If we think green reflects, most FR and NIR reeeeeeeally reflect lol..
I think Ive read that, but I'm curious how it works. Somehow FR is more prevalent in the BOD & EOD but I think the atmosphere absorbs FR better than R, so I'm not sure how having more of it to travel through creates for a lopsided ratio in favour of FR. I wonder if its the atmosphere absorbing it and then radiating it back down before sea level gets visible. Like how the tops of trees are the first to get light and then as the "sun rises" more of it gets soaked. The atmosphere directly overhead sees solar before sea level and because visible is transmitted, or more of its transmitted that it just flies right through, but the stuff that's absorbed gets re-emitted down to earth before the low elevation gets the visible?
wietefras
Well-Known Member
No, it's not like that like that at al. It's rather simple science at play.
It's about this chart:
If you want to induce flowering you want to excite Pfr and not Pr. So clearly 730nm it is.
Also, a 730nm led does not emit only 730Nm
Bonus info: Look at the 500nm wavelenght (green light). That does not get absorbed by the Pr variant either. Which is why you can have a green light in the flowering room during the dark period without disturbing flowering.
Chip Green
Well-Known Member
I just gotta say fellas..... Even though a vast majority of the time, I have nary a clue what these discussions pertain to on a practical scale for my purpose....but it is still fascinating to try to get my mind around WTF you guys are talking about.....
SSGrower
Well-Known Member
Its because shorter wv have a greater angle of refracrion. Atmospheric refraction is how we can see celestial bodies that are actually below the horizon. So as the earth rotates shorter wavelengths emitted from the sun hit the earths surface before and after longer wv.
ChiefRunningPhist
Well-Known Member
Well that could explain FR, as its twice as long as UV.
This is a graph showing atmospheric reflection, absorption and re-emmision..
This is a nice graphic showing what you were talking about...
Idk how much atmospheric re-emission effects the color shift phenomemon at dawn/dusk, but I bet what you outlined is a pretty significant factor.
EDIT:
Looks like they have their transmission axis labeled backwards, should be 0 at the top and 100% at the bottom.
Last edited:
JavaCo
Well-Known Member
10% far red was frying some leaf at least at the height I run my light it was. So I slapped a newer XLG-25-AB on the light replacing the non dimmable lpc series driver. For sure going to have to add a PWM module for dimming the far red channel after this run like the other two drivers add a switch to the pot for redundancy. Going to try 12/12 with the far red @ 5% and see what happens. 
Pseudobatrachotoxin
New Member
Just bought RapidLED’s far red initiator and started using it on my ~2ft x 4ft grow closet in my basement - started the run on New Years. New Chilled Logic V3 pucks in the same that I got for Christmas and relocated from Veg (where I was very impressed with their performance in just a couple days). I’ve run the cuts a couple of times and hope I see the yield and timing differences.
I just watch some of bugbee s Videos.
What do you Think about it?
When 730nm enhanche cell growth,could it be used in plant live Phase like end of stretch when flower Starts to grow ,
Would this enhanche total plant grow or
just the part that are the most aktiv at the time .
Would the flower grow bigger but the stems wouldnt grow with (that much)
If i hade a second tent i would love to test it.
Ifr at the end of the stretch for maybe 1 or2 or up to 5 weeks, with low intensety?
What would you say is low how much % of the light ?
What do you Think about it?
When 730nm enhanche cell growth,could it be used in plant live Phase like end of stretch when flower Starts to grow ,
Would this enhanche total plant grow or
just the part that are the most aktiv at the time .
Would the flower grow bigger but the stems wouldnt grow with (that much)
If i hade a second tent i would love to test it.
Ifr at the end of the stretch for maybe 1 or2 or up to 5 weeks, with low intensety?
What would you say is low how much % of the light ?
That sounds great!!!!! But what about the amount of light it takes to turn a strain.....talking short indicas and long sativas is kinda broad . I need some insight into indicas that flower with long days so my mate can get an early harvest or do I tell him to throw some red light in during the day for a while till the flowering kicks in ... and that is his only option it's kinda that way at all the shopping sites anyway....