Ibechillin
Masochist Educator
If the problem seems to be common sense, it may be your lack thereof according to Planck's Principle.
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Information About Grow Light Spectrum, PAR, Photosynthesis, Leaf Surface Temperature
- Thread starter Ibechillin
- Start date
If the problem seems to be common sense, it may be your lack thereof according to Planck's Principle.
If you think a led bud is better than outdoor then your lying. In fact I’ll take a plump HID bud before I take your data as bible
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You want a fact, here’s a fact. LEDS specrum is lacking in everything outside of the visible range of light.
I don’t even care if you want to have an efficient and easy grow with LED. But to talk down on everything else, while it’s visually destroying most LED grows, well...it just ain’t right Mr. Planck
And I guarantee you it’s not just visual. Mr. Planck
I don’t even care if you want to have an efficient and easy grow with LED. But to talk down on everything else, while it’s visually destroying most LED grows, well...it just ain’t right Mr. Planck
And I guarantee you it’s not just visual. Mr. Planck
Ibechillin
Masochist Educator
LED better than outdoor? Talk down on everything else? I think you need to relearn reading and comprehension friend.
In fact Mr. Chillin. One last thing. I want to help you before I move on for the night.
What I think the problem is off the top of my head is I think you need more sensors. You must not be picking up on every single aspect that makes a plant what it is.
You’ve chosen a few things and deemed them to be the almighty measuring stick of a plant. In reality I think you need to fix your sensor and meters. In fact I think you need to track many more compounds before you even get close to cracking nature’s code
Good night Mr. Planck
What I think the problem is off the top of my head is I think you need more sensors. You must not be picking up on every single aspect that makes a plant what it is.
You’ve chosen a few things and deemed them to be the almighty measuring stick of a plant. In reality I think you need to fix your sensor and meters. In fact I think you need to track many more compounds before you even get close to cracking nature’s code
Good night Mr. Planck
Then tell me what I missed
We are talking gases right. And what gets closer to a natural product.
Edit...I don’t want to multi post anymore so I’ll add. I hope you are enjoying the debate. All in fun right. We can all learn something. I don’t claim to know all by a long shot
Edit...I don’t want to multi post anymore so I’ll add. I hope you are enjoying the debate. All in fun right. We can all learn something. I don’t claim to know all by a long shot
Sunlight has great intensity but the spectrum has too much blue light; which results in leafy buds (compared to the ideal). HPS does not have enough blue light so stretch is exaggerated and foliage is reduced. The larger amount of stretch and lower leaf content results in better bud-to-leaf ratio and therefore good indoor yields, but the lack of blue spectrum results in a dulled terpene profile and can underperform on strains that are already stretchy.
I have found from my experience with many bulb types that the ideal spectral ratio in a flowering lamp is about 2:1 red:blue ratio. This contains enough blue light to keep internode distances short, but not so much that it causes the more leafy growth seen in sunlight or cool MH bulbs. 3000K COB LEDs typically satisfy this spectral balance quite well, and many contain even significant output in the 730nm FR spectrum, which seems to result in faster budset and a more vigorous flower development; though I need to test this in a more controlled setting.
In my experience over 15 years, the BEST inddor results I have seen (in terms of overall quality) are from 3000K COB LEDs with 90CRI spectrum. The second best from warm-white metal halide/CMH. Third best from the hybrid MH/HPS combo bulbs. Fourth best HPS (good yield but quality just OK). Blue MH has not been great for flowering since it grows more leaf than buds.
Anyway in this day and age, there is no reason not to go with LED. The costs have fallen to the point where the LEDs pay for themselves in just a couple runs, and bulbs do not need to be changed out. And if you get the right spectrum, the quality and yields are just simply better.
I have found from my experience with many bulb types that the ideal spectral ratio in a flowering lamp is about 2:1 red:blue ratio. This contains enough blue light to keep internode distances short, but not so much that it causes the more leafy growth seen in sunlight or cool MH bulbs. 3000K COB LEDs typically satisfy this spectral balance quite well, and many contain even significant output in the 730nm FR spectrum, which seems to result in faster budset and a more vigorous flower development; though I need to test this in a more controlled setting.
In my experience over 15 years, the BEST inddor results I have seen (in terms of overall quality) are from 3000K COB LEDs with 90CRI spectrum. The second best from warm-white metal halide/CMH. Third best from the hybrid MH/HPS combo bulbs. Fourth best HPS (good yield but quality just OK). Blue MH has not been great for flowering since it grows more leaf than buds.
Anyway in this day and age, there is no reason not to go with LED. The costs have fallen to the point where the LEDs pay for themselves in just a couple runs, and bulbs do not need to be changed out. And if you get the right spectrum, the quality and yields are just simply better.
funkyhorse
Well-known member
Hi there!
Could you please explain the difference between a 3000K COB LED with 90CRI spectrum and a 3000K COB LED with 80CRI?
Thank you very much for help
Could you please explain the difference between a 3000K COB LED with 90CRI spectrum and a 3000K COB LED with 80CRI?
Thank you very much for help
Ibechillin
Masochist Educator
CRI is a rating of how natural things look while illuminated by the lights spectrum, Higher cri is more natural looking. These pictures should help as they show 2 3000k led with different CRI ratings and spectrums.
CXA3590 spectrums:
CXB3590 spectrums:
CXA3590 spectrums:
CXB3590 spectrums:
Yep, and a similar 90CRI plot from bridgelux, which are the ones I like to use (the 30H line):
As you can see in both cree and bridgelux, the 90cri COBs have quite a bit more relative output at 650nm, and even has useful output in the 730nm FR spectrum. Chlorophyll A&B absorb at 650 and 670nm, so the 90CRI spectrum has substantially more activity than an 80cri bulb in the red spectrum. Of course, 90cri is less efficient, so the improvement is tempered a bit. But having used both 80cri and 90cri LEDs, the difference in morphology in flowering is quite significant. I will endeavor to do a side-by-side with 80cri and 90cri of equivalent wattage to prove this in a controlled way.
As you can see in both cree and bridgelux, the 90cri COBs have quite a bit more relative output at 650nm, and even has useful output in the 730nm FR spectrum. Chlorophyll A&B absorb at 650 and 670nm, so the 90CRI spectrum has substantially more activity than an 80cri bulb in the red spectrum. Of course, 90cri is less efficient, so the improvement is tempered a bit. But having used both 80cri and 90cri LEDs, the difference in morphology in flowering is quite significant. I will endeavor to do a side-by-side with 80cri and 90cri of equivalent wattage to prove this in a controlled way.
Ibechillin
Masochist Educator
Here is a link to the study referenced in post #1 about green lighting (PDF) download button on right in blue:
https://www.researchgate.net/profile/Riichi_Oguchi/publication/24043711_Green_Light_Drives_Leaf_Photosynthesis_More_Efficiently_than_Red_Light_in_Strong_White_Light_Revisiting_the_Enigmatic_Question_of_Why_Leaves_are_Green/links/0fcfd512c13512536a000000/Green-Light-Drives-Leaf-Photosynthesis-More-Efficiently-than-Red-Light-in-Strong-White-Light-Revisiting-the-Enigmatic-Question-of-Why-Leaves-are-Green.pdf
My takeaway from the paper reinforced the benefits of utilizing light movers, overlapping, side or vertical lighting and reflective material to stimulate and saturate chloroplasts in the top and bottom of the leaves simultaneously. When the adaxial (top) surface's chloroplasts become saturated (like from indoor horizontal overhead lighting) photoinhibition takes place on that surface, but not on the abaxial (bottom) surface chloroplasts.
Leaf pigment and thickness both have an effect on light transmission and how the adaxial (top) or abaxial (bottom) sides of a leaf reach photosynthetic saturation. Darker pigments absorb more light and allow less to pass through, Thicker leaves allow less light through as well. This also helps explain the relationship and benefit between the sun rising, dropping and traveling across the sky (as well as light movers and reflective material) providing different angles of illumination on the same leaf.
From the paper:
"The chloroplasts in the lowermost part of the leaf absorb <10% of those in the uppermost part, even at a wavelength of 550 nm at which the absorption gradient is most moderate. For spinach, various estimations have been published. Using the method of Takahashi et al. (1994) , Vogelmann and Evans (2002) and Evans and Vogelmann (2003) indicated that, on a unit chlorophyll basis, the chloroplasts in the lowermost part absorb about 10 and <20%, respectively, of the green light of those in the uppermost part. For wavelengths with strong absorption, such as red and blue, the fractions are much smaller. In C. japonica , the absorption of 680 nm (red) light by the lowermost chloroplasts is <2% of the absorption by the uppermost chloroplasts on a unit chlorophyll basis. For blue light in spinach, the estimated absorption by the lowermost chloroplasts was <5% of that of the uppermost (Vogelmann and Evans 2002 , Evans and Vogelmann 2003 ).
The profiles of photosynthetic capacity along the gradient of light absorption have been reported for Spinacia oleracea ( Terashima and Hikosaka 1995 , Nishio 2000 , Evans and Vogelmann 2003 ) and E. paucifl ora ( Evans and Vogelmann 2006 ). The differences in photosynthetic properties found between the chloroplasts in the upper and lower parts of the leaf are essentially identical to those found between sun and shade leaves, or between sun and shade plants ( Terashimaand Hikosaka, 1995 ). Based on observations of the differences in the shape of light response curves depending on the direction of irradiation, Oja and Laisk (1976) predicted the existence of an intra-leaf gradient in photosynthetic capacity. The most efficient situation is realized when the profile of light absorption and the profile of photosynthetic capacity are perfectly matched, and all the chloroplasts in the leaf behave synchronously with respect to photosynthetic light saturation ( Farquhar 1989 , Terashima and Hikosaka 1995 , Richter and Fukshansky 1998 ).
When leaves are irradiated from the upper side, therefore, there will be a situation in which the upper chloroplasts are light saturated while the chloroplasts in the lower parts still need additional light to reach saturation. In other words, the quantum yield of photosynthesis differs within the leaf.
https://www.researchgate.net/profile/Riichi_Oguchi/publication/24043711_Green_Light_Drives_Leaf_Photosynthesis_More_Efficiently_than_Red_Light_in_Strong_White_Light_Revisiting_the_Enigmatic_Question_of_Why_Leaves_are_Green/links/0fcfd512c13512536a000000/Green-Light-Drives-Leaf-Photosynthesis-More-Efficiently-than-Red-Light-in-Strong-White-Light-Revisiting-the-Enigmatic-Question-of-Why-Leaves-are-Green.pdf
My takeaway from the paper reinforced the benefits of utilizing light movers, overlapping, side or vertical lighting and reflective material to stimulate and saturate chloroplasts in the top and bottom of the leaves simultaneously. When the adaxial (top) surface's chloroplasts become saturated (like from indoor horizontal overhead lighting) photoinhibition takes place on that surface, but not on the abaxial (bottom) surface chloroplasts.
Leaf pigment and thickness both have an effect on light transmission and how the adaxial (top) or abaxial (bottom) sides of a leaf reach photosynthetic saturation. Darker pigments absorb more light and allow less to pass through, Thicker leaves allow less light through as well. This also helps explain the relationship and benefit between the sun rising, dropping and traveling across the sky (as well as light movers and reflective material) providing different angles of illumination on the same leaf.
From the paper:
"The chloroplasts in the lowermost part of the leaf absorb <10% of those in the uppermost part, even at a wavelength of 550 nm at which the absorption gradient is most moderate. For spinach, various estimations have been published. Using the method of Takahashi et al. (1994) , Vogelmann and Evans (2002) and Evans and Vogelmann (2003) indicated that, on a unit chlorophyll basis, the chloroplasts in the lowermost part absorb about 10 and <20%, respectively, of the green light of those in the uppermost part. For wavelengths with strong absorption, such as red and blue, the fractions are much smaller. In C. japonica , the absorption of 680 nm (red) light by the lowermost chloroplasts is <2% of the absorption by the uppermost chloroplasts on a unit chlorophyll basis. For blue light in spinach, the estimated absorption by the lowermost chloroplasts was <5% of that of the uppermost (Vogelmann and Evans 2002 , Evans and Vogelmann 2003 ).
The profiles of photosynthetic capacity along the gradient of light absorption have been reported for Spinacia oleracea ( Terashima and Hikosaka 1995 , Nishio 2000 , Evans and Vogelmann 2003 ) and E. paucifl ora ( Evans and Vogelmann 2006 ). The differences in photosynthetic properties found between the chloroplasts in the upper and lower parts of the leaf are essentially identical to those found between sun and shade leaves, or between sun and shade plants ( Terashimaand Hikosaka, 1995 ). Based on observations of the differences in the shape of light response curves depending on the direction of irradiation, Oja and Laisk (1976) predicted the existence of an intra-leaf gradient in photosynthetic capacity. The most efficient situation is realized when the profile of light absorption and the profile of photosynthetic capacity are perfectly matched, and all the chloroplasts in the leaf behave synchronously with respect to photosynthetic light saturation ( Farquhar 1989 , Terashima and Hikosaka 1995 , Richter and Fukshansky 1998 ).
When leaves are irradiated from the upper side, therefore, there will be a situation in which the upper chloroplasts are light saturated while the chloroplasts in the lower parts still need additional light to reach saturation. In other words, the quantum yield of photosynthesis differs within the leaf.
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CRI is a very poor measure of grow light efficiency. I look at several other output characteristics. Red rendering, output levels across the full spectrum and at specific nm, and so on. Actually, I just realized that you all are discussing LEDs! bahahahahaha sorry. I would never short my plants on the spectral output and spectral coverage when I can run a variety of CMH bulbs and really hit their sweet spots.
Exactly! I am the last person to throw negativity around but........
Damn! This thread is mostly complete bullshit! The OP that started it doesn't know shit about lighting. Citing very old and outdated info. Pushing LEDs
What a waste of time and server space.
Too much blue light creates leafy buds? You are so wrong! Complete ignorance. The old blue makes leaves and red makes buds....... That is OLD and a total FARCE!
You probably believe that plants don't use green or yellow light!
I need to close my browser and walk away from this junk thread.
Sunlight isn't the right spectrum?
Wow...put the pipe down.
I'd expand but this is kinda funny
Wow...put the pipe down.
I'd expand but this is kinda funny
Douglas.Curtis
Autistic Diplomat in Training
Thank you Ibchillin, the more information I absorb on this subject the happier I get. After a seed run with a few SILs, I'm already convinced LEDs are capable of producing great quality cannabis. I'm looking forward to building a few specialized systems with real LEDs now.
Keep dropping the awesome information, it's greatly appreciated around here.
Keep dropping the awesome information, it's greatly appreciated around here.
Ibechillin
Masochist Educator
Red to Blue spectrum ratio affect on growth example:
As someone with a biological science background and 35+ years growing experience I think I can add further to the discussion.
The lower the colour of your light the better the calyx to leaf ratio. Temperature is also a factor, with colder temperatures typically resulting in leafier buds, especially in sativa's and hybrids.
Jack Herer clone from the early 2000's, here is the same Jack Herer clone grown under CMH and HPS. Under HPS, the branches stretched considerably more and filled in with solid, almost leafless buds. The 3000K CMH (plus cooler temps) shortened the internodes dramatically and result in much leafier buds.
The same clone, same grow box, same watts (600hps v 2 x 315w cmh), same nutrient, same media, same grower lol
I prefer HPS because of this one significant difference. Abundant red light gives good stretch and stacks flowers.
Both Jack clones were the same as always - advanced clones about 8-10 inches in height raised under florescent light. Veg was done under the flowering light in both cases.
2100K 600w Sunmaster single-ended hps bulb: Veg takes about 2 - 2.5 weeks, Stretch during the first 4 weeks of flowering is around 150 - 200%. At maturity (around 7 weeks) the top 18 inches of all branches are laden with solid, leafless buds as shown in the photo at around 6.5 weeks.
3100K CMH: Veg takes about 2.5 - 3.5 weeks as they take longer to get to sufficient size. Stretch during the first 4 weeks of flowering is about 100%. The photo was taken at 4.5 weeks after the stretch was done. At maturity the only the top 6 to 10 inches have solid buds and those below the first 4-5 inches are more leafy and not as dense.
Ibechillin
Masochist Educator
How flowering Is Initiated In Cannabis (and other short day plants):
The phytochromes are a family of chromoproteins with a linear tetrapyrrole chromophore, similar to the ringed tetrapyrrole light-absorbing head group of chlorophyll. Phytochromes have two photo-interconvertible forms: Pr and Pfr.
Pr absorbs red light (~660nm - ~729nm) and is immediately converted to Pfr.
Pfr absorbs far-red light (~730nm - ~800nm) and is quickly converted back to Pr.
Pfr naturally converts to Pr in darkness over time (after about 2 - 2.5 hours)
Absorption of red or far-red light causes a massive change to the shape of the chromophore, altering the conformation and activity of the phytochrome protein to which it is bound. Pfr is the physiologically active form of the protein; therefore, exposure to red light yields physiological activity. Exposure to far-red light inhibits phytochrome activity. Together, the two forms represent the phytochrome system.
Unfiltered sunlight is rich in red light but deficient in far-red light. Therefore, at sunrise, all the phytochrome molecules in a leaf quickly convert to the active Pfr form, and remain in that form until sunset. In the dark, the Pfr form takes hours to slowly revert back to the Pr form. By sensing the Pr/Pfr ratio at sunrise, a plant can determine the length of the day/night cycle. In addition, leaves retain that information for several days, allowing a comparison between the length of the previous night and the preceding several nights. If the night is long (as in winter), all of the Pfr form reverts. If the night is short (as in summer), a considerable amount of Pfr may remain at sunrise.
Link to source:
https://courses.lumenlearning.com/ivytech-bio1-1/chapter/plant-responses-to-light/
So to clear up any confusion:
Its the ratio of how much time either Pr or Pfr is the active phytochrome that dictates the flowering response in short day plants like cannabis.
Red light between 660nm - 729nm converts Pr in the plant to Pfr which helps the plant remain in veg.
Infra red light between 730nm - 800nm converts Pfr in the plant to Pr which helps the plant begin flowering.
Naturally at sundown/lights out it takes around 2 - 2.5 hours of uninterrupted darkness before PFR begins converting to PR. Then the plant needs 10 more hours uninterrupted darkness to shift towards flowering expression totaling 12 hours dark. My research suggests blasting plants with 730nm far red for ~30 minutes after sundown/lights off will force plants to flower with only 10 hours darkness since your not having to wait the extra 2 hours for PFR to convert to PR naturally. This could be used to make outdoor and greenhouse plants begin and finish flowering earlier in the season as well.
The phytochromes are a family of chromoproteins with a linear tetrapyrrole chromophore, similar to the ringed tetrapyrrole light-absorbing head group of chlorophyll. Phytochromes have two photo-interconvertible forms: Pr and Pfr.
Pr absorbs red light (~660nm - ~729nm) and is immediately converted to Pfr.
Pfr absorbs far-red light (~730nm - ~800nm) and is quickly converted back to Pr.
Pfr naturally converts to Pr in darkness over time (after about 2 - 2.5 hours)
Absorption of red or far-red light causes a massive change to the shape of the chromophore, altering the conformation and activity of the phytochrome protein to which it is bound. Pfr is the physiologically active form of the protein; therefore, exposure to red light yields physiological activity. Exposure to far-red light inhibits phytochrome activity. Together, the two forms represent the phytochrome system.
Unfiltered sunlight is rich in red light but deficient in far-red light. Therefore, at sunrise, all the phytochrome molecules in a leaf quickly convert to the active Pfr form, and remain in that form until sunset. In the dark, the Pfr form takes hours to slowly revert back to the Pr form. By sensing the Pr/Pfr ratio at sunrise, a plant can determine the length of the day/night cycle. In addition, leaves retain that information for several days, allowing a comparison between the length of the previous night and the preceding several nights. If the night is long (as in winter), all of the Pfr form reverts. If the night is short (as in summer), a considerable amount of Pfr may remain at sunrise.
Link to source:
https://courses.lumenlearning.com/ivytech-bio1-1/chapter/plant-responses-to-light/
So to clear up any confusion:
Its the ratio of how much time either Pr or Pfr is the active phytochrome that dictates the flowering response in short day plants like cannabis.
Red light between 660nm - 729nm converts Pr in the plant to Pfr which helps the plant remain in veg.
Infra red light between 730nm - 800nm converts Pfr in the plant to Pr which helps the plant begin flowering.
Naturally at sundown/lights out it takes around 2 - 2.5 hours of uninterrupted darkness before PFR begins converting to PR. Then the plant needs 10 more hours uninterrupted darkness to shift towards flowering expression totaling 12 hours dark. My research suggests blasting plants with 730nm far red for ~30 minutes after sundown/lights off will force plants to flower with only 10 hours darkness since your not having to wait the extra 2 hours for PFR to convert to PR naturally. This could be used to make outdoor and greenhouse plants begin and finish flowering earlier in the season as well.
