Stunned
Well-Known Member
also running QB's
last harvest, 4 plants, 751 grams
last harvest, 4 plants, 751 grams
Looking for the best LED for a grow tent 4x4
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atthehelm
Active Member
actually green light is absorbed by the plant and several newer LED companies like Fluence Bioengineering are making lights that are full spectrum, more closely resembling the sun- which is not purple.
Green Light Drives Leaf Photosynthesis More Efficiently than Red Light in Strong White Light: Revisiting the Enigmatic Question of Why Leaves are Green
The below is an abstract on a study done-
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
The below is an abstract on a study done-
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.
Emilya Green
Well-Known Member
I call BS on this one... sorry.
Let's talk physics, without all the extra mumbo jumbo and sales pitch to sell full spectrum lights. Light has 3 primary colors, red, blue and green. Mixing these colors in equal amounts results in white, therefore we know that in a full spectrum [white] there are equal amounts of these 3 primary colors.
Many studies have been done on plants and the opposite of what you claim has been found to be true. In veg, there is much more photosynthesis in blue light, and in flower, red light becomes the most powerful.
Lastly, why do we see green leaves? We experience the leaves as green because all the other colors are being absorbed by the leaf or pass through it. We know that red passes through the leaves much more easily than any other color, and is the primary reason that red light in flower gives us so much better penetration power. The leaves look green to us because the green spectrum is what is reflected back to our eyes off of the leaves. Red and Blue are not reflected... only green. If the light is being reflected, it is not being absorbed. If it not being absorbed, it is not being used.
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Bigtone13
Well-Known Member
Good information, thanks!
OldSchoolToker
Well-Known Member
Thank you atthehelm very informative and much appreciated, we are always learning her at 429 that is why I enjoy reading the posts, so much wisdom is available here.
atthehelm
Active Member
Plants grown with 50 percent green and 50 percent red light were approximately 25 percent shorter than those grown under only red light, but approximately 50 percent taller than all plants grown under more than 25 percent blue light (Photo 2). Therefore, blue light suppressed extension growth more than green light in an enclosed environment. Twenty-five percent green light could substitute for the same percentage of blue light without affecting fresh weight. However, the electrical efficiency of the green LEDs was much lower than that of blue LEDs. To read more about this experiment, please read “Growing Plants under LEDs: Part Two” in Greenhouse Grower.
source below-
Green light: Is it important for plant growth?
source below-
Green light: Is it important for plant growth?
atthehelm
Active Member
I see you can't see the URL- it is Michigan State University - findings from a study their ag dept did.-
Emilya Green
Well-Known Member
apples and oranges my friend... that whole study talks about internodal length, not the efficiency of the photosynthesis at different colors. You can't win the discussion by arguing something completely new.
Gadfly
Well-Known Member
We ran the lights at night so the plants were in the dark during the hot CA days. Cost saving shit, you know. So when working in the bloom room during the day, it was pitch dark, minus the green light we used to see. If the plants were using green light, I assume it would’ve disrupted our 12/12 cycle at least for the plants closest to the bulb. It didn’t.
Why would green light from an Led be different? Or am I missing something? Regardless, I’m always cautious around studies coming from these led companies. They all seem to have fancy math formulas and studies that say their set up is best. Black dog say white light is bs, newer white lights coming out say blurple is old and busted. It’s almost as if they all want to convince me to buy something.
Why would green light from an Led be different? Or am I missing something? Regardless, I’m always cautious around studies coming from these led companies. They all seem to have fancy math formulas and studies that say their set up is best. Black dog say white light is bs, newer white lights coming out say blurple is old and busted. It’s almost as if they all want to convince me to buy something.
No Pain
Well-Known Member
I’m relatively new at this but what I learned about lighting was to pay attention to the “core coverage “ of the spectrum. In my flowering tent which is 4x4, I went from 600 LED to a Bestva 2000 LED that gives a larger coverage. There is equal abundance of light in every inch. I also grow sativas which love intense light. I keep four flowering plants at a time which completely fills the tent but they all get equal light as measured by a meter. I do keep a fan blowing over plants for heat and keep light 24-30 inches. My plants love it and flourish.
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Bigtone13
Well-Known Member
I agree. I actually bought a new 1500 w LED. And it’s a HUGE difference already. This wild Thailand I’m growing is 100% sativa. So from what I’m reading they do grow different. Smaller leaves, more stretched out buds then indicas.
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Bigtone13
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Bigtone13
Well-Known Member
Much different haha
No Pain
Well-Known Member
I'm glad you have found your new light and that you are happy with it .Now I know they seem to be pricey but I still highly recommend to you and anyone else to move to Full Spectrum led . If I where to explain the differences as to why and why I recommend spectrum king in the full spectrum led market , it would be about three pages long. Here is a picture of one of the tents (before I converted the room) with the last grow I ever did with those lights in my custom high pressure areo system. If you think what you see is good , all I can tell you it can be way better with full spectrum.
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Bigtone13
Well-Known Member
Awesome. Something I’ll have to work up to. But def interesting. And great to know.
atthehelm
Active Member
no Emilya- my original argument was that GREEN light is used by the plant- go back and refer to the thread I said Green light IS used by the plant cuz you said it was a wasted spectrum my dude.
As for the validity of my Scholarly article and proof of the fact that GREEN LIGHT IS USED BY PLANTS-
IDC if its used to make nipples for baby butterflys to milk at night and sell to elves during the day- point is ALL light is used- Real Deal though- riddle me this batman- does it make sense that plants would evolve under a FULL spectrum sun and not utilize all wavelengths? Wouldn't it make better sense that somehow unknown to us dumb monkeys that a plant has a plan for ALL the available FREE energy? It costs more in the kingdom of plants and animals to not only not use a readily abundant energy source but to altogether block it-
Maybe I'm wrong- but I'd bet the sun is the best grow light- and it ain't purple.
As for the validity of my Scholarly article and proof of the fact that GREEN LIGHT IS USED BY PLANTS-
IDC if its used to make nipples for baby butterflys to milk at night and sell to elves during the day- point is ALL light is used- Real Deal though- riddle me this batman- does it make sense that plants would evolve under a FULL spectrum sun and not utilize all wavelengths? Wouldn't it make better sense that somehow unknown to us dumb monkeys that a plant has a plan for ALL the available FREE energy? It costs more in the kingdom of plants and animals to not only not use a readily abundant energy source but to altogether block it-
Maybe I'm wrong- but I'd bet the sun is the best grow light- and it ain't purple.
Emilya Green
Well-Known Member
First, let me make it clear that I am a dudette.
Second, you are just flat out wrong. It is well known in the cannabis world that our plants ignore green light. We can turn on green lights and spend as much time as we want in the grow room at night, and the plants do not stop blooming. It is as if the green lights were never on. Scholarly or not, your article that no one besides you has been able to read yet, is wrong. Your argument about the sun being full spectrum is not actually correct either, but I will let that slide because it is already clear that you don't know what you are talking about and seemingly are trying to promote full spectrum lights using that flimsy argument. Sometimes nature does not work in ways that we might think are common sense but to me common sense and physics fairly closely align, and when a leaf is reflecting all of the green light that hits it back to me, I know good and well that light was not used, absorbed or passed through, it was reflected. Nothing you can say will convince me or anyone else who has passed a high school physics class, or studied horticulture 101, that the plants in any way use the green light. I can see better arguments for the use of UV and IR than the green.
Actually, some years ago your sun argument was used to sell HPS lights saying that their yellow spectrum was much closer to that of the sun, and many people swore by them being superior over any other light, in both veg and flower, because of it. This was before we were introduced to LED, where it was so easy to create a pure blue or pure red light. Once we could experiment, tests were done on growth rates during various stages at all spectrums of light to see where we should design our new fancy LED lights, since we could have chosen any color in the spectrum, and the clear scientific evidence came back that certain parts of the blue spectrum were superior in veg and the reds were superior in flower, and the deep reds had a special function to allow the plants to adjust internodal spacing. This is the science, documented and well tested.
And then comes you... touting the advantages of white light, which we know is equal parts of red, blue and green. Since we know that the plants ignore green... you do the math and tell me how much energy is wasted in that white light when trying to grow a plant. If this is difficult for you, let me help. It is 60% inefficient when compared to tuned light.
Gadfly
Well-Known Member
Did you read all of it? It concludes that the green light "potentially" reduces eye strain for employees working under them, "may" assist with deeper canopy penetration, and that using various combinations of lighting can alter growth rates.
That study counters the argument that "plants don't use green light for photosynthesis" by stating that that is only "partly true" and that "the majority of green light is useful in photosynthesis."
Why didn't they do a run using 100% green light then?
Why can I walk around in my bloomroom during the dark period with my green light and not screw everything up?
As a scholar, I can tell you not all scholarly work is worth a shit and money is one hellava motivator. BTW the study was funded largely by Osram Opto Semiconductors and they just happen to be in the business of quantum lighting for tvs, shit like that, and led lighting. Their focus seems to be is on viewable spectrum, not horticulture.
I have no beef with Quantum lighting, in fact I bought one just to see for myself what all the fuss is. Is the green light really useful or does it need to be combined with other spectrums to get anything out of it? These are things that I want to know and the study you provided barely scratches the surface in this regard.
