BuddyColas
Well-Known Member
Sounds kinda kinky. But what goes on between a guy and his ladies in the privacy of their own grow tent…hey that’s their business!
Old news for potheads ...
- Thread starter stardustsailor
- Start date
frica
Well-Known Member
http://www.ledsmagazine.com/articles/2016/01/transcend-launches-broad-spectrum-led-based-t5-tube-for-horticulture-applications.html
Transcend takes the input of academia and its customers in crafting products with SPDs for specific applications. “Many companies build horticultural lights with just the blue/far red spectrum because of the hypothesis that these are the only wavelengths used for photosynthesis,” said DeMilo. “Although this hypothesis had some great logic, that chlorophyll A and B absorb these wavelengths more strongly, it turns out that plant growth is far more complicated than this. Some of our customers have grown fantastic plants using 100% green light during testing. This makes sense as plants evolved for billions of years under sunlight. Many recent studies have shown that full-spectrum lighting with properly balanced ratios of wavelengths, say red to far red or red to blue, supports the most efficient plant growth.”
You might not think that white light is important in the application. But as our horticulture feature discussed, growers still need white lighting to work with the plants. Ironically, one of the 30W T5 LED tubes that Transcend offers as a replacement for 64W fluorescent lamps happens to have a CRI of 94 due to the broad SPD and significant energy in the red region.
Today, Transcend is offering the LED tubes in two SPDs. One is a broad-SPD called Seed-to-Harvest Photosynthetic White, and the other is a red-centric Fruit-and-Flower Wide-Band Deep Red. The tubes sell for $70. But Transcend plans other formulations. For example, the company has even developed an SPD for salt- and fresh-water coral growth working with a European partner.
Transcend takes the input of academia and its customers in crafting products with SPDs for specific applications. “Many companies build horticultural lights with just the blue/far red spectrum because of the hypothesis that these are the only wavelengths used for photosynthesis,” said DeMilo. “Although this hypothesis had some great logic, that chlorophyll A and B absorb these wavelengths more strongly, it turns out that plant growth is far more complicated than this. Some of our customers have grown fantastic plants using 100% green light during testing. This makes sense as plants evolved for billions of years under sunlight. Many recent studies have shown that full-spectrum lighting with properly balanced ratios of wavelengths, say red to far red or red to blue, supports the most efficient plant growth.”
You might not think that white light is important in the application. But as our horticulture feature discussed, growers still need white lighting to work with the plants. Ironically, one of the 30W T5 LED tubes that Transcend offers as a replacement for 64W fluorescent lamps happens to have a CRI of 94 due to the broad SPD and significant energy in the red region.
Today, Transcend is offering the LED tubes in two SPDs. One is a broad-SPD called Seed-to-Harvest Photosynthetic White, and the other is a red-centric Fruit-and-Flower Wide-Band Deep Red. The tubes sell for $70. But Transcend plans other formulations. For example, the company has even developed an SPD for salt- and fresh-water coral growth working with a European partner.
stardustsailor
Well-Known Member
Old news -( at least for me ..)
I knew all about it since 2010 ....
Yeap ,I've to brag about it ...
I've received really hard critisism in the past ,inside this forum ,for my choice of white broadband spectrum ,
instead of the "blurple" that was " mainstream" / "trend" ,back then ....
Cheers and thanx for da link ...
flaxseedoil1000
Well-Known Member
These are CXB3590
Got the numbers from http://www.cutter.com.au/proddetail.php?prod=cut2809 and threw them into a spreadsheet for a visual comparison
Unfortunately all they had numbers for were 3000, 3500 and 4000k
A simple comparison of wavelength groups by percentage. I did not bother with sub 400 because they were puny.
A simple comparison of each cob's total output. Keep in mind they measured from less than 8 inches.
Got the numbers from http://www.cutter.com.au/proddetail.php?prod=cut2809 and threw them into a spreadsheet for a visual comparison
Unfortunately all they had numbers for were 3000, 3500 and 4000k
A simple comparison of wavelength groups by percentage. I did not bother with sub 400 because they were puny.
A simple comparison of each cob's total output. Keep in mind they measured from less than 8 inches.
jewbag
Well-Known Member
is NASA testing spectrum-tuned cob's? kinda looks like it: https://www.nasa.gov/image-feature/flowers-harvested-on-the-ground-and-in-space-for-deep-space-food-crop-research
kmog33
Well-Known Member
flaxseedoil1000
Well-Known Member
UPDATE
These are CXB3590
Got the numbers from http://www.cutter.com.au/proddetail.php?prod=cut2809 and threw them into a spreadsheet for a visual comparison
Unfortunately all they had numbers for were 3000, 3500, 4000 and 5700k
I dropped 700+ IR because it's more of a trigger than growth contributor
Added 5700k
Keep in mind they measured from less than 8 inches
These are CXB3590
Got the numbers from http://www.cutter.com.au/proddetail.php?prod=cut2809 and threw them into a spreadsheet for a visual comparison
Unfortunately all they had numbers for were 3000, 3500, 4000 and 5700k
I dropped 700+ IR because it's more of a trigger than growth contributor
Added 5700k
Keep in mind they measured from less than 8 inches
frica
Well-Known Member
Credit to:
https://www.reddit.com/r/HandsOnComplexity/comments/17nxhd/sags_plant_lighting_guide_linked_together/
May be a little old, may be a little double, may be posted before
Here is a spectral reflectivity profile of a high nitrogen marijuana leaf (Jack Herer). About 90% of the green light is being absorbed (it's on an 18% reflective gray card used in photography)
https://pcp.oxfordjournals.org/content/50/4/684.full.pdf+html
Green Light Drives Leaf Photosynthesis More Efficiently than
Red Light in Strong White Light: Revisiting the Enigmatic
Question of Why Leaves are Green
why plants are green can be found here
http://onlinelibrary.wiley.com/doi/10.1046/j.1365-3040.2000.00563.x/pdf
Ours eyes have a combined sensitivity curve where the peak of our sensitivity is also were the peak reflectivity is going to be for a green plant. (The individual sensitivity of our 3 color sensitive cone cells in our eyes is this). So it's true plants do reflect more green light, but the way we perceive light is naturally much higher biased for green light (555nm sensitivity peak which is the same as a green plant's reflectivity peak). This fact means that less electrically efficient green LEDs can still be used in red/green/blue LEDs and we wouldn't perceive the difference. Most green LEDs are about 525nm or so which is outside the peak reflectivity of a green plant but because of the electrical inefficiency of green LEDs relative to red and blue LEDs, white LEDs that have a large green component would be typically used instead (the vast majority of white LEDs are actually a blue LEDs with a phosphor. One problem with red/green/blue LEDs for general illumination is color shadowing which is white LEDs are used instead.
https://www.reddit.com/r/HandsOnComplexity/comments/17nxhd/sags_plant_lighting_guide_linked_together/
May be a little old, may be a little double, may be posted before
Here is a spectral reflectivity profile of a high nitrogen marijuana leaf (Jack Herer). About 90% of the green light is being absorbed (it's on an 18% reflective gray card used in photography)
https://pcp.oxfordjournals.org/content/50/4/684.full.pdf+html
Green Light Drives Leaf Photosynthesis More Efficiently than
Red Light in Strong White Light: Revisiting the Enigmatic
Question of Why Leaves are Green
why plants are green can be found here
http://onlinelibrary.wiley.com/doi/10.1046/j.1365-3040.2000.00563.x/pdf
Ours eyes have a combined sensitivity curve where the peak of our sensitivity is also were the peak reflectivity is going to be for a green plant. (The individual sensitivity of our 3 color sensitive cone cells in our eyes is this). So it's true plants do reflect more green light, but the way we perceive light is naturally much higher biased for green light (555nm sensitivity peak which is the same as a green plant's reflectivity peak). This fact means that less electrically efficient green LEDs can still be used in red/green/blue LEDs and we wouldn't perceive the difference. Most green LEDs are about 525nm or so which is outside the peak reflectivity of a green plant but because of the electrical inefficiency of green LEDs relative to red and blue LEDs, white LEDs that have a large green component would be typically used instead (the vast majority of white LEDs are actually a blue LEDs with a phosphor. One problem with red/green/blue LEDs for general illumination is color shadowing which is white LEDs are used instead.
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BobCajun
Well-Known Member
Interesting how much far red there is, especially in the 3000k. This must be why plants do tend to stretch a lot when flowered under COBs. A possible solution, for people who don't use end of day far red, is to use end of day red. It supposedly neutralizes the far red induced stretching. It wouldn't slow flowering, which would stay the same except the night would be 15 minutes shorter, or however long you run them. As with far red, only low intensity is required. I don't know if yield would be lower or not.
Also, here's a good article about RGB producing more weight that RB or cool white fluorescents, at least with lettuce. Why did RGB not become popular, no good green LEDs around? It would look white so you wouldn't really notice much difference from COBs visually.
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Abiqua
Well-Known Member
green's are hard to make....
BobCajun
Well-Known Member
What would make RGB better than white COBs is no yellow at all, the worst band in the spectrum. Yellow may actually suppress growth. The article says green light only increased growth when it was up to 24% of the light. So like 3 red, 1 green and 1 blue.
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Abiqua
Well-Known Member
all I am saying is that Physically the diodes themselves to make green or greenish light are based on iridium and is the hardest mono to reproduce....in manufacturing....
churchhaze
Well-Known Member
If yellow is such a useless part of the spectrum, why does HPS do such a good job at flowering?
BobCajun
Well-Known Member
But how much better might it do with the yellow filtered out?
BobCajun
Well-Known Member
Yeah okay. Maybe it's impractical to use them for grow lights then. I know there are LED lamps around that do use RGB though, just probably more expensive than phosphor type white. I'll have to look into it more. Thanks for the info.
if you filter out the yellow light in hps you will have hardly any light left.
truth of the matter is flowering cannabis loves that yellow\prange\red light if you haven't figured that out by now you ought to give up growing.
Herbal_Essence
Well-Known Member
I believe this is true as well
the only reason its "working" for people is because its usually a low watt CFL or something dim like that. and that is not strong or long enough to wake up entire crop anyway (because usually only big gardens need that light )
dionysus4
Well-Known Member
nevergoodenuf
Well-Known Member
I am starting one right now. I am doing 2 4000K 80cri Luna 300s @ 160w each VS. 2 3200K 95cri Luna 300s. It will be a side-by-side with one plant per COB and a divider from the light to the net. I will flip this weekend. The area is 4'x5' @ about 30 watts per square foot.