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That Guy
Registered: 08/12/08
Posts: 4,035
Loc: Southwestern US 
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 Dissecting Sunlight 
#231609 - 05/25/09 09:22 AM (15 years, 5 months ago) |
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I am curious about the makeup of the solar spectrum.
I have seen in various articles, graphs depicting the relative intensity of different wavelengths of light in sunlight and various lighting setups. This interests me because i believe that the LED technology that they sell for grow lights has a lot of promise, but i also feel that one could improve on their designs. So I have a few questions to ask since I cant seem to find an answer.
What is the approximate percentage of light (include units please) of red-orange and blue light in sunlight? I know that there is about 4% UV radiation of all types...but i need to know this to get a ballpark calculation for light equivalencies.
Also...besides UVB, are there any other wavelengths that you guys think plays a key part in the flowering portion, because I have heard people say that LED grow lights are good for vegging but suck during flowering. My question is what seems to be missing?
Feel free to throw out theories...I'm very interested in this subject.
thanks in advance  
agmotes165
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“The Universe is under no obligation to make sense to you” -NDT
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Harry_Ba11sach
cannoisseur
Registered: 04/20/08
Posts: 11,753
Loc: Nepal
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Re: Dissecting Sunlight [Re: Data]
#231610 - 05/25/09 09:36 AM (15 years, 5 months ago) |
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I've heard of plants that photosynthesize specifically on the infra-red and near-IR spectrums, completely ignoring visible wavelengths. This obviously isn't the most efficient approach, but it's a smart one since IR is emitted by all surrounding objects instead of just the sun, so shade is of very little concern.
My point: I don't think you should discount ANY portion of the solar spectrum for any reason. Cannabis evolved on this planet over hundreds of thousands of years, so it's logical that the best wavelength for them to grow under is exactly the same spectrum as the sun.
I'm sure you've seen tons of graphs similar to this, but here it is anyway;
This just shows that although energy output by the sun is maximum at the wavelengths between .35um and .78um (the visible spectrum) I don't think it's very efficient to focus on specific wavelengths such as LED lights tend to do. They generally have half the LED's in the red spectrum and half in the blue, and they miss out on hundreds of other colors in between.
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That Guy
Registered: 08/12/08
Posts: 4,035
Loc: Southwestern US
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interesting...i wonder if you could rig up so that you have the ultrabright LED's in the red-orange and blue ranges...and have other color LED's mixed that would be less bright but would cost less and produce less heat...that way it would have a higher red-orange and blue output, but also include other colors that would kind of round out the misses wavelengths...
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“The Universe is under no obligation to make sense to you” -NDT
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Harry_Ba11sach
cannoisseur
Registered: 04/20/08
Posts: 11,753
Loc: Nepal
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Re: Dissecting Sunlight [Re: Data]
#231963 - 05/26/09 12:07 AM (15 years, 5 months ago) |
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Could be possible, But I think you'd be best just finding an LED with a white glow that would be broad-spectrum coverage
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That Guy
Registered: 08/12/08
Posts: 4,035
Loc: Southwestern US
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the problem with that is that most high brightness led's max out at about 400 lumen per .35 amp LED...and direct sunlight is anywhere b/w 30000 and 130000 lumen/meter2...so if you used the average of those 2 values over my square meter grow tent area...you would need 200 of those 400 lumen LED's...which i think sell for somewhere around 16 to 32 dollars a pop...which would run anywhere from 3200 to 6400 dollars just for the led's...and then probly a 500 dollar or more power supply...and the labor to do all that...so up to 7000+ dollars for something that I think could be done for less than 500 if you eliminate some of the unnecessary wavelengths...and could achieve a white-light equivilent at say 20000 or even 10000 lumen/meter2 using the most efficient light in ultrabright leds, and supplementing the light with other wavelengths at a smaller magnitude of brightness...this would also be good for people doing stealth grows where heat output and energy loads could be a problem...such as residential where you are trying to run the grow setup in a closet...on a 15Amp circuit...that is also tied into the resident's room...filled with stuff that is already loading the circuit...this is something that would require little or no extra construction...just a growtent set up in a closet...with a fan and carbon scrubber assembly...and a 100W LED light....and actually grow good bud...
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“The Universe is under no obligation to make sense to you” -NDT
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 ethnoguy
E to the G
Registered: 04/21/08
Posts: 429
Loc: your momma's house
Last seen: 15 years, 3 months
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Re: Dissecting Sunlight [Re: Data]
#232575 - 05/26/09 08:31 PM (15 years, 5 months ago) |
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My problem with LEDs is that they don't penetrate the canopy very well. I'm probably going to get one for rooting clones, but that is more about height restrictions and my curiosity 
EG
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Yrat
Happy Planting
Registered: 04/20/08
Posts: 886
Last seen: 10 years, 9 months
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Quote:
Harry_Ba11sach said:
I don't think it's very efficient to focus on specific wavelengths such as LED lights tend to do. They generally have half the LED's in the red spectrum and half in the blue, and they miss out on hundreds of other colors in between.
this is why they have red and blue LEDs:
it doesn't make sense to have green or yellow LEDs when that light will just be reflected. waste of energy and space, considering some blues or reds could be there instead. a range of colors is really not needed.
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 "Prohibition will work great injury to the cause of temperance. It is a species of intemperance within itself, for it goes beyond the bounds of reason in that it attempts to control a man's appetite by legislation, and makes a crime out of things that are not crimes. A Prohibition law strikes a blow at the very principles upon which our government was founded." - Abraham Lincoln
"There are a thousand hacking at the branches of evil
to one who is striking at the root"
~ Henry D. Thoreau
Strike The Root
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Harry_Ba11sach
cannoisseur
Registered: 04/20/08
Posts: 11,753
Loc: Nepal
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Re: Dissecting Sunlight [Re: Yrat]
#232784 - 05/27/09 08:34 AM (15 years, 5 months ago) |
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trust me, I've not only seen that graph, I've made quite a few myself for many different plants. However, you'll note that most LED's release light in a band only 5-10nm wide at most (some are so specific they claim a range of only 1nm!). so even if you get 4 different color LED's you're still missing out on quite a large range of active photosynthetic spectrum
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Yungpunk
NewKidOnTheBlock
Registered: 05/17/09
Posts: 304
Last seen: 12 years, 11 months
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you guys go so far over my head sometimes! lol i love it! ive just started getting into growing and learning about plant life and i just love to read what you guys talk about. keep up the good conversations! 
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Riots are the voices of the unheard.
Those who make peaceful revolution impossible will make violent revolution inevitable.
  
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Data
That Guy
Registered: 08/12/08
Posts: 4,035
Loc: Southwestern US
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Re: Dissecting Sunlight [Re: Yungpunk]
#233068 - 05/27/09 06:26 PM (15 years, 5 months ago) |
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but if photosynthesis is just producing ATP and NADPH...then it shouldnt matter that you arent covering all of the solar spectrum of radiation...since red-orange and blue are the most efficient wavelengths...and the photosystem is based on converting light energy into molecular resonance...or making the molecules vibrate...in order to drive the photosynthetic pathway...wouldn't one just use the most efficient wavelengths...coupled with a few extra colors in the flowering stage just to supplement any photo reactive hormones or systems that would promote healthy flowering...and maybe couple that up with a UVB light to increase trichome production...
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“The Universe is under no obligation to make sense to you” -NDT
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Yrat
Happy Planting
Registered: 04/20/08
Posts: 886
Last seen: 10 years, 9 months
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Re: Dissecting Sunlight [Re: Data]
#233078 - 05/27/09 06:30 PM (15 years, 5 months ago) |
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Quote:
Harry_Ba11sach said:
However, you'll note that most LED's release light in a band only 5-10nm wide at most (some are so specific they claim a range of only 1nm!). so even if you get 4 different color LED's you're still missing out on quite a large range of active photosynthetic spectrum
but that doesn't matter, if you've got some LEDs that emit at 450nm, and some at, say, 670nm, you're exciting chlorophyll a and b just fine. the addition of any other wavelengths won't matter.
Quote:
agmotes165 said:
but if photosynthesis is just producing ATP and NADPH...
photosynthesis produces sugars from carbon dioxide, but the rest of your reasoning about colors is correct.
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"Prohibition will work great injury to the cause of temperance. It is a species of intemperance within itself, for it goes beyond the bounds of reason in that it attempts to control a man's appetite by legislation, and makes a crime out of things that are not crimes. A Prohibition law strikes a blow at the very principles upon which our government was founded." - Abraham Lincoln
"There are a thousand hacking at the branches of evil
to one who is striking at the root"
~ Henry D. Thoreau
Strike The Root
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