[quote=" HortScience. 2004 Dec;39(7):1617-22"[/quote][/SIZE]
[SIZE=3]The addition of 24% green light (500 to 600 nm) to red and blue LEDs (RGB treatment) enhanced plant growth. The RGB treatment plants produced more biomass than the plants grown under the cool-white fluorescent lamps (CWF treatment), a commonly tested light source used as a broad-spectrum control.
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[URL="http://www.ncbi.nlm.nih.gov/pubmed/15770792"]Green-light supplementation for enhanced lettuce growth (HortScience. 2004)[/URL]

I kind of stumbled on this info, but it seems to be an invaluable resource for LED researchers looking into plant growth.

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I am on this site because pot smokers are some of the most innovative people I know. I am an avid gardener, and am always looking for ways to improve my harvest of lettuce, cayenne peppers, basil, and chives.


---->You're braking the law if you don't pay taxes on your drugs...

I thought cannabis reflected most green light. wouldn't it be useful to use green lights to enter the grow room during dark cycle? just seems like a waste to put in green LEDs when you could just add more blue or red, or UV, which the plant uses more efficiently and can get more energy from. remember the study is only comparing an LED setup which is made to give out more of the right kind of light to a cool white fluorescent.

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hrm thats interesting havent seen that before. i knew that just Blue and Red doesnt really represent all the light plants need, just the most vital. the sun is the whole spectrum, and when producing artificial light the point is to try to imitate the sun. there is a graph around here somewhere that shows the amount of light needed in each spectrum ill search around for it.

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"Remember, you can never overdose - you can only under-dose. We are just making sure we aren't under-dosing."

I am a medical marijuana patient - my plants and use are covered under State Law. I do not endorse illegal activities in or out of the state/country. So don't tread on me.

Spring '09 Grow Chocolate Thai: http://www.greenpassion.org/f24/back-action-spring-09-grow-7928/

Current Fall '09 'Red Diesel' LED Grow http://www.greenpassion.org/f24/fall-09-pure-led-grow-show-red-diesel-14415/

I dont know-I still wouldnt crack open the tent after lights out, I'm waiting to hear about hermies from these green lights.I'm no expert tho- but I hear things about green leds on the other side too-I'll see if I can find it, but I read something about green light helping to penetrate a thicker canopy-cant confirm or deny this tho-havent tried it. Funny we're starting to see all these useless colors creep into led units-orange, white,and now I'm hearing about purple 410nm.I think that our favorite plant has some pretty complex processes going on, and every color is needed at some point or other-it's just a matter of finding what, and when.I'm looking at prosources new 5 band tri-spectrum units.2 bands of blue, and 3 seperate bands 0f red/orange-red-and deep red.

If anybodys interested-a friend of mine sent me this-the "official" useable color spectrum.Very different from what led manufacturers put out in their literature.In time their chart will, hopefully, look like this.

Attached Images

Plant.jpg (19.5 KB, 19 views)

I can totally understand placing a few white LEDs in a red/blue grid to kind of fill out the gaps...To mimic that curve, all you'd need are some RGB LEDs, and some orange/yellow...

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I am on this site because pot smokers are some of the most innovative people I know. I am an avid gardener, and am always looking for ways to improve my harvest of lettuce, cayenne peppers, basil, and chives.


---->You're braking the law if you don't pay taxes on your drugs...

i think i asked once about exactly how would we know what leds to buy... are they all the same? leds are still a bit confusing. are there good leds and bad leds?

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any 1w diode unit(like the ufo's) you buy should have cree-luxeon 4th quarter chip-set diodes-the real 2nd gen ufo's have these.Cree is the manufacturer of these diodes-you can buy them I believe up to 20w per diode-your power would run to each diode(which is attached to a large heatsink-this absorbs the heat that the leds make- the fans in the un its pull hot air away from the heatsink.For real led growth you need real power-cree 1w or higher diodes.Really stay away from any diode under 1 watt.

Oh yeah the ratio would be 8 660nm red/ 1 460nm blue/1 615nm orange-this is the ratio I've had the most success with.I also add a little pure white to balance out the spectrum

and you use only leds or supplement with other lights? are there any advantages, or not?

bf that was very very helpful... Where can I find the LEDS your talking about do you have a site.... Is it So it would be blue red orange n white?

this is the best resource site I've come across-this guy gives you all the honest info on led's- plus lists o suppliers for a diy project

so if i was to build 3 panels of 200 led's each panel I would do more red then all? so each panel would house..?

do they made LEDS where you dont need a resistor? like on the stand leds where you need them resitors hooked up.. I saw they have square LEDs

Okay, gimme, the best ratio is 8-14% of your lights shoult be blue. If you add white to fill in the gaps, then you can replace some of the blues with whites since the white LEDs produce a lot of blue. They also do not make any LEDs that don't need a resistor, but most LED shops can help you find the right resister to use.
the most powerful LEDs I've found are the Cree MC-E- but so far they only come in white.

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I am on this site because pot smokers are some of the most innovative people I know. I am an avid gardener, and am always looking for ways to improve my harvest of lettuce, cayenne peppers, basil, and chives.


---->You're braking the law if you don't pay taxes on your drugs...

Here Is Some Good Stuff.

The Nature of Light | Back to Top

White light is separated into the different colors (=wavelengths) of light by passing it through a prism. Wavelength is defined as the distance from peak to peak (or trough to trough). The energy of is inversely porportional to the wavelength: longer wavelengths have less energy than do shorter ones.
Wavelength and other saspects of the wave nature of light. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.
The order of colors is determined by the wavelength of light. Visible light is one small part of the electromagnetic spectrum. The longer the wavelength of visible light, the more red the color. Likewise the shorter wavelengths are towards the violet side of the spectrum. Wavelengths longer than red are referred to as infrared, while those shorter than violet are ultraviolet.
The electromagnetic spectrum. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.
Light behaves both as a wave and a particle. Wave properties of light include the bending of the wave path when passing from one material (medium) into another (i.e. the prism, rainbows, pencil in a glass-of-water, etc.). The particle properties are demonstrated by the photoelectric effect. Zinc exposed to ultraviolet light becomes positively charged because light energy forces electrons from the zinc. These electrons can create an electrical current. Sodium, potassium and selenium have critical wavelengths in the visible light range. The critical wavelength is the maximum wavelength of light (visible or invisible) that creates a photoelectric effect.
Chlorophyll and Accessory Pigments | Back to Top

A pigment is any substance that absorbs light. The color of the pigment comes from the wavelengths of light reflected (in other words, those not absorbed). Chlorophyll, the green pigment common to all photosynthetic cells, absorbs all wavelengths of visible light except green, which it reflects to be detected by our eyes. Black pigments absorb all of the wavelengths that strike them. White pigments/lighter colors reflect all or almost all of the energy striking them. Pigments have their own characteristic absorption spectra, the absorption pattern of a given pigment.
Absorption and transmission of different wavelengths of light by a hypothetical pigment. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.
Chlorophyll is a complex molecule. Several modifications of chlorophyll occur among plants and other photosynthetic organisms. All photosynthetic organisms (plants, certain protistans, prochlorobacteria, and cyanobacteria) have chlorophyll a. Accessory pigments absorb energy that chlorophyll a does not absorb. Accessory pigments include chlorophyll b (also c, d, and e in algae and protistans), xanthophylls, and carotenoids (such as beta-carotene). Chlorophyll a absorbs its energy from the Violet-Blue and Reddish orange-Red wavelengths, and little from the intermediate (Green-Yellow-Orange) wavelengths.
Molecular model of chlorophyll. The above image is from http://www.nyu.edu:80/pages/mathmol/library/photo.
Molecular model of carotene. The above image is from http://www.nyu.edu:80/pages/mathmol/library/photo.
Carotenoids and chlorophyll b absorb some of the energy in the green wavelength. Why not so much in the orange and yellow wavelengths? Both chlorophylls also absorb in the orange-red end of the spectrum (with longer wavelengths and lower energy). The origins of photosynthetic organisms in the sea may account for this. Shorter wavelengths (with more energy) do not penetrate much below 5 meters deep in sea water. The ability to absorb some energy from the longer (hence more penetrating) wavelengths might have been an advantage to early photosynthetic algae that were not able to be in the upper (photic) zone of the sea all the time.
The molecular structure of chlorophylls. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.
The action spectrum of photosynthesis is the relative effectiveness of different wavelengths of light at generating electrons. If a pigment absorbs light energy, one of three things will occur. Energy is dissipated as heat. The energy may be emitted immediately as a longer wavelength, a phenomenon known as fluorescence. Energy may trigger a chemical reaction, as in photosynthesis. Chlorophyll only triggers a chemical reaction when it is associated with proteins embedded in a membrane (as in a chloroplast) or the membrane infoldings found in photosynthetic prokaryotes such as cyanobacteria and prochlorobacteria.
Absorption spectrum of several plant pigments (left) and action spectrum of elodea (right), a common aquarium plant used in lab experiments about photosynthesis. Images from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.

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Thanks, Hatch!

You just saved me a LOT of work.

Here's the thing. You can't just string together a bunch of lights and get a good result. There are more variables than have been discussed here and there are a hundred ways to mess stuff up.

The bottom line is this: if all you had to do to make a good LED grow light was string together x amount of blue LEDs, y amount of reds and z amount of far-reds/infrareds, then we would have had awesome LED Grow Lights available a LONG time ago.

But, it's just not that easy - and even the slightest miscalculation or miscalibration will screw stuff up in a big way.

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-Michael

WOW Hatch! I am going to copy this to the charts and graphs thread...this could help a lot of techie peeps!

Peace

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Life,
j-angel

aka GP purrie kittie attack cat!


My Little Grow LST'ing w/Hardware

My Outdoor Odyssey 2008 BONSAI MUMS

My Little Grow Indoor To Outdoor 2009

Hey, Hatch... if you get bored, check out the shade avoidance system and the Emerson Enhancement effect. They are key enhancements attained with the new 5-Band Illuminators.

Incidentally, the Emerson Enhancement Effect is one reason HPS works so well. They emit a lot of far-red/infrared.

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-Michael

a little food for thought... green light is a waste for your led array .. plants cannot absorb this spectrum and there is much research on this issue.. so check your facts and you will see that i am right and plz dont go wasting precious watts on lights that do nothing
cheers!