Help needed for building a LED grow light.

lasercrazy · Feb 17, 2007

My plants are doing very poor with the current florescent setup I have and I want to build a led setup. I'd prefer to use luxeon type leds instead of the 5mm. What wave lengths should I use? Any help is appreciated. Mods feel free to move this to the homemade forum if it's better suited there.

gorn · Feb 17, 2007

LED grow lights seem to be the new thing for the pot heads. They use just a fraction of the electricity of normal grow lights. If you do a search on google for LED grow lights you will find more info on them then you ever wanted.

TORCH_BOY · Feb 17, 2007

If you have lots of plants Metal Halide is the way to go

nightshade · Feb 18, 2007

Grow lights,eh? He-Heeeee

liveforphysics · Feb 18, 2007

T5HO is definately superior to MH. T5HO is definately superior to LEDs. High pressure Sodium can often be better than T5HO, but it comes down to thermal issues at that point.

New LEDs can make the light needed, but the wavelegnths are crap for growing.

I've been growing corals for years now, and I've tried every type of lighting available. I've found T5HO to be the absolute best for growth, power usage, coral coloring, bulb life, and thermal control.

Remember, the advantage in T5HO all comes from the reflector shape. Most reflectors are garbage, so do not skimp on the reflector.

I've tried many units and found the setups sold by the Ebay Seller "hightechgardensupply" to be the best units available at any cost. They are not super cheap, but I get higher PAR readings from the 4bulb units from Hightechgardensupply than I do with many other 8bulb units... Reflector material is of marginal importance, but reflector shape is critical. The units have the correct reflector shape.

Best Wishes

lasercrazy · Feb 18, 2007

Thanks for the replys guys. Oh and no this isn't for growing weed.

Edit: I just searched ebay and I couldn't find the seller mentioned and they seem kind of expensive.

Ken_McE · Feb 18, 2007

lasercrazy said:
My plants are doing very poor with the current florescent setup I have and I want to build a led setup... What wave lengths should I use?

Chlorophyll has absorbtion peaks in the red and blue. It has no use for green.

lasercrazy · Feb 18, 2007

Ken_McE said:
Chlorophyll has absorbtion peaks in the red and blue. It has no use for green.

Thanks, what nm red and green is best if you know?

2xTrinity · Feb 18, 2007

Ken_McE said:
Chlorophyll has absorbtion peaks in the red and blue. It has no use for green.

Interesting. I know that red and blue are the most efficient colors for bare LEDs -- seems like the best bet may be to separte red and blue emitters rather than a "White" LEDs (lots of output in the green).

Illum · Feb 18, 2007

gorn said:
LED grow lights seem to be the new thing for the pot heads. They use just a fraction of the electricity of normal grow lights. If you do a search on google for LED grow lights you will find more info on them then you ever wanted.

NASA and various ITs.. [Institute of Technology] has been trying to develop a lightsource for growing plants underground or in space using the necessary wavelengths of light and nothing else for higher operational efficience...
This is a first for me to hear about LEDs being used to grow pot... :ohgeez:

lasercrazy · Feb 18, 2007

Newbie knows about almost everything maybe he can help. :anyone:

Ken_McE · Feb 18, 2007

lasercrazy said:
Thanks, what nm red and green is best if you know?

It varies some. I would suggest you aim for blue-to-violet and red-to-slightly-orange. I spoke too quicky when I said green is useless. The orange-yellow-green range can help a little.

2xTrinity said:
Interesting. I know that red and blue are the most efficient colors for bare LEDs -- seems like the best bet may be to separte red and blue emitters

Yes.

2xTrinity said:
rather than a "White" LED

White LEDs are designed to work well with the human eye. Plants don't have eyes and so don't really care about white. White LEDs do have a lot of blue in their spectrum, but a plain blue LED is more efficient.

2xTrinity said:
lots of output in the green.

Plants look green because they bounce off most of the green light that strikes them. This is because they don't have much use for it, so they mostly just send it away unused. This is why they look green to us.

lasercrazy · Feb 19, 2007

Should I use just plain red or red and amber or the red/orange leds? Should i use plain blue or cyan or even royal blue? Do the plants absorb uv or ir?

Ken_McE said:
It varies some. I would suggest you aim for blue-to-violet and red-to-slightly-orange. I spoke too quicky when I said green is useless. The orange-yellow-green range can help a little.

Yes.

White LEDs are designed to work well with the human eye. Plants don't have eyes and so don't really care about white. White LEDs do have a lot of blue in their spectrum, but a plain blue LED is more efficient.

Plants look green because they bounce off most of the green light that strikes them. This is because they don't have much use for it, so they mostly just send it away unused. This is why they look green to us.

liveforphysics · Feb 19, 2007

All plants and algaes (not all cynobacterias) contain clor-A. Clor-A only cares about light between 415nm-430nm, and light right at 670nm. The 460nm we see from efficient blue LEDs will do nothing for them. Chlor-B is able to use 460nm, and 700nm, but this is much less common.

In otherwords, your answer depends on the plants you are growing, however, white LEDs will be essentially useless for most growing needs. The "daylight" compact florecent bulbs sold commonly in stores are similarly useless for growing most photofeeders.

My specialty is coral and not plants however, so keep in mind I am not a plant expert.

Wim Hertog · Feb 19, 2007

I recently designed a small experimental LED growlight. I did some research and came up with the following:

Chlorophyll a is the most abundant pigment. Its absorption spectrum peaks at 430 nm and 662 nm. There's also a small peak around 630 nm and a larger peak at 400nm.

Carotenoids are believed to aid in the energy transfer and thus play an important role in photosynthesis. Almost all of them are active between 450 and 500 nm.

more info and graphs here: http://darwin.nmsu.edu/~blyons/BCHE_397/Plant_Pigments.htm
http://www.lumitronixforum.de/viewtopic.php?t=1161

A ratio of 20% blue and 80% red seemed to be ideal (NASA) but some German people did quite a few succesful experiments with only blue and white LEDs...

http://www.lumitronixforum.de/viewtopic.php?t=429&postdays=0&postorder=asc&start=200

If you don't understand German, try babelfish and read the whole topic...very interesting information!

My own array consists out of 100 5mm Red LEDs (660nm GaAlAs), 18 5mm Blue LEDs (465nm), 18 5mm Cyan LEDs (480nm) and 18 5mm violet LEDs (395nm). This should cover the whole absorption band.

Total power should be about 4.5W (I know, that's not a lot, but we'll see what it does). The beam angle of all LEDs is 20-25°.

Now I only have to find some pepper seeds to start the experiment

Wim

PS: will post some pics later.

lasercrazy · Feb 19, 2007

Thank you for the info. I'm interested how your setup does.

Wattage isn't an issue for me so I'll put as many leds as I need for the plants to grow like mad.

Wim Hertog said:
I recently designed a small experimental LED growlight. I did some research and came up with the following:

Chlorophyll a is the most abundant pigment. Its absorption spectrum peaks at 430 nm and 662 nm. There's also a small peak around 630 nm and a larger peak at 400nm.

Carotenoids are believed to aid in the energy transfer and thus play an important role in photosynthesis. Almost all of them are active between 450 and 500 nm.

more info and graphs here: http://darwin.nmsu.edu/~blyons/BCHE_397/Plant_Pigments.htm
http://www.lumitronixforum.de/viewtopic.php?t=1161

A ratio of 20% blue and 80% red seemed to be ideal (NASA) but some German people did quite a few succesful experiments with only blue and white LEDs...

http://www.lumitronixforum.de/viewtopic.php?t=429&postdays=0&postorder=asc&start=200

If you don't understand German, try babelfish and read the whole topic...very interesting information!

My own array consists out of 100 5mm Red LEDs (660nm GaAlAs), 18 5mm Blue LEDs (465nm), 18 5mm Cyan LEDs (480nm) and 18 5mm violet LEDs (395nm). This should cover the whole absorption band.

Total power should be about 4.5W (I know, that's not a lot, but we'll see what it does). The beam angle of all LEDs is 20-25°.

Now I only have to find some pepper seeds to start the experiment

Wim

PS: will post some pics later.

Help needed for building a LED grow light.

lasercrazy

Flashlight Enthusiast

gorn

Enlightened

TORCH_BOY

Flashlight Enthusiast

nightshade

Enlightened

liveforphysics

Enlightened

lasercrazy

Flashlight Enthusiast

Ken_McE

Flashlight Enthusiast

lasercrazy

Flashlight Enthusiast

2xTrinity

Flashlight Enthusiast

Illum

Flashaholic

lasercrazy

Flashlight Enthusiast

Ken_McE

Flashlight Enthusiast

lasercrazy

Flashlight Enthusiast

liveforphysics

Enlightened

Wim Hertog

Enlightened

lasercrazy

Flashlight Enthusiast

Similar threads

Latest posts