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What type of LEDs are used for grow LED lights?

I've been googleing about the advantage of LED grow lights and how it saves energy and how they last longer. After looking to buy them I realized they were very expensive. However, I also found a few do-it-yourself guides which I thought were pretty neat and straight forward. The only thing I didn't see was if the LEDs they used were special or just any red/blue led lights can be used. Hope to get an answer and save a few bucks but most importantly save energy, Thanks in advance !!

Mogger4 years ago
Plants use the Photosynthetically Active Spectrum, also called PAR. But it is more involved: Chlorophyll photosynthesis has two bands with peaks, one in the blue range (maximum at 430- 440 nm) and the other in the red range at 670 nm (info from an old GRO LUX TL grow lamp datasheet). Now, Phototrophism has another band which is responsible to let the plants grow low and broad or high and slender. Here it is is a curve with two peaks, starting around 410 nm with a peak at 430 nm, and a second one at 475 nm, sloping down finally at 500 nm. If we want to to grow plants with LEDS, we must match the maximum curves with a mix of LEDS consulting the LED datasheets- Spectrum curves. Until now, I did not find yet LEDS in the precise spectral range that the plants need- so we must again mix here and find LEDS which are the closest to the maximum in the curves. I was selecting Blue, Royal blue and RED Luxeon Leds. Also important is the lumen ( light output ) of the LEDS and their distance over the plants, with RED LEDS beeing a lot weaker than the blue ones. So in any design, the RED leds must outnumber well the blue. There are a lot of LED grow lights out there now- but the PRICES! CREE LEDS seem to be the best ones at the moment for this use and I just checked out Luxeon today. Chinese exporters offer also a lot of grow lights and there are even aquarium lights now. (LED GARDENER e-journal is one nice source of information- google it up). In any case, plants may differ in spectral requirements and the best is setting up experiments and test run the LED rigs. (For example: we have an in vitro Lab running during 12 h a day 80 pieces of 120 cm white TL lamps of 40 Watts with old reactors which consume also 40 watts, wasting energy in heat. This is a load of 6.4 KW every hour. Therefore I am looking to stop this nonsense and work with LEDS.
Red and blue...Cree's are the best, you can buy 1W LED's that way. Only problem is having to buy them in bulk (last time I looked I had to buy 1K at a time @ $3-4 each). I would put intensity controls on the red and blue circuits and tune until the plants appear black or at least very dark colored. Basically if the plant appears black then it is not reflecting any light, therefore there is no wasted light (plants reflect the green therefore they are not using it).
the intensity controls would be something to see, actually something on the whole setup you've got would be fantastic
noahw5 years ago
monchito7 (author)  noahw5 years ago
So from what I understood, yes you can use regular LEDs to grow (would probably need lots of them to make a decent amount of light though) bujt they suggest high power LEDs which gives better results. I guess now my research will be more on high power LEDs lol
110100101105 years ago
the way i understand it : each plant needs various ranges of light - each for another need. the light source should match as much as possible the needs of the plant - supply enough light in each range here are some images that show this (the light sources are taken from lamptech.co.uk) some plants need dawn-like light to grow and day-like light to flower
plant.jpeghalide.jpeghelium.jpgpl.jpgsodium.jpgtungsten.jpg
monchito7 (author)  110100101105 years ago
awesome graphs really gives a visual for some question i had, thank you !
rachel5 years ago
LEDs emit light on only one wavelength. The sun emits a huge range of wavelengths. LEDs are not made in all of the wavelengths found in sunlight. If LED grow lights work, it must mean that plants only need certain wavelengths, or are able to use a more limited mix. This makes sense, but I would expect it to vary somewhat by plant species. This doesn't answer the question but hopefully gives some context.
monchito7 (author)  rachel5 years ago
From what i've been reading so far you need red and blue LED lights the blue would help the seedlings and the red promotes flowering, there are many website out there that sell them already arrange in a certain matter but they range from 150$-600$ it's very new and doens't create much heat or use much energy.
monchito7 (author) 5 years ago
Thanks for the replies everyone much appreciated.
ikke_12065 years ago
I guess you should use IR leds(for emitting warmth) and UV leds, in that way the plants get all the radiation needed to grow
IR LEDs don't radiate light in the "warmth" area of the spectrum. There are two wavelengths of IR, called "near" and "far." Near IR is what LEDs produce, Far is what radiant heat sources like fire and heat lamps produce. You may go ahead and use just regular old red and blue LEDs; plants need little else. UV may actually damage the plants, and IR doesn't do anything.
monchito7 (author)  jeff-o5 years ago
Thank you very much, makes sense:)
I know you can't use normal red and blue LED's for growing plants as they emit a very narrow range of wavelengths. I don't believe there are any specifically "UV" type LED's, though I've seen many infrared. I do know that certain normal diodes of the non light-emitting variety actually do emit UV radiation, though at what wavelength, and what intensity, I don't know.
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