Led veg light spectrum

Discussion in 'Hydroponic Growing' started by inbetweendreams, Jan 19, 2014.

  1. #1 inbetweendreams, Jan 19, 2014
    Last edited by a moderator: Jan 19, 2014
    I am trying to construct my own led veg light fixture. I have done my research into which led's and drivers I will use but I am still trying to find concrete information on the exact proportion of spectrums to use. I am building a 120W lamp. I am planning on using 1 120w lamp for a sq meter of vegetation (all 3w leds) and I have calculated that I can get 15,000 lumens out of 120w. I understand that the plants needs 480nm (cool blue) spectrum but I am also planning on incorporating a few royal blues, whites and even reds (possibly incorportating other parts of the spectrum as well, even all the way down to uv). I Know there is not much research into leds, even the company websites give you a general estimate of spectrum and lumes/ma but I would like to see if there are any other nerds out there who have built a successful light. To be honest, I would really like to start the conversation on leds, led grow light spectrums and even compare real world results between 3w, 5w, 10w, and 12w diodes (and the variety that they are available in).
    Good vibes to you all

  2. #3 PeterParker, Jan 21, 2014
    Last edited by a moderator: Jan 21, 2014
    Read about all you can stand about:
    Photosynthesis lol
    It's super complex in detail, and isn't a simple which light frequency should I use kinda question. It's easier to understand it's a spread from one particularly reactive wavelength that is specific to the plants color.
    Just trust the graphs such as, more complex and specific one below which looks useful for selecting LED wavelengths.
    And learn about LED's and their "spread" from the rated wavelength, and the lumen output for that particular wavelength.
    Basically you can see from the above graph, use any wavelength except for green...which makes sense for a green plant lol
    Oh and you may enjoy reading this page, Tons of info on it Scroll down to the "What Light Do Plants Need" part
    And here is the video
    Very revealing as far as wasted energy goes, and really think about it. 750 or so watts is one horsepower, plants don't need one horsepower of energy to grow lol though most of that energy is heat... which we tend to use more energy to remove.
    LED's can accomplish huge savings if someone made it with the right measuring equipment.
  3. Fantastic information! This helps very much! As interesting as induction lighting is, I still am interested in using led technology. I was going to make my light with 30% cool white but it seems that would be wasting light energy. Here was my light breakdown before, 15% royal blue, 50% true cool blue, 30% cool white and 5% standard red. Now I am considering to lower the whites to 10% and raising the royal blues and reds both 10% making it: 25% royal, 50%true blue, 10% whites and 15% red (remember, I am using all phillips luxeon 3w and I plan on using 48 leds for this vegetation light). Let me know what you think, this will be my first plant light and I want to get it right.
  4. ...I am thinking that adding dark red wouldnt hurt as well, maybe take 10% from the blue and add in 10% dark red.
    I personally think LED can achieve what induction does and much much cheaper. 
    "first plant light and I want to get it right."
    What is "right"?
    even incandescent lights could sustain a plant. It's about efficiency right? Using HPS as the comparative, the goal would be less heat/power.
    Also note that you can give a plant too much light! That is too much energy of a particular wavelength.
    If I was building an LED light, I'd get the wavelengths specified in the graph, Using a the same number of LED for the blue end, for example 5 LEDs @ 440nm, 5 @ 448nm, 5 @ 460nm, 8@ 485nm, 5 @ 505nm and for red 5 @ 645nm, 10@ 660nm, 5 @ 675nm.
    Also maybe try and find scientific support for the whole "more red light for flower" claims. I haven't seen any myself.

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