No announcement yet.

Help with LED spectrum

  • Filter
  • Time
  • Show
Clear All
new posts

    Help with LED spectrum

    Hey guys,

    I'm planning to do myself a LED Grow Light and need some help with it.

    I've been checking some from big brands and noticed that some lights have only the blue color (different specs of blue) for veg stage and red color (different specs of red) for flora. But also I read a article saying that a mix of red and blue are the best in all stages.

    What do you guys think? If I have a small place, would be better to get only blue at veg stage or a mix of blue/red with a bigger amount of blue?

    Also, if I will be growing a single plant in a 2 feet sq place, 150W will be enough? And how to choose between 90 or 120 angle lens?

    Thanks guys!

    Hi danbwc.
    Are you planning to homebuild your light?
    Right now the homemade "tide" is with full spectrum cobs, or ready-made boards like ChilLED that have a variety of bands of color spectrum build in.
    Have you found GrowMau5 yet? He's got some great videos and discussions on homebuild lights.
    The plants need a broad spectrum of light, and in my limited and utterly unscientific experience I have found that the more spectrum bands you cover the better.
    I would definitely advise against going with just one or two bands of light (there is a cool test out there where someone grew a bunch of clones under single bands of light, the growth was really weird).

    Lenses are typically used on single diode LEDs rather than COBs and are unnecessary in ready-made boards. This said, the decision between 90/120 lenses is going to be a tough one without actually trying them in your specific situation (and measuring with an expensive PAR meter). At a guess I'd say 90 degrees will work given your small tent and only one plant. 150W of LED will grow you a fine plant for sure.

    If it were me, and price was the #1 factor I'd do a single COB light homebuild. If I was feeling a bit more flush I'd go for a ChillLED board build.

    The hard truth is the cannabis specific light spectrum research just hasn't been done thoroughly yet.
    Sand, sea, sun, sausages, and sinsemilla.

    About all you can do in life is be who you are. Some people will love you for you. Most will love you for what you can do for them, and some won't like you at all.

    -Rita Mae Brown

    My Small Tent, Monthly Harvest, Perpetual Auto Grow

    My IG


    • danbwc
      danbwc commented
      Editing a comment
      Hey man!

      Thank you for answering.
      Yes, it's homemade but I'm going for the board.

      30x 3W LED red spec (600 ~ 660)
      20x 3W LED blue spec (440 ~ 480)
      All sticked with thermal paste on an aluminium heat sink and 4,8" fans.

      I've been searching about the lens and maybe going for 120 cause 90 can be too strong in the middle of the canopy.

      But I'm thinking about adding a couple UV-B and Far-Red. What do you think about these? And what is the reason for cool/warm white LEDs?

      Thanks again man!

    • Beach_Town_Brit
      Beach_Town_Brit commented
      Editing a comment
      I'm no expert on this but you certainly need some green light in there. I believe the white LEDs will give you good green.
      I use far red for late flower and it seems to work for me but I've not done any "experiments" to judge how much it works.
      Be careful with UV-B you only need a little by all accounts.
      To be honest, I'd be tempted to just copy the spectrum mix from a Quantum or Chill board.

    Nice man, thanks for the reply!


      I bought (2) 300W LED's with red, white and blue lights for $70 ea on Amazon. Very happy with them. They light one Water Farm. They are advertised as 5000 Kelvin, which is close to sunlight.
      I've read more confusing articles than I can recall about grow lights. These work great for my needs, low heat, great buds. My last plant was a bit over 24" tall and gave me well over 4 ozs.
      Hydro, GH Flora Trio + CalMag +. Nothing special after that.
      Good luck.


        Nice dude! How far is your LED from the plants?


          Originally posted by danbwc View Post
          Nice dude! How far is your LED from the plants?
          18 to 24 inches. I keep an eye out for burned leaf edges and have found none. Good air flow between light and plant top is essential, as is good air flow in general.
          I also have a 315 CMH for my second Water Farm, which I like very much. I don't like the heat output, but the girls love it. That one I keep 24 to 30 inches away from the plant top.


          • danbwc
            danbwc commented
            Editing a comment
            Thanks for all the support man! It does help a lot

        Check out our new growing community forum! (still in beta)

        Subscribe to Weekly Newsletter!