Too many lumens?

Discussion in 'Growing Marijuana Indoors' started by CannabisCrush, Nov 9, 2014.

  1. Hey guys, just wondering if there is such thing as too much lumens, or K, in your grow area? I have a metal halide going which puts out 4500K and I also have two 45w full spectrum lights with 6500K. Is that too much lumens?

  2. How many lumens is it? K is not lumens.

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  3. 6500 Potassium? :p
    6500 Potassium? :p
  4. I'll give you a more helpful response.
    the K refers to Kelvin, which is a measure of temperature, but it refers to the overall colour of the light.  Hotter things emit bluer (whiter) light, cooler things emit redder light, so that's why they use that scale to measure the "colour" of the light from a light source.
    The 6500K CFL bulbs look "white" and emit light in various frequency ranges, and the emit more of the frequencies that are used by the plant during veg.
    The other common 2700K CFL bulbs look more "warm" with their light, and they emit frequencies that are used more when the plant is flowering.
    Both types of light emit frequencies that the plant can use throughout the grow just fine.  And to be clear, if you have a thousand 2700K bulbs, although it is very bright the overall light is still the same set of frequencies, the same colour, 2700K.
    There is a type of CFLs that emit 5000K, these are a kind of "worse of both worlds", they are good for seeing but not great for growing.
    Metal halide lights function in a completely different way, so although the "colour" of the light is 4500K (which would probably be crappy for a CFL), they emit a completely different range of frequencies to the CFLs, and they emit lots in the range usable by plants.
    Lumens is a measure of total light power or total brightness (in simple terms).  More lumens = brighter/more light.  You can't really have too much light when growing cannabis, I presume you don't have two 1000w MH lamps.  As long as it doesn't get too hot in your grow space, more lights = better.
    For a rough comparison, your 45w CFL is probably emiting somewhere around 3000 lumens, and a 250w HM bulb is going to emit something like 30000 lumens.
  5. ^ good post. But you can have too much light, which results in light burn.

    4000k is a spectrum that many consider to be "full" spectrum and cmh is the technology lots of people use from seed to flower under that spectrum and report phenominal results, but i agree, hard to overdue it with cfls LOL

    And lumens are simply a measure of footcandles, or what human eyes can see, whereas PAR (photosynthetically active radiation) is what plants "see"

    Still, excellent post :smoke:
  6. True about the light burn, that's why I jokingly mentioned the 2000w lighting system.  If he had that, there'd be no point in having the CFL running as well  ;)  For most people I think heat is going to be the problem they run up against before they get to the light burn stage.
    It's interesting what you say about how the plant "sees", I suppose you could think of it like if we could only see red and blue, and every other colour, green, yellow, pink, just looked either really faded or black, then we would see like a plant.
    Obviously there are LEDs as well, which emit a very narrow spectrum of light frequencies, so you need to have the correct ones, not any old red or blue ones and especially not any old white one!  Chances are that none of the light is "seen" by the plant at all.  But if you get the right ones, they do seem to be pretty damn efficient.  I'd like to see it for myself though.
  7. Im about to jump down the rabbit hole myself with leds, and these are gonna need to impress because im going from two 600w hids :smoke:

    Follow me on my journal and when i start the new grow journal youll be the first to know.
  8. I don't know the light chart by hand but Google it... it doesn't matter how you get there, ie: LED, CFL, etc, so long as you do...
  9. To add fuel to this fire, I recently switched from CFLs to a 600w hid and 6inch fan with filter in a 24x48x60 grow tent ,would running the cfls I already have with the HID be and extra boost of yummy food or a waste of energy? I have a few bigger sized CFLs, including a flowering spectrum one or two (they're in storage so I don't remember). I'm just searching for a few opinions from this respectable community of farmers ;)
  10. Is that like, 2 feet x 4 feet x 5 feet?  I think 600w is filling that pretty well already, I'm not sure you'll get any real benefit by including the CFLs.  The HID is going to be a couple of feet away from the plants but the CFLs need to be really close to be worthwhile, so not sure how you'd work that in that space.  Also, you'd need like 100 watts of cfls to make even a 10% increase in the lumens, doesn't really seem worth the payoff.
    If your tent was twice the size, maybe the CFLs would be more useful, but they'll be great for a small vegging cupboard.
  11. Keep the 600w HID ditch the CFL's. I have the same set up and that 600w saturates that space FULLY without the need for supplemental lighting.

    Save urself the extra heat and hanging and adjusting cfl bulbs for minimal return on investment. You're set with that 600w. I hope you have a cool tube or air cooled hood for it though because that small space heats up quick even WITH it. Good luck.

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