Lumens and Lies

Discussion in 'Lighting' started by bulletcatcher, May 23, 2010.

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  1. Seems like more people are catching on to the fact that lumens aren't really all that matters these days. But the scary thing is that even most people who know that don't know just HOW wrong lumens are as a rating for grow lights.

    It's not just a little wrong, it's actually harmfully misleading.

    Luminous flux - Wikipedia, the free encyclopedia

    (the black line on the graph is used to rate a light's luminous flux)

    As you can see, it is an incredibly skewed representation of the actual energy output of the light. Wavelengths in the deep red and high blue spectrums are rated at nearly 0, regardless of energy intensity. And of course those ranges are the MOST photosynthetically-active.

    But perhaps some of you have seen this graph for PAR:

    It's comically wrong. And surprise surprise, it's overlaid on the spectrum graph of every HID bulb I see. Makes HPS look great with the fake peak at yellow. It also shows green light as MORE active than blue light, which is pretty comical. Green light is of course non-active in plants to any real degree since it's reflected by chlorophyll.

    Lumens overrates HPS and MH bulbs while underrating lights with better spectrums. HPS gets overrated the most by the lumen system since sodium throws out its peak at yellow. I'm sure that's also why people don't use red-spectrum HPS en-masse. It won't be long before people figure out that targeted fluorescents (most major fluorescent manufacturers make pure red/blue T5s) and LEDs vastly outperform HID systems at equivalent wattages. I'm happy to see many other growers on this forum are discovering this as well.

    I was repeatedly told that fluorescents would not give good bud density, there wouldn't be any canopy penetration, etc. I did a small grow with 3 125W CFLs and everything claimed was completely wrong. I'm guessing people who have had poor results were hanging the lights feet away from the plants, and/or trying to use 125W of fluorescents to replace 400W of HPS and being surprised when it doesn't work.
  2. What are you using to compare you CFL grow to? I too have doubts about how important lumens are when it comes to growing, however I don't think a CFL can out grow a HPS. At all.... look the sun grows best of all right, then HID, then CFL, then LED. That's been proven time after time by reputable growers on this site and outside GC.

    CFL and T5 is a great technology and can outgrow a HID system in some settings, but I wouldn't go around saying it's better for all. Large plants and larger set ups (more then 3 plants) will see better growth with HID. You just don't have the same energy in a CFL that you get in a HID, even with a narrow specta.

  3. What you stated has NOT been proven time and time again by ANYONE. I routinely see poor comparisons that stack unequal wattages of lights against eachother and then try to make a reasonable comparison. I also see lots of grows mixing spectrums during flower, getting worse results, and blaming the BULBS, not themselves for using an inferior spectrum. MH is a mixed spectrum... it flowers worse than HPS. It seems pretty clear to me that the same is going to hold true no matter what kind of bulbs you use.

    The only thing HID lights have going for them is price/output. And that's only good once you get above 400 watts. LEDs and fluoros are going to come down in price more and more and overtake HID for growing. I would guess that happens within 3-8 years.

    Here's what a proper amount of wattage and spectra can do with fluoros. I'll be taking more pictures soon, and the buds are getting massive.
  4. Check out rumps review of LEDs. Pretty good show of what they can do.

    Bottom line is floros don't have the energy HID lamps do. Period you can't argue with that. This has a direct effect to plant growth. Stop waisting your time looking at spetra charts. Plants need more then the grow light to stay healthy. They need other wl for micro nute prosessing man.
    Sure people don't use their lights to the maximum efficancy (you included man) but I'll stick with my statement that HID is better then floro.

    I should also say that I deal with the phisics and science of light for my profession...
  5. #5 Possuum, May 28, 2010
    Last edited by a moderator: May 28, 2010
    Bullet, I think I’m in overall agreement with you but I'm confused on your PAR conclusion. Are you referencing Photosyntheically Active Radiation (PAR), or Parabolic Aluminized Reflector (PAR) lamps?

    If the former then I’ll politely disagree. Photosynthetic Active Radiation is analogous to the wavelength range of 360 -700 nm. i.e. the wavelength which activates photosynthesis. This is the wavelength that LED grow lights target specifically.

    Otherwise, I agree “lumens” is a poor way to judge light quality (compared to quantity) for growing purposes. I think HID’s will be in the grow room for years to come but I am excited to see the continued development with LED grow light technology. Just imagine when 2w LED bulbs are common place thereby increasing both light quality and quantity in a very small low wattage footprint! There is a point that is reached with light saturation at which no additional photosynthesis can occur. I don't know how to calculate that and the variables supplied by the grow environment are many. But, plant physiology dictates how much "light" can be used and that which can't be is, in the case of HID, wasted as a lot of heat. That said, a lot of folks just throw a 1000w light in the flower room and generally reap great rewards. They might, however, do just as well with less light luminescence and better managed grow room variables.

    One question I have and have not been able to find the answer for but perhaps you know. Does the inverse square law apply equally to LED light as for other lighting sources? Since the inverse square law applies specifically to luminescence I’m curious as to its purpose and usefullness in measuring wave length intensity (penetration) in the visible spectrum i.e. 360 – 700 nm of that put out by LED grow lights. IMHO I think this is critical to understand fully when opting for LED over HID.

  6. #6 bulletcatcher, May 28, 2010
    Last edited by a moderator: May 28, 2010
    No, that's actually an awful show of what they can do. It was an underpowered unit using crappy LEDs, and they flowered with a mix of blue/red. Look around for LED grows using more modern units that actually work. They look just like HPS grows to me, and use less wattage.

    And your "bottom line" is wrong. T5s output a similar watt/lumen as HID, AND they don't get the benefit of being massively overrated by lumens like HPS.

    If you were right about plants needing much of the other spectrums, HPS would be terrible for growing, and MH would beat it every time.

    Also the physics and science of LIGHT is significantly different than the physics and science of lighting technology, which you apparently are not up to speed on.

    edit: oh and they told rumple to keep his grow in the high 80s, which is another reason it blew.
  7. #7 bulletcatcher, May 28, 2010
    Last edited by a moderator: May 28, 2010
    I'm not really sure what you're disagreeing with. How the plant uses/reacts to light is dependent on its wavelength. How efficiently photosynthesis can utilize light is also dependent on its wavelength. Wavelengths near green have almost no activity because chlorophyll reflects them.

    Photons are photons, and they obey all the same laws. If you can find a way to distinguish a photon at a given wavelength from an HID light from a photon of the same wavelength from a fluoro, there's a nobel prize in it for you. That's why the claim that fluoros can't "penetrate" is utterly absurd.

    edit: lumens is a hilariously terrible way of measuring light quantity. 1 trillion photons at 400nm = ~0 lumens. Awful. Green gets rated the best by one lumens scale, too. Go grab a green T5, fuckin GREAT lumen count. It'll grow like mad, right?
  8. And for general information, RADIANT FLUX is what SHOULD be used for lighting, since it's not weighted by wavelengths in a way that's meaningless for growing.
  9. This link give a different graph of photosynthesis/light spectrum than that which you shared. In your graph GREEN spectra is specifically dominant and you correctly stated has no value in photosynthesis. I'd say the two graphs are importantly different. Light Absorption for Photosynthesis

    I guess I misinterpreted that you were referencing PAR being “comically wrong” whereas you were just pointing out the GREEN spectra in the PAR graph. I misunderstood. PAR is the universally (world wide at least) accepted standard for identifying the wave lengths of light that are specific to photosynthesis. i.e 360 – 700 nm

    If photons are photons can you expound on how LED light penetration is equal to that of much higher wattage HID sources but produce that light penetration at much lower levels of luminescence? This is the part I don't quite get. I've seen very impressive grow results with 200/400w LED lighting systems that rival that of 400/1000w HID systems. If the inverse square law applies equally, how does this occur? What drives the LED capability of deep light penetration?
  10. #10 bulletcatcher, May 30, 2010
    Last edited by a moderator: May 30, 2010
    Oh, I see the misunderstanding now.

    That par graph I linked is comically wrong, in that it doesn't correctly portray PAR. As you can see, the green spectrums don't drop down like the proper par graphs you linked.

    And every HID bulb I see in stores lists the incorrect PAR graph that makes their spectrums look good.

    LEDs are AMAZINGLY efficient compared to HID. They simply throw out a ton of photons per watt. Lumens are lies, remember? Since LEDs throw all deep blue/deep red light, they get SEVERELY underrated by lumens. If you were to measure the radiant flux of LED vs HID, it would become clear that the LED is putting of waaaaaay more light per unit of input energy. And the way you penetrate is just shoving more light into the same area (or using gamma radiation, but you probably don't want to do that).

    edit: for a good display of how lumens are VERY misleading, see this page:

    Same exact bulbs at the same exact wattages. Completely different lumen counts. Obviously the same bulbs with different phosphors emit the same amount of light, so the only difference is the lumen wavelength weighting. Makes that green bulb look fantastic... heh.
  11. I've flowered under mh and hps usin same clones for control and theres little or no dif in yield,I've also used t5 with grow and bloom bulbs with same results yield is bout the same.You can spend 200 buks get a hid or spend 600 to get same yield outta flouros.

  12. Yeah man. I'm sipping on the LED koolaid and keeping my eye on it. The advances science has made understanding plant physiology and tuning the light spectrum in via LED is awesome. Interesting to note your comment on the amount of photons. Not being a physics guy I keep forgetting that all light is matter and in that are all kinds of photons, electrons, and all kinds of stuff I'll never need to process...LOL... but it sure does help by understanding things a bit better. Put a microchip to work and voila! very efficient light spectrum without all the wasted heat.

    Thanks to space exploration and agronomics I think we'll see the truth on LED grow technology real soon as the new standard.

    Thanks for the link I'll go check that out. +rep

  13. Depends on your growspace. For me, it would have been a lot more work and probably more expense to go with HID, since I'd need a vented sealed reflector and a high pressure fan, and would probably STILL have way more heat complications, since venting it anywhere good would be a bitch.

    But yes, if you want to throw a bunch of 1000 watters into a giant grow tent, HID will be the cheapest way to go currently. Largely that seems to be because going from 400W-1000W is like $100 more.

    Seems to me that LEDs and spectrum-targeted T5s (or other better fluoro technology) will overtake HIDs fairly soon. They're obviously close as is, and the LEDs are doing it at like half the HID wattage.... imagine when the prices come down to the point that we can do watt for watt comparisons.

  14. Thanks for the rep. And yeah, what initially really bugged me about HID lights being held up as the gold standard was all the heat. Every bit of engineering sense was telling me that anything producing that much heat couldn't possibly be the best solution.

    It will definitely be an exciting next 10 years or so for growing light technology, I think.
  15. Ok you guys sound like a bunch of HS science nuts but your still missing the point. I compleatly agree with you that the industry is starting to come up with better performing diodes. However in today's market you can't beat HID for the single reason of power.

    Photosinthesis is creating sugars through a photochemical prosess that can be measured in Kcal.
    A calorie is about 4.2 Joules; or 4.2W/sec

    No where in this is the efficancy of the specrta taken into account you may notice. This is what I work with when I say I work with the science and engeneering of light this is the part I work with. A part of the research I work in is in developing light meda that is controlable and mesureable within these variances.

    Now back to Lumens and Lies;
    I still state that in today's market, someone will have continued better results with an HID source over floros or LED's. Photosinthesis requires ionized radion and LED's can not produce the same amount as and HID source.

    The problem we are encountering is photosinthesis seemes to bridge the gap between ionized and non-ionzed radiation. We see in lab results the same thing you do with LED grows. However as we try to scale the model up we run into massive issues with maintaing diode outputs; same as people have seen here and in home grows. But the more frustraing problem is when we start to look at the micro end of things. We can see a corrolation between the specra differences and the enzyme reaction to these changes. We can't however see any difference to the celular activity...

    So yes keep hoping. I hope it's sooner then 10 years!!
  16. Um... no. See, LEDs produce MUCH more output energy per unit of input energy. That's what efficiency means. Anything producing as much heat as an HID system does cannot be considered efficient in that manner. The reason grow systems have low lumens are all the things I've outlined in the OP. Lumens mean nothing. Stop paying attention to them or trying to argue using them. Watt for watt, LED wins ALREADY. It's not debatable.

    The only thing HID systems have is cost efficiency. And that's going to go away pretty soon.

    And what do you mean "ionized radiation"? Radiation is comprised of photons, which are not matter, and therefore cannot be ionized. Perhaps you mean ionizing radiation, and are referring to UV wavelengths. UV wavelengths increase potency. UV LEDs and fluorescents exist... there's really no problem there.

    Also, yes, the efficiency of the spectrum IS considered in that equation. The problem is that you're considering the equation in a box without the external conditions and drawing incorrect conclusions. Different wavelengths of light have different availabilities as energy to the plant, which is the entire point of the PAR photosynthesis activity curve.

  17. Alright last post here unless you can stop going in circles and start producing some data to back you up.
    Ok first off; I work as a researcher in this field.... Trust me I know where we sand as far as efficacy goes on this subject.

    Once again in TODAYS market you can not beat an HID for the output energy and spectra covered. An LED today throws at best 100nm (for a high output) Well we are starting to see that plants need a range of about 300nm during each cycle of life; this range shifts about 600nm over its life cycle.
    So your rig will need to contain 6 different LED banks to reach the efficacy of an HID source; that causes your cost to go up 6 fold.

    Ionized radiation (or ionizing radiation if you read wikapedia) is an interesting topic. Research in this field has been minimal because of the cell phone scare. People started looking into non-ionized radiation (the radiation a cell phone gives off) then the funding was cut and it became a chore to research in this field.... I'll keep personal comments out....
    But what were seeing is that a plant uses both ionized and non ionized radiation from the sun. Radiation is photons.? Not going to start that discussion with you.

    Remember that plants are natural and complex critters. We are having a hell of a time developing an efficient system that can supply all of the energy needs for plants. I can't wait for the day that a single household can run off of 20a of renewable electricity. The day is coming but give us some more time. For now keep playing with LEDs. One thing I would like to see is a multi-generational grow done under only LED. We develop some strange mutations in the 3rd generation with concern to root growth. I'd like to see if people get the same results; we were evaluating other variables so I can't say for sure what caused it, and my RT didn't find it interesting enough.

    peace guys
  18. #18 bulletcatcher, Jun 8, 2010
    Last edited by a moderator: Jun 8, 2010
    Argument from authority. Fail. If you actually were who you claimed to be, you'd know that.

    Wrong again. This paragraph doesn't even make sense. And yes, you CAN beat HID for energy input/output as light. LEDs do it. It's not debatable. "Spectra covered" is meaningless. Plants don't see green, and yellow is shit.

    There is no range that it needs, and it does not shift. Blue light reduces internode spacing. Red light increases available flowering hormone. The plant's needs are always the same, but adjusting the spectrum can make it grow more in the way you desire.

    Also you can simply mix LEDs in the same bank to get different spectrums. There is no increased cost as you claim.

    HID is cheap. That's all it has. Obviously, that will go away in time.

    Ok, you're obviously lying now and trying to cover it. You are not a researcher.

    ionized radiation - Google Search


    Try every source on the internet, and everywhere else.

    This is what ionized means:

    Ionization - Wikipedia, the free encyclopedia

    "–verb (used with object)
    to separate or change into ions.
    to produce ions in.
    –verb (used without object)
    to become changed into the form of ions, as by dissolving."

    Photons have nothing to do with ions.

    edit: and if you REALLY want to be technical, electromagnetic radiation is made of photons. Obviously we were speaking of EM radiation since we were talking about light emitted from a light bulb.
  19. I love dialectics, even outside of proper form.

    The first graph posted shows the luminosity function of the human eye. Or, the correspondent sensitivity of human optics to different wavelengths.

    Here's my chart, bask in it's glory. Take your time...savor it.


    The angry bullet is correct when talking about LED lumen output being a poor judgment of their effectiveness on plants as the luminosity function of plants and humans is very different, as displayed in that wonder graph above.

    This is true, but misleading. You do not explain Lumens as the measurable 'visible' lilght in relation to human perception as juxtaposed to chlorophyll pigment reception.

    It's not skewed, it does as it should do. You're right that lights should be measured in irradiance, not luminous flux. But as few if any manufacturers list radiant intensity, your point isn't very helpful.

    Many use w/sqft rules when calculating light requirements. This is actually a measurement of irradiance (w/m2). If you want to get fancy, you can try and calculate spectral irradiance in conjunction with the PAR data.

    There is such thing as ionizing radiation. In fact, ionizing radiation, in conjunction with natural oxidizing agents in the atmosphere (O2, H2O2, O3), are responsible for the sterilization of the surface of the planet.

    Thanks, sun.

    Such ionizing radiation is commonly used to serilize slow moving water and air. Often in the form of UV spectrum light, AKA. UV Sterilizers.

    GeneticEngineer (GC civy, smart dude) is using special CFLs to deodorize and sterilize his grow.

    So....photons have something to do with ions.

    Using LEDs wouldn't require a full spectrum of 6 wavelengths as exposure to optimal photoreceptive wavelengths of Chlorophyll A and Chlorophyll B can be balanced using a combination of the two peak wavelength emitting diodes.

    But WA, I'd love to see your data regarding the 300nm range and 600nm shift over time. Seriously, I'm interested and asking. Educate me.

    I'd like to see numbers related to your claims of output efficiency. I'd like to know what SI unit you're measuring in.

    I think Spectral Irradiance would be ideal. The most accepted it seems is photosynthetically active photon flux density (PPFD). Of course you gotta calculate based on a universal dependent distance variable. So for the sake of argument, let's say 1ft.

    Even so, it'd be hard to calculate given the different shapes & materials of a HID luminaire, and the arrangement and radiant angle of the LEDs.

    I dunno man. This debate's been raging for a while now. I don't see an end in sight, quite yet.

    Make those 5w Luxeons for $.25 a piece and we can talk.
  20. Hold on there. Never said there wasn't ionizing radiation. This other guy is trying to claim that it's called "ionized radiation" and implied that I know nothing about science and must get all my information from wikipedia because I used the correct term: ionizing radiation.

    Photons are energy, and cannot be ionic, therefore the term "ionized radiation" is nonsensical. Obviously, ionizing radiation affects matter and creates ions.

    This is just a matter of time.
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