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Red and Blue LED lights

Discussion in 'Indoor Growing' started by Tokahontas, Jan 21, 2007.


    Tokahontas Active Member

    I heard that you can use red and blue LED lights to add the red and blue spectrums to your plants without adding the extra heat of other lights. Is there any truth to this? I havent had time to research it, but its intriguing and I want to know. Anyone know?

    GraF Well-Known Member

    I actually just saw an add for that type of thing in a high times magazine so yes it does exhist.. performance wise though, I havent the slightest idea.

    High Times makes money for themselves... not others. So........ get it?

    VictorVIcious Well-Known Member

    thought i saw graf back the other day, Still haven't figured out what he meant?? VV

    Robertx Well-Known Member

    I did some field research on LED lights. There are LEDS of ANY light spectrum/temperature you can think of. They consume VERY little energy. They do not generate heat. BUT.... they have VERY LOW luminosity. I saw huge LED systems, they can iluminate a big room for the human eye, BUT they send like 400 lumens. And as far as we are concerned, plants like lumens, thay need energy not just human visible light.
    So, after this field research, I think the LED systems of today are not a good idea.

    Oh, it is important to note that I researched common LED systems and not those sold for plant growing purposes. I couldn't find them here in Fantasy Island!


    shiftythunderf*ck Member

    My 1 wk old seedlings are doing well with 2 blue and 1 red LEDs. However this only illuminates 1 plant.

    budsmackenzie Member

    I read somewhere that plants do not use enough of the green color spectrum for it to be useful. Red, Blue, Orange are the most important.

    With L.E.Ds its not about lumens its about spectrum wavelength.

    I have got good results from mine. Although i did a L.E.D./CFL combo, heard that was the way to go. No fluctuation in the electric bill, no worries about temps, very nice for stealth ops.

    ganjman New Member

    LEDs work but their terrible compared to other lights, cost way too much and you'll never get a harvest big enough to pay the lights off.

    jaysteed Member

    LED's are not measured in lumens the same way HPS lighting is. That said the 14 watt panel would be roughly equivelent to a 50w HPS bulb and the 45 watt would be roughly equivalent to a 150w HPS and a 55 watt panel would be roughly equivalent to a 175w HPS.

    "LED grow lights are not measured in lumens because a lumen is a measurement of light that is tailored to the human visibility spectrum (primarly green/yellow) and photonic light meters are designed to measure the intensity and brightness of this type of light at the source. This allows humans to measure and standardize brightness levels from one white light to the next for easy comparison. LED Grow lights will ALWAYS have a lower LUMENS rating then an HID grow light because of the colors used. For example, if you look at the light spectrum the colors are brightest in the middle - green and yellow. As you move to the right of the spectrum towards red, the color gets darker and as you approach far red it becomes invisible when you hit infra-red (heat) Moving in the other direction to the left of green you have blue moving towards violet and then ultraviolet (UV). Again, the light darkens as you move away from green and yellow. The point is, red and blue will always appear darker to HUMANS (thus a lower lumens value) but this is actually the light plants need most.”

    “An HID light hung 20 feet in the air may produce 10,000 lumens. If you put that same light 1 foot over the plants it is still 10,000 lumens. But this does not tell you how much light (quality and quantity) is actually being delivered to the plants. What is important is the photon flux density (or how much light is delivered to the plant measured in micromoles) and PAR values (Photosynthetic Active Radiation). This is where LEDs excel. PAR values for LED lights are 100% meaning all the light emitted is used for plant growth vs traditional lighting (fluorescents and HIDs) where PAR values are closer to 20% (UV/IR and other colors in the spectrum created but not used). Trying to compare the lumens rating of an HID grow light to an LED grow light is an apples to oranges comparison. Put another way, plants could care less about lumens.”

    maxpesh Active Member

    Hi there. I'm currently doing my first LED grow, I must admit that it has turned into a full time experiment, however I am learning more with every mistake, and most of my mistakes were made due to a lot of disinformation on the internet about LED growlights, so here we go.

    This has been going on for about three months now.

    First off I have built the lights myself.
    So I'm going to try to separate the fiction and bulls**t from the facts. There is no way that we can do any type of reliable mathematical equation to compare them to other type of traditional lighting as the color spectrum that a plant "sees"is approximately opposite to what a human eye perceives as brightness. So when we are talking about lumens or brightness we normally talk about white light when infact a plant "sees" blue content in the light for vegetation stages and red content for the flowers to form healthy. OK, blue colour that has produced the best vegetative growth was 465-470Nm. Now at this stage what we don't require is an LED with a viewing angle that is wide, if we have lots of LEDs we are better going for an LED with a vieving angle of approx 20 degree's. This means that more of the light output it being squeezed into a more directional beam. OK, so after trying different makes I eventually found the ones that I was after on the internet that actually performed amazingly well. I was only growing in soil but was getting veg growth of about 1 inch per day and not spindly either. So anyway that's me finished with experimenting with the veg state, just gonna build more of these babies to see what happens. Now I had started with doing the 75% red and 25% blue as stated in the bullshit on the net and the results were rubbish, but once I went pure 465Nm blue the plants started growing great. OK next big mistake I made, according to advice on the net--"plants require only red for flowering stage". Well this I found out to my horror is simply not true and I could have kicked myself for nearly killing my plants, because I assembled my homemade red lights and took out the blue ones,,oops. Well suffice to say that the BLUE LED's ARE STILL REQUIRED for the plants to survive and grow further in flowering stage however after putting back in the blue lights mixed with the red in equal quantities the plants are once again thriving and after 1 week the little buds are full of hairs (happy days). the blue Led's have an output of 8000mcd each over a viewing angle of only 20 degrees and the red ones have an output of 12000mcd over the same angle..Oh btw the colour spectrum for the red is 625-630Nm. Now that I have perfected all of this (I think), like I said I am gonna build more lights for more peformance as I am now in the process of building a large aeroponic unit for next grow so will post on here regular with pics when I get it all started. So anyway I am not selling anything nor do I proffess to be any sort of growing guru, I am just hoping to share my failures and succeses with you all to save you a bit of time money and trouble. Peace to all :-)

    CaptainPointless Active Member

    I hate to be the dick that says this, but you need to use the search function before your cursor heads to the "new thread" button. There are literally hundreds of threads discussing the benefits and disadvantages of LED growing. A simple search will bring you to a large list of these. I'll provide one of the best ones that I've (as of yet) found.


    ^^ This one is extremely comprehensive, and the discussions are pretty stimulating (except for the arguments between HID fanboys and LED fanboys).

    To answer your question, yes, there is a large amount of truth to the red and blue spectrum question, but the gray area is in the quality of various grow lamps available. It isn't as simple as adding a few blue and red LEDs to the mix. All manufacturers claim the same thing, that their lamp, at the very least, will outperform an HID of the same wattage. But given that there are manufacturers ranging from the average DIY job all the way up to commercially-built, high-power lamps. Choose wisely. If something sounds too good to be true, it generally is. Meaning if a 14W lamp is stated to have higher yields than a 600W HPS or MH, obviously something is fishy. If a 300W lamp is stated to be equivalent or better than a 400W or 600W lamp, this is significantly more feasible.

    Again, in the future, please use the search function before you add another thread to the hundreds or thousands there already are discussing the topic you're curious about. Having too many threads is the reason there is so much misinformation about things, being that various people comment on various threads with various information -- this, of course, creates high amounts of inconsistency in the discussions.


    Very interesting article. I would love to know where u purchased ur boards from. I love the led panel I have,but want to construct one with a bigger footprint. Any direction u can give me will help. I have several thousand led's ready to install.Thanx.

    LEDs New Member

    Hi Maxpesh

    I am interested in knowing the ratio you believe is best for growing, using the Blue & Red spectrum,
    the ratios blue:red for vegetative and
    the ratios blue:red for flowering.

    There is so much erroneous theory out there, it is refreshing to hear from someone who actually knows something.
    I am playing around with 120 degree angle high powered LEDs and would like some honest guidance. I find this area of study exciting and very interesting.

    syphex Member

    25% blue light is all thats needed for reduced stem elongation. Beyond that red light is 30% more efficient.

    Where are you guys ordering your diodes? Cree? Phillips? Epistar? etc?

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