1. Grasscity.com August contest: Follow us on YouTube to be entered to win a PAX 2 Vaporizer! Winner will be announced Sept 1st
    Dismiss Notice

Blue Light is Better for Flowering

Discussion in 'Indoor Marijuana Growing' started by shivaganesha, May 5, 2008.

  1. an HPS lamp is the best lamp that you can have for flowering. it has the most amount of red and blue light spectrums and my plants have not been hurt by it so dont believe everything that you read.
  2. +100000
  3. Yes well... interesting comments although they don't really tell me anything. When I read your comments then go back and read that guys posts he says a lot more than... 'blue light is best for flowering and red light harms your plants'... do you see what i mean? He actually explains it all very well.
  4. i use an 600 watt hps with no problems , the only problem i have is keeping them cool
  5. Well I've been doing a little research. Isn't it great when a subject like this turns up and literally forces you to want to know more.

    The original poster was not saying that red light is harmful to an extent where red light will kill your plants, just that it does more harm than blue does. All light hurts your plants. Also that red light is of a lower quality to plants than blue light.
  6. Interesting article, thats for sure.
    I am good with whatever seems to mimic nature the best.
  7. Yes very interesting... and the second thing you mentioned is the whole point of the article. The sun naturally throws out far more red than blue, which is why plants have adapted to use the red light more, but the article is suggesting that the sun is not the best light source for plants. It is the best, but only because of it's power... but were we to have a different sun, one that throws out much more blue we would have bigger and more potent plants growing on this planet.

    So as an indoor grower it is not our job to replicate the suns light, but to replicate a light source that is more beneficial to plants.

    That is what I gleaned from the article and the little bits of research I've done seem to back up this guy's theory.
  8. thats badass. i can see us with a different sun. thatd be a sweet movie. everything all tropical, ya know? anyways. cool read, by far better than any other topic on mj lighting. maybe some LEDs or another type of bulb would Aid the HPS during flowering?
  9. Yes they would, all extra light particularly if you can mix up the spectrum is beneficial to your plants. In fact i read a test once on kidney beans, they were only tested under green and red light. The green light proved to germinate the beans faster although the resultant plants were very yellow and weak looking compared to the red light, but the green light still worked best for germination.
  10. ive still heard from a billion and one more sources that hps flowers better plants, and that metal halides vegetates better plants. i read the article and it is very interesting. plus rep for bringing it to our attention. there seems to be something damaging about both HID's, somebody is always pissed off at one and someone else is always pissed off at the other. im a first time grower, and i bought 2 1000w mh's. both of which are taking a breather giving my 600w hps a chance to shine. i could have flowered my plant a month or two earlier but i insisted on using a hps to flower.
  11. That's exactly the thing amnesiac... thankyou for taking the time to post your thoughts as it has hit upon something important. I remember reading that blue has the slight edge on potency while red has the slight edge on yield. Slight edge? Who decided that?

    It seems to me that if the blue photons are richer than the red ones, then providing a rich blue light source would benefit the plants more than providing a rich red one does.
  12. From what i have read and observed from a few years of steady extracurricular research is that marijuana plants are best able to utilize red and blue light (i cannot recall the specific frequency ranges). Blue light has been shown to result in shorter inter-nodal lengths (possibly because of triggering the plant to produce higher amounts of giberillic(sp?) acid) and red light has been shown to trigger/quicken the onset of fruit production (BUDS!!!). Most all frequency's of green light are useless and are reflected - this is why we see most plant matter, in this case marijuana, as being green.

    A simple experiment could validate any of this. For example, try growing one set of plants from seed/clone to maturity with only a metal halide (more blue), one set of plants with only high pressure sodium (more red), and one set under metal halide for the vegetative cycle and high pressure sodium for the flowering cycle. As has been proven time and again by growers around the world, the latter of the three is the method of choice for experience growers who have tried it all - I am inclined to believe that there may be something to this!;)

    to each his own, and to all a good grow,

  13. Well it's actually chlorophyll that makes the plants green... the natural colour of the leaves behind the chlorophyll is a reddy, orangey, browney colour... or the colours of autumn, or as the guys in the US would call it 'Fall'. I would like to see the source for this information you give on red light encouraging the onset of fruit production...

    Also the mention of gibberillic acid... as you said, blue light promotes this hormone, but then surely blue light would obviously be better for flowering... as gibberillic acid actually promotes flowering.
  14. True chlorophyll appears green to the human eye because the wavelength of the reflected light is processed as being "green" by most human beings thru the cones/rods in their eyes...thank you for support and clarifying what I said. ;)

    Think about it, if red spectrums of light are detrimental to the sacred plant, why is it that the harvest sun (which is quite red in the afternoons and evenings) causes outdoor plants to flower?
  15. Both red and blue irradiance is detrimental to plants (kinda like a cup of coffee, it rehydrates yet dehydrates at the same time, but the rehydration should beat out the dehydration... only with the sun the good points far outweigh the bad), and in fact the green spectrum helps to nullify this irradiance.

    Plants only flower beneath more red because this is what the sun mostly puts out and plants have adapted around it. A sun that puts out more blue should result in bigger, better, more potent plants.
  16. I posted it before but I will post it again since some people don't seem to know the correlation between the 2 spectrums of blue and red they go hand in hand. :)

    Light Spectrum. \t
    \tThe average color temperature of the \tsun is 5800 Kelvin throughout the year. What we see on earth has \tbarely measurable spectrum differences between spring and fall.
    \tThe sun produces energy in pulses, \tlike a carrier wave. Let us consider the photosynthetically active \tportion of this pulse, from the lowest frequency--red (675 nm)--to \tthe highest frequency--blue (400 nm). (“nm” means “nanometer”. \tA lightwave that is one nanometer is one billionth of a meter in \tlength.) \t
    \tThis pulse is like a train, with the \tblue in front and the red in the rear. The Red light acts like an \tengine placed at the end of the train, pushing the orange, causing a \tchain reaction, the whole spectrum working together synergistically. \tThe best light for plant growth is full spectrum, like the sun, with \ta slight increase in red spectrum due to evolution and the fact that \tred travels through forest canopy better than blue. \t
    \tRed light is the most efficient \tmonochromatic spectrum for plant growth. However, all the colors \thave functions. If a person were especially good at hearing bass \tsound, that means the other pitches should be emphasized, so that \tone could hear the whole melody. For light to be efficient for plant \tgrowth, it must be full spectrum with close to equal linearity and \tamplitude through the production of 400-700 nm, with a slight bump \tin the red.
    \tThe blue spectrum has \tthe highest energy and shortest wavelength [see: Light Measurement \tHandbook (1997), by Alex Ryer, page 8]. \t
    \t \t
    \tBlue is in the front of \tthe light train, acting like a spearhead to penetrate the leaf, \tcarrying the other colors with it. The far blue range includes UV-B, \tsimilar to what is found at high altitudes, and increases the prized \tphenolic compounds. This increases the flavor of peppermint, \tlicorice, pepper, etc. \t
    \tConventional wisdom dictates that \tthe growth phase be illuminated by a quartz metal halide (for blue \tlight), the bloom phase by a high pressure sodium (for yellow/
    \torange light). However, \ta full spectrum is needed for all phases for a variety of functions. \tBlue induces growth hormones and rooting, and reduces stem \telongation. Red induces flowering hormones, and provides energy for \tgrowth of flowers and leaves. Using only quartz halide during growth \tphase results in slow growth due to less red light. Using only HPS \tlight during flowering stage often causes leaf yellowing, due to \tlack of growth hormones; and tends to cause stem elongation. \t
    \tAn artificial light \twhich reproduces a red-enhanced full spectrum is the “Ceramic \tMetal Halide” or “High Pressure Metal Halide”. This has more \tblue than a metal halide with a conventional quartz arc tube, and \tmore red than an HPS, so it's spectrum is optimum for all stages. \tThe Ceramic Metal Halide (CMH) features a ceramic arc tube like an \tHPS, and uses an HPS magnetic ballast. Philips has recently come out \twith a horizontal version of this bulb, resulting in longer bulb \tlife and 1000 lumens more compared to a vertical cmh bulb operating \thorizontally. Generally, horizontal works best. \t
    \tFor those limited to magnetic \tballasts, CMH is probably the best plant light available. For the \tLife Light electronic ballast, Life Lights also produces \tfull-spectrum pulse-start metal halide bulbs. These are more \tefficient than normal halides, with better spectrum. They are \tdesigned to accommodate the 100,000 pulse rate of the Life Light \telectronic ballast. These come in four spectrums: \t
    \t*6K for rooting and early veg
    \t*4K for general growth/bloom
    \t*3K for late bloom
    \t*10K for finishing (last 2 weeks)
    \tIf you can't afford all four \tbulbs, the 4K is fine for all stages.
    \tThe CMH has a better spectrum and is \tmore efficient electrically than the retro-fit HPS that operates on \ta MH ballast. The retro-HPS is more expensive, lasts only half as \tlong, and has reduced output, compared to a regular HPS.
  17. :hello::hello::hello: ^^^^^^^^^^^

    To the OP...why in the world would you try and discount decades of research because you read one article that looks pretty? As someone said before...do an experiment and prove yourself wrong. There are grow journals on this very site and all around the internet with side by side comparisons. It has been shown time and again that a CMH bulb is the best bulb to use in any phase...if you can't do that, stick to the conventional, proven way of doing things. Look a few up, then apologize to everyone here at GC.
  18. Who says so? Could you point me in the direction of any scientific research on any plant where tests have proved red light to be better for plant growth?

    Well said, I agree completely that blue light is excellent for the terpenes... even in cannabis and will enhance flavour and aroma.

    Again I agree with everything here except the rooting. Cannabis works hard (using a hormone called cytokinin) to keep its roots to a minimum. The only reason plants have a root system at all is to better take nutrients. I am yet to find a study on the causes of a plants rooting... maybe you could point me in the right direction?

    Of course red is used too for energy... but i am also yet to read a study that says red light induces flowering. In fact everything I have read suggests that blue is the best for this event. The red light, being the weakest, seems to be a waste of time.

    Also by your reasoning on red light, in an absence of red light and an abundance of blue light cannabis would either not flower or flower slower. Is this the case?
  19. the color spec doesn't have anything to do with flowering beggining you just need a dark period of 10 or more hours..... i would agree that blue light is best for flowering on another note though because it is harsher in uvb rays and therefore produces more trichomes=danker nugs bitchesssss metal haldie and hydroponics if you want some super sticky icky and hps and soil if you wanna make some money i thought everyone knew that shit

Share This Page