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    spectrum and light intensity

    OK, apologies to whomever's thread I was on when I lost it_ I was going to reply about what I've been able to find out about light spectrum and intensity and how it can affect flavonoids, terpenes and cannabinoids....but then bam, it was gone.

    I'm no expert but this is what I've been able to "distill" from a lot of confusing and misleading information, so I hope it helps for those interested.

    Concerning spectrum in general one that provides for the best growth and development and provides a good amount of "white light" is the best choice. Regardless whether its LED or a lamp based source (or both). Cannabis does seem to use some green light so having some is better than having none.
    In general all plants use a light spectrum between 400-700 nm.
    Some lights don't provide any green light at all, so I prefer ones that produce a spectrum that includes all wavelengths.

    I'm going to skip over the way PAR, PPF and PPFD affect plant growth under artificial lighting and move on to spectral enhancement.

    The proportion of wavelengths as well as intensity can completely change the photomorphogenic outcomes as well as phytochemical concentrations of secondary metabolites- which affect the production of cannabinoids, terpenes and flavonoids in cannabis. This can affect plant quality in terms of cannabinoid & terpene production, flavonoids, color, resistance to disease, heat, light intensity, taste, scent, effects on humans, etc.
    Increasing light intensity can also induce the production of various secondary metabolites.

    Blue and UV light have the most powerful influence relative to other wavelengths and this scales with intensity. Some strains (or even individual plants) are more tolerant while others require more light intensity to display these variables. This is the hard part...knowing how much intensity of spectral enhancement you need to actually make a difference.

    One method that can be used to get the best of both worlds is to use EOP (end of production) treatment when considering lighting. Initially plants are provided optimal conditions for growth and development (referred to as primary metaboiism) during their growth period through early flowering. White light perhaps enhanced with some blue light during the first few weeks has been found to work well. Once most of the growth process has been completed- basically until the last four weeks of flowering full spectrum combined with some supplemental warm light may be the best choice. An important thing to remember is the enhancement of secondary metabolic processes uses up some of the energy and nutrients that would otherwise be directed towards growth and development. But once most growth has occurred then enhancing with specific wavelengths and intensity can provide additional benefits.

    For instance when considering flavonoids incremental increases in ppfd (umol/m2/s) of up to 100 umol/m2/s can significantly impact leaf color with the addition of blue light primarily.
    Various terpenes that exhibit distinctive scents, flavors and effects can also be affected by spectrum and intensity. Increasing light intensity signals plants to produce more glandular trichomes (trichomes are where terpenes, flavonoids and cannabinoids are produced and stored by the plant). More trichomes make “frostier” and "tastier" buds! Cannabinoids are produced to protect against insect, heat and light damage.

    UV light and possibly even short wavelength of blue light (400-420nm) can stimulate the production of cannabinoids, but the effect is thought to be more of a boost than a final result. Plants use several different photoreceptors and pigments that cooperatively regulate growth.
    For instance rooting and leaf color can be affectively enhanced by light in the blue spectrum and flowering can often be affected by light in the yellow-red spectrum.
    But if your light has a true full white light spectrum the addition of supplemental light may not really produce any benefits.
    Most plants have developed under broad spectrum lighting_ basically white light, and get everything they need from within that spectrum.
    But that doesn't mean some type of supplementation won't benefit your crop under the specific environmental conditions of your grow area.
    This is why a lot of commercial growers use a combination of direct sunlight, LED and HID lighting_ to make sure their plants are getting everything they need to be their best.

    Much is being investigated about which wavelengths of light provided at specific intensities at specific times during a plants life cycle can affect the production of different cannabinoids, terpenes and flavonoids. Once we obtain consistent research on these variables then we can design specific strains for very specific effects and results. Medical or recreational.

    This research will be vital to the future of cannabis so support such research whenever possible and keep on sharing your experiences as well!

    Cheers to all!

    Current grow_ coco based medium, Fluence LED lights, AIT, 5 gallon planters,
    liquid organic nutrients by Advance Nutrients and Vegamatrix. Strains_ Exodus Cheese (feminized), Meltdown (regular) and Caesar (regular).

    #2
    Apart from light-dependant reactions, there are many independent reactions that happen within the plant that would be of interest to look into, supplemental lighting has definitely reached it prime in terms of scientists and corporation fine tuning spectrums each with their own benefits, would be difficult to combine every single grow light in the world and create the ultimate spectrum, and there is still a limit to the amount of total exposure of whatever light the plant can have!
    I’m sure many unusable spectrums by cannabis like gamma, X-ray, infrared, maybe even radio will have their effects on many different areas of growth in the plant. Obviously not safe and or Borderline GMO so there’s a limit to everything!

    I think it’s time for science to look into ways of increasing the hydro-static circulation rate within the plant via vibration/musical therapy, lighting manipulation - horizontal veg/vertical flower, high pressure fogponics, universalising micropropogation, restoring stacked genomes and purifying codes, and off course cannabis as a method to combat pollution in highly pilluted cities.

    Comment


    • DrPhoton
      DrPhoton commented
      Editing a comment
      Spectrum design for grow light technologies is really dictated by factors other than spectrum. Although light spectrum has an effect on plant morphology and photosynthetic efficiency, the effect is very negligable when talking about broad spectrum lighting that is typically used today. Including those red and blue designs. The design focus is mostly directed towards what is most efficient rather than spectral quality (at least in the more serious high end products). However, that doesnt mean we can just use any kind of mixture of wavelengths, its just that there is a large window where differences seen with spectrum quality, do not make as large a difference compared with designs that focus more on photon efficiency.

    • ZigZag
      ZigZag commented
      Editing a comment
      Thats basically thats the impression I got as well....that a nice sufficient spectrum is the best place to start and that when you consider all the environmental conditions that also affect growth- probably more so than very specific wavelengths- especially when you consider the overall life of a plant, that efficiency is the next basic step towards designing/choosing any specific lighting system (?). Would photon efficiency also affect how much "bang for your buck" you get from your electric bill? More effective light for your $?
      That would seem like a large concern for commercial folks growing indoors or under mixed lighting especially...Thanks for your input_ always appreciated, always something new to learn_ thats one thing I love about growing my own.Cheers!

    #3
    Thanks, Ziggy
    Being able to provide the optimum spectrum throughout the plant's life will be a good thing. Lots of unexplored possibilities ahead.
    WHAT???
    5x5 grow space
    900w of Vero's and F-strips
    4-17gal totes self-made UC system.

    Comment


      #4
      Some interesting thoughts here. You have to look at the current research on photobiology with plants, to see how much we have really progressed. Bruce bugbeeb leads this effort and his data so far is invaluable. Which is predominatly the main product that is used by manufacturers in grow light spectrum designs. However this is related to the effects of light spectrum on plant biomass. Which has shown that broad spectrum lighting provides superior results compared to monochromotatic sources (not including red+blue sources). But also that the spectrum quality from broad spectrum sources is mostly insignificant and for the most part, affects plant biomass equally among different spectrums.

      Some of what is being discussed here are the effects of secondary properties from light, mostly cannabinoids. Which is taking some time to get difinitive answers for. The main research that proposed the effects of UV on cannabinoids, was the 1987 by john lydon. However what was not recognised by most and began to be completetly ignored, was the potential effects of other UV wavelengths. Which was excluded from this research and people began assuming that UV-B was the only participant in stimulated cannabinoid biosynthesis. But recent research by magagnini 2018 has suggested that UV-A and blue also has similar effects as UV-B and in one particular configuration, ended up testing with the highest levels of THC and CBG. Some companies such as blackdog had suggested this in the past and were already manufacturing light suppliment products that produced UV-A, which they found was superior to UV-B as it is more energy efficient to produce and appears to not affect yields like UV-B has consistantly shown.
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      Comment


      • ZigZag
        ZigZag commented
        Editing a comment
        It will be very interesting to see what researchers find out about how certain environmental conditions affect different strains and how those effect the relationships between cannabinoids and terpenes within those strains. There are so many strains out there today that it seems like a daunting task! What do you think about the folks who are compiling genetic information on different strains? I don't have much to go on but have found the work by folks such as Phylos Bioscience very interesting. Did you have any other sources you'd recommend? Thanks for any suggestions!

      • DrPhoton
        DrPhoton commented
        Editing a comment
        Theres a few cannabis specific research articles such as that by chandra, but most of the best research is done with non cannabis specific research. Which there are too many to list. If you want to understand what we currently know about plants and light, two key books are "molecular mechanisms of photosynthesis" and "plant physiology" by taiz (must be 6th edition for the most up to date research). Cant recommend these two books enough. Also if you havnt done so already, check out cannabis botany by R.C. Clarke.

      #5
      DrPhoton_ Thanks! Once you start to get past the aspects of how to get a plant to maximize its growth potential it just seems like the next logical step is to learn how to "dial in" the specific attributes you wish to replicate or even develop yourself through breeding. Hope your 2019 produces some awesome bud!
      Current grow_ coco based medium, Fluence LED lights, AIT, 5 gallon planters,
      liquid organic nutrients by Advance Nutrients and Vegamatrix. Strains_ Exodus Cheese (feminized), Meltdown (regular) and Caesar (regular).

      Comment


      • DrPhoton
        DrPhoton commented
        Editing a comment
        Yea, you start visioning genetic potential limotations. Its interesting. Yea you too man

      #6
      Cheers to our 2019 green grows!
      Current grow_ coco based medium, Fluence LED lights, AIT, 5 gallon planters,
      liquid organic nutrients by Advance Nutrients and Vegamatrix. Strains_ Exodus Cheese (feminized), Meltdown (regular) and Caesar (regular).

      Comment

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