UVB lights?

Discussion in 'Growing Marijuana Indoors' started by 13ronin, Feb 10, 2009.

  1. also, I read a thread response where ed rosenthal's suggestion on UV lighting is that it is MOST beneficial in the last 10 dys of flowering. unfortunately, he didnt elaborate as to why, certainly the implication from that is that it is beneficial in the synthesis of THC, why else would it be beneficial at the end of flowering?

    at the end, trich production is at its most, and cannabinoid synthesis is definately afoot. if he recommends UV lighting at this point if no point else, then what other conclusion should be reasonably drawn?
     
  2. #22 amoril, Feb 17, 2009
    Last edited by a moderator: Feb 17, 2009
    more evidence!!!!

    "Conversion of CBD acid to THC acid is the single most important reaction with respect to psychoactivity in the entire pathway and the one about which we know the most. Personal communication with Raphael Mechoulam has centered around the role of ultraviolet light in the bio-synthesis of THC acids and minor cannabinoids. In the laboratory, Mechoulam has converted CBD acid to THC acids by exposing a solution of CBD acid in n-hexane to ultraviolet light of 235-285 nm. for up to 48 hours. This reaction uses atmospheric oxygen molecules (02) and is irreversible"

    taken from : Marijuana Botany, An Advanced Study: The Propagation and Breeding of Distinctive Cannabis
    by Robert Connell Clarke.

    ----

    hmmm, CBD -> THC in a laboratory in the presence of UV light. pretty entertaining, wouldnt you say?

    specifically since it's an irreversible reaction.

    -----

    im getting a better idea. Im finding more and more evidence to suggest that UV light does in fact play a role. You keep nay-saying, but Ive yet to see any evidence in support of that stance. Care to change that? logic is my friend too, but there's actually a boatload of info out there if you search for it, and Im not finding any disproving a thing, and definately some supporting it.
     
  3. #23 amoril, Feb 17, 2009
    Last edited by a moderator: Feb 17, 2009
    same book ::

    Environmental conditions influence cannabinoid biosynthesis by modifying enzymatic systems and the resultant potency of Cannabis. High altitude environments are often more arid and exposed to more intense sunlight than lower environments. Recent studies by Mobarak et al. (1978) of Cannabis grown in Afghanistan at 1,300 meters (4,350 feet) elevation show that significantly more propyl cannabinoids are formed than the respective pentyl homologs. Other strains from this area of Asia have also exhibited the presence of propyl cannabinoids, but it cannot be discounted that altitude might influence which path of cannabinoid biosynthesis is favored. Aridity favors resin production and total cannabinoid production; however, it is unknown whether arid conditions promote THC production specifically. It is suspected that increased ultraviolet radiation might affect cannabinoid production directly. Ultraviolet light participates in the biosynthesis of THC acids from CBD acids, the conversion of CBC acids to CCY acids, and the conversion of CBD acids to CBS acids.
     
  4. #24 amoril, Feb 17, 2009
    Last edited by a moderator: Feb 17, 2009
    a real cool, and useful, paragraph from the chemical ecology of cannabis ::

    "This CBC pigmentation hypothesis would imply the development of an alternative to the accepted biochemical pathway from CBG to THC via CBD. Until 1973 (Turner and Hadley 1973), separation of CBD and CBC by gas chromatography was difficult to accomplish, so that many peaks identified as CBD in the preceding literature may in fact have been CBC. Indeed, it has been noted (De Faubert Maunder 1970) and corroborated by GC/MS (Turner and Hadley 1973) that some tropical drug strains of Cannabis do not contain any CBD at all, yet have an abundance of THC. This phenomenon has not been observed for northern temperate varieties of Cannabis. Absence of CBD has led some authors (De Faubert Maunder 1970, Turner and Hadley 1973) to speculate that another biogenetic route to THC is involved. Facts scattered through the literature do indeed indicate a possible alternative. Holley et al. (1975) have shown that Mississippi-grown plants contain a considerable content of CBC, often in excess of the CBD present. In some examples, either CBD or CBC was absent, but in no case were plants devoid of both. Their analysis of material grown in Mexico and Costa Rica served to accentuate this trend. Only one example actually grown in their respective countries revealed the presence of any CBD, although appreciable quantities of CBC were found. The reverse seemed true as well. Seed from Mexican material devoid of CBD was planted in Mississippi and produced plants containing CBD. "

    first implication is that CBC and THC are not mutually exclusive compounds, but instead CBC is competitive with CBD. Assuming this, THC is the end byproduct from the deterioration of either of the cannabinoid processes. This would also support the evidence that there are 4 naturally produced isomers of delta-9-thc. 2 have been easily demonstrated to have come from CBD decomposition into THC.

    And, the differences in the 4 variants are said to be minimal in psychoactive effect (intensity), although they are said to have different felt effects. this would explain the different type of high associated with indica and sativa. note that the mississippi example where mexican weed with high CBC content was grown in miss and had high CBD content, not CBC. boom, cannabis adapts almost immediately to what the environmental surroundings are. we already know this.

    theres a cool article somewhere about inducing sativas. basically, any plant, breed 2-3 times, can become more sativa by changing the light. http://www.cannabisculture.com/articles/2600.html
     
  5. Amoril, I have read the article before on the optics of marijuana. I am surprised that anyone would consider this a serious piece of work much less bring this up as evidence. Never mind that the unknown author doesn't provide a single study or method for how he supposedly determined the lens capability of trichs. This is pure speculation and even the author at the end states that he has "more questions and answers about the resin spheres' magnifying power. The problems of the resin-spheres-as-lens theory are manifold.

    Yes, indeed, early trichomes have a transparent looking dome shaped appearance, and you can certainly imagine it being a lens but imagination is hardly a good way to do science. Looks can be deceiving. The problem is that a transparent cannabis glandular trichome has very little or no THC in it!

    Once the trichome begins producing THC, the trichome becomes cloudy. Cannabis growers recognize the first signs of THC when they notice their trichs becoming white or cloudy. And if you have a cloudy sphere, there goes the lens theory.

    But that doesn't stop this author from speculating further, oh no. He then tries to connect the yellow tint in trichs as a method of correcting for chromatic aberration! You see, lens manufacturers put a yellow tint in lens to correct chromatic aberration so therefore (don't you see?), this must also be why trichs turn yellow.

    But trichs turn yellow as they age and not only do they become less transparent but the globe upper surface begins to dimple and deform. I hope you're beginning to see how silly this theory is.

    It gets worse.

    Once the THC particles separate away from the disc cell layer and into the upper half of the globe (and mixed with other cannaboloids), you now have UVB ABSORBERS floating in the globe. And if you believe that the purpose of THC is to protect the plant from UVB, you now have THC preventing UVB from reaching the disc cell layer where THC is formed!

    [See Immunochemical Localization of Tetrahydrocannabinol (THC) in Cryofixed Glandular Trichomes of Cannnabis, by Eun-Soo Kim and Paul G. Mahlberg].

    And we know that UVB absorbers convert UVB to infrared (heat). So now you have a condition where the trich gland head becomes a cloudy little OVEN!

    Hey, but wait! Maybe it's the INFRARED radiation that's triggering THC production. That's the ticket! Hey everyone, lets all replace our UVB bulbs with heat lamps!

    NOT!

    It doesn't make any sense yet this is exactly the kind of "evidence" people are using to justify buying UVB bulbs.
     
  6. I have no assertions about the primary functions of trichomes. Again you misunderstand my position here. The assertions come from scientific studies. My point about humidity was to show that it has as great or a greater correlation than does UVB. And again, I state, correlations don't prove causations.

    But why would you think that an antidessicant should be present during the greatest exposure to light? On the contrary, it's in the summer when the plant is smaller and surrounded by wet vegetation and high heat exposure when the highest humidity occurs. Your assumptions are false. Greater humidity tends to occur during the summer and the least during the winter.

    "im going to admit, that after a TON of reading the last few days, I believe more now in UV light than I did before this conversation..."

    Of course. A believer will always find more "evidence" for his beliefs even when that evidence doesn't make any sense. Belief has absolutely nothing at all to do with truth.
     
  7. But that goes AGAINST your belief that THC is there to protect the plant! Cannabis adapts to UVB from seedlings and all through veg, long before stalked glandular trichomes are formed. The vast majority of THC is formed only during flowering. Clearly there is another method cannabis uses to protect itself from UVB. This is also true of other plant species. That alone should, at the very least, spark doubt in your mind.

    But don't let facts interfere with your beliefs.

    "now, heres what i really think of humidity. First, if there is a benefit, it seems more likely a stress related one. For example, a plant in an arid environment doesnt inherently recieve any additional stimulus from its surroundings (as would UVB light provide more energy/photon). The plant *may* respond to the dry stress by promoting trich development, but it doesnt seem likely that it would promote activity within this trichome."

    Indeed low humidity may very well act as stress, and that could be why cannabis adapted to grow trichomes to produce a hydrophobic fluid to protect itself. But the same thing could apply to UVB (if indeed it does cause more trichomes).

    As you said, UVB light consists of high energy photons and that could very well dry out the leaf. Some UVB growers have reported that they used too much UVB or placed their bulb too close and it turned their leaves into dry dead ones.

    So how do you know that the plant is not simply responding to the drying effects of UVB? UVB is known to damage DNA in plants and that alone produces stress.

    But as I said before if a UVB bulb is simply stressing the plant, there are lots of other ways to cause stress without the danger to your eyes or your plant.
     
  8. Why did it suddenly "hit" upon you that ares of low humidity will have higher UV light penetration when I addressed this in my very first post? That was my point of bringing up low humidity in the first place. That's the point; to bring up the idea that both are correlated except the correlation works better for low humidity because in high humid climates with high UVB, cannabis does NOT produce as high a yield. But you continue to reject low humidity as a possible causal agent for trichome production while only promoting UVB. Why is that?

    "however, to bunk the theory that humidity is the greater sole factor, consider that regardless of humidity, cannabis grown on mountains/higher elevations above 45 deg. north latitude produce almost no cannabinoids."

    Again you're creating straw man argument. I never said that low humidity is the "sole factor" and for you to imply that only shows that you either haven't understood what I've said or you refuse to accept another possibility. How many times do I have to repeat that I'm only bringing up low humidity as a correlative basis equal to or greater than UVB? Again: correlations do not prove causations.

    High humidity also, is known to cause poor yields. High humidity doesn't allow the leaf to transpire as well and actually tends to stunt growth.

    But one does not need geographical areas to realize that in grow rooms around the world where there is no UVB at all, growers are producing fantastic cannabis with large numbers of trichomes. And the reason most probable why cannabis is not grown in elevations above 45 degrees is because of many other factors. Firstly, there is less light overall and that alone would cause low THC yields. Secondly, cannabis grows where people are, not necessarily where nature want it to grow.


    Now about Marijuana Man's color chart on tropical zones with high UVB levels. At first I was puzzled by the chart because it shows high UVB only in the northern hemisphere. Now I realize that he was showing a erythermal chart for the SUMMER when UVB is at it's highest!

    You can find seasonal UVB erythermal charts on the internet.

    Cannabis flowers in the autumn or winter when the UVB index is at the lowest. And that is also when the trichomes appear. If Marijuana man showed an erythermal chart for the winter, the red UVB band would shift to the southern hemisphere, but of course that wouldn't agree with his hypothesis. And how many places in the southern hemisphere does cannabis grow naturally anyway where, according to Marijana Man, it should grow?

    So much for the cannabis-grows-in-high-UVB areas theory.

    As as I suggested before, cannabis is not grown in the tropics because of UVB, but rather because that is where people are. Cannabis is a cultivated pant. I also suspect that the ancient spread of cannabis from China to Afghanistan was also spread by humans rather than by natural selection. The spread correlates with the ancient trading routes from China, northern India, through the Khyber pass and onto Afghanistan. It is also now known that cannabis was cultivated by humans at about 3000 years ago or earlier. Some speculate that it may have been the first crop cultivated by man.

    As much as I like Marijuana man, his hypothesis makes no sense, and neither does yours (and I like you too in spite of your bias.) :)
     
  9. Ed, no doubt, brought up the suggestion that UV lighting would most beneficial during the end of flowering because that's when the trichomes appear. The implications could be many things. If, indeed, UVB somehow produces more trichomes, it could be because of stress, not necessarily because it is beneficial.

    What conclusion should be reasonably drawn? No conclusion because he his simply speculating along with many other people. Speculations are not what I want to hinge my grow upon.
     
  10. #30 proteus, Feb 17, 2009
    Last edited by a moderator: Feb 17, 2009
    Intertaining yes, convincing, no? You failed to provide the kicker at the end:

    "however, the yield of the conversion is only about 15% THC acid, and some of the products formed in the laboratory experiment do not occur in living specimens."

    It's also important to realize that there is very little CBD in drug-grade cannabis, usually only around 1%. So even if it did convert in living specimens, if you take 15% of that 1%, you'd only get a miniscule amount of THC for all that UVB bulb effort!

    Is that the kind of results you are looking for by adding UVB bulbs?

    I'm sorry but that doesn't impress me at all, but each to his own.
     
  11. Well that's what I have been saying all along. The correlation of Aridity to THC is just as strong or better than ultraviolet is. Neither has been proven. So why aren't you just as interested in low humidity as you are in UVB? See what I mean? You are only introducing a bias against low humidity but favoring UVB.

    I am not favoring either one. I don't know but I'm not going to believe something without good enough evidence. You, however, are convinced, but you have failed to present a convincing argument.

    "I can live with doubt and uncertainty and not knowing. I think it's much more interesting to live not knowing than to have answers which might be wrong."
    --Richard Feynman
     
  12. If tropical drug strains of Cannabis do not contain any CBD at all, then there goes your point of your previous post about UVB converting THC from CBD. Are you not aware that you are contradicting your own "evidence"?

    This article, again is only speculation. When you see the words "may" or "could" it's showing what I've been trying to tell you. No one knows. The biogenetic route to THC is open to investigation.

    However, there is one obvious observation that you continually seem to ignore. People grow cannabis with high THC levels without UVB lights at all. Clearly then, whatever causes THC in cannabis, it is entirely without the need for UVB.
     
  13. Let's see, you want me to answer your questions but you refuse to answer mine. When I asked you your methods for determining how much THC you have in your plants you remained silent.

    As for my trying UVB bulbs myself, I don't use unproven methods unless there is compelling evidence. There is, however, abundant information and studies that UVB destroys DNA, and produces lower yields in crops exposed to higher levels of UVB. (I will post more information about this later.) UVB bulbs are also dangerous for humans. It can cause blindness and cancer.

    Now why in the world would I want to expose my plants to possible harm and effects that could lower yield? I have scientific evidence for the harm UVB causes but only wild speculations about UVB and THC.

    I choose to use time tested methods that guarantee high quality cannabis, and I don't need UVB to do that.

    And even If I did use UVB bulbs and saw more trichomes, that does not mean more THC. Lots of people fool themselves if they think this is so. Genetics has far more influence on THC than anything else. I also do not have the instruments to measure THC so anything I would say about it would only be an opinion and opinions are not a way to determine facts.

    Lastly, I don't want extremely high levels of THC. I prefer quality, not quanity. Do people really want to get so stoned to the point of collapsing on the floor? Don't answer that; no doubt some people would say "yes". :)
     
  14. Here is one reason why I don't want to expose my plants to UVB. It is because of the known damaging effect of UVB on animal and plant life. Yes, UVB can produce vitamin D in animals which is essential for life, but it also causes DNA damage. There are many scientific studies (not just one) that show the detrimental effects of UVB and only speculations on the benefits of UVB for plants. The following are only two examples from scientific research:

    ------
    UV-B effects on plants

    Agricultural scientists have responded with a series of pioneering investigations on the effect of artificial and solar UV radiation upon plant growth and development. A great variety of physiological and morphological plant responses to UV radiation have been subsequently demonstrated over the past years. Most of these experiments, however, have employed UV lamps which usually emit radiation quite unlike the radiation present in the normal terrestrial solar spectrum. The importance of solar angle, atmospheric turbidity, elevation above the sea level, cloud cover, total atmospheric ozone column, and the UV albedo of the earth's surface with respect to the total UV irradiation intensity and wavelength composition should be considered in UV radiation of natural environments. Though not all the plant responses demonstrated as the result of UV radiation are considered as damaging or disadvantageous for the plant; the majority of evidence indicates that UV irradiation is usually detrimental, particularly UV-B irradiation (Caldwell, 1971). In this section a summery of the UV-B effects on crops from the literature will be presented. The growth of many plant species is reduced by enhanced levels of UV-B radiation (Teramura et al., 1989). The enhanced UV-B radiation generally has negative impacts on growth, yield and quality of some crop plants such as soybean, winter wheat, rice, sorghum, cotton and corn. The response varies with different plant species. Some are very sensitive and some are least sensitive. With enhanced UV-B radiation photosynthesis decreases, plant height and leaf area decrease, dry matter production, yield and quality reduces in many crops. In the study conducted by Tevini et al. (1991b) plant height, leaf area, and the dry weight of sunflower, corn, and rye seedlings were significantly reduced with enhanced UV-B radiation. Rice is among the most important crop plants in the world. Sixteen rice cultivars from several different geographical regions were grown in greenhouses with supplemental levels of UV-B radiation (Teramura et al., 1991). Alterations in biomass, morphology, and maximum photosynthesis were determined. Approximately one-third of all cultivars tested showed a statistically significant decrease in total biomass with increased UV-B radiation. For these sensitive cultivars, leaf area and tiller number were also significantly reduced. Photosynthetic capacity, as determined by oxygen evolution, declined for some cultivars. In a six year field study of a UV-sensitive soybean, Teramura et al. (1990) presented a statistically significant 19%-25% reduction in seed yield in five of the six years under a 25% ozone reduction level.
    http://uvb.nrel.colostate.edu/UVB/uvb_agimpact_uv_effect.jsf

    This study is particularly relevant for indoor growers because the study uses UVB lamps in a greenhouse.

    -------------

    Ozone depletion and UVB radiation: Impact on plant DNA damage in southern South America

    We found that in the spring of 1997, despite frequent cloud cover, the passages of the ozone hole over Tierra del Fuego (55 S) caused concomitant increases in solar UV and that the enhanced ground-level UV led to significant increases in DNA damage in the native plant Gunnera magellanica. The fluctuations in solar UV explained a large proportion of the variation in DNA damage (up to 68%), particularly when the solar UV was weighted for biological effectiveness according to action spectra that assume a sharp decline in quantum efficiency with increasing wavelength from the UVB into the UVA regions of the spectrum.

    --------------

    Although the studies do not directly address our favorite weed, cannabis is a plant. Now why would I want to expose my plants to UVB radiation when there's a possible chance for damage or low yield? Not me.
     
  15. ricard0, I thought I had answered you but apparently my post was deleted for some reason. I'll try again.

    Thank you for you kind comments and interest in this discussion.

    As for why people would use UVB bulbs if they didn't notice tangible results, the problem is their method of "noticing". Believers want to believe their UVB lights work and if they notice an increase in trichomes or whatever, they will more than likely attribute it to the UVB light when it could be something else. The number of people who believe something does not determine truth. (That is called the bandwagon fallacy). The only real way to determine THC levels is to measure it, and unfortunately the instruments are too expensive for the average grower.

    Unfortunately trichome numbers don't necessarily determine high levels of THC. In fact sometimes it could be the other way around. (I have information on this somewhere but I can't find it at the moment.)

    I also respect amoril as a person but that does not mean I should respect the pseudoscience that has been presented here. It is very dangerous to form conclusions on scientific specuations.
     

  16. Related and respected. Message received. I for one cannot see a scientifically supported theory either proving or disproving either side of this debate any time soon. However, and maybe i was a bit vague, my point was (and is) that there are many respected growers practicing this alternative/advanced technique with results they are pleased with. To tuck all of them in with the "believers" blanket implies a diminished level of intellect akin to a cult members' mental state of being. That's just plain rude. I wish some more of the UVB users like AugustWest would stop in to comment on this subject.

    Also, let us not forget that all scientific discovery and practice has very humble beginnings.

    Just so you guys know, i plan on giving the UVB bulbs a try, so if you don't hear from me for a while, it's quite possible i have been turned into a "Believer" incapable of an impartial opinion.

    Or not. I guess if they don't work, i'll know and chunk 'em in the trash. Or will i? LOL. I hardly think that all of these folks have been hypnotized by there new UVB lights, nor do i think i will. I will, no doubt use my own two eyes, nostrils and lungs to draw my own conclusions. I may even sneak a couple joints into the rotation sometime and watch the scene breakdown, field reactions, comments and observations. That's where the rubber meets the road IMO. Not in a machine. Just my $.02. :wave:
     

  17. I understood your point. Perhaps my answer was vague. There certainly is nothing wrong with growers using UVB bulbs. I never said there was. If they are pleased by what they believe is causing their pot to become more potent than all the power to them. As I said before, if you think it's getting you high (even though their plants may actually have lower THC), what does it matter? If you *believe* you're getting higher than you are getting higher. It's all about the end result, isn't it?

    But belief does nothing to establish knowledge about nature, that that's what I'm interested in. And yes, indeed, science had very humble beginnings. It had to struggle against orthodox beliefs. If you had a scientific understanding about something and it conflicted with the beliefs of the day, it could get you killed or ostracized from society. Science still meets with skepticism and has a long way to go.

    Just giving UVB bulbs a try isn't enough to determine if they work or not. Only if it were that simple!. How are you going to determine THC levels? Your eyes aren't enough. And nostrils have little to do with THC. My informants tell me that pure THC doesn't have an odor (at least to humans). The dank smell comes from terpenes and other chemicals. Inhaling THC and determining it's high is too subjective. In my experience, pot is better and stronger when I'm feeling good and weaker when I not feeling so good. But what do I know? :cool:
     
  18. i have been following this thread since i first saw it and i must say this is quite a debate...

    ricard0 has been doing a good job trying to mediate this but i think its best we leave the science to the scientists (no offense bro i couldnt keep up with alotta the shit myself)

    both proteus and amoril make very convincing arguments however lets all remember we're on the same team and ultimately we're all here to help each other do one thing... grow the best weed possible... if im wrong here someone please correct me?

    now perhaps ill throw my hat into the ring... if you already use supplemental cfl lighting in your grow room what would be the harm besides initial cost of using uvb bulbs instead of regular cfl bulbs?
    i mean obviously it helps to use co2 and buy the best strain you can but what if uvb helps that much more?

    i also have read articles that can neither really prove or disprove this but i watches the marijuana man video uvb thc and me and he seems like he knows his shit...

    all im sayin is rather than go so hard to disprove something you havent tried give it a whirl... its not like its gonna ruin your crop
     
  19. Hi xspiggax. Thanks for the comment.

    The reason I don't use UVB bulbs is because there *is* evidence that it could cause damage or poor yields (see my posts above).

    As for marijuana man, he may very well know a lot about cannabis but just because he says UVB may increase THC does not mean that it does. Much of my argument here is to show that his "evidence" is weak and contradictory.
     

  20. it doesnt impress you that in the presence of carboxolic acids, in a laboratory, in the presence of UV radiation, that CBD converts to THC? regardless of yield, it converts. the fact that it converts at least a little with no outside stimulus certainly represents some relationship between the two.

    ----

    also, by showing that tropical cannabis contains no CBD i am most certainly not contradicting myself. It has also been shown that CBC can produce THC (different isomers, but psychoactive properties are said to be similar.

    the interesting thing is that tropical (CBC) plants produced CBD in non-tropical environments, ie mississippi. This shows that not only are cannabinoids not hard-coded into the genetics, but also provides an alternative method to THC production.

    the fact that, even with your evidence, CBC shows the potential best UVB absorption properties, should make this easier to follow. I almost think youre just refusing to open your eyes.


    ---

    still waiting on evidence that shows its bad. I mean, sure UVB causes cancer in humans, but reptiles HAVE to have it. So saying that it damages DNA/ cellular mechanisms in some creatures is foolish. Show me evidence that its harmful to cannabinoids (i dont give a shit if it burns leaves, I dont smoke the leaf).

    There is no evidence that Ive found showing UV radiation harmful to cannabinoids. Plenty supporting the idea that they are beneficial. So, where is it?


    im wondering if your belief statements are true, but you are the one who believes against UV radiation being useful...?
     

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