mrrobert420
New Member
been a lot of serious LED talk lately - The purple red hue is drawing people in lol
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been a lot of serious LED talk lately - The purple red hue is drawing people in lol
One more item is that in order to say how many channels are in the lights most manufactures add UV and IR both of which don't really help plant growth, I would rather have more in other ranges that plants really use. The sad part is the LED does a great job but only for 1 plant maybe 2 if they are kept very small. Because of the footprint I am lucky to get 1oz per plant but it's great shit.
I was always told that UV-B hinders growth but that UV-A is essential to plant growth.
The effects of UV-B radiation on photosynthesis, growth and cannabinoid production of two greenhouse-grown C. sativa chemotypes (drug and fiber) were assessed. Terminal meristems of vegetative and reproductive tissues were irradiated for 40 days at a daily dose of 0, 6.7 or 13.4 kJ m-2 biologically effective UV-B radiation. Infrared gas analysis was used to measure the physiological response of mature leaves, whereas gas-liquid chromatography was used to determine the concentration of cannabinoids in leaf and floral tissue.
There were no significant physiological or morphological differences among UV-B treatments in either drug- or fiber-type plants. The concentration of Δ9-tetrahydrocannabinol (Δ9-THC), but not of other cannabinoids, in both leaf and floral tissues increased with UV-B dose in drug-type plants. None of the cannabinoids in fiber-type plants were affected by UV-B radiation.
The increased levels of Δ9-THC in leaves after irradiation may account for the physiological and morphological tolerance to UV-B radiation in the drug-type plants. However, fiber plants showed no comparable change in the level of cannabidiol (a cannabinoid with UV-B absorptive characteristics similar to Δ9 THC). Thus the contribution of cannabinoids as selective UV-B filters in C. sativa is equivocal.
I understand people want to believe that UV and IR are useful as they are part of the full spectrum of the sun however plants that get a lot of UV protect themselves with oils and I am not talking of increased THC either. As for the IR it has not been shown to be a very useful spectrum and as I have said I personally would rather have a light without either as there are colors which plants use more. IR also produces excessive heat as that is a part of what the spectrum does. UV by several LED makers is added for reduction of mold nothing more. Most people who are new to growing are taking all of the LED info as fact when HID lighting has and still does produce exceptional bud with just as much frost and THC as any LED just look at any good grow book and see the wonderful photos taken using HID lighting.
Yes I do believe LEDs will someday take over but for now all major growers are still using HID world wide. The digital ballast all alow for both MH and HPS lamps so it's easy to veg with one and flower with another. Old time growers with the very best crops had a hard time believing indoor growing would ever turn a profit and look at the specs now. Things change and so do the tools we use, but like every tool made they take time to make them correctly.
Wavelengths beyond 700nm are apparently of insufficient energy to drive any part of photosynthesis. So a huge drop in efficiency has been noticed at 700nm. This phenomenon is called as RED DROP EFFECT. In other words there is a sharp decrease in quantum yield at wavelengths greater than 680nm. This decrease in quantum yield takes place in the red part of the spectrum. The number of oxygen molecules released per light quanta absorbed is called as quantum yield of photosynthesis. This effect was first of all noticed by Robert Emerson of Illinois University. Later on Emerson and his group observed that if chlorella plants are given the inefficient far red light and red light of shorter wavelengths in alternate fashion, the quantum yields were greater than could be expected from adding the rates found when either colour was provided alone. This synergistic effect or enhancement is known as EEE or Emerson Enhancement Effect. This was the first good evidence that there are two photo systems; one absorbs far red light and other red light and both of them must operate to drive photosynthesis most effectively.
Drug and fiber-type C. sativa were irradiated with three levels of UV-B radiation for 40 days in greenhouse experiments. Physiological measurements on leaf tissues were made by infra-red gas analysis. Drug and fiber-type control plants had similar CO2 assimilation rates from 26 to 320C. Drug-type control plant had higher dark respiration rates and stomatal conductances than fiber-type control plants. The concentration of Δ9-THC, but not of other cannabinoids) in both vegetative and reproductive tissues increased with UV-B dose in drug-type plants. None of the cannabinoids in fiber-type plants were affected by UV-B radiation. The increased level of Δ9-THC found in leaves after irradiation may account for the physiological and morphological insensitivity to UV-B radiation in the drug-type plants. However, fiber plants showed no comparable change in the level of cannabidoil (CBD)
I have tried and tried to find results to support your claims but have only found info from LED manufactures and sites supported by LED lighting like this one. Can you show any unbiased results?
UV helps get rid of indoor mold by destroying the fragile growth of the mold itself the same way it destroys skin cells on the body. I originally found the information about it from Advanced LED lighting about 1 year ago. They have sense removed all mention of UV and IR on their web site. I guess they couldn't prove it anymore than UV producing more THC as there is no scientific way to prove with Marijuana being a schedule 1 drug in the USA.
Sorry but it seems at the moment nobody without a biased opinion mentions either UV or IR