Trichomes, THC and UVB light.....

excuse me for butting in but i read this whole thing in the span of 2 days i would get to high and have to take a break lol anyway i read somewhere that uvb light is good vitamin d production. so i was wondering if you guys thought this would be a good light Vitamin D production with Ultraviolet Light

Well, I talked to The Man about this last night, the Guru of Ganja, Ed Rosenthal. He said that UV is useful in the last 10 days of flowering, and since HPS spectrum has none, to switch your HPS to a MH for the last 10 days. Or add a UV lamp for the last 10 days. He said it will increase trichome development, and cause higher potency. He suggested tanning bed lamps.

BTW Ed and I smoked a whole lot of pot!


HTH

Hey pot'... why only the last 10 days?

Yeah, why only the last 10 days? what's up with that? Give any reasoning?

Next time you see Ed, ask him if he'll autograph a 1st edition printing of his book for me.

potroast said:

Well, I talked to The Man about this last night, the Guru of Ganja, Ed Rosenthal. He said that UV is useful in the last 10 days of flowering, and since HPS spectrum has none, to switch your HPS to a MH for the last 10 days. Or add a UV lamp for the last 10 days. He said it will increase trichome development, and cause higher potency. He suggested tanning bed lamps.

BTW Ed and I smoked a whole lot of pot!


HTH

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I'm not 100% positive but doesn't the glass in front of the bulbs _ both HPS & MH _ block uv? I know that the quartz envelope of a HID bulb pretty much filters out all of the uv, before it reaches the glass.

*of course these are my opinions and I'm probably wrong.

Your Grandfather said:

I'm not 100% positive but doesn't the glass in front of the bulbs _ both HPS & MH _ block uv? I know that the quartz envelope of a HID bulb pretty much filters out all of the uv, before it reaches the glass.

*of course these are my opinions and I'm probably wrong.

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From what i could find hps emit very little uvb and the best ones are MVD lamps for emmiting uvb but they all now have to have built in filters according to wiki anyway

Some HID lamps such as Mercury Vapor Discharge produce large amounts of UV radiation and therefore need UV-filters to block that radiation. In the last few years there have been several cases of faulty UV-filters, causing people to suffer severe sunburn and Arc eye. Regulations may now require guarded lamps or lamps which will quickly burn out if their outer envelope is broken.

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the idea of only the last 10 days of flowering is an interesting thought. From a pure physiological perspective, it would seem logical that more consistent and longer term exposure would enhance the plant's ability to accomodate this type of light. However, if in fact the production of trichomes is a stressor response, then maybe only the last period is important. in fact, keeping the plant unexposed would further the stressor response by ONLY exposing in the last days - increasing the trichome production in response to an unusual circumstance and therefore more significant stress. And then the production of THC (as a function of the UV light and precursor compounds) would also be increased.

My current thinking is leading my to using a combination of both MH/HPS bulbs and UV specific bulb. This will be a forthcoming project - I need to finish what I am doing first. I do believe this does warrant some experimental effort though.

good luck tahoe58

natmoon said:

From what i could find hps emit very little uvb and the best ones are MVD lamps for emmiting uvb but they all now have to have built in filters according to wiki anyway

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Sodium lamps use no phosphors, and their low mercury content creates very little UV output, although some high-pressure sodium lamps are coated to reduce glare and to widen light distribution.
Lighting: High-Intensity Discharge Lamps - Upper Peninsula Power Company

I think it is time for a look back...to look forward with a clearer path - at the beginning of this thread I asked three questions - maybe it is valuable to go back through all of this material and see what has been learned so far (so I went back and read the entire thread all over again.....):

Q1. if UV in ionisers is used for odour control, will high UV light conditions (high altitudes) also influence odour – which has been postulated to have important functionality in the life cycle of cannabis?

there is very little that has come forward on this issue. reference has been made to THCV as the source of the smell. I expect that the smell is from the volatility of these terpenes (cannabinoids), higher terpene levels, greater smell - higher concentration of trichomes, higher terpenes? but it still is not clear to me that - if uv ionisers are used in odour control...how do we reconcile that with the higher trichome count?

Q2. should/could we maybe consider the introduction of a “highly limited” level of exposure to UVB to enhance resin production while within the limited of phytological degradation?

there is a lot of info provided by all posters on this issue, incuding some commitments to do some test procedures. the subjects varied, and included increases in defensive enzyme production, the value in meters and measuring UV light, and cautions regarding the risks of uv light (cancer, eye damage). The more I search and read (and a good bulk of the info is related to the early 90's when concern over the ozone hole had everyone wondering what was going to happen to terrestrial ecosystems from the added UV light), the more evidence (mostly anecdotal and some scientific) there is to confirming some positive value in UV light. I believe we have made some progress in at least understanding the fundamentals of this, but require some speicfic experimental evidence to better to support our theories. I hope we get some good feedback from those have said they will move forward with their own test program.

Q3. do we need to take a closer look at the true comparison of the growth potential/potency of using HPS vs. MH vs. MV lights? Have we been incurring a limitation to potency by using HPS lighting for flowering?

again, we have theoretical evidence that this may be true, but experimental evidence is required to further understand the realities. it seems there is some support for the notion that MH may produce higher quality bud with a compromise on yeild/speed. UV does seem to have some support for better bud quality. It is my belief that the move towards HPS has been driven by the "commercially important " yeild and speed objectives - and maybe unknowingly resulted in some quality consequences. However, this is far from unequivocal. there remain conflicting views. further work is needed. I am inclined to explore the option of combining MH/HPS/UV in some as yet undetermined arrangement. this will not deal with the +/- twelve days of dark (without moonlight) that outdoor plants get....during the typical moon cycle? or does that just make things even more complicated. There has even been some discussion about UV LEDs....however, my information indicates that these do not got to the UVB range and only the UVA range, and if true, will not contribute in a way that we currently understand.

thanks tahoe- i swear you just read my mind- i was really hoping to see this thread boiled down!

oh no...another one of those scary coincidences.....you're very welcome...i jst got thinking timing was right to try and provide some full circle...

Interesting stuff
Saltwater fish MH lamps create uv for the coral an lie rock right?
I think so
I might have to pick 1 up
what do you guys think

yes those lights have been also referenced...I'd have to go back to the comparison table...but they are mentioned I'm sure.

Someone needs to get one of those cannalyze kits for testing thc levels and do this scientifically. Get a bunch of clones all from the same mother and see how they respond and how the thc is effected. Sometimes the mind can tell you somethings stronger because you want it to be, I'm not saying this is the case with this, but for me to really believe in it it needs to be properly tested.

hey ngt, totally agree. I too am famous for hearing/seeing what I want to believe. and to answer this properly, your suggestion is exactly what needs to be done. I am not set up adequately to do this, and cannot in my current circumstances. It would be best to have the space and flexibility to take a suitably large enough number of clones from an identical plant, and raise them in identical conditions, with the exception of introducing uv light. consistency in approach, and anally retentive record keeping will be critical. Maybe we wuold be able to provide additional suppoting evidence to that already provided 20 years ago?

Extract from Pate, D.W., 1994. Chemical ecology of Cannabis. Journal of the International Hemp Association 2: 29, 32-37.

The extent to which this production is also influenced by environmental UV-B induced stress has been experimentally determined by Lydon et al. (1987). Their experiments demonstrate that under conditions of high UV-B exposure, drug-type Cannabis produces significantly greater quantities of THC.

Lydon, J., A. H. Teramura and C. B. Coffman (1987) UV-B radiation effects on photosynthesis, growth and cannabinoid production of two Cannabis sativa chemotypes. Photochem. Photobiol. 46, 201-206.

I have not been able to find this other paper as yet.

nongreenthumb said:

Someone needs to get one of those. cannalyze kits for testing thc levels and do this scientifically. Get a bunch of clones all from the same mother and see how they respond and how the thc is effected. Sometimes the mind can tell you somethings stronger because you want it to be, I'm not saying this is the case with this, but for me to really believe in it it needs to be properly tested.

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Well, I didn't ask him "why only the last 10 days."

Because I assumed the last 10 days was when it's beneficial for our purposes. I'm sure that if it was also beneficial sooner, then he would have said so.

I'd say that the UV is the stress that causes something to happen to either the trichomes, maybe producing more, or the resin itself, probably producing more of that in each trichome. Sorta causing the heads to swell up, like a bigger umbrella. Also what is happening at that time of flowering is cannabinoid biosynthesis, what we call the ripening of the bud. So maybe the UV causes more THC to stay around rather than be converted to CBD.

And we use the HPS light for flowering because of its spectrum, the artificial spectrum that is closest to autumn sunlight, as well as HPS has the most lumens output per watt. If you switch to MH, you are giving up lumens.

So I stick with the HPS all the way through flowering, and I'll add the UV at the end.

HTH

In all honesty though pot', any type of extra lighting we can provide in the final 10 days is bound to have a positive effect. There are more lumens flying around, so the plant will respond in growing faster.

If we grew an Afghani strain indoors, we as indoor growers, or even outdoor growers in certain climates will not achieve the same potency as the same plant grown in Afghanistan.

Is potency, like growth, purely down to lumens present?

Everybody seems to know already that it isn't. for example a mixture of MH and HPS is said to produce the best bud.

Does anyone know if there are more lumens in the red part of the spectrum than there is in the blue, in natural sunlight?

hey PR - thanks for those thoughts. I understand what ur saying re: the last 10 days. there has obviously been lots of pot grown exactly in the manner you have described based on years of experimenting already, and with very satisfactory results and stoned smokers.

and Skunk, that also a good question regarding the light intensity (light energy) at different parts of the spectrum. the distinction here then is between the relative importance of spectrum/wavelength and intensity (i.e., is one aspect more critical than the other in terms of enhancing potency?). I don't know the answer. I expect that it is prolly not that easy to separate the two and that as with most variables in biological systems, they are interdependent - change one a little and the other will also change.

Maybe what we need is a comprehensive light metering station in the location known for the highest potency pot, and do a full cycle growth recording of the conditions measuring photoperiod, spectrum, intensity, angle of incidence, etc. do that for 3-5 repititions and come up with some data. or maybe someone did that already....and I should just go back to growing my plants? hahahahahaha

skunkushybrid said:

Does anyone know if there are more lumens in the red part of the spectrum than there is in the blue, in natural sunlight?

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I would assume that it would be true per say. The blue end of the visible spectrum of light has the shortest wavelengths next to violet. I experienced this first hand when putting "HID" look-a-like headlight bulbs in your car was the "cool" thing to do 10 years ago. It became much harder to see at night because the output didn't cover as much ground as the bulbs that have a greater output of the white or red wavelengths of light.