Trichomes, THC and UVB light.....

doobnVA said:

Just a quick question, because I hear everyone saying how dangerous UV light is when it comes to using it for growing despite the fact that we are exposed to UV rays daily from the time we are born.

Is using a UV light for growing really any more dangerous than going outside?

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I have to chuckle a bit when I read this. Have you ever been in a tanning salon? Why do you suppose they insist that you wear eye protection? The answer is yes.

However, if the bulbs used are no more powerful than that of typical equatorial light they are probably fine. If you use bulbs from tanning beds you might come back in an hour to find your plants dried, cured and smoked.

So the question is where the line is drawn. IDK what kind of lumens those reptile lights put out or how they compare to say a Hortilux MH Blue in terms of UVB lumens.

But the question is also if the hypothesis is correct. We already know that UV exposer degrades THC after harvest. The question is, does UVB promote THC production, does it degrade the THC being produced and which happens faster.

It could be the case that UVB light does promote THC production but that in protecting the seed from the UVB (which answers your question about damage), the THC is also destroyed. In that case it might be better to grow a plant that evolved with this mechanism and grow it in the absence of high UVB. We simply don't know.

An interesting experiment might be to take two clones, flower one with say a 100W 2700K CFL and the other with a similar 50W bulb plus a 50W reptile light. Then smoke plant A with three or 4 friends, take notes and then a week later do it again with plant B and compare. Not exactly scientific but at least you might determine if the difference is appreciable. If it's not then why bother with inefficient lights.

many thanks for your thoughts. Not sure if either of these will be of any assistance, but in my view they do have some applicability to your queries. I have readily found all this online. (1) Pharmacological and therapeutic secrets of plant and brain (endo)cannabinoids (2) A CHEMOTAXONOMIC ANALYSIS OF CANNABINOID VARIATION IN CANNABIS (CANNABACEAE); (3) An elaboration on the phytochemical process that makes THC; (4) Marijuana Chemistry (Chapter 2) (6) Influence of low-intensity ultraviolet radiation on extrusion of furanocoumarins to the leaf surface AND (6) Influence of ambient and enhanced ultraviolet-B radiation on the plant growth and physiological properties in two contrasting populations of Hippophae rhamnoides [while acknowledging these are completely unrelated species - the relationship between plant physiology and structure are influenced by uv light]

I skimmed over a lot of this and its got some really great stuff in it. It basically confirms the mixed spectrum theory in flowering.

1. If you can only have one light for an entire grow, get a HPS.
2. If you can afford the metal halide or cfl's for veg, do it as you will get shorter node spacing, and a bushier style plant.
3. When you switch to flowering (if not using HPS the whole grow) add the hps to the current cfl/metal halide setup. By having daylight cfls and the blue from the metal halide, thc production skyrockets from the UV being put out by those two lights. The HPS adds the red spectrum which is used to get fatter and bigger buds.

1.Commercial grade big yield, less potent = Straight hps the whole grow
2.Quality grade big yield, denser buds, more potent = CFL/Metal Halide add HPS when switching to 12/12
3.Quality grade airy buds, less yield, more potent = CFL/Metal Halide the whole grow

This is my current grow with a top44 girl, currently 63 days since that start of 12-12. The "real" flowering started about ten days after the introduction to 12-12. This setup also has fully automated CO@ (reportedly to maintain 1600ppm) and a 400W HPS. And it is in soil with Sensi-Bloom A + B, Molasses, and VoodooJuice.

Of course I cannot say one factor is more or most influential than any other, but I certainly am pleased with these results. Walk On!!~~~~

tahoe58 said:

Of course I cannot say one factor is more or most influential than any other, but I certainly am pleased with these results. Walk On!

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You've done a nice job on your grow. The real strength or promise with UVB is not the size of your buds (and you're buds look nice) it's the amount of and color of the trichomes. As I understand it, UVB does not effect the actual growth but instead the trichome production. What I'd like to see is a close up of the tri's on this bud compared to the tri's on one far away from the UVB.

YGB

YouGrowBoy said:

As I understand it, UVB does not effect the actual growth but instead the trichome production. What I'd like to see is a close up of the tri's on this bud compared to the tri's on one far away from the UVB.YGB

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Funny you should say that, I will try get up some pics for you guys. I have had one strawberry haze plant under the UVB for the majority of its grow (i think i started the 2nd week into flower)...you can actually see the diff with your eyes...and im not even talking too close up!

Room setup
UVB
SH - ST/LS
HPS
SH - SH

BUT they plant beside the Strawberry haze was giving to us from a friend. Its either sweet tooth or lifesaver. Not sure tbh...but that plant doesnt look to have much tri's at all. Weird. The leaves look to have a "plastic" sheen to them!


Oh, and you have a great looking plant tahoe58! What strain is it?

thanks ... for the compliments to my grow. I really appreciate that.

I think I understand what you mean, Like the density of trichomes on each measured area of the leaves/calyxes? Yea, like the overall frostiness. I think that the "volume" of growth comes from the higher ambient concentration of CO2 and commensurate increases in water/fuel intake.

I had a little of a surprise yesterday. I was over viewing my male cohort. The ones outside looked very beautiful and progressing well. But one of the ones that I had in the BBox really for probably close to too long, was actually much more developed (real flowertop seedpod complex) than the one I had put outside a bit ago (and which at the time were further along in their maturity for sure in terms of comparison). It had me thinking that one reasonable explanation for such advanced development by the BBox plant would be that the exact circumstances I describe above which makes the cab grow more advanced more quickly ..... CO2, UVB, HPS, Nutes, Water .... ? or am I just sting the obvious?

it is a top44 ..... which last time (same seed batch) I got a good yield of some pretty speedy smoke, great for activity, and for me, a perma-smile. I have yet to be able to find any convincing geneology for it to really understand it. Thiese plants all demonstrate some broad sativa characteristics, and yet others have said the large single monstor cola is surely more indica. I dunno, I like it, it smokes well, and will be a great alternative for the DQ and MM that are up and coming.

For you guys using UVB 10.0 26 watt CFL's, how far do you keep it from the canopy? I have two of them with my 600 HPS and I plan on using them until a week from harvest. They are running 8 hours/day midway through the 12 hour cycle and I keep them slightly further than my HPS on opposite ends of the grow room.

hey there .... sounds good. It is my understanding that the distance to bulb should not necessarily be more than 18-24 inches or less and 4-6" . I have inadvertently had leaves within inches of the light and they do receive damage. Penetration is poor. So I believe it is just important to not be too close. The further away ones? they get what they get unless you added more uvb lights

Here's my Cola as she stands today.

Thanks for the reply Tahoe58. That makes my job easy, since I can keep the lights within the upper range of my 600 HPS. I caught the chart on page 62, and it seems if I keep the two UVB's at opposite ends of my 10-12' footprint, it should spread pretty well throughout the canopy.

This may be anecdotal, but my local Kush which I have grown twice from seed, is showing sex a lot earlier (day 2 vs 6-10 days previously). Don't know if that is genetics or the effect of UVB...but definitely something to keep in mind for future grows.

excellent, thanks for the feedback and appreciate your thoughts. Walk on!!~~~

tahoe58 said:

excellent, thanks for the feedback and appreciate your thoughts. Walk on!!~~~

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Hmmm, no posts in the last few weeks. I would like to thank everyone for their contributions to this "illuminating" discussion (OK I couldn't resist). Especially you, tahoe58, thank you for all you have done the past few years.

I decided to investigate this for the end of my ScrOG grow. I have written a journal for it, but it is on another site. I found a Zilla Low Profile Double Fixture. It has two 18 watt, 30 inch T5 bulbs in it. It was on clearance at Petco for half off ($40). I plan on suspending the lamp 3 to 6 inches above the screen on one side of the grow and tilt the lamp 45 degrees so the radiation can spill out to the middle. This should allow me to see if the response of one plant's bud tops under the various levels of UV radiation. As I get towards the middle of the screen, the UV radiation level should fall to undetctable levels. I'm going to install it tonight and I'll post any results here as well.

ooooo anxiously awaiting results

very many thanks ..... I appreciate your effort and your thoughts. I will be interesteed in what your results show. thanks again.

munki said:

Hmmm, no posts in the last few weeks. I would like to thank everyone for their contributions to this "illuminating" discussion (OK I couldn't resist). Especially you, tahoe58, thank you for all you have done the past few years.

I decided to investigate this for the end of my ScrOG grow. I have written a journal for it, but it is on another site. I found a Zilla Low Profile Double Fixture. It has two 18 watt, 30 inch T5 bulbs in it. It was on clearance at Petco for half off ($40). I plan on suspending the lamp 3 to 6 inches above the screen on one side of the grow and tilt the lamp 45 degrees so the radiation can spill out to the middle. This should allow me to see if the response of one plant's bud tops under the various levels of UV radiation. As I get towards the middle of the screen, the UV radiation level should fall to undetctable levels. I'm going to install it tonight and I'll post any results here as well.

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hey man thanks for the visit. Yea certainly time for an update.

TheGreatPretender said:

ooooo anxiously awaiting results

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so the top44 was harvested. 128g dry. not a bad haul for one plant for sure. she was a special bitch! hahahaha! The smoke is fabulous ..... a little more heady than my last grow. and I like it a little more that way. Some of the earlier bud that I harvested is more speedy, but still a great smoke.

My next grow is underway. I have DairyQueen and a GooeyBreeder strain. Only a sinlge plant each. Both are doing well. This is a shot of the DQ at 4-5wks. Pretty frosty foo shur.

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Beautiful looking plant Tahoe! I'm midway through week 6 of my White Rhino and Carnival grow. The plants are surely packing on the ''sugar'' especially the ones closest to the UVB. I have been running the 10.0 CFL about 4 hours a day and the plants aren't showing any particular stress from it. I will post some budshots in 2-3 weeks when I harvest the first few plants.

excellent, and many thanks for your contribution .... we all look forward to your pics ... thanks again for sharing!! Walk on!!~~

bulkybud said:

Beautiful looking plant Tahoe! I'm midway through week 6 of my White Rhino and Carnival grow. The plants are surely packing on the ''sugar'' especially the ones closest to the UVB. I have been running the 10.0 CFL about 4 hours a day and the plants aren't showing any particular stress from it. I will post some budshots in 2-3 weeks when I harvest the first few plants.

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Before deciding how you want to introduce UV lighting to your plants, check out this site.

http://www.uvguide.co.uk/index.htm

A shame they dont have tests done on the Solar Glo.

If this link was already posted somewhere deep in this thread, my apologies.

This is an interesting read.

http://www.springerlink.com/content/v55778540771772j/

For those of you that are too lazy to actually check out the link about lights, I would suggest the Mega Rays. They seem to be what most reptile owners consider top of the line, and they last alot longer than other brands. Dont forget they put off alot of heat, so make sure your grow area can deal with it before purchasing one.

http://www.reptileuv.com/

This is awesome by the way. I would have never guessed that a plant that makes people feel awesome would lead us all to such high level botany. It is sad that we are required to grovel and hide, it is sad that this research cant be better organized and shared hindrance free with a world that is ready to process it. (kicks soapbox off-stage)

I have grasped the concept of light spectrum analysis and the effect of specific wavelengths on not only plant growth but trichome development, but I am having trouble pinpointing the correct wavelength or series of alternating wavelengths that will jump start the THC potency we are all looking for. If UVB is the answer and it is generally agreed upon that bud grown outside TENDS to have greater potency why don't we use black lights? According to this website and graph... (which I found on this thread)

http://www.anapsid.org/uvtable.html

black lights produce the exact same amount of UVB as the sun, they also don't create as much heat as reptile lamps. Granted it wont breed super bud but what if this is a missing link for indoor grows? I want to thank not only this site but especially tahoe58. I will continue to +rep as I progress back through this thread and see people who have contributed valuable and useful information.

I am currently on my first serious grow (my first 2 weren't so hot) and will be purchasing black lights to throw in my flowering tent along with my 1000watt HPS (which after reading this thread I hope wasn't a waste of my money). I will post updates in my journal for any who are interested (unless someone has information that debunks my black light theory). If I do not see an increase in trichome development I will continue on to testing the various reptile lights.

Best of luck to all, and PLEASE criticize anything I say as it is pure conjecture and I would love solid facts to work off of. Because waiting in almost 3 month cycles to evaluate the effects of my whack experiments is very frustrating.

I read through that article and I did not find anything stating that blacklights produce the same levels as the sun. I did read that they produce low levels of UVB radiation. Point it out in the article for me If Im wrong.