UVB lighting late in flower

I've heard the stories of increased trich production from uvb lighting, and decided to run a "test".

The strain was flo..4 cuttings from the same mother, 600 watt hps flower..co2 up until final 2 weeks. When I turned off the co2, I set up 2, hanging 23watt 10.0 uvb bulbs, with round reflectors over 2 plants (one side of the grow chamber) The reflectors were directly over the "test" plants and did not reach the "control" plants.

Started the uvb on a separate timer. 15 min per hour to see how the girls reacted. It became apparent within 2 days (moving the 15 min to 15 on 15 off...then 45 on 15 off) that they weren't bothered at all by the uvb.

As a matter of fact, they seemed to "like" it. But whatever you want to call it, they responded by producing noticeably more trichs than the other side of the room. The yield form the "uvb" plants and the non uvb side was equal. So, no weight increase..just light, fluffy, snow...

Fairly inexpensive to set up, just wondering if anyone has played with uvb, and if you saw result...

did you notice any difference in smoke or the high?

NoCeilings said:

did you notice any difference in smoke or the high?

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Yes..the flavor and smell became "hashier" and the potency was...enhanced noticably over the plants without the uvb.

Under 100x magnification..the effect was amazing. The buds without were very nice, don't get me wrong. But the buds that had UVB, under a scope, you could just see more...layers..of trichlomes. They were simply everywhere.

After a one month cure, the buds though "crispy" to the touch, still contains the "essential oils" of the plant. Best to grind, then let sit a minute before burning. I just like the strain I guess.

Kudos for doing a side by side test. I have read many threads about it but nobody performed many side by sides. I am curious as to which light you were using. From what I have read, many of the florescent UVB bulbs gave off little to no UVB (in relation to how much the sun puts out). I was looking at the mega ray lizard bulbs as they put out a shit ton of UVB... Like don't go in the room when it's on levels.

Do you have any pictures of the different buds?

which is why im keeping my 600w MH over my flowers

RawBudzski said:

which is why im keeping my 600w MH over my flowers

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MH will give you some uvb...and 600 watts is some MH. I, unfortunatly don't have an mh bulb I veg under t5's, then go to hps for flower

Iv'e heard that using MH and HPS in flower also helps the overall "health" of the plant..did you notice more "vigor" under both types of lighting?.

legallyflying said:

Kudos for doing a side by side test. I have read many threads about it but nobody performed many side by sides. I am curious as to which light you were using. From what I have read, many of the florescent UVB bulbs gave off little to no UVB (in relation to how much the sun puts out). I was looking at the mega ray lizard bulbs as they put out a shit ton of UVB... Like don't go in the room when it's on levels.

Do you have any pictures of the different buds?

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I used 10.0 uvb rated, 23 watt cfl lizard lights. Bought them at Petmart. My understanding is the "10.0" are the strongest uvb lizard lights...though they certainly get bigger than 23 watts. According to the box, the uvb penetration is 20 inches. Very little to no heat produced by the bulbs..

Yea. they made my eyes feel funny if I looked at them. I unplugged them from the timer when I tended the garden, but it's hard not to "check and see if they are on" when you first fire them up.

My camera won't focus in close enough for a trich picture. You can definatly see the difference under a scope however. Considering how much equipment and lighting cost to begin with..adding uvb was fairly inexpensive. About $40 per fixture, and the bulbs will go alot of hours.

I have a legal medical grow..and am limited to 12 total plants. I only flower 4 at a time. (4 in flower, 4 in veg and 4 "rooting") that more or less gives me a "perpetual" grow...Different strains may react differently as well...but with Flo, the results were worth the effort. Increased trich production became apparent after the second "night" cycle. Seems they produce the trichs as "sunscreen' to protect themselves from the uvb. Interestingly, even the fan leaves and stems showed much more trich development than the plants without uvb. (handy for any "hash makers" out there.)

I'd say it's worth a try for anyone, assuming that your grow room is "tweaked". IE: plenty of light, co2, temp control etc etc are well managed. I'd recommend getting all you other "environmental" conditions optimal before playing with the uvb..Like anything else, I'd also recommend starting the uvb slowly, until you see how your strain reacts. Build up exposure time slowly, start with the uvb farther from the plants, until you see what your ladies like.

I'm about to try this myself.

Do you run uvb 12/12?

You can run UVb on 12/12 if you wanted

I use a similar bulb or the same one, Reptisun cfl 10.0. You will want to keep the plants 3 to 5 inches away from the bulb as the measured uw is over 500 at 3 inches. At around 10 or 12 inches from the bulb the uw falls to about 150, which is the low end of effective uw. This is without a reflector, bulb hanging vertical in center of grow.

My plants were all very frosty but I think the uvb does more to the profile of the resin glands than it does to make more of them. Creeper high, stronger high, trippier, more complete and longer lasting buzz are some of the effects you might notice.

I ran the uvb bulb for the last 45 days of flower for several hours each day.

The mh or cmh lights produce a tiny amount of uvb which is not helpful imo. Looking at the uvb bulbs without uvb blocking sunglasses is like looking at the sun. I turn the uvb light off when working in the grow.

No bulb will ever outdo the sun. Put as much UV/B in as you want.

3 Pounds of Weeden said:

No bulb will ever outdo the sun. Put as much UV/B in as you want.

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The problem is getting that big ass thing in the house.

Mookjong said:

The problem is getting that big ass thing in the house.

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lmfao, that ended up being really funny for some reason.

I use UVB as well and am convinced of its effectiveness... however,... for science sake... it is quite possible that because he was using only HPS that the increased vitality of the bud may have been from the added blue spectrums coming from the other 90% of the pet lamps output.. activating different PS pathways... for example...
grow room with only HPS...add to one side a few 6500k CFLs... no UVB... the side with the 6500K cfls will have higher quality bud. especially sativa dom varieties.

WE could throw hypothesis at it all day. My guess is that the UVB did add some benefit along with the benefit provided by complimentary blues, etc...
UVB tests done with CMH/CMH+UVB would give better data as to effects of UVB, IMO.

All of the UVB reptile bulbs that I know of have significant amounts of light in the UVA and the actinic blues range (400 - 450 nm).
so yes I agree its hard to know how much of the effect is stricty because of the UVB, versus other Blues.

PurpleBuz said:

All of the UVB reptile bulbs that I know of have significant amounts of light in the UVA and the actinic blues range (400 - 450 nm).
so yes I agree its hard to know how much of the effect is stricty because of the UVB, versus other Blues.

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i use MV bulbs i can tell you that UVB is very effective.

PurpleBuz said:

All of the UVB reptile bulbs that I know of have significant amounts of light in the UVA and the actinic blues range (400 - 450 nm).
so yes I agree its hard to know how much of the effect is stricty because of the UVB, versus other Blues.

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From what I have read, blue spectrum does have positive effects on floral growth of cannabis, I'm not sure if UVA has any studies on it yet pertaining to its effect on cannabis' overall growth (unless someone has something, by all means please link the sources)~

cannawizard said:

From what I have read, blue spectrum does have positive effects on floral growth of cannabis, I'm not sure if UVA has any studies on it yet pertaining to its effect on cannabis' overall growth (unless someone has something, by all means please link the sources)~

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i forget where i read it but there is an article somewhere(im looking) that states the reactivity in the production of essential oils, on terms of both the energy of light and the percentage of oil production. UVa was something like 20% less effective. and 420nm-460nm was like 15% down to 5% as effective as UVb in terms of oil production for the amount of light it took and the energy needed to create the light.

sorry dont mean to not have much more that, other than ive flowered under all these said conditions and UVb visibly had the most effect. i am actually more thoroughly testing the blue light conditions now, as i have paired a t5 with 10000k bulbs and an HPS the frost has been pretty good, comparable to the UVB but not quite the same.

polyarcturus said:

i forget where i read it but there is an article somewhere(im looking) that states the reactivity in the production of essential oils, on terms of both the energy of light and the percentage of oil prosecution. UVa was something like 20% less effective. and 420nm-460nm was like 15% down to 5% as effective as UVb in terms of oil production for the amount of light it took and the energy needed to create the light.

sorry dont mean to not have much more that, other than ive flowered under all these said conditions and UVb visibly had the most effect. i am actually more thoroughly testing the blue light conditions now, as i have paired a t5 with 10000k bulbs and an HPS the frost has been pretty good, comparable to the UVB but not quite the same.

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Good info~ I'm with you on the UVb, it's pretty much been the main focal point of my personal research & experiments~ btw, have you seen any studies or footnotes concerning UVb exposure leading to more CBD% (for CBD strains)-- the enzymatic processes that happen in that tiny sphere(trichomes) is mind bogglin' hehe