UV A And UV B In Late Flower

[testiclees]

After checking out rm3's crazy christmas tree flocked buds ,I decided to add some 15000k+uv led to my led grow as well.Ive ran the arcadia d3 12% reptile bulb in the past.

Which UV led are you thinking? What type of setup?

 

[Resinhound]

15000k+uv kessil aquarium led is what im using right now.Its designed for saltwater aquariums. 35watts covers my little area well.

 

[whitebb2727]

I dont know for a fact that UVB can stunt growth but plenty of folks state that it is so. Also, there is a graph on RIU that shows the efficacy of the UVB bulbs and then there's a NASA graph that shows the UVB irradiance at different points on earth. I think just a few t5 12% UVB close to a plant would be more intense UVB than anywhere on Earth.

"This paper reviews growth chamber, greenhouse, and field studies on the effects of ultraviolet-B (UV-B. between 280 and 320 nm) radiation on agricultural crop plants. Our understanding of the physiological effects of UV-B radiation comes primarily from growth chamber studies, where UV-B is artificially supplied via filtered lamps. Both photosystems I and II, as well as carboxylating enzymes, are sensitive to UV-B radiation. Ultraviolet-B radiation also affects stomatal resistance, chlorophyll concentration, soluble leaf proteins, lipids, and carbohydrate pools. In general, the effects of UV-B radiation are accentuated by the low levels of visible radiation typically found inside growth chambers.

Ultraviolet-B radiation has also been shown to affect anatomical and morphological plant characteristics. Commonly observed UV-B induced changes include plant stunting, reductions in leaf area and total biomass, and alterations in the pattern of biomass partitioning into various plant organs. In sensitive plants, evidence of cell and tissue damage often appears on the upper leaf epidermis as bronzing, glazing, and chlorosis." *

Teramura, A. H. (1983), Effects of ultraviolet-B radiation on the growth and yield of crop plants. Physiologia Plantarum, 58: 415–427. doi: 10.1111/j.1399-3054.1983.tb04203.x

I will agree with that. All those studies also say that varies wildly between species and about 30% are not effected by it.

I know that there are no blanket statements for cannabis and strains can vary.

Why is there so much indica in today's pot. Mostly to increase yield. The best indica's come from terrain high in altitude and higher UV exposure. I don't recall any grows with serious negative effects from UV. Used in conjunction with mixed spectrum you get yields to.

 

[BobCajun]

You may be right after all.

You are also comparing apple and oranges.

Loss of yield comes from running a mh or other types of bulbs in an all blue configuration. That has more to do with color than UV.

Running UV bulbs mixed with other bulbs of mixed spectrum is the way to go in a t5 and mh/hps combo for his.

Loss of yield is not from the UV.

Okay, turns out you're right, at least according this article. Cannabis doesn't grow any differently with high UV-B than with none, just the THC levels change. You got me that time. I figured it was the same for Cannabis as other plants and I've read posts where people said it had negative effects. Maybe it was something else though.

 

[whitebb2727]

You may be right after all.

Okay, turns out you're right, at least according this article. Cannabis doesn't grow any differently with high UV-B than with none, just the THC levels change. You got me that time. I figured it was the same for Cannabis as other plants and I've read posts where people said it had negative effects. Maybe it was something else though.

You are right with what you said. It does cause decrease in yield in about 70% of plants.

In cannabis with proper mixed spectrum you get both yield and increase in resin production.

 

[BobCajun]

You are right with what you said. It does cause decrease in yield in about 70% of plants.

In cannabis with proper mixed spectrum you get both yield and increase in resin production.

I just put the two 26w Exo Terra 150s in the cab, since there's no downside. Besides, I don't believe it would be as good if it was only for the last 2 weeks. It's the end of week 4 now so they'll get a good 6 weeks of it. Hopefully, that'll be enough wattage.

 

[whitebb2727]

I just put the two 26w Exo Terra 150s in the cab, since there's no downside. Besides, I don't believe it would be as good if it was only for the last 2 weeks. It's the end of week 4 now so they'll get a good 6 weeks of it. Hopefully, that'll be enough wattage.

I was using the regular factory 54w t5 bulbs. I went to agromax bulbs. 2-10,000k+uva, 2-pure par, 2-6400k, and 2-3000k. 432 watts in a 2x4x6 cab.

 

[BobCajun]

I was using the regular factory 54w t5 bulbs. I went to agromax bulbs. 2-10,000k+uva, 2-pure par, 2-6400k, and 2-3000k. 432 watts in a 2x4x6 cab.

Sounds like a good setup. You may need UV-B though. To make it more potent it's supposed to be 290-315 nm. UV-A may help some though.

 

[whitebb2727]

Sounds like a good setup. You may need UV-B though. To make it more potent it's supposed to be 290-315 nm. UV-A may help some though.

I'm going to swap one uva out for the uva/uvb bulb. I will get some uvb from the 10,000 and 6400k bulbs.

 

[BobCajun]

I'm going to swap one uva out for the uva/uvb bulb. I will get some uvb from the 10,000 and 6400k bulbs.

You won't get any more than maybe 1/40th of the UV-B of sunlight from any bulb that's made with normal glass, because it filters almost all of it out. The reptile lights are made with special glass. BTW, you will never see an LED grow light that has 290 nm UV-B LEDs in it, because they are very costly, for some reason. UV-A ones are cheap and so are UV-C. That's why some LED grow light companies include UV-A. But it won't make the plants more potent, maybe more healthy in some way but not more potent. I tried blacklight CFLs and no improvement, that's UV-A. Besides, UV-A is about the same level at all altitudes, yet Cannabis only gets more potent in areas with high UV-B.

 

[Resinhound]

Do we really need to start the decaroxylation process on the plant? I was under the impression uva leads to an increase of trichomes and oils.THCA can be converted to THC in a seperate process after harvest.I havent seen anything that shows uvb Itself is responsible for more oil production only to raise THC levels by prematurely converting THCA to THC on the plant.

 

[BobCajun]

Do we really need to start the decaroxylation process on the plant? I was under the impression uva leads to an increase of trichomes and oils.THCA can be converted to THC in a seperate process after harvest.I havent seen anything that shows uvb Itself is responsible for more oil production only to raise THC levels by prematurely converting THCA to THC on the plant.

Doubtful, because they probably used simple gas chromatography to test for THC and that process uses heat and results in all the THCA being turned to THC. Besides, we know from reports that people definitely can tell the difference between the UV-B weed and regular. It's possible that the UV converts some of the THCA to THC, but if you're going to smoke it then it would be converted anyway. No, it's not some kind of illusion, the strength of the weed goes up by about a third. People report only needing 3/4 as much as usual for the same effect. Whether it just makes more resin or if the resin itself becomes higher in THC than normal, I don't know. You would have to test shatter from both types and see if they differ. Maybe you just get a third more resin.

 

[whitebb2727]

You won't get any more than maybe 1/40th of the UV-B of sunlight from any bulb that's made with normal glass, because it filters almost all of it out. The reptile lights are made with special glass. BTW, you will never see an LED grow light that has 290 nm UV-B LEDs in it, because they are very costly, for some reason. UV-A ones are cheap and so are UV-C. That's why some LED grow light companies include UV-A. But it won't make the plants more potent, maybe more healthy in some way but not more potent. I tried blacklight CFLs and no improvement, that's UV-A. Besides, UV-A is about the same level at all altitudes, yet Cannabis only gets more potent in areas with high UV-B.

I don't think it is as simple as that. Agromax makes horticulture bulbs. I'm sure they are making the 10,000k+uva for a reason and if it lets uva, some uvb will be provided to. They also make a better uva/uvb bulb than reptile bulbs.

I'll see this run at the difference it makes.

 

[BobCajun]

I don't think it is as simple as that. Agromax makes horticulture bulbs. I'm sure they are making the 10,000k+uva for a reason and if it lets uva, some uvb will be provided to. They also make a better uva/uvb bulb than reptile bulbs.

I'll see this run at the difference it makes.

The 10000k are apparently to boost the blue spectrum of HPS, that's what they say. Any glass lets UV-A through, but blocks almost all UV-B, so you wouldn't get much from those. They do sell pure UV tubes though. But look at the microwatts at various distances. They'd have to be about 1 inch from the plants for high UV.
The ones with the UV-A you mentioned must be these ones. Here's what they say about it;

"UV-A Plus FLOWERING: To be used as a supplemental lighting source for any HID lighting system including HPS. The UV-A Plus spectrum is primarily 10,000K with an added UV-A spectrum which is deficient in all HID systems especially HPS. It is believed that without the presence of the UV-A spectrum that plants can never reach their full potential as UV-A is present in Sunlight but deficient in common indoor grow light sources."

Notice how it says nothing about potency, just "full potential". I've never seen one study showing that UV-A increases potency, though it may have some beneficial effect. I've seen ones where they said they use UV-A and B together, but never UV-A alone.

 

[Resinhound]

The 10000k are apparently to boost the blue spectrum of HPS, that's what they say. Any glass lets UV-A through, but blocks almost all UV-B, so you wouldn't get much from those. They do sell pure UV tubes though. But look at the microwatts at various distances. They'd have to be about 1 inch from the plants for high UV.
The ones with the UV-A you mentioned must be these ones. Here's what they say about it;

"UV-A Plus FLOWERING: To be used as a supplemental lighting source for any HID lighting system including HPS. The UV-A Plus spectrum is primarily 10,000K with an added UV-A spectrum which is deficient in all HID systems especially HPS. It is believed that without the presence of the UV-A spectrum that plants can never reach their full potential as UV-A is present in Sunlight but deficient in common indoor grow light sources."

Notice how it says nothing about potency, just "full potential". I've never seen one study showing that UV-A increases potency, though it may have some beneficial effect. I've seen ones where they said they use UV-A and B together, but never UV-A alone.

Well if you arent including parts of the spectrum the sun has been providing for them for several millenia,it seems like that would affect potency to some degree.I really dont think its plausible to pick a narrow band out of the spectrum and say "this is what affects potency and nothing else".Obviously the book isnt closed on this yet,just because you haven't seen a study doesnt mean anything...maybe one hasnt been done yet.It was only a few years ago,that it was found plants do absorb green light.There wasnt many studies 10 years ago on that either.Time has a way of answering these questions.

And btw "I can tell its more potent" isnt exactly scientific proof.Nor is " and so and so says its more potent too".It takes gas chromatography and several thousand samples to prove the increased thc content.

 

[BobCajun]

Well if you arent including parts of the spectrum the sun has been providing for them for several millenia,it seems like that would affect potency to some degree.I really dont think its plausible to pick a narrow band out of the spectrum and say "this is what affects potency and nothing else".Obviously the book isnt closed on this yet,just because you haven't seen a study doesnt mean anything...maybe one hasnt been done yet.It was only a few years ago,that it was found plants do absorb green light.There wasnt many studies 10 years ago on that either.Time has a way of answering these questions.

And btw "I can tell its more potent" isnt exactly scientific proof.Nor is " and so and so says its more potent too".It takes gas chromatography and several thousand samples to prove the increased thc content.

Fine. Let us know how it turns out then. Personally, I'm a desert reptile CFL guy, though perhaps surprisingly, I'm not a reptilian.

 

[BobCajun]

I'm already noticing more potency, just after a few cycles with the rep CFLs. I made my own reflectors from the smallest aluminum baking pans, for small lasagnas or something. I pulled the sides and front out some to make it more roundish, cut a flap into one end and bent the flap out and wrapped and zip tied it to the socket thing. Worked real nice. Now the UVB is all directed down from the horizontally mounted CFLs at each end of the cab.

The difference is so easily noticeable that I got quite high just from a skinny secondary I tested. Two 26 watters in a half sq meter cab is just about right, so like 100 w per sq m or about 10-20% of main light wattage (20% in my case). Is it just my imagination? Maybe, I sure got high though whereas with non-UVB crops I had to extract the resin from the trimmings and bottom bud and dry it onto the buds to make it worth smoking. The trimmings weighed about 1/3 of the weight of the good buds so that increased potency by about 1/3. Now it's actually smokable as is. I also get a little bit of extra usable PAR light from the Reptile CFLs. It fills in the ends of the cab, which were less bright than the center where the LEDs are.

 

[Resinhound]

I think youre right uvb probably does increase potency,but there is also a thing called the placebo effect thats real too.Its worth experimenting with but I hesitate to call "I can tell the difference" proof.This industry has a habit of adopting anything as proof at the slightest hint of evidence.

 

[BobCajun]

I think youre right uvb probably does increase potency,but there is also a thing called the placebo effect thats real too.Its worth experimenting with but I hesitate to call "I can tell the difference" proof.This industry has a habit of adopting anything as proof at the slightest hint of evidence.

True enough, which is why I'm still cautious about it. Could just be because I haven't been smoking as heavily lately. But let's face it, there's enough evidence out there to conclude that it does work. I'm just confirming it. If it's this potent at 4.5 weeks then it should be uncommonly good when ripe.

 

[greasemonkeymann]

I don't think it is as simple as that. Agromax makes horticulture bulbs. I'm sure they are making the 10,000k+uva for a reason and if it lets uva, some uvb will be provided to. They also make a better uva/uvb bulb than reptile bulbs.

I'll see this run at the difference it makes.

you guys use the 10k 600w mh bulbs yet?
I've used it for one grow (on my second) and you can VISUALLY see the difference in the glands produced on the MH side.
I'm running a normal 600hps and then the 10k 600w mh.
You can see the difference, very easily.
I've used mixed bulb setups for yrs and yrs, and I have always thought the mixed spectrum produced a MUCH better product.
Now that they finally have made a 600w mh, it's just awesome.
It's cheap, go buy the bulb and try it for yourself. Most will be fired in most digital ballasts.
Also make sure to take off the hood reflector glass on any aircooled setups, you want the bulb bare.
I don't think i'll go back to a pure HPS setup.
To the naked eye the mh seems MUCH brighter than the hps, but that's all just the visible light.
You also may want to buy some acetylene cutting torch glasses, and long-sleeved labcoats for when the light is on.
90% of my maintenance is done during the night schedule