PSA: UV-B bullsh*t

[Rocket Soul]

Just curious, do you ever do double blind, a/b tests?

I stop playing around with light manipulation after my Lumigrow 325 but have always been intrigued with additional UV lighting. Just never thought it would really add enough "bottom line" THC to be worth the effort, at least for me. I already grow more than I can consume.

I respect your knowledge of lighting.

No, we didnt. Im not even sure if its thc or terps but it was clearly better, hands down.

Theres not very much info on that light but par maps look a bit poor compared to more modern lights. If i understand correct its a blurple + white? Doesnt seem to really be any uv there. Just playing with standard blue will only get you so far.

 

[Rocket Soul]

Men in white coats are boasting about 7.5% efficiency for UV LEDs. That is in their lab. It's conceivable that 8% of your light output in the UV region, would mean a UV rig consuming as much power as your main lights. I did a brief search for what we can buy, and found a 1.9w LED producing 0.055w of UV. That's not a tenth of what a compact fluorescent produces. These sort of numbers just don't work. It's why the EU has effectively banned flo's, except for UV generation, where there is no alternative.

Lol, what are you talking about? Nichia have +70% efficient 405s, even cheaper off brands go over 1000mW @500mA (around 60%) if you know where to look. 365 is generally a bit lower or pay more for +50%.
I think you looked years ago, tried what you could but and made your opinion on this. Maybe time to try again. Im not sure why you couldnt get results from uv-tubes, seems most people ive seen try got at least something. Id try again if i were you.

 

[Normannen]

this picture is from the 3rd paper cited by OP...I think I will be adding UVA+UVB...if anything all these papers tell me the quality of grow lights in the led department really needs to step up its game and embrace sunlike spectra instead of marketing gimmicks.

 

[Rocket Soul]

View attachment 18929198
this picture is from the 3rd paper cited by OP...I think I will be adding UVA+UVB...if anything all these papers tell me the quality of grow lights in the led department really needs to step up its game and embrace sunlike spectra instead of marketing gimmicks.

We get tricome rails on our rainbow chip somewhere between uva and uva+uvb pic using regular 3000k 80cri, no uv, pics dont allways tell a full story.
Apart from subjective taste our results where validated by a 10% increase in yield value. Were quite happy with this as yield didnt seem to go down but still chasing a better quality.
I sincerely recommend trying out uv if your main light is standard led. UVA would be the easiest to start with and also seems where you get more bang for buck.
If you start with a standard HE spectrum, 4000k + 660, then i would probably try to add both red and uv. Even far red and uv, i think kingbrite has stock of strips.

 

[Normannen]

We get tricome rails on our rainbow chip somewhere between uva and uva+uvb pic using regular 3000k 80cri, no uv, pics dont allways tell a full story.
Apart from subjective taste our results where validated by a 10% increase in yield value. Were quite happy with this as yield didnt seem to go down but still chasing a better quality.
I sincerely recommend trying out uv if your main light is standard led. UVA would be the easiest to start with and also seems where you get more bang for buck.
If you start with a standard HE spectrum, 4000k + 660, then i would probably try to add both red and uv. Even far red and uv, i think kingbrite has stock of strips.

and cyan is nowhere to be seen...

 

[Ca++]

Lol, what are you talking about? Nichia have +70% efficient 405s, even cheaper off brands go over 1000mW @500mA (around 60%) if you know where to look. 365 is generally a bit lower or pay more for +50%.
I think you looked years ago, tried what you could but and made your opinion on this. Maybe time to try again. Im not sure why you couldnt get results from uv-tubes, seems most people ive seen try got at least something. Id try again if i were you.

Indeed, a lot happened for UV LED as covid pushed for germicidal products. Nichia have some out next year for horticulture with a whopping 0.09w of UV, from 1.6w consumed. That's near 5%

Nichia will launch UV-B (308nm) and UV-A (330nm) LEDs | Products | News Room | NICHIA CORPORATION

www.nichia.co.jp

Where is your 70% ?

Edit: I thought your 405 reference was a series I was unfamiliar with. You mean 405nm? We are talking about UV.
Notice the final statement from Nichia. It's the same as mine. They will carry on trying to make better ones, in the hope of replacing florescents*. Which I did get results from, but not favourable ones. However, I did get results, because I did have some UV.


*I choose flo's as my mercury lamp, as they are suited to most situations. If you have a high roof glass-house situation, you may use MBF. Everyone used to use MBF, and that's important, because nobody does anymore. Without outside guidance, we all stopped using UV and didn't miss it. This has been an ongoing situation, from MBF to MH, HPS and finally LED, where it's gone.

 

[Rocket Soul]

and cyan is nowhere to be seen...

Indeed, a lot happened for UV LED as covid pushed for germicidal products. Nichia have some out next year for horticulture with a whopping 0.09w of UV, from 1.6w consumed. That's near 5%

Nichia will launch UV-B (308nm) and UV-A (330nm) LEDs | Products | News Room | NICHIA CORPORATION

www.nichia.co.jp

Where is your 70% ?

Edit: I thought your 405 reference was a series I was unfamiliar with. You mean 405nm? We are talking about UV.
Notice the final statement from Nichia. It's the same as mine. They will carry on trying to make better ones, in the hope of replacing florescents*. Which I did get results from, but not favourable ones. However, I did get results, because I did have some UV.


*I choose flo's as my mercury lamp, as they are suited to most situations. If you have a high roof glass-house situation, you may use MBF. Everyone used to use MBF, and that's important, because nobody does anymore. Without outside guidance, we all stopped using UV and didn't miss it. This has been an ongoing situation, from MBF to MH, HPS and finally LED, where it's gone.

Well i repeat, maybe you should try with leds, maybe youll get somewhere.
And i repeat: you seem to be taking your opinion rather highly for someone who wasnt able to get favorable results when the majority does.

 

[goingrey]

View attachment 18929198
this picture is from the 3rd paper cited by OP...I think I will be adding UVA+UVB...if anything all these papers tell me the quality of grow lights in the led department really needs to step up its game and embrace sunlike spectra instead of marketing gimmicks.

UVA without UVB seems to increase powdery mildew if we want to draw a conclusion from the photos.

 

[Ca++]

Well i repeat, maybe you should try with leds, maybe youll get somewhere.
And i repeat: you seem to be taking your opinion rather highly for someone who wasnt able to get favorable results when the majority does.

What majority?
Perhaps you should actually use some UV yourself, rather than a placebo

 

[Normannen]

UVA without UVB seems to increase powdery mildew if we want to draw a conclusion from the photos.

But if you put them together it kills it instead....ahaaaaahhhhh

 

[Normannen]

Well i repeat, maybe you should try with leds, maybe youll get somewhere.
And i repeat: you seem to be taking your opinion rather highly for someone who wasnt able to get favorable results when the majority does.

I am growing with LED , and it's the reason I am frustrated at people selling "grow lights"

 

[Normannen]

However, a word of advice before adding UVAor B to your terrariums...unless you already have one.

from wikipedia:

In the past, UV‑A was considered not harmful or less harmful than UV‑B, but today it is known to contribute to skin cancer via indirect DNA damage (free radicals such as reactive oxygen species).[citation needed] UV‑A can generate highly reactive chemical intermediates, such as hydroxyl and oxygen radicals, which in turn can damage DNA. The DNA damage caused indirectly to skin by UV‑A consists mostly of single-strand breaks in DNA, while the damage caused by UV‑B includes direct formation of thymine dimers or cytosine dimers and double-strand DNA breakage.[64] UV‑A is immunosuppressive for the entire body (accounting for a large part of the immunosuppressive effects of sunlight exposure), and is mutagenic for basal cell keratinocytes in skin.[65]

UVB photons can cause direct DNA damage. UV‑B radiation excites DNA molecules in skin cells, causing aberrant covalent bonds to form between adjacent pyrimidine bases, producing a dimer. Most UV-induced pyrimidine dimers in DNA are removed by the process known as nucleotide excision repair that employs about 30 different proteins.[60] Those pyrimidine dimers that escape this repair process can induce a form of programmed cell death (apoptosis) or can cause DNA replication errors leading to mutation.

As a defense against UV radiation, the amount of the brown pigment melanin in the skin increases when exposed to moderate (depending on skin type) levels of radiation; this is commonly known as a sun tan. The purpose of melanin is to absorb UV radiation and dissipate the energy as harmless heat, protecting the skin against both direct and indirect DNA damage from the UV. UV‑A gives a quick tan that lasts for days by oxidizing melanin that was already present and triggers the release of the melanin from melanocytes. UV‑B yields a tan that takes roughly 2 days to develop because it stimulates the body to produce more melanin.

Sunscreen safety debate​

Main article: Sunscreen
Demonstration of the effect of sunscreen. The man's face has sunscreen on his right side only. The left image is a regular photograph of his face; the right image is of reflected UV light. The side of the face with sunscreen is darker because the sunscreen absorbs the UV light.
Medical organizations recommend that patients protect themselves from UV radiation by using sunscreen. Five sunscreen ingredients have been shown to protect mice against skin tumors. However, some sunscreen chemicals produce potentially harmful substances if they are illuminated while in contact with living cells.[66][67] The amount of sunscreen that penetrates into the lower layers of the skin may be large enough to cause damage.[68]

Sunscreen reduces the direct DNA damage that causes sunburn, by blocking UV‑B, and the usual SPF rating indicates how effectively this radiation is blocked. SPF is, therefore, also called UVB-PF, for "UV‑B protection factor".[69] This rating, however, offers no data about important protection against UVA,[70] which does not primarily cause sunburn but is still harmful, since it causes indirect DNA damage and is also considered carcinogenic. Several studies suggest that the absence of UV‑A filters may be the cause of the higher incidence of melanoma found in sunscreen users compared to non-users.[71][72][73][74][75] Some sunscreen lotions contain titanium dioxide, zinc oxide, and avobenzone, which help protect against UV‑A rays.

The photochemical properties of melanin make it an excellent photoprotectant. However, sunscreen chemicals cannot dissipate the energy of the excited state as efficiently as melanin and therefore, if sunscreen ingredients penetrate into the lower layers of the skin, the amount of reactive oxygen species may be increased.[76][66][67][77] The amount of sunscreen that penetrates through the stratum corneum may or may not be large enough to cause damage.

In an experiment by Hanson et al. that was published in 2006, the amount of harmful reactive oxygen species (ROS) was measured in untreated and in sunscreen treated skin. In the first 20 minutes, the film of sunscreen had a protective effect and the number of ROS species was smaller. After 60 minutes, however, the amount of absorbed sunscreen was so high that the amount of ROS was higher in the sunscreen-treated skin than in the untreated skin.[76] The study indicates that sunscreen must be reapplied within 2 hours in order to prevent UV light from penetrating to sunscreen-infused live skin cells.[76]

 

[Rocket Soul]

Indeed, a lot happened for UV LED as covid pushed for germicidal products. Nichia have some out next year for horticulture with a whopping 0.09w of UV, from 1.6w consumed. That's near 5%

Nichia will launch UV-B (308nm) and UV-A (330nm) LEDs | Products | News Room | NICHIA CORPORATION

www.nichia.co.jp

Where is your 70% ?

Edit: I thought your 405 reference was a series I was unfamiliar with. You mean 405nm? We are talking about UV.
Notice the final statement from Nichia. It's the same as mine. They will carry on trying to make better ones, in the hope of replacing florescents*. Which I did get results from, but not favourable ones. However, I did get results, because I did have some UV.


*I choose flo's as my mercury lamp, as they are suited to most situations. If you have a high roof glass-house situation, you may use MBF. Everyone used to use MBF, and that's important, because nobody does anymore. Without outside guidance, we all stopped using UV and didn't miss it. This has been an ongoing situation, from MBF to MH, HPS and finally LED, where it's gone.

Im sorry i think we are missunderstanding eachother. I shoulda understood that you were talking uvb. Yes, its super inefficient but from what ive gathered very little is necessary. As for the uva diodes you cited; i wouldnt really use them as they are not optimal; id go straight to 285 and 365, as far as i gather they are the most bioreactive wavelengths.

The 70% comes from real life tests by LED TEKNIK in australia, not from datasheets. The 405nm peak isnt uv but the tail is. In anycase it doesnt seem like plants mind that. But you can look it up if you like:

https://led-ld.nichia.co.jp/api/data/spec/led/NVSU219CT-E(5891A)U405x.pdf

The reason that used this as example is that its the diode i know has been actually tested independently. Its used by some board makers i know, in part due to its base, it has anode, cathode and heatsink pad, while 395 doesnt.

They are quite pricey i understand. My go to off brand for uv diodes is pro-light opto. Feel free to peruse their datasheets at their website.

What majority?
Perhaps you should actually use some UV yourself, rather than a placebo

Try to focus my friend, i never said i was using that 405 diode. My uv regime is posted in this thread, its 400,365 and 295nm. Which is plainly in the uva and uvb region.

The majority of led growers i know that tried flouro uv has had results from it, as in stronger high and smell. It maybe that whatever gains you would have had would have been cooked off by you HID. Im not sure why you didnt get any results; me and more growers did. Its a pity you dont put the same effort arguing here in understanding why some growers are getting results, as in higher measured cannabinoides in tests. You seem to have your mind made up about this so its probably best we agree to disagree, but i don't understand why you knock something which youve actually not tried properly: efficient uv leds with a led base. Its not the same as HPS and some uv tubes.

 

[Rocket Soul]

I am growing with LED , and it's the reason I am frustrated at people selling "grow lights"

Sorry that wasnt dorected at you, miss quoted.

 

[CharlesU Farley]

No, we didnt. Im not even sure if its thc or terps but it was clearly better, hands down.

Just for intellectual curiosity, you ought to try doing a blind a/b test and see if your objective findings are the same as your subjective findings. Sometimes there can be an inherent bias, even when you're trying to be objective.

My wife loves nothing better than to prove me wrong and when we did a double blind test on vodka, I was astounded at the results. I've never been a Gray Goose or Tito's fan but I was pretty positive I could pick out the Stoli from other premium vodkas.

I could not.

Unbelievingly, I much preferred cheap ass Smirnoff vodka. It wasn't even close.

Try doing an a/b test, it might surprise you like it did me.

 

[Rocket Soul]

Just for intellectual curiosity, you ought to try doing a blind a/b test and see if your objective findings are the same as your subjective findings. Sometimes there can be an inherent bias, even when you're trying to be objective.

My wife loves nothing better than to prove me wrong and when we did a double blind test on vodka, I was astounded at the results. I've never been a Gray Goose or Tito's fan but I was pretty positive I could pick out the Stoli from other premium vodkas.

I could not.

Unbelievingly, I much preferred cheap ass Smirnoff vodka. It wasn't even close.

Try doing an a/b test, it might surprise you like it did me.

I do agree, but all other bud from that grow is already out and away.
Theres some real cannabinoid tests coming up in a few months. Ive been asked by a lightmaker to test their lights and there will be cannabis tests, i think part of the reason they gave me their gear was that they couldnt do the tests at their location; here in Spain its dead easy. But that grow wont start until after the new year.

 

[Normannen]

My wife loves nothing better than to prove me wrong and when we did a double blind test on vodka, I was astounded at the results. I've never been a Gray Goose or Tito's fan but I was pretty positive I could pick out the Stoli from other premium vodkas.

She's doing her job well