Latest UVA vs UVB cannabinoid test results

[PSUAGRO.]

72% efficiency on a uva diode? Very surprised by this..... Crazy bump from a year or two.

 

[Kassiopeija]

JFYI, 405+-5nm isn't "Ultra"-Violet, but just normal Violet and thus, still PAR, - ie. fully photosynthetically radiation - that has very little difference from the typical blue 440nm royal blue in terms of what it does to a plant. It could be labelled as N-UV "Near"-UV

UVA is from 315-395, where usually growers use that term to relate to the usage of 365nm or 385nm mono diodes.
I've recently read a study conducting leaf-fluorence-measurements caused by the upper parts of natural sunlight (including UVB) and it did call the upper UVA region between 315-355 "far"-UVA.
To my knowledge these wavelength aren't really used conventionally except in UV-B tubes

 

[Prawn Connery]

JFYI, 405+-5nm isn't "Ultra"-Violet, but just normal Violet and thus, still PAR, - ie. fully photosynthetically radiation - that has very little difference from the typical blue 440nm royal blue in terms of what it does to a plant. It could be labelled as N-UV "Near"-UV

UVA is from 315-395, where usually growers use that term to relate to the usage of 365nm or 385nm mono diodes.
I've recently read a study conducting leaf-fluorence-measurements caused by the upper parts of natural sunlight (including UVB) and it did call the upper UVA region between 315-355 "far"-UVA.
To my knowledge these wavelength aren't really used conventionally except in UV-B tubes

Hey mate, I tend to agree with most of what you say, but not on this occassion. You're correct in your definition, but when you think about it, 400nm as the cut-off for UVA is a bit of an arbitrary figure. It's not like you get the full benefits of UVA at 399nm and none at 401nm.

I also very much disagree with the statement that there is "very little difference from the typical blue 440nm royal blue in terms of what it does to a plant."

I'm loathe to use the McCree Curve as an example, as there are real misgivings about its accuracy considering it is based on chlorophyll absorption in a solvent (and leaves are made up of water, not solvents), but I will still post it to prove a point – that PAR is not restricted to 400-700nm, and we really need to stop using it as a definition of "full spectrum" (especially as most LED manufacturers still refer to 450nm based white phosphor diodes as "full spectrum" when they are missing everything below 440nm)


Source: https://www.researchgate.net/publication/343488105_Tunable_multiple-LEDs_combination_spectrum_for_plants_based_on_McCree_PAR_spectrum

The Relative Quantum Efficiency of violet and UVA light is still pretty high below 400nm and above 700nm.

Indeed, the "true" colour of chlorophyll may also be much bluer that we realise, with Chl A and B peaks quite different to the ones we are used to: https://www.mpsd.mpg.de/17628/2015-04-chlorophyll-rubio

We use 405nm diodes for three reasons:

1. They are very efficient
2. They fill in the tradiational PAR range below 440nm
3. We have demonstrated significant increases in secondary metabolites through the use of light around 400nm with the added benefit that it is also photosynthetically active and is not as strong as UVB and mid-UVA, so can be used full-cycle (on one channel, which simplifies the lighting fixture).

Again, this graph may or may not be entirely accurate, but with our current understanding of plant absorption spectra there is a lot going on around 400nm – the Chlorophyll A minor peak at 400nm is almsot the same as at 660nm!



Phytochrome absorption is also significant around this area (though look at the UVB region around 285nm, where UVR8 absorption also peaks):



The whole point of adding UV to grow lights is to increase secondary metabolite production, including cannabinoids and terpenes. I think we have proven that this can be accomplished with the use of full-cycle "near" UV and UVA which has another benefit in not impacting yields (as UVB does).

And let's not forget that 405nm diodes also spill over into other spectra as low as 380nm and as high as 440nm. When you have a very efficient diode such as the Nichia NVSU219CT, then a little bit goes a long way.




These diodes are almost too strong, as you can see from this spectograph of the new High Light 420 Gen2 panels:

 

[Grow Lights Australia]

So if I buy clones and put them into flower straight away, you suggest to use the UV from day 1 to finish?
With UV lights on everyday I would just experiment with the amount of time the plants are exposed to UV.
Maybe gradually increase the time from a few minutes to several hours every day during flowering.

Thank you all for your advice!
I am sorry for starting an off-topic discussion in this thread.
If I can find a laboratory in my area to test my results with and without using UV, I maybe can contribute to the original topic of this thread.

Yes. These seedlings were grown under our new propagation spectrum which has about 1% UV. This photo is from a grow by @Prawn Connery. I'm sure he won't mind my posting it. You can see how strong the Nichia diodes are.

 

[Kassiopeija]

Hey mate, I tend to agree with most of what you say, but not on this occassion. You're correct in your definition, but when you think about it, 400nm as the cut-off for UVA is a bit of an arbitrary figure. It's not like you get the full benefits of UVA at 399nm and none at 401nm.

I also very much disagree with the statement that there is "very little difference from the typical blue 440nm royal blue in terms of what it does to a plant."

I'm loathe to use the McCree Curve as an example, as there are real misgivings about its accuracy considering it is based on chlorophyll absorption in a solvent (and leaves are made up of water, not solvents), but I will still post it to prove a point – that PAR is not restricted to 400-700nm, and we really need to stop using it as a definition of "full spectrum" (especially as most LED manufacturers still refer to 450nm based white phosphor diodes as "full spectrum" when they are missing everything below 440nm)

View attachment 5098670
Source: https://www.researchgate.net/publication/343488105_Tunable_multiple-LEDs_combination_spectrum_for_plants_based_on_McCree_PAR_spectrum

The Relative Quantum Efficiency of violet and UVA light is still pretty high below 400nm and above 700nm.

Indeed, the "true" colour of chlorophyll may also be much bluer that we realise, with Chl A and B peaks quite different to the ones we are used to: https://www.mpsd.mpg.de/17628/2015-04-chlorophyll-rubio

We use 405nm diodes for three reasons:

1. They are very efficient
2. They fill in the tradiational PAR range below 440nm
3. We have demonstrated significant increases in secondary metabolites through the use of light around 400nm with the added benefit that it is also photosynthetically active and is not as strong as UVB and mid-UVA, so can be used full-cycle (on one channel, which simplifies the lighting fixture).

Again, this graph may or may not be entirely accurate, but with our current understanding of plant absorption spectra there is a lot going on around 400nm – the Chlorophyll A minor peak at 400nm is almsot the same as at 660nm!

View attachment 5098673

Phytochrome absorption is also significant around this area (though look at the UVB region around 285nm, where UVR8 absorption also peaks):

View attachment 5098674

The whole point of adding UV to grow lights is to increase secondary metabolite production, including cannabinoids and terpenes. I think we have proven that this can be accomplished with the use of full-cycle "near" UV and UVA which has another benefit in not impacting yields (as UVB does).

And let's not forget that 405nm diodes also spill over into other spectra as low as 380nm and as high as 440nm. When you have a very efficient diode such as the Nichia NVSU219CT, then a little bit goes a long way.

View attachment 5098680


These diodes are almost too strong, as you can see from this spectograph of the new High Light 420 Gen2 panels:
View attachment 5098683

Hey Prawn, I think I did word some of that post poorly, it was in no way ment to argue against a more rich UV/blue spectrum extension, it's been really just about man-made definitions... These are sometimes just arbitrary, like for cosmonauts UVC UVB UBA is 100-200-300-400nm.
And the human eye perception has also been extended the "visible light" into UVA & FR.

And in plant physiology UV & blue is usually mostly grouped together. They belong together and plants, and esp. Cannabis, is evolutionairy used to a very high input of UVA/B as at higher altitudes there's less atmosphere to filter the blue out.

Now it is obvious that the normal blue light can do "most of the job" otherwise the plant wouldnt grow physiologically correct under white light (like it would grew only erratically under pure 660nm).

But the difference between other blue or UV wavelength are rather in the details IMO, as plants generate pigments to deal with this energy-rich radiation.

And yes, the leaves can use all of that UVA for photosynthesis, in one way or another, even far UV seems to be promising in that regard. At least, at very low influx to reflect a natural setting and offset negative responses. I could send you some recent studies if you are interested, I personally actually would like to see a much more broader inclusion of UVA into growlights.

Especially when these grow food for human consumption it will be much more healthy under a rich UV spec. Even UV-C dramatically increases some anti-oxidants (e.g. Rutin).

Furthermore, it's way better to distribute "the blue color output" (blue has been proven in many studies to be absolutely mandatory) via several bandwaves as this has a beneficial aspect to chlorophyll-saturation, leaf-transmittance, fluorescence & photoinhibition. As one could go overboard with any color.
So I really think your newest board is a step into the right direction

 

[Prawn Connery]

I could send you some recent studies if you are interested, I personally actually would like to see a much more broader inclusion of UVA into growlights.

Yes, I would love to read anything you have on the subject. I honestly think it is up to growers like us to try different things to see what works in the field as it is obvious to me that there is still so much we don't undertstand, including that link I posted above about the "true" colour of chlorophyll. Yes, I got your PM and as usual, you make some very interesting points.

There is another thread running in the LED section at the moment that I have just read concerning LED binning and efficiency. IMO, efficiency is always good, but it's not that hard to make an efficient light if you simply throw a few colours together and brag amout umol/j. It is much harder to gst that type of efficiency in a "true" full spectrum grow light that includes Far Red, UV, balanced Cyan and blue/violet light below 440nm. Having a broader spectrum in itself makes photosynthesis more efficient because the plant can develop different chloroplast pigments to absorb different wavelengths without being saturated by certain colours (such as red or blue). At least, as far as I understand.

 

[HippieDudeRon]

Hey mate, I tend to agree with most of what you say, but not on this occassion. You're correct in your definition, but when you think about it, 400nm as the cut-off for UVA is a bit of an arbitrary figure. It's not like you get the full benefits of UVA at 399nm and none at 401nm.

I also very much disagree with the statement that there is "very little difference from the typical blue 440nm royal blue in terms of what it does to a plant."

I'm loathe to use the McCree Curve as an example, as there are real misgivings about its accuracy considering it is based on chlorophyll absorption in a solvent (and leaves are made up of water, not solvents), but I will still post it to prove a point – that PAR is not restricted to 400-700nm, and we really need to stop using it as a definition of "full spectrum" (especially as most LED manufacturers still refer to 450nm based white phosphor diodes as "full spectrum" when they are missing everything below 440nm)

View attachment 5098670
Source: https://www.researchgate.net/publication/343488105_Tunable_multiple-LEDs_combination_spectrum_for_plants_based_on_McCree_PAR_spectrum

The Relative Quantum Efficiency of violet and UVA light is still pretty high below 400nm and above 700nm.

Indeed, the "true" colour of chlorophyll may also be much bluer that we realise, with Chl A and B peaks quite different to the ones we are used to: https://www.mpsd.mpg.de/17628/2015-04-chlorophyll-rubio

We use 405nm diodes for three reasons:

1. They are very efficient
2. They fill in the tradiational PAR range below 440nm
3. We have demonstrated significant increases in secondary metabolites through the use of light around 400nm with the added benefit that it is also photosynthetically active and is not as strong as UVB and mid-UVA, so can be used full-cycle (on one channel, which simplifies the lighting fixture).

Again, this graph may or may not be entirely accurate, but with our current understanding of plant absorption spectra there is a lot going on around 400nm – the Chlorophyll A minor peak at 400nm is almsot the same as at 660nm!

View attachment 5098673

Phytochrome absorption is also significant around this area (though look at the UVB region around 285nm, where UVR8 absorption also peaks):

View attachment 5098674

The whole point of adding UV to grow lights is to increase secondary metabolite production, including cannabinoids and terpenes. I think we have proven that this can be accomplished with the use of full-cycle "near" UV and UVA which has another benefit in not impacting yields (as UVB does).

And let's not forget that 405nm diodes also spill over into other spectra as low as 380nm and as high as 440nm. When you have a very efficient diode such as the Nichia NVSU219CT, then a little bit goes a long way.

View attachment 5098680


These diodes are almost too strong, as you can see from this spectograph of the new High Light 420 Gen2 panels:
View attachment 5098683

McCree was not done in vitro(solution). It was done with full leaves.

https://www.vegenaut.com/pl/wp-content/uploads/sites/2/2017/07/PPFD_essential_article.pdf

You're thinking of the chlorophyll action spectra. They are not the same. In vitro action spectra is what you posted at the bottom. Again, pigment vs McCree is not the same, nor were they "done" the same way.

 

[Kassiopeija]

It was done with full leaves.

2.5mm^2 and used monochromatic light. It does give a good basic startup but the methods today are much more on point and sophistocated.
McCree can be critisized from many ways like when he wrote the Emerson - Effect is
negligible (but he used a background white light that peaked at 700nm for "control" [!])... also KOK effect, multilayer-O2 evolution aspects...
Esp. the UV & FR end of the spectrum seem to have been neglected somewhat...

 

[Kassiopeija]

Having a broader spectrum in itself makes photosynthesis more efficient because the plant can develop different chloroplast pigments to absorb different wavelengths without being saturated by certain colours (such as red or blue). At least, as far as I understand.

Yes, there are indeed some differences of how a leaf reacts to, and grows (or organizes itself) depending on light spectra & saturation... on a number of different levels... but the basic chloroplast, esp. the 2 core complexes, are almost identical even between individual species.
With most light just absorbed by Chl-a & b, which still can absorb so much more than in solvent.
There are studies stating that once these complexes near themselves to "light saturation" the speed with which photosynthesis runs is kinda equal for many colours, but still some colors can have a beneficial or destructive effect - if one goes overboard with them - and one way to prevent that would be to distribute the energy more broad

 

[Prawn Connery]

McCree was not done in vitro(solution). It was done with full leaves.

https://www.vegenaut.com/pl/wp-content/uploads/sites/2/2017/07/PPFD_essential_article.pdf

You're thinking of the chlorophyll action spectra. They are not the same. In vitro action spectra is what you posted at the bottom. Again, pigment vs McCree is not the same, nor were they "done" the same way.

Yes, you are correct – my mistake. The "true colour of chlorophyll" link was also in relation to invitro pigment absorption.

 

[Greengrouch]

Dope, finna see what these uva bars can do

 

[amneziaHaze]

your lamps have a huge difference in rest of the spectrums.it could be because of that and not uv

 

[Prawn Connery]

your lamps have a huge difference in rest of the spectrums.it could be because of that and not uv

We've done more than one tets. We've done three so far, and the lights used in the other two were very similar, especially in the first link. The sedon link was between HLG Quantum boards and early High Lights that used similar LED technology and spectra:

More THC testing – UVA vs UVB vs near-UV

We took four samples of the same strain, all grown in coco run-to-waste by competent growers under slightly different lighting set-ups, with two of the samples being provided by the same grower under the same conditions, but grown six months apart (to compare the ageing process or "cure"). This...

www.rollitup.org

THC, CBD, Terpene test results – UVA vs UVB vs none

As some of you might know, former member Or_Gro did a side-by-side comparing three different types of LED boards with supplementary UV reptile bulbs. He also did a control grow without any UV at all. The test results are interesting because UV clearly works – an increase of almost 20%! But...

www.rollitup.org

So you are right to point out the differences in spectrum (that was kinda the point of these tests), but other tests were much closer.

 

[amneziaHaze]

Well you test uv but give the plant 20% more green and red no logic you could have used 300w lamp vs 1000w lamp and say you are testing uv

 

[Prawn Connery]

Well you test uv but give the plant 20% more green and red no logic you could have used 300w lamp vs 1000w lamp and say you are testing uv

"No logic" is stating that each of these lights have "20% more green and red". You did not follow the links I provided, did you?

More THC testing – UVA vs UVB vs near-UV

We took four samples of the same strain, all grown in coco run-to-waste by competent growers under slightly different lighting set-ups, with two of the samples being provided by the same grower under the same conditions, but grown six months apart (to compare the ageing process or "cure"). This...

www.rollitup.org

 

[widowmaker31]

Yes. These seedlings were grown under our new propagation spectrum which has about 1% UV. This photo is from a grow by @Prawn Connery. I'm sure he won't mind my posting it. You can see how strong the Nichia diodes are.

View attachment 5098953

The above light and plants below said light do not reflect full spectrum with UV-A/B. Here is a dead give away - the stems are not purple nor are the leaves stems purple. Thus, the secondary metabolites are not being activated by UV or enough rich BLUE at 437nm or 450nm, etc.

 

[Rocket Soul]

The above light and plants below said light do not reflect full spectrum with UV-A/B. Here is a dead give away - the stems are not purple nor are the leaves stems purple. Thus, the secondary metabolites are not being activated by UV or enough rich BLUE at 437nm or 450nm, etc.

Why is that a give away? The anthocyanins that are responsible for purple stems/high irradiance response is generally due to a combination of high light intensity combined with low temps. This happens very often in standard spectrum.grows, especially with led not bringing any heat, and usually purpling would be an indication of plant unhappiness

 

[widowmaker31]

Why is that a give away? The anthocyanins that are responsible for purple stems/high irradiance response is generally due to a combination of high light intensity combined with low temps. This happens very often in standard spectrum.grows, especially with led not bringing any heat, and usually purpling would be an indication of plant unhappiness

Agree to disagree! Best of luck to you! Real infrastructure with real lighting and scientific results speak for themselves

Stay Lifted !

 

[Rocket Soul]

Agree to disagree! Best of luck to you! Real infrastructure with real lighting and scientific results speak for themselves

Stay Lifted !

Thtas some very nice lighting. What are these scientific results you talk about?

 

[Charles U Farley]

Agree to disagree! Best of luck to you! Real infrastructure with real lighting and scientific results speak for themselves or listen to the ego it's free for a lifetime! ~

Stay Lifted !

Holy shit, now that's some light!! Here I thought I was the king of overkill because I used to have a 1 kw MH light blasting in a 2x5 grow closet but after seeing your set-up, I'm just not fucking worthy!

The term urge-overkill comes to mind.