Or_Gro and the epic smackdown

[IbnVapin]

Hey man, hope you’re doin well. Was gonna ask sticky tomorrow to let you know...welcome!

How are your babies?

They're doing great man. All 4 seeds popped. Got 2 Auto Diesel's in from Royal Queen, and then the two Alaskan Purple from Seedsman I guess. Gonna see if I can't work out an 8-line mainline this time with them. I am doing well, still some lingering stomach issues but nowhere remotely as bad as before lol. Still got that appointment on the 12th of July, just wish it would hurry up and be the 12th already I wanna know what's going on in there lol.

Yep, i been thinkin about how hard it is to wait for an apptmt like that...well hopefuly those girls distract a little...only 3 wks now...

A lot better than the two months it used to be lol!!

Plants coming up hella fast now, they've got tiny string roots in the res now. Autos look good too!

[unkle_psycho]

I think the video was advising using a single 10mw 285nm diode for a regular growspace, and said they managed to do most of their work without damaging plants. I guess that means their power levels were really low.

0.1mw/ cm2 was enough to increase THC by 10%, and some cannabinoids and terpenes by up to 100%. It was also affecting the different aging processes in the bud, including trichomes turning amber faster.

Iirc, thc is the only cannabinoid shown to increase due to uvb, in the study i linked. In my own grow, i didn’t notice any diffs in “bud aging” or in trich ambering.

Could be they are seeing effects that are specific to their method...and not generalizable.

The video is in the general section. Sucks, that theres a simple registration procedure to see it, but I'd say its well worth it. Hope I'm getting these numbers right, but I think it was 10% THC and over 100%CBG, with a reduction in CBD. Then there were the terpenoids.

[Or_Gro]

I think the video was advising using a single 10mw 285nm diode for a regular growspace, and said they managed to do most of their work without damaging plants. I guess that means their power levels were really low.

0.1mw/ cm2 was enough to increase THC by 10%, and some cannabinoids and terpenes by up to 100%. It was also affecting the different aging processes in the bud, including trichomes turning amber faster.

Iirc, thc is the only cannabinoid shown to increase due to uvb, in the study i linked. In my own grow, i didn’t notice any diffs in “bud aging” or in trich ambering.

Could be they are seeing effects that are specific to their method...and not generalizable.

The video is in the general section. Sucks, that theres a simple registration procedure to see it, but I'd say its well worth it. Hope I'm getting these numbers right, but I think it was 10% THC and over 100%CBG, with a reduction in CBD. Then there were the terpenoids.

Can you post a link?....i probably was looking at it, but didn’t see it....thanks

[Marine2143]

https://event.webcasts.com/viewer/event ... 2f04a8d7d3

[Or_Gro]

https://event.webcasts.com/viewer/event ... 2f04a8d7d3

Thanks, but it craps out just when the guy starts talking about uvb and greenhouse glass/acrylic...

Prawn Connery can prob talk about the uvb leds from seoul semi; some of their diodes are in his lights.

[Prawn Connery]

Yes, on paper they are good LEDs and have a good range from 367nm to 420nm. Seoul Semiconductor are pushing their UV mono LEDs and UV-based white phosphors - which we use on our High Lights - for the horticulture industry, because they understand the importance of full spectrum LED with added UV to target secondary metabolite production.

Or at the very least, they understand that trying to match broad-spectrum sunlight - in light (pun intended) of our ever-changing understanding of how different spectra affect plant growth - is a great marketing gimmick!

I don't pretend to be an expert on the subject, so can only offer some observations. Firstly, I don't know where some of these companies get their ideas that 285nm and 365nm are the most efficient sources of UV for plants, as I haven't seen any real scientific basis for this. They may be based on one particular study that exposed plants to UVB or not, but other more recent studies have shown that pretty much all UV light will elicit stress responses in cannabis that increase cannabinoid production.

It seems logical, therefore, that the higher the frequency (lower nm) and energy of a wavelength, the greater the stress response in a plant over a given timeframe.

However, the trade-off is that these stress responses are exactly that: responses to stress factors (DNA damaging UV light) that would otherwise harm the plant.

So UV light can force a plant to produce more THC, but it can also damage the plant in the process and stunt growth. It may also be a very inefficient use of energy, as the energy required to provide UV light is not helping the plant grow.

The tradeoff, therefore, is THC production vs overall yield.

My own view is that there is probably a balance somewhere, between optimum use of UV light to provide a mild stress response to improve terpene and cannabinoid production, and wasted energy/damaging UV that either stunts growth, damages the plant, or does not promote growth - resulting in lower yields.

Very few growers want lower yields. And quality can be very subjective.

I have smoked UVA/B exposed buds and non-UV exposed. The UV exposed bud has been grown under lights, and grown outdoors.

You can clearly notice the difference in potency - it is tangible (even if you don't have a mass spectrometer to measure THC levels). But does it improve the experience? Is the quality of the high "better" or just "stronger". And if it is merely "stronger" (higher levels of cannabinoids), then does that make up for any lack of "quality" in the high? By which I mean, a strong, nasty (paranoia-inducing) high is still a nasty high.

Increasing THC production when other cannabinoids are not increased by the same proportion could, in fact, ruin the "high" profile and turn what may be a pleasant smoke into something a little less pleasant.

Nearly all of today's modern strains were bred under almost no UV (HPS lights, or sometimes Metal Halides that usually had UV-blockiung iron incorporated into the protective glass).

Even plants that evolved outside where never subjected to high levels of UVB: 285nm almost doesn't exist on our planet, as it is nearly all filtered out by the atmosphere. The UVB to UVA ratio averages around 20:1, and even that only makes up around 5% of all light energy that reaches the earth (meaning UVB makes up 5% of 5% - or 0.25% of all light energy). And of that 0.25%, only a tiny, tiny fraction is 285nm - if at all at sea level.

So if we are really using sunlight as the yardstick when creating artificial light, then we probably only need 5% maximum UV, and of that, 95% should be UVA. And it should probably be broad spectrum UVA, too - not just one wavelength.

But as I said, I'm no expert, and these are only my observations.

[Chiefrunningphist]

What's up guys, just thought I'd pop in and say hi.

As for the "UVI vs UV measurement" ...

The unweighted UV measurement will always be a considerable amount more than the UVI × 25mW/m2. The UVI × 25mW/m2 is only the area under the created curve, you'd have to divide the created curve by the erythemal curve and then integrate from 280nm to 320nm to be able to compare apples to apples.

The UVI curve (*) is created by multiplying the erythemal curve (*) by the actual radiation curve (*, actual SPD curve) for every nm of WV from 295 to 400 (I think it's all the way to 400nm). So its multiplying the lights individual WV intensity at 295 by 100%, 296nm at 93%, 297nm at 87%, 298nm at 80% 299nm at 74%, ect ect. all the way till 400nm. It's just multiplying the actual SPD by the erythemal to create a UVI curve that's further integrated and divided by 25mW/m2 for a final UVI.

At ~309nm the erythemal weighting has already diminished to ~10% with 295nm being 100%. So if your UVB meter is reading 800μW/cm2, you have to remember that barely any of that is <296nm, and at 309nm you're only about 10% weight, let alone 1% at 319nm. The 800μW/cm2 is being recorded unweighted and the majority of that unweighted emmission recording is primarily from 320nm due to the SPD of the bulb, so the total reading should be much greater than the weighted reading.

debilt20020601.gif (10.58 KiB) Viewed 1264 times

^^^The yellow portion is the UVI index that still needs to be divided by 25 to achieve a UVI. The area under the "measured" spectrum from 280nm to 320nm is the total quantity of UVB that your UVB meters will pick up...


Ill have to check out the video, sounds interesting.

[Or_Gro]

What's up guys, just thought I'd pop in and say hi.

As for the "UVI vs UV measurement" ...

The unweighted UV measurement will always be a considerable amount more than the UVI × 25mW/m2. The UVI × 25mW/m2 is only the area under the created curve, you'd have to divide the created curve by the erythemal curve and then integrate from 280nm to 320nm to be able to compare apples to apples.


USER_SCOPED_TEMP_DATA_orca-image--2083017694.jpeg_1559517491818.jpeg
The UVI curve (*) is created by multiplying the erythemal curve (*) by the actual radiation curve (*, actual SPD curve). At ~307nm the erythemal weighting has already diminished to ~1% with 295nm being 100%. So if your UVB meter is reading 800μW/cm2, you have to remember that barely any of that is <296nm, and at 319nm you're already about 0.01% weight. So the 800μW/cm2 is being recorded unweighted and the majority of that unweighted emmission measurement is primarily from 320nm due to the SPD of the bulb, so the total reading should be much greater than the weighted reading.


debilt20020601.gif
^^^The yellow portion is the UVI index that still needs to be divided by 25 to achieve a UVI. The area under Sun's SPD from 280nm to 320nm is the total quantity of UVB that your UVB meters will pick up...

Ill have to check out the video, sounds interesting.

Good to see ya chief....one question:

Can you translate that into grower english?

[Chiefrunningphist]

What's up guys, just thought I'd pop in and say hi.

...

Ill have to check out the video, sounds interesting.

Good to see ya chief....one question:

Can you translate that into grower english?

Lol

Translation = imo, go by UVI·hrs for a more accurate metric quantifying "PAR UVB"

It seems people are having success using a variety of bulbs, solarcure, agromax, uvb150, arcadia, ect. They all have different SPDs but some are closer to 285nm or have more short WV radiation than others so we have to adjust hang heights ect. Because UVI targets the shorter WV's the most, and because it seems MJ is affected by short WV UVB more than long WV UVB, I think it's best to determine UVB doseage by UVI than total UVB.

What Ive been trying to determine is how accurate is the erythemal curve? Is 100W of 295nm really equivalent to 100W of erythemally weighted UV? Ie can you take a naturally occurring 10.0 UVI ( = 250mW/m2 of weighted UV) and achieve the same results with 250mW/m2 of 295nm? Can 1 WV replace the effects of an entire UVB range? It seems that varying intensity of the other WVs (UVA - FR) will allow for more or less UVB doseage, but strictly speaking of the UVB effect, can it be achieved targeting a single WV(?) or does it need a little bit of all of them?

[Jolly Green Giant]

A guy from Pedro's Grow Room stream told me you were here Or_Gro, couldn't miss out on your wisdom bro.

a really "giant" guy. lol welcome man!!