CMH vs LED vs HPS

[Brother Nature]

A question for the CMH guys...

I haven't seen a lot of discussion about the 10000k bulbs. Is this something that you guys use? I see it pushed a lot at our locals, but it's not something I can find a lot of research on. There's some half-assed threads here, but they're very old. They're 'finishing lights' meant to assist pack on resin at the end of life.

Indoor Sun CMH 315W Lamp 10000K | Hyalite New Zealand

Indoor Sun CMH 315W Lamp 10000KThe CMH PRO series is designed to produce all required grow light parameters from start to finish.Generally, the UV spectrum is not suitable for plant growth, flowering or fruiting. When higher trichrome production is required, UV lamps can be used for the...

hyalite.co.nz

I had an amazon link, but it didn't work...

 

[Crooked8]

A question for the CMH guys...

I haven't seen a lot of discussion about the 10000k bulbs. Is this something that you guys use? I see it pushed a lot at our locals, but it's not something I can find a lot of research on. There's some half-assed threads here, but they're very old. They're 'finishing lights' meant to assist pack on resin at the end of life.

Indoor Sun CMH 315W Lamp 10000K | Hyalite New Zealand

Indoor Sun CMH 315W Lamp 10000KThe CMH PRO series is designed to produce all required grow light parameters from start to finish.Generally, the UV spectrum is not suitable for plant growth, flowering or fruiting. When higher trichrome production is required, UV lamps can be used for the...

hyalite.co.nz

I had an amazon link, but it didn't work...

Im very curious, never used these before.

 

[Hammerhead]

Ive never used 10K either. Suppose to increase resin?. Mostly blue.

 

[snakedope]

The 10k bulbs are supposed to be finisher bulbs with more uv and blue, apart from being a high cri bulb in general, I think most of their use is for the uv hype, people claim mixed results with them, not conclusive.
I wouldn't use them (although I own a couple) simply because giving less light at the final stretch seems not very sensible
If top quality is everything, a mix of these 10k bulbs with hps will do wonders

 

[Crooked8]

The 10k bulbs are supposed to be finisher bulbs with more uv and blue, apart from being a high cri bulb in general, I think most of their use is for the uv hype, people claim mixed results with them, not conclusive.
I wouldn't use them (although I own a couple) simply because giving less light at the final stretch seems not very sensible
If top quality is everything, a mix of these 10k bulbs with hps will do wonders

I know this falls on deaf ears for some but as I said a while ago. They tested uva, uvb and uvc for the usu course for science and technology of medical cannabis and none of them had any impact on cannabinoid or terpene tests. Not my research, their own.

 

[goingrey]

I know this falls on deaf ears for some but as I said a while ago. They tested uva, uvb and uvc for the usu course for science and technology of medical cannabis and none of them had any impact on cannabinoid or terpene tests. Not my research, their own.

No impact is not in line with other research.

This study found a decrease in THC, and for some terpenes a decrease and others an increase. Big changes in morphology too (lower yield).

Frontiers | Cannabis Inflorescence Yield and Cannabinoid Concentration Are Not Increased With Exposure to Short-Wavelength Ultraviolet-B Radiation

Before ultraviolet (UV) radiation can be used as a horticultural management tool in commercial Cannabis sativa (cannabis) production, the effects of UV on ca...

www.frontiersin.org

Less THC, less terpenes, less yield... doesn't sound good. But it's definitely an impact. And could be maybe still used to our advantage once better understood. I'm thinking to "finish off" plants or something like this. Like the authors say, "it is still possible that the alternate UV treatment protocols may have more positive results".

 

[JKD]

Interested if there is an ‘entourage’ type effect with light. It doesn’t look as though they considered this with regard to the earlier Lydon study they reference. Would be good to see a uv filtered/unfiltered sunlight side by side in controlled conditions.

 

[sallyforthDeleted member 75382]

LED UV fixtures are not emitting UV at the right intensity and so the experiments will determine UV had no effect etc. That was the fixture used in the paper above. I use UVB fluorescent tubes with great results. The energy of the UV photons is the correct wave for plants from a tube as opposed to LED. It's the duality of light that's important, its a wave and a particle.

 

[Cerathule]

No impact is not in line with other research.

This study found a decrease in THC, and for some terpenes a decrease and others an increase. Big changes in morphology too (lower yield).

Frontiers | Cannabis Inflorescence Yield and Cannabinoid Concentration Are Not Increased With Exposure to Short-Wavelength Ultraviolet-B Radiation

Before ultraviolet (UV) radiation can be used as a horticultural management tool in commercial Cannabis sativa (cannabis) production, the effects of UV on ca...

www.frontiersin.org

Less THC, less terpenes, less yield... doesn't sound good. But it's definitely an impact. And could be maybe still used to our advantage once better understood. I'm thinking to "finish off" plants or something like this. Like the authors say, "it is still possible that the alternate UV treatment protocols may have more positive results".

I have a few questions:
- Why didn't they use a "high THC" (chemotype I) strain, which constitutes most of the typical grower genetics usually called "sativa" (I'm putting that in brackets because that denomination is actually wrong when judged by phyllogenetics). When, e.g. the studies that confirmed a positive effect for UVB did use Chemotype I. I mean, they are referencing it but then criticising it but nowhere using the same setup. Actually Lydon did already confirm that plants that are high-CBD will not react to UVB. No look at their strains they have just 5% THC or so.... Why didn't they use chemotype I, II & III?
- Why did they only use so very little light? (400 umol at the tops) when we know that the production of cannabinoids is very energy-costly. Additionally, UV creates damage that needs to be repaired (which costs energy as well) and all the responses to it also are dependant on energy. Lydon for example put the plants in a greenhouse in such a timeframe that would replicate exactly the same environmental conditions that the particular southern american wildtype cannabis did have at it's normal habitate (it grew at somewhat an altitude) then use screens to block out the UVB from the sun, and then supplemented a various amount of UVB in order to assess how "the UVB effect" under almost natural circumstances is. Result: He found a linear increase in THC. And that cannot be the result from a lab error (like Bugbee claims) because errors always appear in a random (chaotic) fashion. But it is totally linear.
- The 2 "scientists" have just done 5 studies alltogether (!). These are students learning... supervised by a Prof. (which apparently doesn't know how much light Cannabis needs etc pp). Now Lydon had, at the time of his study, a history of 20 years of investigation the effect of UVB on plants (it was in times when the ozone-hole still emerged as a potential threat)
- They did supp UVB but no UVA at all. We know that repair (also PSII) is driven by UVA/violett, see

and in nature, UVB never comes without UVA, actually UVA preceeds UVB timely, and in flux strength by an order of magnitude. Plus, the effects of harsh diurnal sunlight on leaf optimcal properties, internal chemosynthesis etc pp are well known... but all of this has been completely disregarded by these youngster, but instead they refer to other bad research like Magagnini.

 

[Crooked8]

No impact is not in line with other research.

This study found a decrease in THC, and for some terpenes a decrease and others an increase. Big changes in morphology too (lower yield).

Frontiers | Cannabis Inflorescence Yield and Cannabinoid Concentration Are Not Increased With Exposure to Short-Wavelength Ultraviolet-B Radiation

Before ultraviolet (UV) radiation can be used as a horticultural management tool in commercial Cannabis sativa (cannabis) production, the effects of UV on ca...

www.frontiersin.org

Less THC, less terpenes, less yield... doesn't sound good. But it's definitely an impact. And could be maybe still used to our advantage once better understood. I'm thinking to "finish off" plants or something like this. Like the authors say, "it is still possible that the alternate UV treatment protocols may have more positive results".

I appreciate what youre saying. Im just informing you of their research teams findings.

 

[snakedope]

LED UV fixtures are not emitting UV at the right intensity and so the experiments will determine UV had no effect etc. That was the fixture used in the paper above. I use UVB fluorescent tubes with great results. The energy of the UV photons is the correct wave for plants from a tube as opposed to LED. It's the duality of light that's important, its a wave and a particle.

That's why you see high intensity in the uva/b regions with the 10k bulbs, having types of waves is the first thing, but the energy to drive them enough so they will reach the plant for the proper dose and effect is also key.
I think that's why CMH bulbs are giving good results, they mimick the sun best.

 

[exoticrobotic]

I think that's why CMH bulbs are giving good results, they mimick the sun best.

The spectrum is most like the sun but you also get a friendly leaf temperature/light intensity with CMH hung at a 50cm or so above canopy

Under LEDs i find it is difficult to get this ratio correct unless it is summer.

(Broscience Alert!! )
Even then in summer under LEDs i feel their intensity/spectrum skews nutrient uptake in a way that does not favour full expression of cannabinoids and terpenes.

 

[exoticrobotic]

LEDs are great with :-

additional heating
additional UVB
additional UVA
additional far red
additional calcium

CMH/HPS are great straight out of the box.

 

[exoticrobotic]

I'm all for the evolution of cannabis growing but not at the expense of simplicity and effect.

I'm not growing on a spaceship.

 

[Cerathule]

I'm currently advising a LED lamp producer in Canada how to do proper scientific photobiological studies. They are small scale still, but judging from what I could see from his trials with growing indoor hemp and drug-type cannabis, they are really trying to make a difference by altering colour ratios. Not gonna mention their name, as I don't wanna do advertising at all, but their current best light is "full spec" in the snese of 2 white light diodes as base spec and then supplemented by 450nm and 660nm all on individual channels in order to be able to influence the photomorphogenic response. So, a stocky indica can get more red or a stretchy sativa more blue if that's what you want.

The concept itself isn't failproof because you cannot expect that your average cannabis growers knows about the intricate details of photosynthesis. Nor do I know that.... but I think the base concept of "higher blue = shorter plant" (and vice versa) is kinda easy to grasp. And actually, with modern chips included in LED fixtures, actually the light could do all kinds of spectral changes within the UVA/blue and Farred region in a somewhat automated state, if just delivered some information about canopy distance, tolerable max plant height, personal preference, maybe even a process of learning from one grow to another, in a sort of adaptation process. Usually a fixture is bought, mounted at a space, and then grows the same kind of plant and the people running that facility would expect to have better results over time.

Now they wanna set up some trials to further do light testing with Cannabis that includes full spectrum LED lights and a proper control, together with, at least, 3 major universities of Canada. I'm a bit sceptical here because since the legalization there was a "deluge" of really bad studies out of (e.g.) Guelph and I'm not sure if things can be remedied via simple online messages. Because, I'm, always wondering why they don't know "this stuff" already I mean there's books for everything.
But there are just way too many naive photobiological studies where researchers throw monochromatic red, green or blue light at plants and then expect to be able to find out what these colours do. That's false. Under a monochromatic light a plant/leave/photosystem doesn't work properly like under white light. And when the white light is still lacking in particular wavelengths then even that control is insufficient to draw a broader conclusion from it.
But here is the thing, if you want to build a custom "sunlike NASA" fixture you'd have to include like 2000 monos to get this spec at a reasonable output. There's currently nothing in existance even for scientists. Even 1nm laser diodes are also severely lacking, so some really finetuned studies also hit that hardcap.
In other words, we are all waiting for the diode manufacturer industry to deliver more otherwise no lamp producer will be able to adjust specs in accordance of what academic education hints at.

 

[exoticrobotic]

In other words, we are all waiting for the diode manufacturer industry to deliver more otherwise no lamp producer will be able to adjust specs in accordance of what academic education hints at.

Cmon China

But here is the thing, if you want to build a custom "sunlike NASA" fixture you'd have to include like 2000 monos to get this spec at a reasonable output.

i jus wanna grow good weed bro

I'm not exactly sure when leds went from a good HID lighting alternative if heat/height is an issue to better than HIDs.

 

[chilliwilli]

I have a question for the cmh pros too.
Do the double ended cmh give the same advantage as the de hps or is it just 2 bulbs in one lamp?

 

[exoticrobotic]

Now they wanna set up some trials to further do light testing with Cannabis that includes full spectrum LED lights and a proper control, together with, at least, 3 major universities of Canada.

Don't these trials always find that leds far outperform hids?

Because, I'm, always wondering why they don't know "this stuff" already I mean there's books for everything.

 

[goingrey]

I have a few questions:
- Why didn't they use a "high THC" (chemotype I) strain, which constitutes most of the typical grower genetics usually called "sativa" (I'm putting that in brackets because that denomination is actually wrong when judged by phyllogenetics). When, e.g. the studies that confirmed a positive effect for UVB did use Chemotype I. I mean, they are referencing it but then criticising it but nowhere using the same setup. Actually Lydon did already confirm that plants that are high-CBD will not react to UVB. No look at their strains they have just 5% THC or so.... Why didn't they use chemotype I, II & III?
- Why did they only use so very little light? (400 umol at the tops) when we know that the production of cannabinoids is very energy-costly. Additionally, UV creates damage that needs to be repaired (which costs energy as well) and all the responses to it also are dependant on energy. Lydon for example put the plants in a greenhouse in such a timeframe that would replicate exactly the same environmental conditions that the particular southern american wildtype cannabis did have at it's normal habitate (it grew at somewhat an altitude) then use screens to block out the UVB from the sun, and then supplemented a various amount of UVB in order to assess how "the UVB effect" under almost natural circumstances is. Result: He found a linear increase in THC. And that cannot be the result from a lab error (like Bugbee claims) because errors always appear in a random (chaotic) fashion. But it is totally linear.
- The 2 "scientists" have just done 5 studies alltogether (!). These are students learning... supervised by a Prof. (which apparently doesn't know how much light Cannabis needs etc pp). Now Lydon had, at the time of his study, a history of 20 years of investigation the effect of UVB on plants (it was in times when the ozone-hole still emerged as a potential threat)
- They did supp UVB but no UVA at all. We know that repair (also PSII) is driven by UVA/violett, see
View attachment 18811262
and in nature, UVB never comes without UVA, actually UVA preceeds UVB timely, and in flux strength by an order of magnitude. Plus, the effects of harsh diurnal sunlight on leaf optimcal properties, internal chemosynthesis etc pp are well known... but all of this has been completely disregarded by these youngster, but instead they refer to other bad research like Magagnini.

A lot if not most research will be done by PhD students with professors supervising spending their time trying to get funding. That shouldn't be a reason to discredit the work. Your other criticism is valid but I think the paper still answers the question "does UV do anything" with a rather reliable "yes".

 

[Cerathule]

Don't these trials always find that leds far outperform hids?

No, for example here HPS is superior taken all together
Light Quality Impacts Vertical Growth Rate, Phytochemical Yield and Cannabinoid Production Efficiency in Cannabis sativa
but these are not good LED specs. And HPS is the control. It's kinda funny when a single central bulb emittor is the control for many 4 COB arrays with 90° beam angle.

It's very easy to test actually also in your growtents, if you have different fixtures operating at a different beam-angle, you can adjust canopy PPFD to equal levels but then take another measurement at, say, +10cm, +20cm etc distance and you'll confirm that different lamps have a different level of "penetration" power.

The only way to do away with this is sinply using the same hardware constructs, just altering the colours, nothing else.