LED and BUD QUALITY

[Ca++]

Even with HID, under 25c was wasting my time. Things didn't really swing until 27 or more. It's actually about 30c where the plants rockin. With a couple each side being of no real importance, unless you are otherwise perfect. Which means plant specific perfect. Years of doing the same grow.

How the plant gets to 30c is what we are really looking at. Air temp, or radiant heat from the lamps.

Hot at the top is a bit more like the plant expects. Taking passively moved ions to the growing points. If we heat the entire plant, it's actually a bit different. Shaded bits getting a bit more feed than typical. However air flow is just as much a controlling factor, where the stomata are not quite doing the job. I have found that a hot top and not a great deal of air movement through the plants is optimum. Some to keep things fresh, but fields of plants have certain notable conditions. Ones they must thrive in, or fail to compete. These conditions seem to push them the best. Though single plants are just fine, it's canopies I like. With cooler damper conditions within. Receiving less light and less of the passively moved ions.

I'm going to do a mixed light run again. 50/50 as it works in my space. It will increase power consumption about 20%, making IR that here in cold-land, isn't that wasteful.

I really enjoyed getting my heirloom lighting about again. Cleaning off the pro-ultra and greenpower. I'm going magnetic, though have electronic. Just for the 'bong' as they come on

 

[Cerathule]

one thing that bugbee mentioned was that far red is not directly photosynthetic but acts as a synergistic accessory pigment.

Ehm, it actually is photosynthetic, but only in the presence of PAR light. But most farred will transmit through a leaf, esp. the longer wavelengths beyond >750nm.

Proof:

 

[greyfader]

Ehm, it actually is photosynthetic, but only in the presence of PAR light. But most farred will transmit through a leaf, esp. the longer wavelengths beyond >750nm.

Proof:
View attachment 18812813
View attachment 18812815

thank you! i am wondering if it has some other effect than enhancing photosynthesis. signaling maybe?

 

[armedoldhippy]

I'm going to do a mixed light run again.

i'll be watching for that. i used to mix HPS with lots of vertical side lighting using fluorescents on the sides. are you mixing HPS and LEDs, i suppose? i want to watch...

 

[Ca++]

i'll be watching for that. i used to mix HPS with lots of vertical side lighting using fluorescents on the sides. are you mixing HPS and LEDs, i suppose? i want to watch...

I have a 1.4 tent, with a 6 in the middle, and a 120w QB in each corner. They are hung and wired, but progress on that project is very slow. At 2sqm I would be happy with 1000w of hps, so the QBs won't be doing even half the work. I guess I could run a 400 and pump up the QB's towards full. I'm of a mind the 6 provides about 400w in LED terms, and 200w more in IR.



I think two posters are saying basically the same thing about far red. Alone, it's not much use. However when accompanying 660 light, this 730 actually produced growth of comparable use. However, the 660 only supports a certain amount of 730 usefully. IIRC using an amount of 730 that was greater than 40% of the 660, wasn't supported. Or in numbers, 50umol of red could support the use of 20umol of far red.
My number regarding 40% won't be right. It's from an image of a bar chart in my mind, that I didn't want to remember. As any amount of 730 was not more use than the same amount of 660, I lost interest. I can use some use where 660 is maxed out, and you want to level the spectrum though. Ultimately, it's the signalling I'm interested in. It's a tool I actually use. This greater penetration of far red, means the red/far red balance shifts as we go lower through the plant. The red levels dropping quicker than the far red. This, to a cannabis plant, is a monitoring method of shade. Not exactly a signaling colour, but one used in signaling to stretch. Which is vegetative growth. Spending time on vegetative growth during flower doesn't seem to extend the flowering window long enough for any gain. However, shaping the plant can lead to great gains. I feel this was a HPS trait we didn't fully recognise. People spoke of penetration, but I don't see it that way. I see plant leads of many diverse lengths under HPS, as the main leads bolted for the lights, leaving lesser ones behind. This gave a canopy of longer main leads, and each was effectively getting side lighting. These reached out from the lower stuff, which then took on a field of green effect. With LED we don't see them leads shoot up, leaving lesser bits behind. We just get the sea of green. Where everything is much more uniform in size. The higher yields under LED are a surprise to many, as it all comes from a smaller area. The sea, without leads reaching out. I'm looking to grow them leads, with LED. Yet I don't want 730s in my lighting. I have that in separate units. Stretch lights. That I can stop vegging with when I'm done with them. So far, so good.

 

[Cerathule]

thank you! i am wondering if it has some other effect than enhancing photosynthesis. signaling maybe?

Yes, Farred 700-780nm will heavily influence the Phyochrome Stationairy State. It is used by plants to evaluate the ratio of direct vs shadelight. That being said, Farred counts as shadelight:

As you can see, "Pfr" (=phytochrome farred) has a max peak at around 730nm, whereas Pr (phytochrome red) at 660nm antagonizes this (and vice versa). Basically most of PAR (read: visible light) does that, and bluntly that is its function - to check/measure the day- and nightrise, and if the leaves are subjected to sunlight or the plant is sitting somewhere in the shade.

 

[Cerathule]

I think two posters are saying basically the same thing about far red. Alone, it's not much use. However when accompanying 660 light, this 730 actually produced growth of comparable use. However, the 660 only supports a certain amount of 730 usefully. IIRC using an amount of 730 that was greater than 40% of the 660, wasn't supported. Or in numbers, 50umol of red could support the use of 20umol of far red.

This is due to a false interpretation of some earlier studies, where scientists just use 660nm as a means to supplement PAR light. They oftentimes do this, it's not wrong but is done in order to reduce available parameters used. They also oftentime just use blue and red 1:10 just for that.

Here is some of the latest action spectrum showing which wavelengths predominantly excitate the 2 photosystems:

As you can see, Photosystem II (Y II) absorb better across the whole PAR region until 680nm (which is where the end of the antennas funnel p680 absorbs) and then, PSI takes over. Only in the blue and cyan-green is the absorption almost similar. This is due to PSII being somewhat larger, and PSI having several special 'darkred' chlorophyls surrounding the complex.

Now it is the work of PSII to split water and hand over the gathered electrons to PSI, which, in turn, can then build ATP and NADPH from CO2. (very crudely writing...)

There have been studies about what light to give in order for the 2 photosystems to work at an equal rate in tandem, and it needs, at least, 20% (of PAR) 700-780nm in order to not have an electron buildup at the binding site of PSII to PSI. That said, direct sunlight reaches around 30% FR.

 

[Ca++]

It's hard to digest how some of these study results are presented. I'm not sure why two studies are on one graph as if a comparison is worth making. For the yii they are using far red, for the yi near infra-red. Two different methods.
What I would like to see is three graphs, with both systems on each. One graph monochrome, one graph the 730 and one the 810.
Here we have one system with 730 and one with 810. I have no baseline, and any comparison needs one.

 

[Brother Nature]

LSD and Brain Quality???

 

[Cerathule]

It's hard to digest how some of these study results are presented. I'm not sure why two studies are on one graph as if a comparison is worth making. For the yii they are using far red, for the yi near infra-red. Two different methods.
What I would like to see is three graphs, with both systems on each. One graph monochrome, one graph the 730 and one the 810.
Here we have one system with 730 and one with 810. I have no baseline, and any comparison needs one.

???
No, *you* are completely wrong here.

First off, that diagram shows you the quantum yield of PSI & II in comparison.

It's not "2 studies", but an examination into the light-harvesting of the 2 systems responsible for photosynthesis.

The global quantum yield of PSI (Y I ) was measured using low-intensity monochromatic light flashes and the associated transmittance change at 810 nm. The 810-nm signal change was calibrated based on the number of electrons generated by PSII during the flash (4 · O 2 evolution) which arrived at the PSI donor side after a delay of 2 ms.

They didn't excitate the 2 photosystems with different light, they actually used any kind of PAR light to do so. But then used the IRL to check on the leaf transmittance change ^^^^

These photosystems need to work in tandem (as already explained above) and this is important to understand to be able to evaluate McCree diagrams (where he used monochromatic light in 25nm steps - which, as you can see from 2 curves, aren't able to drive both photosystems equally, except for the violet, green and orange (somewhat) region.

This is actually an old hat. You can read it in a way more crude form starting with Emerson 1957, Rabinovitch and Govindjee.

And I take it you didn't read the study at all as if you would have done that, you wouldn't have to speculate so much on "why Cannabis wants to flee from blue light" (see previous pages) because it's as easy as that: (also taken out of that study):

At wavelengths less than 580nm about 30% of excitation is absorbed by pigments poorly connected to either photosystem, most likely carotenoids bound in pigment–protein complexes.

In other words, about 30% of the blue light is simply lost to sunscreen pigments. That's why plants supplemented with the very same quanta of blue vs red will have reduced yields.
And that is true for all sunplants. They screen out potentially harmful rays, though this effect is diminished indoors (if grown under low PPFD).

 

[Ca++]

What is FRL, if not far red light

Edit: No I have not seen the whole article, or a link to it. I just have what you posted

 

[greyfader]

Yes, Farred 700-780nm will heavily influence the Phyochrome Stationairy State. It is used by plants to evaluate the ratio of direct vs shadelight. That being said, Farred counts as shadelight:
View attachment 18812977
As you can see, "Pfr" (=phytochrome farred) has a max peak at around 730nm, whereas Pr (phytochrome red) at 660nm antagonizes this (and vice versa). Basically most of PAR (read: visible light) does that, and bluntly that is its function - to check/measure the day- and nightrise, and if the leaves are subjected to sunlight or the plant is sitting somewhere in the shade.

thank you! i should have said that i'm aware of the pr-pfr ratio elongation response, but i am wondering is there is anything else going on with signaling in the far-red region.

i have used blue dominant light to control growth both with mh light and leds.

the total absence of far-red doesn't seem to affect any other processes, but there could be more to it than that.

indoors we need to control morphology for an ideal shape.

my approach to this has been to limit far-red in veg and stretch. this makes short, fat, bushes which are then ideal for flower.

bugbee mentions in "far-red, the forgotten photon", that it may not be a good idea to supplement far-red with cannabis or other high-light plants.

i'm thinking that supplementing 660nm dark red would more than compensate for any lost photosynthetic effect from deleting far-red.

i just did some reading on the effect that radiant heat has on plants and i think that may be what we need to supplement leds with.

water is a great conductor of heat and since the plant is mostly made up of water radiant heat may drive the photosynthetic apparatus more efficiently than just ambient heat alone

ambient heat heats the whole plant but radiant heat penetrates the leaf tissue and heats the leaves better internally.

some folks might look at this and say "why don't you just go back to hps for flower".

it's an obvious response, but we know that such a huge portion of hps light energy consumption occurs in the far-red and infrared that they are extremely inefficient electrically.

led spectrum produces a better overall plant and produces higher cannabinoids and terpenes content per mass.

i'm thinking we need a lower percentage of radiant heat than we get with hps lighting. the figure i have seen in some papers suggests that the (highest) level used to heat water-filled tissues is 100 mW/cm2. above this and we are wasting energy and much below this we may be limiting the cellular response.

just a few ideas.

editing to add that the 100 mw/cm2 is the highest level to use because of overheating.

one suggestion for a working amount i saw was 8 mw/cm2.

 

[Cerathule]

thank you! i should have said that i'm aware of the pr-pfr ratio elongation response, but i am wondering is there is anything else going on with signaling in the far-red region.

Well, "penetration". As seen here:

because of this:

That's including FR/IR, here's for Cannabis:

So basically most of PAR is filtered out by a dense canopy - I mean it's sort of dependant on the gardeners manipulation techniques used but usually Cannabis will grow like a bush with a dense canopy of foliage that will just reduce PAR to very very little PPFD. Only FR remains at some strength, perhaps complimented by a little green. What then follows in the deep is a Pfr response.
The individual question is, is that wanted/needed, or totally unneeded.

But there is no other alternative to use the spectrum to bring down light to where, indoors, practically there is none light left. (The other option would be sub- or intra canopy lighting, which has its own problems [space, distribution, extra hardware]).

i'm thinking that supplementing 660nm dark red would more than compensate for any lost photosynthetic effect from deleting far-red.

I've yet to see real scientific data regarding dry harvest mass for Cannabis on this. Growers who use it swear by it but others reject it fully due to being unsuitably. From a biophysical- and physiological point of view the 660nm does things way different for the plant than 730nm does, both in terms of phytochrome and the photosystems. BUT, ultimately, these are all still photons, and if there is an universal agreement then it's the number of photons available to a plant that will have the greatest raw impact on its ability to acquire mass. And because the 660nm are so efficient, you may currently even be better off with those.

Thing is plants can adapt their photosystems to almost all spectrums, to still harvest light efficiently. So if scientists venture deep inside to show intricate details or differences regarding various light spectras, in may ultimately not matter much for a grower. What's happening in the antennas is extremely fast, even a slow spectral power diagram will grow a plant satisfactorily if photonflux is equal. It's the bio-chemical reactions after the light-reactions 1+2 that are way slower (by 100-10.000 times) and so, these need to be looked at with way higher focus.

i just did some reading on the effect that radiant heat has on plants and i think that may be what we need to supplement leds with.

water is a great conductor of heat and since the plant is mostly made up of water radiant heat may drive the photosynthetic apparatus more efficiently than just ambient heat alone

ambient heat heats the whole plant but radiant heat penetrates the leaf tissue and heats the leaves better internally.

some folks might look at this and say "why don't you just go back to hps for flower".

it's an obvious response, but we know that such a huge portion of hps light energy consumption occurs in the far-red range that they are extremely inefficient electrically.

It would also be natural and in a way, plants had so much time to adapt to the sun. But i don't know if it's better as that can be seen from many sides... electricity is expensive and diodes operate best when cool. That all needs to be compared, I'd love to see more NASA light comparative studies with IR included.

My current own idea would be to re-think the current red/darkred LED spectras (630, 660, 730) and investigate into 690, 700 or 710nm. I've seen data where they used 1nm laser light to report that up to 712 (or so) the plants stomatas still stay open (whereas 730nm has a tendency to close the stomatas [not fully - what stomatas do is always influenced by several factors simultaneously (in vivo)])
In other words, some Farred has still the same quality as PAR in that regard, but it may only be 10nm into FR. It kinda depends on from where we draw the border. Currently, 660nm is the last wavelength the horticultural fixtures deliver for supplementing straight PAR light. Then from 680nm PSII absorbance drops and PSI takes over. Then around 700nm Pr and Pfr cancel each other out. And here we also have the last "normal" (without phonons) photon-absorption (by p700) and the so-called 'red drop', that is accompanyied by a sharp increase in leaf transmittance (actually that begins a bit sooner).

If we just compare some action or absorbtion spectra of phytochrome, the 2 photosystems and some leaf optical properties we'll see that, around the region of 'the red drop' alot of diagramatic max peaks, cancellations and "valleys" happen, some at the very same wavelengths. But these are actually derived from different plant chromophores (!) or objects:

This region does have several unique qualities that no other waveband can offer.

 

[Cerathule]

What is FRL, if not far red light

Edit: No I have not seen the whole article, or a link to it. I just have what you posted

It's attached if you wanna give it some time

 

[greyfader]

@Cerathule, thank you for the input! it is helping my thinking about what a led grow light should be.

and i'm thinking that most commercial lights are one size fits all compromises.

not ideal for either veg or flower.

i'm sure you remember a ways back in this thread where @vermontman showed his flowers and the galaxy light that produced them.

we have no way of knowing the chemical profile of that plant but we can see that the flowers got huge.

that light only had a few "white" light diodes and 2 740nm diodes. 8% 660nm, a few in the blue range.

but it was mostly 630nm. like 80+ %.

some reading suggests that the larger flowers grown under predominately red have a lower % of cannabinoids and terpenes per mass than smaller flowers grown under a heavily blue-weighted spectrum.

i have been using 2700k and 5000k white light in every experimental combination you can think of for the last two years.

no supplemental 660nm, far-red, or ir used.

i have gotten potent, trich-covered, terpene heavy flowers depending on strain but have not gotten the huge flowers i got with hps.

leds have a better overall spd than hps but are lacking in these three things.

most people buy a light and live with it, regardless of the results.

there are so many lights offered and so much conflicting info being given out by the manufacturers that i decided to build my own.

i do want to build nice, modern, electrically efficient lights someday soon, but decided to experiment with screw-ins first.

i think that i need to supplement 660, far-red, and ir but i have been looking at different ways to do it.

the all-led method sounds attractive up front but then i'm buying specific frequency diodes and trying to balance them in a useful ratio.

none have a continuous spectrum. one that includes these three supplemental ranges in one emitter.

hps and mh lamps have a continuous spectrum but create too much heat.

some here have suggested hybrid lighting. using leds in conjunction with a hid source.

but these two are not an ideal fit for supplementing leds because they create some duplications of the led white light spectrums. and the heat issue again.

most are too bulky and cumbersome to hang with a led fixture. and too powerful to be used supplementally.

so, i've been searching through various types of lighting for an answer.

and i found this;

"Compared to sunlight, modern-day electric lighting, and in particular LED lighting, is sorely deficient in near-infrared radiation. Figure 2 illustrates the problem, where the terrestrial solar spectrum has been approximated by a blackbody radiator with a color temperature of 5500 K. Look at the spectrum of incandescent lights – they clearly provide the near-infrared radiation that we need. By comparison, 3000-K LEDs (and indeed, any white light LEDs) provide no near-infrared radiation whatsoever."


this taken from; https://www.ies.org/research/fires/the-science-of-near-infrared-lighting-fact-or-fiction/

here's another one, showing some far-red. and a lot of red passing through the 660nm mark.

more than white light diodes like the 2700k.

i have also read, recently, that incandescents have a greater portion of red light than the sun.

"By definition, photosynthetically active radiation (PAR) is light with wavelengths from 400 to 700 nm. Thus, far-red is outside of the PAR waveband. One way to quantify far-red is by its percentage relative to PAR plus far-red (i.e., 400 to 800 nm). About 25% of sunlight within the 400 to 800 nm waveband is as far-red. Incandescent lamps emit a lot of far-red (about 52%), but those are increasingly obsolete. Other conventional electric lighting fixtures emit relatively little far-red light, such as high-pressure sodium (6%), metal halide (8%) and cool-white fluorescent (2%)."

taken from;

Technically Speaking: Far-red Light in Greenhouse and Indoor Farming - Greenhouse Product News

Far-red is a waveband of light that is marginally visible to us but has profound effects on plant growth and development. Far-red light is often described as radiation with a wavelength between 700 and 800 nanometers (nm). However, the waveband between 700 and 750 nm is of most interest because...

gpnmag.com

so, with low-wattage incandescent lights, it looks as though i might be able to supplement red, far-red, and ir. and get a more sunlike continuous curve

what do you think? they even have some uv.

 

[JKD]

Horticultural research growth chambers used to quite often use fluorescent and incandescent lamps in combination before LEDs became the standard.

 

[FranJan]

From BIOSlighting, (you know, the actual "guyz from NASA",

The Ideal LED Grow Light Spectrum for Plants

What is the ideal grow light spectrum for plants? Do different plants need different LED lights? What about for cannabis growth? Learn more from BIOS!

bioslighting.com

Magagnini G, Grassi G, Kotiranta S. (2018), The Effect of Light Spectrum on the Morphology and Cannabinoid Content of Cannabis sativa L, Med Cannabis Cannabinoids, 1:19-27. Available:<https://doi.org/10.1159/000489030>
"In conclusion, an optimized light spectrum improves the value and quality of cannabis. Current LED technology showed significant differences in growth habit and cannabinoid profile compared to the traditional HPS light source. Finally, no difference of flowering time was observed under different R:FR (i.e., the ratio between red and far-red light)."

Kalaitzoglou, P., van Ieperen, W., Harbinson, J., van der Meer, M., Martinakos, S., Weerheim, K., Nicole, C., & Marcelis, L. (2019). Effects of Continuous or End-of-Day Far-Red Light on Tomato Plant Growth, Morphology, Light Absorption, and Fruit Production. Frontiers in plant science, 10, 322. https://doi.org/10.3389/fpls.2019.00322.
Available: <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6448094/>
"We conclude that growing tomato plants under artificial light without FR during the light period causes a range of inverse shade avoidance responses, which result in reduced plant source strength and reduced fruit production, which cannot be compensated by a simple EOD-FR treatment."

So maybe a plant grown under a LED light just needs some FR to be a better plant. EoD works from what I've seen but ya gotta know the correct DLI with the proper strain to see any worthwhile increase. I like to think of FR as silica. It won't make your flowers bigger but with the right amount under the right conditions it can make your plant stronger and give it the potential and the chance to grow bigger flowers.

 

[Ca++]

It's attached if you wanna give it some time

PDF reader will report me reading that, to whoever is coded into it. It's part of the analytics. It looks like you are posting from the same study each time though. Is FRL of 740nm used for one curve, and NIR of 810nm for the other.

I'm pretty sure it is, but the graph labeling is inconsistent.




I use incandescent lamps as emitters. I have increased lighting power 10% with their addition. A 60w lamp, per 500-600w of LED. Stretch is increased in a usable manner, but it's not the HPS style or amount at all. No rapid shooting that's almost shocking, and barely has time to turn green. The result is closer to not using it, than it is to using sodium lighting.

I have no played with ratio's but while the effect is most definite, it's no more profound under the lamp, than at some distance away. To a degree, the stuff further might of had to stretch to keep up. It's not how it looks though. I think a token gesture of this extra spectral energy, might be enough to cause a gradient through the canopy, regardless of actual intensity. It's hard to call it.

I'm drawn to the idea that blue:red ratio's are also in play where stretch is concerned. Where blue would play a part in stretch avoidance. My mind goes back to LPS growing, and the ridiculous elongation it caused, said to be a lack of blue. A colour said to be needed to minimal levels. The work of the time, said at our illumination levels, we got the token amount of blue needed, even from HPS. However, if we grew at lower lighting levels, the HPS would need tuning to offer a bit more. Enter the Agro. Then at even lower light levels, some MH lamps would be mixed in. Despite their lower efficiency.
Much of this is no longer relevant, and the explanations behind the results less firm. However, the testing still offers practical examples.

I'm very much guided by such practical results, then finding why later. I have little doubt that the exact 'why' is often much less relevant to me than the result. So this PDF in question is probably something I wouldn't read in it's entirety. I would just like to know what they did, and if I should have a go. I think in my way, I am, with my indiscriminate incandescent lamps. Which I have been using just 3-4 years. So my next move is to be more precise with the wavelengths I apply. Though I'm not exactly wasting much power, or spending much installing a 60w lamp. The science could better explain how a big operation would go about it. Where 10% more power is huge. Even if it is just for 2 weeks.

 

[Cerathule]

PDF reader will report me reading that, to whoever is coded into it. It's part of the analytics.

???

Here I just opened it:

I'm using SumatraPDF and it doesn't report anything.

Last time (when you wrote "green light does kill Cannabis") and I uploaded a well-known study, you claimed it was full of viruses. But never showed any proof of that, neither came forward with that link to show how green light would kill Cannabis (even to think that any kind of PAR light set at the right fluxstrength would kill a plant is ridiculous to begin with...)

It looks like you are posting from the same study each time though.

WTF?!?

There's charts from, at least, 3 different studies in that post, while 4 are actually from other sources.
2 diagrams taken from the WWW - one article from Fluence-science, one about phytochrome, the Cannabis-spec(s) is/are actually from ICMag (before its revamp), and the photosystem diagram is from a schoolbook on photobiology (hardcopy).

Is FRL of 740nm used for one curve, and NIR of 810nm for the other.

I'm pretty sure it is, but the graph labeling is inconsistent.

They just use that radiation to check on the changed leaf transmission in order to get their data. They need to use a wavelength outside the testing wavebands in order to not influence the results, and since PSI absorbs way more redshifted as PSII it's justified to take a wavelength as close as possible to the cutoff.

I use incandescent lamps as emitters. I have increased lighting power 10% with their addition. A 60w lamp, per 500-600w of LED. Stretch is increased in a usable manner, but it's not the HPS style or amount at all. No rapid shooting that's almost shocking, and barely has time to turn green. The result is closer to not using it, than it is to using sodium lighting.

I have no played with ratio's but while the effect is most definite, it's no more profound under the lamp, than at some distance away. To a degree, the stuff further might of had to stretch to keep up. It's not how it looks though. I think a token gesture of this extra spectral energy, might be enough to cause a gradient through the canopy, regardless of actual intensity. It's hard to call it.

I'm drawn to the idea that blue:red ratio's are also in play where stretch is concerned. Where blue would play a part in stretch avoidance. My mind goes back to LPS growing, and the ridiculous elongation it caused, said to be a lack of blue. A colour said to be needed to minimal levels. The work of the time, said at our illumination levels, we got the token amount of blue needed, even from HPS. However, if we grew at lower lighting levels, the HPS would need tuning to offer a bit more. Enter the Agro. Then at even lower light levels, some MH lamps would be mixed in. Despite their lower efficiency.
Much of this is no longer relevant, and the explanations behind the results less firm. However, the testing still offers practical examples.

I'm very much guided by such practical results, then finding why later. I have little doubt that the exact 'why' is often much less relevant to me than the result. So this PDF in question is probably something I wouldn't read in it's entirety. I would just like to know what they did, and if I should have a go. I think in my way, I am, with my indiscriminate incandescent lamps. Which I have been using just 3-4 years. So my next move is to be more precise with the wavelengths I apply. Though I'm not exactly wasting much power, or spending much installing a 60w lamp. The science could better explain how a big operation would go about it. Where 10% more power is huge. Even if it is just for 2 weeks.

I remember reading a study where they used incandescants to boost the spectrum of some typical growlights like HPS and LED. As I recall I think it was from a lamp producer, gotta have to search a little but the effect registered kinda low in the SPD.

One thing about incandescants is the will also emit alot of energy in the wrong wavebands, thus wasting a lot of energy. They also do not last long. They are actually good to use as a night lamp when one has to control plants during their sleep, as the higher Pfr will offset the little PAR light.

 

[beta]

???

Here I just opened it:
View attachment 18813876
I'm using SumatraPDF and it doesn't report anything.

I think what they're saying is the they don't like opening PDFs because they can be programmed to discreetly report back to the original author with information about the reader any time they're opened.