LM301H vs LM301H-EVO

[Have2]

Hey Dan, LED Teknik and I have this duscussion all the time: spectrum vs efficiency.

Teknik is a LED guru. I'm a grower (and have been for 30+ years). Much of what I've learned about LEDs is through him, and much of what he's learned about growing is through me, so we bounce ideas off each other all the time. To his credit, Teknik was the one who suggested bumping the far red to much higher levels than even I thought we should after I noted some observations about growing with it. The main things I observed were:

1. Faster flowering times – up to a week faster finishing times with the same yield (ie; accelerated flowering and an increase in yield over cultivation time = defacto yield increase).
2. Bigger leaves (shade avoidance/photomorphogrnic response)
3. Longer internodes . . . except in the presence of UVA. Which, incidentally, is what I have always noticed about growing outdoors: sunlight may be 25% far red, but you don't see outdoor plants stretching in full sun because there is also UV, which is responsible for cell contraction (as opposed to cell expansion).
4. Happy, healthy plants – pretty much all the plants I've put under our high-far red spectrum have thrived. Especially shade-loving tropicals and ornamentals, like aroids.

I've been interested in UV ever since I noticed the difference in growing under Metal Haldie vs High Pressure Sodium vs comnbing the two at a ratio of 2 HPS to 1 MH. CMH came along later and pretty much combined the two.

But I also took note 20 years ago when some local hemp farmers I was freindly with started complaining about their Chinese seed stock showing elevated THC levels when grown under the Australian sun. The Chinese had tested their stock at <0.3% THC (below the legal limit), but once exposed to the higher UV index in Australia, those levels spiked to 0.5-1.0%.

We've since done our own tests that show a small amount of UV exposure does indeed increase cannabinoid levels, but it is not as simple as "UV or not UV" (little Shakespearean pun there, lol). There is some debate about the merits of UVA in relation to cannabinoids, but the most frequently cited experiments were not ideal – they only exposed the plants to UVA and UVB in the last 20 days of flowering and they also have very defined spectral bands. Still, there were more visible trichomes on the UV samples.

But I digress. This is perhaps not the thread for an in-depth discussion about UV or Far Red.

What you – and I suspect every other grower and/or light manufacturer wants to know – is, is it worthwhile sacrificing efficiency for spectrum?

My answer is yes. And there are several reasons for it:

* Broader spectra seem to grow healthier plants with fewer signs of nutrient lock-out (possibly transpiration or photo-oxidative stress related) and better quality in relation to yield.

* LED technology is advancing all the time. Efficiency will always improve – so you are always chasing your tail in that respect – whilst spectral balance has real benefits. My ultimate aim is to find the best spectra that works under most (typical) indoor conditions with cannabis as the primary crop and then pursue efficiency. And the reason for that is, we may find it hard to produce far red or cyan or 420-430nm violet now, but that may not always be the case. Once we have cracked the spectral code (so to speak), then it is simply a matter of sourcing the most efficienct diodes (as they continue to improve) to make that spectra.

* Lastly, sunlight is "true" full spectrum. LED is not. Sunlight may be dynamic – it's UV/RGB/IR ratios may change at different times, seasons, latitudes, altitudes, atmospheric conditions – but plants have evolved under FULL SPECTRUM. They have mechanisms for handling all sorts of radiant conditions that we don't truly understand yet, but are learning as we experiment. You are not going to discover the advantages of this spectrum or that spectrum by seeking the most efficient white phosphor/monochromatic red combination, because you are missing large parts of the spectrum (cyan for excample) or particular wavelengths altogether (far red, violet, UVA, UVB).

Spectrum vs efficiency is very much at odds at times – especially in relation to medicinal cannabis. Ultimately, producers want to sell either flowers or extracts. These two aims can compete when you are chasing dry yield over cannabinoid content or vice versa. It may well be in the interests of producers to grow the most cannabinoid content for the least amount of dry yield, as it makes processing easier and more cost-effiective.

So now it becomes a matter of, does a high-efficiency LED light produce more dry yield per joule of energy, or more cannabinoids per joule of energy, and how much extra energy is required to process each crop? If you could produce a spectrum that made trimming easier, that would save a lot of energy!

I guess in my case, there is no real mystery to producing a highly efficient LED grow light . . . but there is still plenty of mystery when it comes to finding the ideal spectrum that works for any given aim or crop. So that's what I'm mostly interested in.

But hey, that's just me.

I'm curious on your input about 660/730 combination.

Any experiment/feedback/conclusion?

 

[rshackleferd]

Still using cxb3590 3500k and love the spectrum. It’s easy in the eyes and right in the middle of what you need. I’m all in on 3500k

 

[KitnerPush]

Pretty much been saying this all along. R-W-FR ratios are much more important than the color temp of the white diodes. In fact you don't even want that much phosphor in your white diodes because it makes them both optically inefficient, as well as, thermally inefficient. Also, just read about a study on light intensity in cannabis where weight was highly dependent on output, where 1800ppfd was the optimal output. They used up to 2500ppfd.

 

[Rocket Soul]

Pretty much been saying this all along. R-W-FR ratios are much more important than the color temp of the white diodes. In fact you don't even want that much phosphor in your white diodes because it makes them both optically inefficient, as well as, thermally inefficient. Also, just read about a study on light intensity in cannabis where weight was highly dependent on output, where 1800ppfd was the optimal output. They used up to 2500ppfd.

So post it

 

[hillbill]

I can’t go over about 1200ppfd without light-burning the piss out of the girls. I don’t use CO2. When I ran 10 1/2 hours “lights on” I could go to about 1500ppfd. Seems Daylight Integral was the determining factor rather than ppfd. Can’t get near that at 12/12.

 

[KitnerPush]

So post it

I read a lot, and I don't keep a record of sources, but I found it. Here you go: https://www.cannabisbusinesstimes.com/article/growing-under-high-light-intensities-lighting-report/

 

[Rocket Soul]

I read a lot, and I don't keep a record of sources, but I found it. Here you go: https://www.cannabisbusinesstimes.com/article/growing-under-high-light-intensities-lighting-report/

Thank you so much, im actually the same so i really appreciate it.

Edit: cant seem to get more than very basic info regarding the study or the organisation that made it: yields increase linear from 1000 to 1800ppfd, 1 percent more light 1 percent more bud. But no info on absolute values or yield per square foot and adviced that you have to keep everything condition and environment tip top. A little hard to draw conclusions from this, we can certainly not replicate that in our grow. It kinda depends on what the yield was in weight, if they went from 2.5 ounce per square foot to 4 that would indeed be really eye opening but if it was 1.5 to 2.5 its less of a slam dunk. Weve never been able to hit those intensity without problems with bleaching/light burn.

Incidentally: they also quoted a spectrum test where the fluence R4 spectrum was the best yielder even over more red heavy spectrums. Fluence R4 seems to pretty much be 3500k + 660, just as @RainDan said.


Ive seen at least one dream run by former member Or-gro where hitting similar light levels, some tops at 1500 with no ill effects but it was a specialised spectrum, the old prawn boards pre GLA.

 

[tstick]

Interesting article. I'd sure like to know the exact cultivars they use for these tests because, at the moment, I have five different plants and four different strains growing -all of which are under the exact same growing conditions, i.e.,lights, water, ferts, air movement....everything....and I've got five completely morphologically-different plants. Even the strain that I have two of (Chernobyl), are expressing very different characteristics. One is very leafy. One has thicker stalks. One is really tall....etc. Some like being close to the lights. Others like being farther away.
So, with all this variability among the plants that we are talking about on this website, which ones are "the" test subjects for determining what the lights are contributing/not contributing to the growth?
In other words, the plants are always variable -and sometimes extremely so. So what good does it do to split hairs over a few nanometers of difference in the color of the light as if it there is a secret key to be found within that given spectrum, that will unlock the growth in all plants? It seems like the best lights should be designed to be as variable as the plants. So if there is a "fixed" spectrum, then it can't possibly provide an ideal spectrum -unless it is just one, particular strain/cultivar that is being tested.....right? I'm not trying to be sarcastic or anything. I just don't understand how this ongoing search for the holy spectrum is going to finally play itself out. It seems like the only real way to address the variability of the plants is to create lights that are variable in their spectral output.

 

[cdgmoney250]

Incidentally: they also quoted a spectrum test where the fluence R4 spectrum was the best yielder even over more red heavy spectrums. Fluence R4 seems to pretty much be 3500k + 660, just as @RainDan said.

Ive grown under quite a few light light sources at different light intensities. I also happen to use Fluence R4 spectrum. To date, the best yields I’ve gotten were under that spectrum at high light intensities. Some tops we’re getting to 1700-1800 PPFD, but most were between 1300-1500 PPFD. I experienced some light avoidance (leaf edge curling) on certain strains, but not on others. Also no bleaching on any buds.

while the diodes on the Fluence fixture aren’t anything special, I’ve mentioned a few times that I personally feel that the 660nm peak is in a good balance to the rest of the spectrums. As discussed previously, different spectrums are likely have different absolute maximums (light intensity/DLI) that plants can take and different total photosynthesis yields. This likely varies with species/variety/phenotype.

 

[hillbill]

LED light burn can exhibit many symptoms.
GrowWeedEasy Plant Doctor offer good info.

 

[Charles U Farley]

...So what good does it do to split hairs over a few nanometers of difference in the color of the light as if it there is a secret key to be found within that given spectrum, that will unlock the growth in all plants? It seems like the best lights should be designed to be as variable as the plants.

Whether it be light spectrum, soil, fertilizer, growing method, etc. there's always going to be people who will debate the finer/exotic aspects of growing cannabis. These are the people who have extensive knowledge of a very specific niche, in this case light spectrum, and try to optimize every aspect of growing cannabis.

That's why I'm monitor these threads.

There's a _tremendous_ amount of knowledge to be gained, even if it's not applicable to _my_ specific situation, by observing knowledgeable people debate the specifics of what they feel so passionate about.

That's what drives us forward.

Here's a light from back in the day that was exceedingly variable with its light output, depending on how you adjusted it.



Any discussion of light frequency/intensity and the response of cannabis to it, needs to take into consideration the _genetics_ of the plant. SouthEast Lights has a history of _exceedingly_ massive amounts of light exposure in a very small space, so I have absolutely no problem whatsoever with light burn, no matter how close the lights are:



That's a Spider Farmer SF4000, about 3" from the canopy, 3 months into veg.

 

[KitnerPush]

I guess more back to the initial question. How important are color temperatures of white diodes in relation and in combination with 660nm red diodes? So we've established that if we want to use less red diodes, then we must use more phosphorous infused white diodes, if we want to use more red diodes then we can use less phosforous infused white diodes. My convinction still rests on the latter, for obvious reasons. 1. Higher system efficiency through better optical and thermal efficiency of higher color temperature diodes along with the incorporation of 437nm white diodes and 'Mint' series diodes. In terms of cost, yes, do like the chinese... use as little red diodes or lesser quality red diodes and blast at 3-3500k. This seems to have been the 'standard' in LED lighting until relatively recently.

FR/UV aside, what would be the best combination of H-EVO highest efficiency diodes and 660nm red, for the most balanced and effective light? That's the real question. In other words, how do we utilize the photons of each of these diodes to optimize photosynthesis in short-day plants like cannabis? And... without having to use 2 different spectrums for vegetative and flower...

It seems there is a tendency to 'cry blue' regarding the H-EVO's and especially the 'Mint' series. Studies prove that the 437nm pump contributes to overall plant health and vitality, which is what we want for our plants. We also want a light which will give us higher efficiency so that we can push our plants beyond the 1000ppfd threshold, as cannabis surely makes use of a lot more photons in nature. We talk about UV and FR 'treatments' but we neglect talking about 'intensity treatments.' My assumption is that both of these treatments are valid in determining plant growth and potency. Yeah, genetics play a role in potency, but the right type of stress also does. It's clear this type of stress can be mediated through light.

So if you do not mind, let's discuss how to merge the 'colder' H-EVO efficiency with 660nm red ? Daylight spectrum is 6500K, just saying..

 

[KitnerPush]

Thank you so much, im actually the same so i really appreciate it.

Edit: cant seem to get more than very basic info regarding the study or the organisation that made it: yields increase linear from 1000 to 1800ppfd, 1 percent more light 1 percent more bud. But no info on absolute values or yield per square foot and adviced that you have to keep everything condition and environment tip top. A little hard to draw conclusions from this, we can certainly not replicate that in our grow. It kinda depends on what the yield was in weight, if they went from 2.5 ounce per square foot to 4 that would indeed be really eye opening but if it was 1.5 to 2.5 its less of a slam dunk. Weve never been able to hit those intensity without problems with bleaching/light burn.

Incidentally: they also quoted a spectrum test where the fluence R4 spectrum was the best yielder even over more red heavy spectrums. Fluence R4 seems to pretty much be 3500k + 660, just as @RainDan said.


Ive seen at least one dream run by former member Or-gro where hitting similar light levels, some tops at 1500 with no ill effects but it was a specialised spectrum, the old prawn boards pre GLA.

A full brain... is a scattered one Most people who do paid-for research tend to keep that shit private. So I can totally respect that. I think what he was talking about regarding the R4 spectrum was that the plants didn't seem to develop bleaching or burning at super high intensities. Not 100% it was regarding yield? 1% yield to 1% intensity, means that 50% more intensity yields about 50% more yield, no? I think that's the clue anyways. What's interesting is that this was true up till 2500, although diminishing returns over 1800ppfd. He also mentions that burning/bleaching was mostly true when red light was above 50%, yeah?

I'm not sure what type of facilities you have available in your testing, but it seems they are running in chambers which I am sure makes this at all possible, and which I am also sure commercial growers will be investing in, in the future.

He also mentions that he is looking more and more away from spectrum, and more and more towards intensity... although they will be doing analysis on spectrum in relation to intensity when they get their new chambers... which is a certain type of chamber I'm very unfamiliar with.

 

[Rocket Soul]

A full brain... is a scattered one Most people who do paid-for research tend to keep that shit private. So I can totally respect that. I think what he was talking about regarding the R4 spectrum was that the plants didn't seem to develop bleaching or burning at super high intensities. Not 100% it was regarding yield? 1% yield to 1% intensity, means that 50% more intensity yields about 50% more yield, no? I think that's the clue anyways. What's interesting is that this was true up till 2500, although diminishing returns over 1800ppfd. He also mentions that burning/bleaching was mostly true when red light was above 50%, yeah?

I'm not sure what type of facilities you have available in your testing, but it seems they are running in chambers which I am sure makes this at all possible, and which I am also sure commercial growers will be investing in, in the future.

He also mentions that he is looking more and more away from spectrum, and more and more towards intensity... although they will be doing analysis on spectrum in relation to intensity when they get their new chambers... which is a certain type of chamber I'm very unfamiliar with.

The article quotes one study about intensity which kinda goes counter to what ive seen in our grow; over 1000ppfd has been hard to use even with spectrums similar to their R4. Not sure what to make of it and how generalizable it is. Yes, they saw 1 to 1 increase in yield above 1000ppfd. But never state what was their yield weight at 1000ppfd so hard to evaluate.

Then they quoted another study theyve made where that 3500k + 660 was their yieldiest. But not so much mention about their other spectrums but i guess you can get that from fluence. If you dont know what youre comparing with its hard to know and evaluate.

No, no grow chambers here. Separate diy lights over each tray. 8 trays, 2 spaces on flipflop schedule and veg. Our grow is limited by amps. So theres a lot of high tech stuff but also low tech stuff. My growbuddy is setting up a wood fired stove for heating now to see if we can save some amps and up lights. Every time im away he gets antsy and start freelancing. Hes the day to day and really a much better grower than me but fairly growbro. I do development with the mission of improving crop value and squeeze out more from our limited installation. We are not in a legal grow environment but not as bad as black market, here in Spain it more like grey market. They just dont want you to be obvious. The ones they go after are gangs with bad habits, stealing power and bothering neighbours. But we still have to keep a low profile, this is why i cant really post photos. Will hopefully have something for show and tell after the new year, side by side or growlog with GLA strips. I pretty much convinced my growbuddy to do it, but maybe using imgur for control over pics (so we can delete afterwards) and only a little section of the full grow.

 

[Greengrouch]

I don’t know about diode brands really, I know the flower grown under the warmer mars hydro lights spectrum was tastier and greasier than the flower I grew under a cooler samphon light. Same strains but not clones so it could’ve been genetics but that everything under the warmer spectrum was better than the cooler has me leaning towards it having been the light.

Think samphon is the same manufacturer as medicgrow. They have identical lights just with different names

 

[KitnerPush]

I don’t know about diode brands really, I know the flower grown under the warmer mars hydro lights spectrum was tastier and greasier than the flower I grew under a cooler samphon light. Same strains but not clones so it could’ve been genetics but that everything under the warmer spectrum was better than the cooler has me leaning towards it having been the light.

Think samphon is the same manufacturer as medicgrow. They have identical lights just with different names

I'm not sure I quite understand the the science behind that statement, but it is interesting to get different experiences... terpenes, cannabinoids in cannabis, and other edible plants report to be higher under light which leans further towards the violet and into ultraviolet ranges. I.e HLG's lights are fairly blue...and people win cups with them all the time.

 

[Prawn Connery]

I'm curious on your input about 660/730 combination.

Any experiment/feedback/conclusion?

I've posted a bit already about both red and far red in this thread, so without repeating myself (and cluttering up this thread), what exactly is it you would like to know?

 

[Prawn Connery]

Pretty much been saying this all along. R-W-FR ratios are much more important than the color temp of the white diodes. In fact you don't even want that much phosphor in your white diodes because it makes them both optically inefficient, as well as, thermally inefficient. Also, just read about a study on light intensity in cannabis where weight was highly dependent on output, where 1800ppfd was the optimal output. They used up to 2500ppfd.

That's because they also use 1200ppm of CO2, so not surprising they can push PPFD levels with 3x as much atmospheric CO2.

They don't actually state what their yields are, either, so we don't know what sort of GPW or yield per area they are getting compared to other growers. Their plants certainly look pretty stressed to me.

 

[Rocket Soul]

That's because they also use 1200ppm of CO2, so not surprising they can push PPFD levels with 3x as much atmospheric CO2.

They don't actually state what their yields are, either, so we don't know what sort of GPW or yield per area they are getting compared to other growers. Their plants certainly look pretty stressed to me.

I think its more to that story than just co2. Now wintertime our grow always has loads of co2 due to heatin the house thru wood fire. And we most def cant give 1800 without bleaching

 

[Prawn Connery]

Here are a couple of images of the grow in question. Not sure if it was the test grow, but these are the images attached to the article.

First image shows how deep the canopy is and how bleached the tops are.

As far as I'm concerned, they are simply sacrificing the tops to get better penetration in the lower canopy to make up the yields.


Clear signs of light stress in the image below, but one of the other phenomena that's going on is that at very high light levels, plants will tend to continue flowering past their normal cycle. You can see it with these buds – especially the one at the back – where the lower calyxes are mature but the top calyxes are continuing to stack due to the higher light intensity.

So another quetion would be, are harvesting times increasing along with yield? And if so, doesn't this represent an increase in yield over watt-hours or not? If you increase yields by1% but your watt-hours increase by 2%, then you have actually gone backwards.


My final observation is, where were the light readings taken? The canopy is very uneven with a few tall buds sticking out – is this where they were getting 1800 PPFD? And if so, what were the readings amongst the bulk of the canopy below? There's probably a good 30cm between the tops of these buds and the main canopy below.