What would you pick led or hps?

cdgmoney250 said:

Plants grow under light more so than not. Many studies have shown that increasing DLI has a positive correlative influence to plant growth, when mitigating stress. I’m proposing a cloudless season, where irrigation replaces rain. Again this hypothetical is in a controlled growing environment.



If I could legally grow in a fully equipped, climate controlled, light deprivation greenhouse in my backyard, I wouldn’t care much about LEDs and “indoor”growing.

If you have some links to some 380nm-780nm LED chips that have a true sun imitating spectrum for for each hour of the day, please post the links and help a brother out. Otherwise, as a hobbyist non-academic pot grower, I think I’ll have to make do with the chips I have available to me. Which seemingly nobody else is using in grow fixtures, because the ppf/joule won’t be high enough.

If the plants perform “better” (there’s that word again) under a broader spectrum compared to a run of the mill “grow” spectrum, for similar electrical usage, then that’s a win in my book. If plants perform ”better” under a changing broad spectrum, than a static broad spectrum, that would be another win. That’s all I want to know.

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I just watched this video and it might allow you to draw some conclusions. The presenter is Mitch Westmoreland who was a PhD candidate under Bugbee at the time the video dropped (11/23). As best I can tell, his PhD work is/was on the topic of lighting for cannabis.

I don't know if the text below is verbatim but it is what I captured in my notes. I think it's from the 40:00 mark
"This is really one of the other reasons that light quality gets too much attention. If you deliver more light to the plants and nothing else is limiting, the yield just keeps going up. Physiologically, this is amazing."

"light quality" - spectrum

Westmoreland's work supports Bugbee's statement that' light quality drives plant shape, light quantity drives plant yield.

Westmoreland discusses the results of his research as well as providing some details. It's not an "intro plant lighting" video but, if a viewer has picked up the basics of plant lighting, it provides an extremely valuable body of knowledge.

Though this doesn't address your issue directly, the results that he discusses re. light quantity are very similar to the results that are discussed in the attached paper.

@Delps8 theres a few takeaways I’d like to brush on from that video.

When he mentioned that Spectral Quality is over emphasized (around the 25:00min mark), it was in the context of cost effective growing and yield. Meaning to get the most plant growth, spectrum is less important than total DLI. Which I totally agree with. This is when he was talking about the percentage of blue light in the spectrum relative to yield. He did also say they didn’t experience a statistically noticeable difference in cannabinoid content. But all 4 led models used are your basic 80 CRI Warm/Cool spectrums, 2 having 660nm added with the same 450nm pump and the same limited photon bandwidth.



I’m not as interested in yield comparisons as I am interested in knowing if plants receiving 380nm-780nm have higher/different cannabinoid content and terpene content while achieving similar yields. Sure, some of these parameters are predetermined by genetics, but how much has to do with environmental factors as well (including and focusing on spectral quality). How much of the plants full natural expression can we achieve with certain limiting factors, including spectral quality, as well as nutrition/soil food web stuff (different tangent).

If this spectrum (pictured below) would have been included in the study, would the results fall in line with the others, or stand out in some measurable way?


I’m no phd scientist, but if I had the resources at my disposal, I would be posing these questions. This spectral distribution graph is from Yuji LED and has been around since 2017 or 2018. Yet in studies done by phd students, they are still using the same basic spectrum formulas that were created almost 10 years ago. I just want to see the possibilities explored further.

Not only the spectrums, but whichever cultivars they were dealing with. Different cultivars have different light optimums. These studies never seem to name specific cultivars....It's just to be assumed that all marijuana is the same and will respond to whatever spectral adjustments in the same way. I can't believe that would be accurate. Therefore, these studies on cannabinoid production increase/decrease/etc. need to name the cultivar that's being tested. Clearly, an equatorial, landrace, Sativa cultivar will respond differently than would a bushy Indica cultivar.....And then there's a billion different hybrid cultivars. Where do you start?

cdgmoney250 said:

@Delps8 theres a few takeaways I’d like to brush on from that video.

When he mentioned that Spectral Quality is over emphasized (around the 25:00min mark), it was in the context of cost effective growing and yield. Meaning to get the most plant growth, spectrum is less important than total DLI. Which I totally agree with. This is when he was talking about the percentage of blue light in the spectrum relative to yield. He did also say they didn’t experience a statistically noticeable difference in cannabinoid content. But all 4 led models used are your basic 80 CRI Warm/Cool spectrums, 2 having 660nm added with the same 450nm pump and the same limited photon bandwidth.

View attachment 5382259

I’m not as interested in yield comparisons as I am interested in knowing if plants receiving 380nm-780nm have higher/different cannabinoid content and terpene content while achieving similar yields. Sure, some of these parameters are predetermined by genetics, but how much has to do with environmental factors as well (including and focusing on spectral quality). How much of the plants full natural expression can we achieve with certain limiting factors, including spectral quality, as well as nutrition/soil food web stuff (different tangent).

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I've only been through the video once and I'll admit that area wasn't one I was focused on. This is from my notes (typo and all):
"When it comes to quality, genetics are the dominant contribution. Generally, speaking, the environment ahs a pretty small effect."

There is a transcript available for that video. I didn't copy, paste, and clean it up (I will do that at some point) but, perhaps, if you grab the transcript and just to a Find in the raw text, that should provide the context around that quote.

cdgmoney250 said:

If this spectrum (pictured below) would have been included in the study, would the results fall in line with the others, or stand out in some measurable way?
View attachment 5382260

I’m no phd scientist, but if I had the resources at my disposal, I would be posing these questions. This spectral distribution graph is from Yuji LED and has been around since 2017 or 2018. Yet in studies done by phd students, they are still using the same basic spectrum formulas that were created almost 10 years ago. I just want to see the possibilities explored further.

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Bugbee has come out fairly recently and said that their recommended spectrum is white + far red. That's somewhat of a change, with the far red, but, you're right — it's a "bog standard" spectrum. Per my comment above, I think it'd because that's t

In the video, Westmoreland is pretty careful to caveat his research and to discuss the lengths that they went to, trying different combinations of UV light. He also said that he realized there were many other combinations of duration and intensity that that hadn't attempted.

My impression is that, understanding that even though they had only tested a small percentage of the possible number of combinations, his approach was "throw photons at it" and I think that's because his focus is on cannabis as a crop and commercial growers aren't interested in incremental changes. With the market being flooded and with price of electricity going up up and away, his focus on efficiency and yield are understandable.

In contrast, the personal/small grower looks at the problem differently and that might be a good issue to raise. Perhaps you could email him about it. He did publish his email addy, so follow up with him and see what he says.

Looking at that spectral graph, that's a really interesting spectrum. I use a dedicated veg light and have ended up with "a shrubbery" — 18" tall and 30" wide. With this spectrum, you'll get a similar morphology but lacking red and far red, it won't be that tall and the grams/joule will tend to be lower because of the lower efficiency of the blue photons. Where is that spectrum used?

tstick said:

Not only the spectrums, but whichever cultivars they were dealing with. Different cultivars have different light optimums. These studies never seem to name specific cultivars....It's just to be assumed that all marijuana is the same and will respond to whatever spectral adjustments in the same way. I can't believe that would be accurate. Therefore, these studies on cannabinoid production increase/decrease/etc. need to name the cultivar that's being tested. Clearly, an equatorial, landrace, Sativa cultivar will respond differently than would a bushy Indica cultivar.....And then there's a billion different hybrid cultivars. Where do you start?

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Westmoreland/Bugbee use Trump and Cherry in a lot of their research so they do "name names".

The second part of your posting deserves a definitive answer from an expert (not me!)

Re. different behavior - I suspect that the cultivars will respond differently but it will be in the degree of change rather than the direction. That just some asshole on the interest (moi) saying that but my thinking is that it is the same species so they will tend to behave/respond in a same manner.

Having said that, you raise an excellent question that really is the elephant in the room. Send Dr. Mitch an email and see what he says.

Delps8 said:

Westmoreland/Bugbee use Trump and Cherry in a lot of their research so they do "name names".

The second part of your posting deserves a definitive answer from an expert (not me!)

Re. different behavior - I suspect that the cultivars will respond differently but it will be in the degree of change rather than the direction. That just some asshole on the interest (moi) saying that but my thinking is that it is the same species so they will tend to behave/respond in a same manner.

Having said that, you raise an excellent question that really is the elephant in the room. Send Dr. Mitch an email and see what he says.

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"Trump and Cherry"? I've never even heard of that one! LOL! But, that's my point.....The selection of the cultivars must just be random -whatever was available at the time of testing or something...And I get what you're suggesting, but in my own experience, there are cultivars that have extremely different growth patterns and habits -sometimes, the same strain will have multiple expressions among its cultivars. So, while the people are trying to qualify the ideal spectrum, the plants, themselves, are constantly shifting and adapting to the environment, too. Even a plant type that shows improvement in growth under a given spectrum, on the first run, may change (under the exact same conditions), on the next run. Environmental conditions can be repeated, but there is no guarantee that plant response will be consistent.

And then there is the question of HOW the light is applied?.... Is it in a tent where the light is reflected off the walls, as well? Is it in a greenhouse? Is the lighting set up to move and change throughout the lights-on period? Or, is it stationary, overhead?

As growers, we are the nurture. But the nature of plants can vary in so many ways, it's difficult to know what type of nurture is best. I think it's best for the equipment to be able to be adjustable according to what a grower feels their plants are asking for -adjustable spectrum lights with separate channels for blending/changing the color.I think that's a better direction to go in, rather than looking for the "golden ticket" spectrum. I don't believe it exists in any kind of uniformly-applicable way.

tstick said:

"Trump and Cherry"? I've never even heard of that one! LOL! But, that's my point.....The selection of the cultivars must just be random -whatever was available at the time of testing or something...And I get what you're suggesting, but in my own experience, there are cultivars that have extremely different growth patterns and habits -sometimes, the same strain will have multiple expressions among its cultivars. So, while the people are trying to qualify the ideal spectrum, the plants, themselves, are constantly shifting and adapting to the environment, too. Even a plant type that shows improvement in growth under a given spectrum, on the first run, may change (under the exact same conditions), on the next run. Environmental conditions can be repeated, but there is no guarantee that plant response will be consistent.

And then there is the question of HOW the light is applied?.... Is it in a tent where the light is reflected off the walls, as well? Is it in a greenhouse? Is the lighting set up to move and change throughout the lights-on period? Or, is it stationary, overhead?

As growers, we are the nurture. But the nature of plants can vary in so many ways, it's difficult to know what type of nurture is best. I think it's best for the equipment to be able to be adjustable according to what a grower feels their plants are asking for -adjustable spectrum lights with separate channels for blending/changing the color.I think that's a better direction to go in, rather than looking for the "golden ticket" spectrum. I don't believe it exists in any kind of uniformly-applicable way.

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These kind of lights would be awesome...for like 6 people... Hardcore nerds... They are all in this thread lol. For everyone else, I'm glad that Vivosun has already went through the work of selecting a decent spectrum for veg and then a decent spectrum for flower. My lights even have "sunrise and sunset" ramp up and ramp down features. Having a completely tunable set up when you can just get one already set up sounds like a failing business move. Sure, it will be cool as hell, for like 6 people lol.

Well, I can't disagree that your Vivo sun lights will do the job just fine. Almost any light will grow weed. I know that from growing weed under every kind of light there is for the last 50 years. And yeah, the equipment craze is in full swing now. We've got Cannatrol for curing weed. We've got freeze driers for bubble hash....programmable controllers...You name it, the "6 nerds" have thought it up already.
Do you honestly believe that your Vivosun lights are going to be the end-all to lighting for growing weed? LOL! Maybe for you, they will be. However, technological advancements are the only direction that won't ever end when it comes to weed growing. There's never going to be the day when manufacturers just say, "Okay, we've done it all, now! Let's stop!". And, just in case you didn't know it, programmable lights are already starting to appear on the market. Growers realize that there is no one "golden ticket" spectrum for growing weed -only light manufacturers that want you to think there is because that's where most of the lighting manufacturers are limited to at the present time. There will be more and more programmable/separate channel lights coming out in the future. They will be expensive at first and then the prices will continue to drop until they become affordable to everyone....And then, after that, they will become the norm. It's just a matter of time.

EDIT: There used to be an OLD debate, back in the day, about which light was better for weed: Metal Halide or High Pressure Sodium? Those used to be "THE" two, serious choices among growers, at that time. Metal Halide had advantages in one way and HPS had advantages in other ways. The problem was that they each required their own, separate kind of ballast to work. You couldn't just switch the bulbs into the same fixture/ballast......That is, until some nerd invented an HPS conversion bulb that DID allow a grower to merely unscrew the MH bulb and switch it out for the HPS bulb without having to switch out the entire system. Voila! That was an early version of controllable-spectrum lighting for weed. It was like the analog version of it! Now we've got people hemming and hawing over singular/"ideal" spectrums, again....This time it's digital and LED. So, once again, the question goes back to, "How are growers going to gain more control over how they want to apply their lighting?"

Delps8 said:

With this spectrum, you'll get a similar morphology but lacking red and far red, it won't be that tall and the grams/joule will tend to be lower because of the lower efficiency of the blue photons. Where is that spectrum used?

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I'm not sure where or what this particular spectrum application it is used in, but it doesn’t have the traditional cyan/lime green dip that most of the standard chips use and covers the blue/green end of Chlorophyll absorption much more broadly. I think it would be super interesting to pair that spectrum with a separate channel to augment red/dr/fr and play around with ratios and intensities. I just haven’t gotten around to it myself.

cdgmoney250 said:

I'm not sure where or what this particular spectrum application it is used in, but it doesn’t have the traditional cyan/lime green dip that most of the standard chips use and covers the blue/green end of Chlorophyll absorption much more broadly. I think it would be super interesting to pair that spectrum with a separate channel to augment red/dr/fr and play around with ratios and intensities. I just haven’t gotten around to it myself.

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I don't have those specific yuji diodes, but I did snatch up some Seoul Sunlike 5k strips a while back that have a similar approach to their spectrum. I haven't used them yet but would like to think they bring a nice balance to some of the standard white spectrums.


I'm hoping this summer to finally be able to set up a 2x4 tent and build something for a more proper space. I've just used my growlightsaustralia first gen boards in my small 2x2.5 for the few grows the past couple years. Those boards use these same seoul diodes as part of their build, just 6500k if I remember correctly. I know their efficiency is quite dismal, but they seem to bring some nice aspects to the overall spectrum.

I've stocked up on tons of random things (all different temps and cri -- no mono diode options though) through all the arrow deals and other random purchases so I'll have to post a thread and see what kind of things people would like to see compared. Not an expert grower by any means so not really sure what I can offer, but I'm definitely open to suggestions if people wanted to see something specific.

cdgmoney250 said:

I'm not sure where or what this particular spectrum application it is used in, but it doesn’t have the traditional cyan/lime green dip that most of the standard chips use and covers the blue/green end of Chlorophyll absorption much more broadly. I think it would be super interesting to pair that spectrum with a separate channel to augment red/dr/fr and play around with ratios and intensities. I just haven’t gotten around to it myself.

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Agreed - it's a very unusual spectrum because of the lack of red. If you add in red, how does the spectrum vary from, say, a white LED + far red?

Doing any kind of experimentation with spectrum is tough work and a lot of that work has already been done.

We've seen research on UV (Bugbee has found no benefit and, remember, Lyden said the results were "equivocal"), blue makes plants short and stock with lots of foliage, and red and far red knock boots AKA the Emerson affect.

Have you checked out "the research"?


I grow with veg and flower lights (Growcraft) and I went that route because I wanted to control plant shape with the blue heavy veg light and then switch to the flower light. In my last three grows, my plant has been 30" x 20" x18" tall — a "shrubbery".

They've been beautiful plants but I have no idea about cannabanaoids - my 2301 grow got bud rot and my current grow (2401), I mucked up by mistakenly adding H2O2 to the humidifier so my yield will be "modest" at best. Yeh, it's been a long 12 months…

Delps8 said:

We've seen research on UV (Bugbee has found no benefit and, remember, Lyden said the results were "equivocal").

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what do you mean Bugbee found no benefit?

Delps8 said:

Agreed - it's a very unusual spectrum because of the lack of red. If you add in red, how does the spectrum vary from, say, a white LED + far red?

Doing any kind of experimentation with spectrum is tough work and a lot of that work has already been done.

We've seen research on UV (Bugbee has found no benefit and, remember, Lyden said the results were "equivocal"), blue makes plants short and stock with lots of foliage, and red and far red knock boots AKA the Emerson affect.

Have you checked out "the research"?


I grow with veg and flower lights (Growcraft) and I went that route because I wanted to control plant shape with the blue heavy veg light and then switch to the flower light. In my last three grows, my plant has been 30" x 20" x18" tall — a "shrubbery".

They've been beautiful plants but I have no idea about cannabanaoids - my 2301 grow got bud rot and my current grow (2401), I mucked up by mistakenly adding H2O2 to the humidifier so my yield will be "modest" at best. Yeh, it's been a long 12 months…

View attachment 5383164

View attachment 5383163

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I have a few issues with Bugsbees UV research (the paper, not seen the vid):
- Spectrum and supplemental model: they add uva and uvb in almost equal proportions and same duration, also uva/violets has almost with no cover between 375 to 450nm. Usually the proportion is 1:20 uvb to uva in sunlight.

- the "plant specific uv dose" measure he uses; the uv dose is scaled according to "established measures" which im not sure i agree with regarding THC production. It just basicly look like the action spectrum for sun tan, basicly covering the end of uva and all of uvb. This type of weighing means that the paper starts with the assumption that whatever part of uv not covered wont have any effect. I think this assumption is made a bit precipitated.

-the way it is touted online/on forum as proof of no effect of uv on thc. There was some effect in these test only not statistically significant. With the way the atudy looks id say it is an error to say it proved no effect. At most generous you could say that the study didn't give any statistically significant response to targeting uvb with a fluorescent, doesnt really say anything about uva or a more balanced uv supplement treatmeant, id suggest separating uva and uvb in channels, or even uvb +365nm on one channel and wide blue from 385 to 430ish nm on the other channel; tgis way you could add photosynthetically active uv/violet and more signal related uv (285nm and 365nm) separately. Adding half and half uvb and uva does not make sense to me, seems as likely to burn through any gains by uvb degradation.

After having used,
This:

This:

This in the 5K variant:

This:

And This:



I now use this and have been very happy with both Veg and Flower Performance:

Rocket Soul said:

I have a few issues with Bugsbees UV research (the paper, not seen the vid):
- Spectrum and supplemental model: they add uva and uvb in almost equal proportions and same duration, also uva/violets has almost with no cover between 375 to 450nm. Usually the proportion is 1:20 uvb to uva in sunlight.

- the "plant specific uv dose" measure he uses; the uv dose is scaled according to "established measures" which im not sure i agree with regarding THC production. It just basicly look like the action spectrum for sun tan, basicly covering the end of uva and all of uvb. This type of weighing means that the paper starts with the assumption that whatever part of uv not covered wont have any effect. I think this assumption is made a bit precipitated.

-the way it is touted online/on forum as proof of no effect of uv on thc. There was some effect in these test only not statistically significant. With the way the atudy looks id say it is an error to say it proved no effect. At most generous you could say that the study didn't give any statistically significant response to targeting uvb with a fluorescent, doesnt really say anything about uva or a more balanced uv supplement treatmeant, id suggest separating uva and uvb in channels, or even uvb +365nm on one channel and wide blue from 385 to 430ish nm on the other channel; tgis way you could add photosynthetically active uv/violet and more signal related uv (285nm and 365nm) separately. Adding half and half uvb and uva does not make sense to me, seems as likely to burn through any gains by uvb degradation.

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I'd be surprised to hear that it was stated "proved no effect." The word "prove" is an absolute statement, generally speaking, researchers avoid making absolute statements such as that. Certainly, it does run contrary to what I've heard Bugbee or Westmoreland say so perhaps it was a faux pas rather than a definitive statement of their position.

I do recall that Bugbee uses the word "equivocal" which is how Lyden spoke of his research and have seen him say many times that "the research does not support that" or "there is no evidence to support that".

You might contact the Westmoreland/Bugbee with your suggestions.

Hollatchaboy said:

what do you mean Bugbee found no benefit?

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Bugbee has said that the results were "equivocal", quoting Lyden.

Bugbee discusses UV in a number of his videos and Westmoreland covers it in some detail. The Westmoreland video is more concise so watching that video might provide some helpful background.

Delps8 said:

I'd be surprised to hear that it was stated "proved no effect." The word "prove" is an absolute statement, generally speaking, researchers avoid making absolute statements such as that. Certainly, it does run contrary to what I've heard Bugbee or Westmoreland say so perhaps it was a faux pas rather than a definitive statement of their position.

I do recall that Bugbee uses the word "equivocal" which is how Lyden spoke of his research and have seen him say many times that "the research does not support that" or "there is no evidence to support that".

You might contact the Westmoreland/Bugbee with your suggestions.

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Its not stated in the paper as "prove no effect" it sure is how its touted around forums by most. Most people dont really understand the finer points of research (as you do) and see "no statistic significance" as the same as proven not to work.
I dont have any comments on that video, ive only read the paper but ill have a look at it when i get some time. Just to understand:
"I do recall that Bugbee uses the word "equivocal" which is how Lyden spoke of his research and have seen him say many times that "the research does not support that" or "there is no evidence to support that"

what are bugbee and lydon (?) talking about? The bugbee paper or something else? Or is this directed to someone else?

Happy growing

Delps8 said:

Bugbee has said that the results were "equivocal", quoting Lyden.

Bugbee discusses UV in a number of his videos and Westmoreland covers it in some detail. The Westmoreland video is more concise so watching that video might provide some helpful background.

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Got it. I'm not as savvy with spectrums like you guys are. I just remembered in the video, him saying there was benefit.

Hollatchaboy said:

Got it. I'm not as savvy with spectrums like you guys are. I just remembered in the video, him saying there was benefit.

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Where/when did he say that?

I don't have my notes handy…

Delps8 said:

Where/when did he say that?

I don't have my notes handy…

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In the migro video I posted.