High CRI White LED Chips/Strips

cdgmoney250 said:

I hadn’t looked into these Vesta’s yet, I very much appreciate the suggestion! In that build that you did, were those the 90CRI tunable strips? Just looking through their catalog and I see that they have those Vesta TL in the Thrive 98CRI series as well! I’ll definitely be pouring over some more data sheets. I just wish they had like a 3000k/5000k or a 4000k/6400k option. Seems all the tunable modules are using 2700k for their warm side.

For tunable strips all the data sheets list the spectrums separately, but each spectrum has different flux outputs, so they wouldn’t look normalized to 100% like the spec sheets show when they over lay different color temps on the same graph. It’s nice to be able to compare individual spectrums, but not so nice when you want to see what they look like blended at nominal power. I’m sure someone smarter than me could do the math to correlate the difference in luminous flux to make the adjustments to the relative spectrums manually, but I’d rather just see a spectrometer reading lol.

I love the idea of tunable strips, not so much for being able to go full term (although that is certainly one way to go), but at some point I’d like to mess around with changing the spectrum throughout the day to mimic sunrise/sunset/full sun. And eventually seasons if budget/design don’t get too ridiculous.

Also, I’ve been looking through some different options to cover the DR/FR end of the spectrum with white/red phosphors to get broader nanometer coverage. I think that is probably still the best bet at supplementing for the warm end and filling the spectrum, but supply issues are killing me on that search as well. I’d like to avoid monos if possible, but maybe just a few on separate channel for UV supplementation.

For the visible violet wavelengths, Yuji and Seoul seem to have those covered better than Bridgelux, but both Bridgelux and Seoul have big dips in Cyan region. I guess you can’t win em all, which is why I like the idea of mixing different strips and putting them on different channels.

I do like those Seoul Strips, but there are some pretty big supply issues with a lot of these high CRI modules at the moment, so availability might be in play as well as performance/price.



Awesome post!

And that has been my question for a number of years, but I haven’t been able to experiment until “now” (soon).

“Which matters more for natural plant expression?
PPFD or Spectrum?”
Or is it both?
It is my theory in my mind that light spectrum is the limiting factor in total photon flux that a plant can handle, given the same environmental conditions. I believe this is why plants will often stress indoors under artificially light under high PPFD conditions, and also why maintaining VPD is even more critical. I want to know if indoors, under artificial light of equal intensities, if a plant would grow to a higher degree of expression?

In the same realm of questioning:

Is spectrum a limiting factor in total potential yield?

Will a plant under a fuller more “natural” spectrum be able to photosynthesize at a higher overall ppfd situation under similar environmental conditions, with less light stress than a “narrower spectrum”? In my personal experience, the answer is yes, but it’s subjective and anecdotal. I want to actually test this theory. I remember that side by side @Rahz did back in the day of different color temps and 80CRI vs 90CRI, and those were the questions that immediately came to my mind even then.

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grotbags said:

imo, the sunrise/sunset, spectrum/intensity thing is a waste of time. when the plants are awake get em grafting as quick as possible. the only daily spectrum manipulation i do is far red after main lights out for end of day treatment.

i think spectrum and intensity manipultion over the course of a full crop cycle makes more sense for pushing quality and weight.

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Rocket Soul said:

Using and Testing Vesta Strips

They're something similar to the Growgreen boards I've got. 2 channels, 3000k and 5000k boards, 3500k and 5000k boards. Only one channel with 90 Cri tho. They work great.

www.rollitup.org

Heres some nice testing of the vestas, also with the both channels spectrum aswell as ppf/w. Its a pity TEKNIK is not around anymore he had awesome testing gear.

Spectrum/intensity/sunlight/vpd: theres several thing about sunlight that make it different, not only spectrum. The fact that the light moves around the sky and changes intensity matters a lot. If you were to count in DLI and ramp up and down linear: the total amount of light given to the plant at midnoon 2000ppfd would be the same as 1000ppfd during the whole 12 hours.

Also, the massive amount of IR: it both drives transpiration and metabolic rate.

When you talk about VPD for a grow: its not the only way to cause transpiration, blue/violet also cause transpiration. So having a blue/violet/uv channel separate could help with this if you cant get vpd to collaborate.

i remember that grow from rahz. The one thing about it though is that there was a fair bit of vegging done under each spectrum: plants couldnt be considered going into flower the same really as the more stretchy spectrums had much bigger cannopy.

as for vestas + monos: my approach was to arrange 3 vestas in series, channels separately, then join the outputs and send it thru some custom strips from kingbrite, i think it was roughly 50/50 660 and 630, which was what i had about. If id be able to redo id go for something like 660/730/400 third each. This setup meant i got a string of roughly 100V, 75v vestas and about 25 of monos, max amp is 700ma. So about 70-75w each section, with about 25% of that being monos.

theres sorta 2 ways on going for spectrum, one, try to get the perfect static spectrum. For example the GLA boards. Or going for plant expresion/morpholgy: more like grotbags approach with several different channels were you target wave lengths for what the do to the in plant.

WHen it comes to spectrum i think its hard to say why you see "better" growth with a "better" spectrum. Is it photosynthetic efficiency or morphological effect that is playing out in front of you?

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cdgmoney250 said:

Thanks for sharing that SPDwith the different levels of relative intensity on the different strips! I will definitely have to play around with that configurator tool!



This is where I would respectively have a difference of opinion. I’m with @Rocket Soul that same total DLI can be met with varying duration and intensity of light received. I personally like the idea of varying light intensities throughout the day so you could run higher ppfd than they could normally take static throughout the day, such as the “midday” hours, and then scale it back down while still meeting DLI goals. Doing this allows higher ppfd to the lower/inner canopy on a daily basis without frying the tops of the plants from too long an extended photosaturation period. This midday time is also the time I would supplement UV if I were to do any of that.

This is likewise why I wonder if changing the spectrum throughout the day has any favorable morphological impacts that could be seen? The suns spectrum is warm from sunrise with the spectrum steadily shifting towards a blue/green peak (full sun) by about about mid morning onward until about mid afternoon where it starts to shift back towards the warmer balance until it’s mostly red (similar to your end of day red supplementation) for sunset . So In addition to the sun’s spectrum changing throughout the day, it shifts less towards blue/green and more towards the red as the summer season changes. This is why the idea of a “full cycle” light doesn’t necessarily seem ideal to me. The plants receive different ratios of different wavelengths throughout the day and the year. I just feel like there has to be something to it.
Maybe changing the spectrum throughout the day is a waste of time, but if we spend so much time trying to create optimum spectrums by mixing different strips/chips (because there is not a “perfect” artificial spectrum), why not try to find combinations that can come close to mimicking the different changes in spectrum and intensity with different channels/controllers? I think it will be a fun experiment!



That’s cool seeing Tekniks test of the dual band strip at equal power. Gives me confidence moving forward and picking spectrums to blend.

I totally agree that there is a lot going on with the sun, more than just spectrum [ see rant above ]. One thing I would note though about the sun moving throughout the sky, is not only it’s relevance to intensity, but the spectrum also changes relative to the solar angle. Likewise, as the suns angle gets higher or lower from season to season, this also causes midday sun to shift in relative intensities between the different wavelengths.

With you on transpiration, a whole host of factors that affect it. I mention VPD as a potential limiting factor of LED grows, because I feel a lot of people don’t measure their leaf temps and don’t realize how far off track their environments are for high ppfd conditions.

Shy of having the perfect tunable “full cycle” spectrum, I think the most practical thing to do would be to optimize the spectrum for each stage of the plants life (veg/flower). And maybe play around with some daytime spectrum /intensity tuning if I go down the rabbit hole far enough.

“WHen it comes to spectrum i think its hard to say why you see "better" growth with a "better" spectrum. Is it photosynthetic efficiency or morphological effect that is playing out in front of you?”

When I say better, i’m referring to a plant that would more resemble itself in nature under great conditions. Better as in higher net photosynthesis under the same flux conditions, or more terpenes being expressed from the same cultivar. Higher yield? Maybe more efficient nutrient uptake, less deficiencies? At least these are things I would hope to see under a “better” spectrum.

Back to the data sheets for me.

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cdgmoney250 said:

Thanks for sharing that SPDwith the different levels of relative intensity on the different strips! I will definitely have to play around with that configurator tool!



This is where I would respectively have a difference of opinion. I’m with @Rocket Soul that same total DLI can be met with varying duration and intensity of light received. I personally like the idea of varying light intensities throughout the day so you could run higher ppfd than they could normally take static throughout the day, such as the “midday” hours, and then scale it back down while still meeting DLI goals. Doing this allows higher ppfd to the lower/inner canopy on a daily basis without frying the tops of the plants from too long an extended photosaturation period. This midday time is also the time I would supplement UV if I were to do any of that.

This is likewise why I wonder if changing the spectrum throughout the day has any favorable morphological impacts that could be seen? The suns spectrum is warm from sunrise with the spectrum steadily shifting towards a blue/green peak (full sun) by about about mid morning onward until about mid afternoon where it starts to shift back towards the warmer balance until it’s mostly red (similar to your end of day red supplementation) for sunset . So In addition to the sun’s spectrum changing throughout the day, it shifts less towards blue/green and more towards the red as the summer season changes. This is why the idea of a “full cycle” light doesn’t necessarily seem ideal to me. The plants receive different ratios of different wavelengths throughout the day and the year. I just feel like there has to be something to it.
Maybe changing the spectrum throughout the day is a waste of time, but if we spend so much time trying to create optimum spectrums by mixing different strips/chips (because there is not a “perfect” artificial spectrum), why not try to find combinations that can come close to mimicking the different changes in spectrum and intensity with different channels/controllers? I think it will be a fun experiment!



That’s cool seeing Tekniks test of the dual band strip at equal power. Gives me confidence moving forward and picking spectrums to blend.

I totally agree that there is a lot going on with the sun, more than just spectrum [ see rant above ]. One thing I would note though about the sun moving throughout the sky, is not only it’s relevance to intensity, but the spectrum also changes relative to the solar angle. Likewise, as the suns angle gets higher or lower from season to season, this also causes midday sun to shift in relative intensities between the different wavelengths.

With you on transpiration, a whole host of factors that affect it. I mention VPD as a potential limiting factor of LED grows, because I feel a lot of people don’t measure their leaf temps and don’t realize how far off track their environments are for high ppfd conditions.

Shy of having the perfect tunable “full cycle” spectrum, I think the most practical thing to do would be to optimize the spectrum for each stage of the plants life (veg/flower). And maybe play around with some daytime spectrum /intensity tuning if I go down the rabbit hole far enough.

“WHen it comes to spectrum i think its hard to say why you see "better" growth with a "better" spectrum. Is it photosynthetic efficiency or morphological effect that is playing out in front of you?”

When I say better, i’m referring to a plant that would more resemble itself in nature under great conditions. Better as in higher net photosynthesis under the same flux conditions, or more terpenes being expressed from the same cultivar. Higher yield? Maybe more efficient nutrient uptake, less deficiencies? At least these are things I would hope to see under a “better” spectrum.

Back to the data sheets for me.

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Rocket Soul said:

Im not personally for the whole "ramp up" idea in flower. It would mean you need more driver power than youd normally need since the peak has to be higher.
Edit: another issue with ramp up: if you are close to your max amps of your installation then whats the point of having much higher watt peaks for same DLI?

Id like to try it in vegg though; see if the plants harden better to higher light intensity at midday before hitting flower.

As for better spectrum better growth: you mention stuff as higher net photosynthesis: how would you see that? Faster growth right? But faster growth could also be down to morphology, if the spectrum really "tickles" the action spectrum (think targeting chloro peaks, a bit like blurple) the plant tends to grow a bit more aggressively. So same outwardly behaviour. My question was formed around this: how would one know if the "better growth" under a new light/spectrum is just down to the plant being more efficient under the new spectrum, or if this is the plant "understanding" that in this light situation the best thing to do is to grow as fast as possible with little consideration to the downsides of over growing? How would one know?

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Rocket Soul said:

Im not personally for the whole "ramp up" idea in flower. It would mean you need more driver power than youd normally need since the peak has to be higher.
Edit: another issue with ramp up: if you are close to your max amps of your installation then whats the point of having much higher watt peaks for same DLI?

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grotbags said:

dont get me wrong im not saying there would be no effect at all from daily light intensity/spectrum manipulation its just imo the benefits you might gain would be tiny compared to the work/cost needed to pull this off accurately.

like rocket touched on for a normal single spectrum light to double the intensity at miday you would need double the driver capacity and double the diodes. if you wanted what is still a pretty basic two channel light of say 2700k and 6500k and wanted to give them double the intensity of just a blue shifted spectrum at miday now you need quadruple the driver capactity and quadruple the

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Rocket Soul said:

As for better spectrum better growth: you mention stuff as higher net photosynthesis: how would you see that? Faster growth right? But faster growth could also be down to morphology, if the spectrum really "tickles" the action spectrum (think targeting chloro peaks, a bit like blurple) the plant tends to grow a bit more aggressively. So same outwardly behaviour. My question was formed around this: how would one know if the "better growth" under a new light/spectrum is just down to the plant being more efficient under the new spectrum, or if this is the plant "understanding" that in this light situation the best thing to do is to grow as fast as possible with little consideration to the downsides of over growing? How would one know?

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grotbags said:

then have you got the lab like conditions and the growhow so that the test grows are perfectly repeatable, can you keep the enviroment exactly the same between runs ect, can you gaurantee repeatable cutting stock ect, the list goes on.

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