# Ok, for real... does changing the R/G/B output of LED lights change how plants grow?



## Ddrizzle (Jan 30, 2019)

I was reading about PAR vs PUR on the seneye site, and then saw someone in here stating that lowering the green in a Current LED Plus Pro can affect how plants grow. Say, taller vs shorter and bushier.

Is there any truth in this? Why would lowering green outout make plants bushier if the reds and blues never changed intensities? 

Side question, how does the white even work on these? And what kind of PUR does it add?


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## Seattle_Aquarist (Jun 15, 2008)

Hi @Ddrizzle,

An excellent question. Cara Wade, when she was with Build My LED (BML), did a couple of talks for our club here in Seattle. During her talk she discussed 'Myths' about plant lighting and growth. She cited an experiment by Dr. Bruce Bugbee, Utah State University Dept of Plants, Soils, and Climates. (BTW, he also founded Apogee Instruments that makes PAR meters). Dr. Bugbee grew the same species of plants in a variety of light spectrum maintaining the same light intensity (PAR) in all cases. Here are the results:










Basically there was no discernible difference in growth if the PAR level (light intensity) was the same for each spectrum. If someone backed down on the green light for instance and did not increase the red, yellow, etc to maintain the same light intensity then the plant would become more 'leggy'.

BTW, Cara Wade will be one of the many speakers including Christel Kasselmann, Dennis Wong, Cory McElroy, and Vin Kutty at the 2019 AGA International Convention in Seattle, May 2 - 5


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## jeffkrol (Jun 5, 2013)

Yes......

BTW: White LED's are Royal blue leds w/ a "yellow" phosphor..
There are fancier kinds..Warm whites add a bit of red phosphor..









thing is, for most spectrums one would run it's minor differences for the most part.
Some are even "internal" like vitamin protein content..

Early playing around w/ spectrum. Actinic hgh k white multichips..about 7w's each
note the "tufts" of Water wysteria..Granted they were a bit high in the wc..so fairly intense light.








Grew w/ practically zero internodal space, highly (even more than normal) dissected leaves..

nothing is real consistent though.

Aquatic photosynthetic organisms can respond in the reverse.. i.e seeing a lot of red spectrum implies high light. A lot of blue low light.
Opposite of many terrestrial plants..
Just a bit of err.. "wisdom"....


> No matter what plant you are growing indoors, the most crucial colors needed are red and blue. Some sources say to have 10% blue and 90% red. Other say a 30% blue and 70% red is best.
> It will depend on what you want your plants to do.
> It will also depend on what plants they are.
> You can add other colors from the spectrum, using the information above, to add other growth characteristics.


https://www.urbanorganicyield.com/does-the-color-of-light-affect-plant-growth/


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## Ddrizzle (Jan 30, 2019)

Huh, two posts back to back that are contradicting each other?

The first one gives photographic evidence which is nice.


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## Seattle_Aquarist (Jun 15, 2008)

Hi @Ddrizzle,

Flip a coin? lol


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## jeffkrol (Jun 5, 2013)

https://digitalcommons.usu.edu/roch/56/


> Abstract
> 
> *Increasing blue light from LEDs reduces leaf length in kale
> *
> ...






> > *It will depend on what you want your plants to do.
> > It will also depend on what plants they are. *


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## Immortal1 (Feb 18, 2015)

The best I can offer to this thread - would you consider this a normal size for a Bacopa Caroliniana? Several have commented at how big the leaves are. Can only say that when using a Satellite Plus Pro they were NOT this big.










Lighting levels


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## jeffkrol (Jun 5, 2013)

Found this..
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0202386



> The relative quantum efficiency curve represents the direct effects of the radiation spectrum on instantaneous photosynthesis per unit of leaf area [1]. However, when plants are grown under a particular radiation spectrum over time, they can acclimate by altering the relative size of the photosystems, chlorophyll composition, and chlorophyll content [43, 45–46]. Photosynthetic acclimation to the radiation spectrum optimizes electron transport and improves photosynthetic efficiency [47]. Therefore, photosynthetic acclimation at least partially diminishes the direct effects of YPFD on instantaneous photosynthesis, resulting in no clear correlation between YPFD of each radiation spectrum and whole plant net assimilation.


and this:
https://www.semanticscholar.org/pap...gbee/00808ae5e9280789ff5a064b2ac37af3f8f6578e













> Blue light did not affect total dry weight (DW) in any species but significantly altered plant development. Overall, the low blue light from warm white LEDs increased stem elongation and leaf expansion, whereas the high blue light from cool white LEDs resulted in more compact plants. For radish and soybean, absolute blue light was a better predictor of stem elongation than relative blue light, but relative blue light better predicted leaf area. Absolute blue light better predicted the percent leaf DW in radish and soybean and percent tiller DW in wheat. The largest percentage differences among light sources occurred in low light (200 mmol·m·s). These results confirm and extend the results of other studies indicating that light quantity and quality interact to determine plant morphology. The optimal amount of blue light likely changes with plant age because plant communities balance the need for rapid leaf expansion, which is necessary to maximize radiation capture, with prevention of excessive stem elongation. A thorough understanding of this interaction is essential to the development of light sources for optimal plant growth and development.


It's complicated..


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## Ddrizzle (Jan 30, 2019)

Immortal1 said:


> The best I can offer to this thread - would you consider this a normal size for a Bacopa Caroliniana? Several have commented at how big the leaves are. Can only say that when using a Satellite Plus Pro they were NOT this big.
> 
> 
> 
> ...


Ok, you have my attention. What light did you use instead?


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## Immortal1 (Feb 18, 2015)

@Ddrizzle - these are Radion XR15Fresh Water lights. The graph is output from Seneye PAR meter.


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## Ddrizzle (Jan 30, 2019)

Immortal1 said:


> @Ddrizzle - these are Radion XR15Fresh Water lights. The graph is output from Seneye PAR meter.


Ugh ok, I was hoping to get an unbiased opinion since that is the only company using this type of informationto sell their product.


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## Greggz (May 19, 2008)

Here's the thing.

I believe plants grow better and develop more color under high PUR.

However, I could be wrong. 

But in any case.......I can tell you for sure......they LOOK better under better color. 

There is no question about that. And that includes fish too.

Bump:


Ddrizzle said:


> Ugh ok, I was hoping to get an unbiased opinion since that is the only company using this type of informationto sell their product.


I can assure you, @Immortal1 is unbiased.

Not sure why the attack on someone who just tried to answer your question??

Good luck with everything. I think you are going to need it.

Be sure to show us when you have it all figured out.


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## Ddrizzle (Jan 30, 2019)

Greggz said:


> Here's the thing.
> 
> I believe plants grow better and develop more color under high PUR.
> 
> ...


Not sure why you feel like I'm attacking someone. Do you want to talk about it?


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## Wobblebonk (Feb 13, 2018)

Pfft are they ever coming out with this seneye spectra or what?! :/ been thinking of running some experiments with as closely matched little cube aquariums as I can and different par38 bulbs with par matched as best I can with a seneye reef... I've got 2 extra full 20lb co2 tanks and a regulator just need a manifold and... to choose some "bulbs". I have 18.5W 60degree soraa bulbs for now... need to choose some like all blue / red / green leds or something.


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## Ddrizzle (Jan 30, 2019)

Looking at the current led pro plus light specs here: https://current-usa.com/satellite-freshwater-plus-pro-led/

It seems like it produces almost no reds. Is this typical? Seems bad after reading more.


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## Wobblebonk (Feb 13, 2018)

They're okay, I think they're overpriced for what you get though, the fluval 3.0 is a much better value IMO especially with the seemingly never ending 15% off code at kensfish. Actually the "fluval" coupon code also applies to aquaclear filters, fluval canister filters and northfin food (are they owned by hagen I never understood why that was part of this coupon code heh)

Most of the cheaper commercial fixtures are lacking in red light and I don't particularly like how the current has 9352085203 resistors. If only the fluval had a battery so it didn't lose the time from a power outage


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## jeffkrol (Jun 5, 2013)

Ddrizzle said:


> Looking at the current led pro plus light specs here: https://current-usa.com/satellite-freshwater-plus-pro-led/
> 
> It seems like it produces almost no reds. Is this typical? Seems bad after reading more.


Well...part of that is the chart is probably "relative"......but no they aren't red rich.
Whites have a lot of blue then you have the blue diodes.. Dim those a bit and red would "spike" a bit on the charts.
There RGB part is a bit weak as well, in relation to the 6500k's.
Point is if one can sacrifice PAR they can be richer in red..



This sort of light used to be common-er. Ray II is probably the last for Finnex brand of weak red (all 8000K).
Finnex planted plus, 24/7 (somewhat, still more Current like), Fluval, some Beamsworks, ect ect are semi-enriched in reds from "old school" thinking.

Besides some of this is marketing and bad "legends".. 
People generally prefer crisper than yellowish tanks and some still adhere to 6500k (though correct in a sense it depends on the "quality" of the 6500k. Not all 6500k is created equal)


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## OVT (Nov 29, 2011)

Immortal1 said:


> @Ddrizzle - these are Radion XR15Fresh Water lights. The graph is output from Seneye PAR meter.


Twice the light for twice the price.
That Bacopa looks big enough to eat.


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## burr740 (Feb 19, 2014)

It will definitely change how the plants look to our eyes, which is just as important.

Check this out, 5 little Crypt flamingos. Pics were taken one day aft I got them in the mail from another hobbyist. They'd all been grown in the same tank and were in the exact same condition.

I put 4 in a tank with heavy red and blue T5HO, and 1 in a tank with mostly 6500K T5HO. See how much difference the type of light shining on them made

Strong red and blue -









Mostly 6500K -









Also see how different the AR mini looks under different lighting.

Here is Staurogyne purple under strong red and blue










And here is one of those same plants I pulled out, holding it under a 6500K bulb










I'll leave the "growth" debate to folks smarter than I am.  But if you want your plants to show vivid colors then you need strong colors in the light


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## OVT (Nov 29, 2011)

@burr740, for the Flamingos, is the PAR / PUR similar in both tanks at the crypt's level?

For sure - the more colorful the lights the more colorful the surroundings. Disco halls figured that out the late '70s and Las Vegas longer before that.


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## burr740 (Feb 19, 2014)

The "dull" tank is about 80 par at the sub and the colorful one is about 100


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## Immortal1 (Feb 18, 2015)

jeffkrol said:


> Well...part of that is the chart is probably "relative"......but no they aren't red rich.
> Whites have a lot of blue then you have the blue diodes.. Dim those a bit and red would "spike" a bit on the charts.
> There RGB part is a bit weak as well, in relation to the 6500k's.
> Point is if one can sacrifice PAR they can be richer in red..
> ...



Well put. I have a 24" model of Satellite Plus Pro running on my 20g low tech tank. I believe the white channel is down to 35-40%, green at 20%, red at 100% and blue around 60%. 

Tank looks decent, plants grow decent, and algae is about as expected for a mostly neglected tank (there is some). Using the Seneye, the PUR rating of that light is now close to that of my Radions - but at only 40PAR. The PUR rating is pretty sad when the light is at full power. Those results can be seen in my Seneye review thread.


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## Quesenek (Sep 26, 2008)

burr740 said:


> It will definitely change how the plants look to our eyes, which is just as important.
> 
> Check this out, 5 little Crypt flamingos. Pics were taken one day aft I got them in the mail from another hobbyist. They'd all been grown in the same tank and were in the exact same condition.
> 
> ...


Wow, if you didn't tell me the before and after pictures were of the same plant I never would have guessed.

Some one may be able to answer this for me -

I see those are T5HO bulbs, would the same be true for LED? 
I run a diy led build 7 LUXEON ES 6,500K stars and 2 LUXEON ES WARM WHITE which are placed more or less evenly over my 10 gallon and so far the plant growth even dimmed to ~20-30% power is explosive.
Would adding a couple each of red, blue and green luxeon rebel ES stars be able to get me colors like in the picture, or would it not be worth the effort?


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## Wobblebonk (Feb 13, 2018)

Quesenek said:


> Wow, if you didn't tell me the before and after pictures were of the same plant I never would have guessed.
> 
> Some one may be able to answer this for me -
> 
> ...


You can but there's a lot to consider like they don't all put out the same lumens or par at all... different voltage drops/max currents (you uhh probably don't need max)... want to be able to dim r g & b separately ideally... and probably gotta dim the whites even further~

You can certainly enhance the colors quite a bit though might take quite a lot of work to match his exact tones or something if that's your goal but individual dimming channels can help with that a bit.


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## jeffkrol (Jun 5, 2013)

Cheapest route would be a row of "full spectrum" on a dimmer..more in a bit


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## Quesenek (Sep 26, 2008)

Wobblebonk said:


> You can but there's a lot to consider like they don't all put out the same lumens or par at all... different voltage drops/max currents (you uhh probably don't need max)... want to be able to dim r g & b separately ideally... and probably gotta dim the whites even further~
> 
> You can certainly enhance the colors quite a bit though might take quite a lot of work to match his exact tones or something if that's your goal but individual dimming channels can help with that a bit.


Thanks, 
From my initial research into diy LED I believe I have the logistics of how I would need to expand my system for the different channels and dimmers/controller.
What I was really wanting to understand is, would I be able to get more or less the same color pop as the T5HO setup simply by adding RGB to my array? Of course with trial and error of the percentages of each channel.


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## Wobblebonk (Feb 13, 2018)

to truly match the exact same color pop may require separately tunable ambers cyans etc in addition to standard rgbs but you can get close yeah...

Like my colors are "enhanced" here








and under just whites my flamingo probably doesn't look nearly as nice. My %s of colors change during the day though so pics in my journal can be all over the damn place color wise.
I have only leds on this tank

I had way more than just rgbs here though like true blues, lots of cyan, a few limes & broad ambers, lots of reds and deep reds, some hyper violet... which the camera sees better than the eye...and a whole bunch of very dim whites.


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## jeffkrol (Jun 5, 2013)

Quesenek said:


> Thanks,
> From my initial research into diy LED I believe I have the logistics of how I would need to expand my system for the different channels and dimmers/controller.
> What I was really wanting to understand is, would I be able to get more or less the same color pop as the T5HO setup simply by adding RGB to my array? Of course with trial and error of the percentages of each channel.



White LEd's have plenty of green.
Most of the t5's that create that "pop" have little green, at least in comparison to "white" tubes..


This will explain a lot of it.

https://www.advancedplantedtank.com/light-buying.html












currently you are oly short some enhanced red/blue.. like I mentioned.
Keep in mind tubes use RGB phosphors so the band smears much more than red or blue LED's.
I'll ignore green LEd's for now though its more "like" a green phosphor than a narrow spectrum red/blue.


One of the reasons I mentioned the cheap "full spectrum 3W LEd's is the fact that they use a broad spectrum red phosphor w/ a blue pump for the emitter..
You can, more or less easily throw a bunch of LED colors to match a tube but simple RGB just won't do it..
It actually may be easier w/out white diodes. 



Anyways.. lots of ways to play..


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## Quesenek (Sep 26, 2008)

jeffkrol said:


> White LEd's have plenty of green.
> Most of the t5's that create that "pop" have little green, at least in comparison to "white" tubes..
> 
> 
> ...


Thanks for the reply,
By full spectrum LED's you mean something like the luxeon 2700k and 3500k or the luxeon sunplus cool white stars, correct?


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## jeffkrol (Jun 5, 2013)

No like these:
https://www.aliexpress.com/item/Led...-50w-led-grow-chip-50-driver/32600877555.html

You can find "3W" Bridgelux type all over the place.
They call them "full spectrum" but obviously aren't ..lack green.
Basically a royal blue emitter w/ possibly 2 red phosphor types..

Ther is sort of a fundamental difference between t5's and LEd's in the design.
It makes it difficult but not impossible to emulate each other.
Actually a lot is "manuf. choice" more than anything.
Now if one goes w/ a violet LED pump (emitter) and uses RGB phosphors ala T5's the "gap" is practically eliminated, but that is another story.
I've only played w/ a Finnex 24/7 but achieving the "grolux" look isn't too hard. Prob. is it's not a "subtle". Narrow emissions of LED "punch" more color w/ "gaps" that create a more stark look than the gentler look of tubes..AT LEAST in my opinion..
Guess the best way to describe it is it's "too glowy"..

Then there is the violet/cyan thing..


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## jeffkrol (Jun 5, 2013)

Should add it's not impossible w/ just rgb and relegating whites to be a fill color.. Kind of the opposite of normal..
SPECTRA

Playing w/ the above calculator gives one all sorts of ideas..
You just want to hit that purplly range (magenta) w/ enough green to not stray too far out of a decent (though far from perfect) CRI range..









Would love to get some spectrographs of "working" tube arrays.. Not like they use only one color.. 

I could gather a bunch..










Almost a perfect white but lowish in deep red.

"Improved" Wavepoint via lots of leds.


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## Ddrizzle (Jan 30, 2019)

jeffkrol said:


> Should add it's not impossible w/ just rgb and relegating whites to be a fill color.. Kind of the opposite of normal..
> SPECTRA
> 
> Playing w/ the above calculator gives one all sorts of ideas..
> ...


Can you do some scientific testing on growth and sell the above lights 🙂

Or just tell us what to buy?


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## jeffkrol (Jun 5, 2013)

Any light can grow plants..and people differ in their wants/needs..
Just try to prevent this:


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## Wobblebonk (Feb 13, 2018)

Is it possible for me to add sunplus nonsense or at least like... broader pc amber and lime? I'm just like... guestimating an approximation of an approximation with greens instead of lime (pretty sure it's RB with phosphors?) and approximating PC amber etc... and then I accidentally hit clear 

I think my lights are pretty high cri ... though definitely not in that pic while I'm blasting the reds and the whites are super dim.


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## rebelrebel (May 26, 2018)

What I've found is that I don't like the look of many of the commercial LED fixtures that I have seen. I have not yet seen ADA solar RGB or Twinstar SA which are some of the highest regarded.

I recently modded my Chihiro A series light and added a RGB dual row 5050 LEDs to the middle row at 100%. Instantly the AR mini was rendered in a better colour and the yellow look from the fixture was greatly reduced. I tried it only using 100% red and 100% red and the tank gets a slight purple tint with way better reds. Growth is similar because I had to adjust fixture dimming up to compensate for the lack of brightness with the 5050 LEDs.

You may need to experiment with a few different LEDs combos to see what you like. The ideal combo for plants may not be your preference.

Wish BML stayed in the aquarium space though. They would have figured out better spectra for us all....


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