The disadvantage to mixing warm white with cool white

MrFlux said:

IMO just through every light you have at your plants...

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Because it would be more interesting, or because you think that I would get better results that way? I Don't mind loosing a few grams, just curious. I understand that a comparison between 3000k and 4000k would be more exciting for many people, but wouldn't it be a bit interesting to see how plants flower/grow under 4000k vs. 4000k + ~20% extra red.. Off course driven at a very similar wattage..

MrFlux said:

IMO just through every light you have at your plants...

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Think that I misread your message. Broken English, and a bit tired.. My original plan was to dim lights down anyways.. Do you think that more always is better? If I through all my light at my plants it will be ~7000 lumen/square feet..

But you are probably right.. Much light, much 4000k and much red..

Sorry CH if I've gone of topic with my personal topics!

I love the non-normalize graphs mr flux...
I have 5000k's I will be supplementing with red as a expirienment...but I should have gone 4K's instead. When there is a 4-6 week lead time one can think/buyers regret a lot.

I love my setup of 3 3000k to 1 5000k ratio. For me anyway it produces nearly identical but is more "frosty" then using a 3000k and supplement with blues and reds.

All top bin btw.

The 5000k leds some to use a slightly different mix of phosphors than 2700k, 3000k, 3500k and 4000k (all 80cri). The wide band output is centered at a lower wavelength than the 80 cri phosphor blends.

churchhaze said:

The 5000k leds some to use a slightly different mix of phosphors than 2700k, 3000k, 3500k and 4000k (all 80cri). The wide band output is centered at a lower wavelength than the 80 cri phosphor blends.

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By definition that is the way it should be...
CRI=color rendering index..."blankCRI" means blank% of the colors will be shown naturally like the sun does. It's actually based off a candle flame. Incandesents also have 100cri.
So 80cri's vs 70cri's will show 10%more colors accurately. With LED spectrums, much of that increase to the CRI come from the red/deep red zones.

I'm pretty sure they all have different phosphorus mixes...hence the different spectrums...it's all the same base. It's not just more of the same phosphor mix to change it.

I've found that the added blues or 5000k in my case to the all 3000k made the flowers themselves and the suger leaves much much frostier on the same strain in each setup of course.

purplegrower1 said:

I love my setup of 3 3000k to 1 5000k ratio. For me anyway it produces nearly identical but is more "frosty" then using a 3000k and supplement with blues and reds.

All top bin btw.

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Gaies used that 1:3 mix as well. It's spectrum is nearly identical to the glorious Vero 4000K

Yes yes I remember seeing his build awhile back. I'm thinking about adding one more 5000k so 9 3000k and 4 5000k and using the exact plants again (clones of same plant) to see if it slightly reduces stretch in early flowering and increase trichome production.

It has also been a guessed at number by many people on here like supra and myself what is the actual needed amount of blue during flower. I believe just using a 3000k by itself is somewhere around 14% blue. Which grows amazing plants but obviously more blue has seemed to have a better outcome. The question is just how much more blue?

What does better out come mean? Does it out yield the 3000K's? Or just produce shorter and potentially(need to see real lab test) frostier plants.
I have heard people say they are shorter. I don't have a problem with even the way hps grows plants. And even 3000k is less stretch than hps. I want my plants to grow rapid during the first couple weeks...then all that space will fill out. I hate using the word stretch...stretch implies too much growth that won't fill in. But like I said...even hps fills in all the way.
My apache's stretched less in the side by side...most likely the blue increase over hps. Still filled in all the way.

I guess my question is...what/why is it that people are wanting no stretch at transition? I pretty much only use the after flip growth...the rest is pruned. If plants aren't filling in throughout the grow, then it sound like there is not enough light/photons, not necessarily the spectrum.

Greengenes yea people have different takes on "stretch" when I say it I'm just referring to that extremely rapid growth that happens at the start of flower. The blue limits it and gas a tendency to grow branchier instead of taller plants. All my plants fill into basically solid colas since I mainline my plants In one room and do a SOG In the other so I basically just have colas. The added blue seems to not grow as tall in those 2 weeks after the flip but instead fills in more and creates bigger colas in my experience. As you stated without actually lab testing this is basically as here say but it's still better then nothing.

One would think that bulbs with a higher CRI would be more beneficial, is that not the case? Why would you settle for 80 CRI bulbs when 93+ CRI bulbs are readily available for the same price? If you can more accurately match the suns spectrum wouldn't that be better?

There are a few threads here where a member here (I think MrFlux? Correct me if I'm wrong) did the calculus and provided us with an absolute spectral power distribution chart, and it showed that the area under the curve for 93+ CRI was less than for 80CRI. (less efficient)

Reroll said:

One would think that bulbs with a higher CRI would be more beneficial, is that not the case? Why would you settle for 80 CRI bulbs when 93+ CRI bulbs are readily available for the same price? If you can more accurately match the suns spectrum wouldn't that be better?

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The are less efficient. In order to make them higher CRI they basically dim/filter down light to make the spectrum more even and full. Not a different phosphor of the same efficiency. And like said above...when you look at them as actual power not relative/normalized...you aren't really missing anything.

Anyone can look at the spec sheets and see the high CRI takes a big hit on the lumens. The gist of the thread makes sense. It's complicated but the question comes down to whether avoiding heavy green is more efficient for the plant. If there's an overall lumen loss, but the total lumens in red/blue increases it might be worth using two color spectrums. There might be a way to deduce that from the charts but I'm not sure how it would be done.

So, do the 2700s contain more red than the 3500s, or just less green/blue?

My current spectrum 3000/4000 at about a 2:1 ratio really puts a damper on the stretch. I've gotten maybe 8" in the first 4 weeks, and with scrog that's not much. Kinda makes me wish I had went with the 2700s, but if it were sacrificing lumens without increasing the total amount of red I might change my position.

Lumens doesn't tell the entire story. In general, a light that produces more lumens is usually better, but not all lumens are the same power, so it's not always true. 10,000 lumen of 660nm light is ~240W of radiometric power while 10,000 lumens of 555nm is only ~15W. It can be somewhat deceptive when comparing lights with very different spectral distributions.

What we really want is radiometric power, which is measured in watts, or photon flux, which is measured in umol/s.

Determining which wavelengths are more efficient for the plant is a lot more complicated than originally expected when led pioneers started out making R+B arrays. From all the results, it seems like R+B is good under low intensity, but at high intensities, "lower quality" wavelengths start to become essential for high yields and good health.

The main difference between the 2700k and 3500k, given the same CRI, is the amount of phosphor coating used, but the spectral peak of the wide band produced is not shifted to a higher wavelength. (at least not significantly)

All of the higher CRI phosphor blends have a wide band peak more toward the red than the 80cri versions. Adding more phosphor will not cause the band to move, and have minor affect on the bandwidth. The band only gets larger in both peak and the area under the curve (total power).

If you really want more red, you should get 660nm leds and produce that narrow band directly. The 2700k at 80cri gives you more "yellow" more than it gives you more red.

Rahz said:

Anyone can look at the spec sheets and see the high CRI takes a big hit on the lumens. The gist of the thread makes sense. It's complicated but the question comes down to whether avoiding heavy green is more efficient for the plant. If there's an overall lumen loss, but the total lumens in red/blue increases it might be worth using two color spectrums. There might be a way to deduce that from the charts but I'm not sure how it would be done.

So, do the 2700s contain more red than the 3500s, or just less green/blue?

My current spectrum 3000/4000 at about a 2:1 ratio really puts a damper on the stretch. I've gotten maybe 8" in the first 4 weeks, and with scrog that's not much. Kinda makes me wish I had went with the 2700s, but if it were sacrificing lumens without increasing the total amount of red I might change my position.

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it´s sometimes not only the phosphor

a warm white led. blue peak is here at 465nm.


a cold white led, CCT says: hue is a bit greenish. blue peaks here at 430nm


and these two in the mix...1CW : 3WW

Thanks guod

The different blue peak is a nice addition..no?
One thing I think I am missing out on a tiny bit. Narrow blue peak not necessarily a good thing.

But then again..gavita DE does just fine making beautiful colas with very little blue at all.



But for a closer to the sun spectrum...terpene expression etc... more bandwidth needed I presume.