Mixing colorspectrum samsung diodes.

Hi, I want to customize two 1000w fixtures and my Idea is to mix
3000k lm301h evo chips with
5000k lm301b chips
with added 660 and some 730nm.

but what ratio between 3k and 5k is ideal? how many % of white led should be at what kelvin?
Would appreciate any input! I want to flower under this fixture mainly, I dont care about veg specific spectrum!

Thanks

50-50 3k to 5k is exactly the same as 100% 4k

@Rocket Soul , any concensus on the subject?
I know it's been discussed many times

coreywebster said:

50-50 3k to 5k is exactly the same as 100% 4k

@Rocket Soul , any concensus on the subject?
I know it's been discussed many times

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As far as i know youre correct but might be a bit different if using different make diodes.
This is based on some tests posted long time ago from hlg: 4k and 3k 50-50 results in exact 3500k.

I think the reason we see 5k/3k mix is for fabrication/comercial purposes: if you buy 5k and 3k as a company you can then make something closer to 5k or 3k by mixing proportions. If you go straight for 4k you cant play with the spectrum in the same way.
But there is no extension of spectrum, or "5k for veg/3k for flower" validity; the plant cant chose which light hits its leaves for obvious reasons.


Though reading back to OPS post, its evos veraus regs: id probably go for something with a bit more 3k evo than 5k regs to equalize the blue peaks, maybe around 60-40 to 70-30.

But at the same time id say that if i were making a custom spectrum id probably use different whites, im not super happy with how approx 4k + reds grow to be honest. Buds get nice and dense but not the same flavours as otger of my lights.

So thank you for quick reply and I guess it has been discussed somewhere many times, appreciate your input anyway!

I will ask to make
60%-EVO3000k and
40%-5000k301b
225whites (100x5000k+125x3000k), 40x660nm, 23x730nm

But @Rocket Soul What other lights produce better flavours? I have the possibility to play with the ratio of leds. maybe I sould go 75%301h and 25%5000k? I heads a student from Utah university stating that light intensity is more important than spectrum, thats why I was thinking 50%/50% was a "sweet spot" so to say.

What would be a good ratio if using lm281b+pro and 3000k+6500k spec. 60/40 or even more 3000k? is the difference in photons between 3k and 6.5k that much?

Some Fixtures on ali are selling green diodes in a 36% and 23% ratio(red and blue are free variable). they call it nasa science...

propaganja68 said:

So thank you for quick reply and I guess it has been discussed somewhere many times, appreciate your input anyway!

I will ask to make
60%-EVO3000k and
40%-5000k301b
225whites (100x5000k+125x3000k), 40x660nm, 23x730nm

But @Rocket Soul What other lights produce better flavours? I have the possibility to play with the ratio of leds. maybe I sould go 75%301h and 25%5000k? I heads a student from Utah university stating that light intensity is more important than spectrum, thats why I was thinking 50%/50% was a "sweet spot" so to say.

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Im not sure what to say cause my advice would go a little bit against what most people would advice. Yes, for yield efficiency or better said light intensity is more important but the differences in efficiency are quite small, i prefer to just add a little extra wattage to get the intensity and spectrum i like.
Id go for 2700k 90cri + 660 + 400nm personally for flower.

My general sort of reasoning is that low green, high red and wide blue (as in throwing some near uv or violet in there) is better for quality, and the more green you add the better yield and density but with a slight loss in flavours.

The ratios you quote above: i dont have direct experience of growing with evos so i cant say a 100% but the numbers you quote seems ok to me.

3500k evo \ 3000k 301b + 660nm

brazzik25 said:

Frontiers | The role of red and white light in optimizing growth and accumulation of plant specialized metabolites at two light intensities in medical cannabis (Cannabis sativa L.) (frontiersin.org)

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Thanks for posting this, very nice.

Rocket Soul said:

Im not sure what to say cause my advice would go a little bit against what most people would advice. Yes, for yield efficiency or better said light intensity is more important but the differences in efficiency are quite small, i prefer to just add a little extra wattage to get the intensity and spectrum i like.
Id go for 2700k 90cri + 660 + 400nm personally for flower.

My general sort of reasoning is that low green, high red and wide blue (as in throwing some near uv or violet in there) is better for quality, and the more green you add the better yield and density but with a slight loss in flavours.

The ratios you quote above: i dont have direct experience of growing with evos so i cant say a 100% but the numbers you quote seems ok to me.

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I understand what you are saying, thanks! I think you might be right, I need to try it out myself. now I already placed a sample order but I think I will order later another 1-2 samples with the specs that you and brazzik25 suggested, they both sound super reasonable! people grew great bud under red HPS spec, maybe its already a good starting point for great quality! Have to find out how much difference in yield is between the specs and if I can smell the difference too. thanks for sharing your oppinion!

brazzik25 said:

3500k evo \ 3000k 301b + 660nm

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This sounds super logical to me and I will try this out in a later order for sure! Thanks, a lot of red and a wide blue sound so right to me, everything else is there anyway but only this two specs are driving most photosynthese activity, as far as I know. Nobody suggests any 730 or 390nm, and I think its much more conveinient to work with separate Uv-bars if needed. thanks man!

propaganja68 said:

I understand what you are saying, thanks! I think you might be right, I need to try it out myself. now I already placed a sample order but I think I will order later another 1-2 samples with the specs that you and brazzik25 suggested, they both sound super reasonable! people grew great bud under red HPS spec, maybe its already a good starting point for great quality! Have to find out how much difference in yield is between the specs and if I can smell the difference too. thanks for sharing your oppinion!

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Did you have a look at the study brazzik posted? There some info regarding spectrum and how much it moves the dial: honestly, not a lot. The one thing that correlates more with yield is wattage and how much light hit your cannopy. A really souped up spectrum may move that 10 to even 20% but since you usually pay a efficiency price for tweaking your spectrum sometimes it could even be a wash. The 2700k 90cri is more productive per unit of light but since its a little less efficient than say 4000k (by about 10%) you might end up with the same amount. But youll have nicer quality and a lower ceiling. Plant optimized spectrum seems to have higher max yield, and also you can always overcome a slight efficiency loss by applying a little more power.
If you get those lights, please post your grow
If youre antsy about posting it hit me up on pms.

I have some citicen 2 cobs of 2700k cri 97 and a pink PRB, I have noticed faster flowering, the maturation ends sooner.

54 days of flower since seed, now I have grown the same variety from clone again and with another 5000k+3000k and 660nm panel and the flowering is getting longer.

igna said:

I have some citicen 2 cobs of 2700k cri 97 and a pink PRB, I have noticed faster flowering, the maturation ends sooner.

54 days since seed, now I have grown the same variety from clone again and with another 5000k+3000k and 660nm panel and the flowering is getting longer.

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Youre in Spain, right? High cri always seemed more popular there, cannabiscafe forum is full of it. Did you see difference in yield and density aswell? If its still in progress update let us know later i love picking up peoples experience on spectrum differences.
Imo 97 cri is not worth it though over 90 cri.

Rocket Soul said:

Youre in Spain, right? High cri always seemed more popular there, cannabiscafe forum is full of it. Did you see difference in yield and density aswell? If its still in progress update let us know later i love picking up peoples experience on spectrum differences.
Imo 97 cri is not worth it though over 90 cri.

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If I am from Spain, I know these cobs are somewhat old and are not the most suitable, but I bought them to carry out tests and comparisons, at cannabiscafe we have done many tests with spectra and clones. You find few differences in the production, but in the flowering time and it can be shortened and lengthened depending on the spectrum or that is my impression. I have also carried out tests with cobs for butcher shops with a lot of red and I have noticed something similar, an earlier maturation.

igna said:

If I am from Spain, I know these cobs are somewhat old and are not the most suitable, but I bought them to carry out tests and comparisons, at cannabiscafe we have done many tests with spectra and clones. You find few differences in the production, but in the flowering time and it can be shortened and lengthened depending on the spectrum or that is my impression. I have also carried out tests with cobs for butcher shops with a lot of red and I have noticed something similar, an earlier maturation.

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When it comes to benefits of high cri growing its important to understand its not the higher cri value that affects the crop, its the red content, how it peaks around 630, close to chloropeak, and not the actual cri number. In my understanding: 97 cri doesnt change red content very much from 90 cri, its mostly details around the cyan range.

There are a few old threads if you still have interest in this, its where i started to take note on this spectrum. @Rahz made this test thread, a pity that there wasnt any pics.

Psuagro had this thread testing the meat chips of vero, i assume the same type of butcher cobs you talked about:

Malocan also used them for a very nice light but only had a little info on them:

Malocan also posted this which i found very interesting: what happens to the spectrum if you measure it behind a leaf, what has been absorbed? Very interesting to me.


This has been retested later by prawn connery with slightly different result but the original spectrum was also different and mono supplemented.

Theres a lot of enjoyable reading from our old members