Best COB (CXB3590) color temperature for flowering?

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Dodongo

Well-Known Member
Hi All,

Curious to what color temperature COBs everyone is using for for flowering. I'm making a CXB3590 array and not sure which color to use. It seems like a good portion of people here use 3000k while others use 3500k (some even 4000k). Any suggestions for the optimal flowering color temp?

Thanks in advance!
 
BecauseIgotHigh

BecauseIgotHigh

Well-Known Member
I will say 3000k, because it has more 730nm for flowering. I saw two graphs of cxb3590, 80cri & 90cri. 90cri the 730nm wavelength was very high. 3000k-4000k, veg & flower all rounder. 3000k cause more stretch, 4000k tighter nodes???? I still prefer the 3000k, already got a 5000k for vegging.

From a book that I'm reading;

Plants absorb or reflect most wavelengths of light. Far-red light passes through; therefore there is a higher ratio of far red to red light in the shade. Plants use the FR ratio to detect being in the shade; they grow longer stems to try to reach the light.

FR promotes elongation; red and blue promote stout stems.
Red and FR light play a role in controlling flowering and other developmental processes red light at 680nm stops plants from flowering. FR light at 730nm just beyond visible red on the spctrum, promotes flowering in the absence of red light.
 
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ttystikk

ttystikk

Well-Known Member
I'm looking at the 90CRI 4000K COBs for bloom. I'm growing vertically and need to keep stretch under control.

I'm currently running Philips 860W CDM lamps, and they are 4000K and 92CRI. I'm extremely pleased at the results and so I'm going to stick with a similar spectrum in LED.
 
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PurpleBuz

Well-Known Member
ttystikk said:
I'm looking at the 90CRI 4000K COBs for bloom. I'm growing vertically and need to keep stretch under control.

I'm currently running Philips 860W CDM lamps, and they are 4000K and 92CRI. I'm extremely pleased at the results and so I'm going to stick with a similar spectrum in LED.
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generally the higher CRI (90 cri) are significantly less efficient than the more standard 80 CRI. It has to do with phosphor technology and what it takes to produce a wider fatter spectrum. In fact I'm willing to bet that an 80 CRI 3500K or 3000K will out produce a 90CRI cob with quality flowers.

If you want the fat spectrum of a 90 CRI without sacrificing the efficiency then add a few royal blues, and Deep Reds to a 3500K or a 3000K cob or mix in a few 65K cobs with 3K cobs.
 
ttystikk

ttystikk

Well-Known Member
PurpleBuz said:
generally the higher CRI (90 cri) are significantly less efficient than the more standard 80 CRI. It has to do with phosphor technology and what it takes to produce a wider fatter spectrum. In fact I'm willing to bet that an 80 CRI 3500K or 3000K will out produce a 90CRI cob with quality flowers.

If you want the fat spectrum of a 90 CRI without sacrificing the efficiency then add a few royal blues, and Deep Reds to a 3500K or a 3000K cob or mix in a few 65K cobs with 3K cobs.
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If I were to stick with just one SKU for my COB choice in order to get a better quantity discount, what would be your choice?

Thanks for the tidbit about the high CRI being less efficient. I don't suppose I absolutely need it, I'm just trying to replicate what I'm happy with now.

I'm leaning towards higher Kelvin specs because I like to keep stretch under control.
 
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PurpleBuz

Well-Known Member
ttystikk said:
If I were to stick with just one SKU for my COB choice in order to get a better quantity discount, what would be your choice?

Thanks for the tidbit about the high CRI being less efficient. I don't suppose I absolutely need it, I'm just trying to replicate what I'm happy with now.

I'm leaning towards higher Kelvin specs because I like to keep stretch under control.
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i'd get the 3k and supplement.
 
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PurpleBuz

Well-Known Member
JimmyIndica said:
GG uses 3500K in the PLC.Dont know what CR but its a good one. I am sure..I think that's 3070 3500 though?
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standalone without any supplements 35K is great, but I'm not GG, and the question was "what would be your choice?"

Generally GG doesn't use high CRI cobs, rather standard 80cri. but he hasn't released the final specs yet for the PLC light afaik.
 
JimmyIndica

JimmyIndica

Well-Known Member
PurpleBuz said:
standalone without any supplements 35K is great, but I'm not GG, and the question was "what would be your choice?"

Generally GG doesn't use high CRI cobs, rather standard 80cri. but he hasn't released the final specs yet for the PLC light afaik.
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I would choose this one then CXB3590 N0HCB30G
 
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Dodongo

Well-Known Member
Thanks for the input everyone. I'm going to go for the 3000k's since Jerry has those in stock. I'll probably start phasing in a couple higher K COBs once I get these first few arrays going. The numbers the 4000k's do look pretty nice though.
 
CobKits

CobKits

Well-Known Member
JimmyIndica said:
GG uses 3500K in the PLC.Dont know what CR but its a good one. I am sure..I think that's 3070 3500 though?
Click to expand...
im not going to speak for him (i think he has me on ignore and probably wont see this) but i suspect because it also does a good job at vegging. for dedicated flowering 3000K might edge it but youre really on the curve of lumens vs spectrum at that point, the PAR is similar across many chips from 2700-4000.

i will say 3000K 90cri is my best seller followed by 80
 
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PhotonFUD

PhotonFUD

Well-Known Member
I am with the lower CCT, more red photon camp.

But in all fairness, you are going to have to find out what is best for what you are growing. Some plants might like more blue than others in which higher CCT will be better.

If you wanted to get an idea beforehand, a quick (if there is such a thing) way is to use a couple of A19 in different CCTs on each side of the plant during a flowering cycle. Skip the scientific analysis and use your own opinion to determine which, if either is better.

You shouldn't have problems with either in any case. Plants will use all PAR.
 
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