COB LED 3500k vs. 3000k veg/flower

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Chiefdog

Active Member
looking into 90cri w/ideal 3500k or 80cri 3000k cob led w/ bjbs. Looking for the best all around for both veg and flower. What is best here?
 
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CobGrower

Member
90cri put out considerably less lumens than 80cri. Get 90 if you want the color to look right to your eyes, otherwise pick 80cri if you want more light that the plants can use.

BXRC-30E10K0-D-7X-SE 3000 80 2100 12565
BXRC-30G10K0-D-7X-SE 3000 90 2100 10125
BXRC-35E10K0-D-7X-SE 3500 80 2100 12565
BXRC-35G10K0-D-7X-SE 3500 90 2100 10491

Last number is the lumens.
 
C

Chiefdog

Active Member
[
Can you explain to me why 80 is better than 90?

QUOTE="CobGrower, post: 13940791, member: 982514"]90cri put out considerably less lumens than 80cri. Get 90 if you want the color to look right to your eyes, otherwise pick 80cri if you want more light that the plants can use.

BXRC-30E10K0-D-7X-SE 3000 80 2100 12565
BXRC-30G10K0-D-7X-SE 3000 90 2100 10125
BXRC-35E10K0-D-7X-SE 3500 80 2100 12565
BXRC-35G10K0-D-7X-SE 3500 90 2100 10491

Last number is the lumens.[/QUOTE]
 
C

CobGrower

Member
Because you get more than 10% more light out of an 80cri vs 90 using the same amount of electricity. Who doesnt want more light for the same cost?

I thought 90cri would be better when I first got into Cobs but Growmau5 schooled me by showing the data sheets and explaining the difference. You want to focus on intesity first, once to get to proper intensity (800-1000 Par if not using co2) then you can tweak the colors if you want to try and eek out a little more, but most would do that by adding mono leds to the light, like extra 660nm reds. That is getting really nit picky though and 99.9% of people wont care to try and squeek out another 1-2% more yield by playing around with adding monos. Cobs do a mighty fine job all by themselves imo.

I have 90cri 2700k crees and 80cri 3500k Veros on my fixture and the difference in brightness is night and day and PAR readings confirm it for me, but my situation is a little more dramatic due to the different kelvin. I think 3k-4k cobs will work just fine and I doubt there is much of a difference in yield no matter if you pick 3k, 3500k, or 4k to flower with. I have vegged under 2700k and 4k and didnt notice any difference in things like stretch or internodal spacing. The extra light the 80cri will put out over a 90cri light will more than make up for any minor spectral deficiencies.
 
C

Chiefdog

Active Member
How did it work out for the better?

I’m just trying to get as much info as possible before I make a decision

QUOTE="theslipperbandit, post: 13943328, member: 909522"]Yeah that 90cri nearly had me fooled aswell but luckily im a cheapskate and for once it worked out for the better[/QUOTE]
 
Snaddehat

Snaddehat

Well-Known Member
CobGrower said:
Because you get more than 10% more light out of an 80cri vs 90 using the same amount of electricity. Who doesnt want more light for the same cost?
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It's a trade-off with 80 vs 90CRI. Slightly higher output with 80, and better flowering spectrum with 90. A lot of people are moving towards 90CRI with cobs and strips now.
 
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Chiefdog

Active Member
What do you mean by cobs and strips? And if you were to buy now which would you go with to use for both veg/flower?



QUOTE="Snaddehat, post: 13945450, member: 907959"]It's a trade-off with 80 vs 90CRI. Slightly higher output with 80, and better flowering spectrum with 90. A lot of people are moving towards 90CRI with cobs and strips now.[/QUOTE]
 
Snaddehat

Snaddehat

Well-Known Member
cob = chip on board , like Vero, Cree, Luminus and Citizen for instance.

strips/boards, as in mid-powered led strips using the same tech as cobs. https://horticulturelightinggroup.com/

Currently, i'm using Cree CXB3590 3000K 80CRI for veg, and Luminus CXM-22 3000K 90CRI for flower. Both could do both veg and flower. Strips are easier to handle when it comes to heat, and spreads light more evenly. I'm loving my cobs, and i know i would be loving strips/boards as well. You can't go wrong with either
 
thetr33man

thetr33man

Well-Known Member
If you want shorter plants and denser buds go with 80, if you dont mind a few extra inches and larger flowers go for 90. 90 also finishes faster, up to 2 weeks in some side by side comparison grows. Buds end up with similar weights, Im guessing if mold is possibly an issue for you, 90 might be better in that regard also. Ive used 70, 80 and 90 and prefer 90 myself...
 
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Chiefdog

Active Member
Ok so 90 but out more and are all around better for better results is what you’re saying? I’m spending some good money building a 12 COB light so i just want to make sure I’m spending it right to get the best all around veg/flower setup
 
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Ryante55

Well-Known Member
CobGrower said:
Because you get more than 10% more light out of an 80cri vs 90 using the same amount of electricity. Who doesnt want more light for the same cost?

I thought 90cri would be better when I first got into Cobs but Growmau5 schooled me by showing the data sheets and explaining the difference. You want to focus on intesity first, once to get to proper intensity (800-1000 Par if not using co2) then you can tweak the colors if you want to try and eek out a little more, but most would do that by adding mono leds to the light, like extra 660nm reds. That is getting really nit picky though and 99.9% of people wont care to try and squeek out another 1-2% more yield by playing around with adding monos. Cobs do a mighty fine job all by themselves imo.

I have 90cri 2700k crees and 80cri 3500k Veros on my fixture and the difference in brightness is night and day and PAR readings confirm it for me, but my situation is a little more dramatic due to the different kelvin. I think 3k-4k cobs will work just fine and I doubt there is much of a difference in yield no matter if you pick 3k, 3500k, or 4k to flower with. I have vegged under 2700k and 4k and didnt notice any difference in things like stretch or internodal spacing. The extra light the 80cri will put out over a 90cri light will more than make up for any minor spectral deficiencies.
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if your theory was correct you would have seen better growth from the 4k it puts out more light than the 2700k so you kinda proved your own theory wrong
 
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Ryante55

Well-Known Member
CobGrower said:
My first grow was with 90cri Cree 2700k, second with Vero29 80cri 3500k. First harvest = 1lb, second harvest, same electricity, 1.5lb, combined them both, 2.5lb. Very consistent results. Proved my theory right in my grow.
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So with 10 percent more light you got 50 percent more bud that makes your theory hold up even less.....again different color temps so maybe 20 percent diff? I wouldnt call your 2 random grows a test I've seen side by sides that came to the opposite conclusion. If you have a side by side with the same color temp and different cri I would love to see it. Also the chips must be the same brand for the test to be anywhere close to accurate
 
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Ryante55

Well-Known Member
CobGrower said:
Not going to debate my results with a keyboard warrior on the internet. LOL. I know what I got, why I got it, and the science behind it. Sorry that you don't.
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Just making sure this poor guy doesn't take your word as gospel a couple random grows from you shouldnt be a factor in his decision
 
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Ryante55

Well-Known Member
CobGrower said:
Not going to debate my results with a keyboard warrior on the internet. LOL. I know what I got, why I got it, and the science behind it. Sorry that you don't.
Click to expand...
Oh an this keyboard warrior probably has alot more cob experience than you but I don't try to pass off my grows as a "cri test" to many factors between different grows
 
thetr33man

thetr33man

Well-Known Member
Id probably do cxm22s or 32s, 90cri 3500k if I was going to build a light, if I was going to do 80cri I would drop down to 3000k.
 
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