Best color temp for veg?

[bicit]

6500k crushes 5000k in my experience. Depends on what you are going for though. 6000-7000k will give dense shorter bushes. 3500k will result in taller lankyer/less bushy plants. For bigger plants 5000k may be a good choice, for a fast, dense, and extremely healthy canopy 6500k is very hard to beat.

Hopefully top bin, 70 CRI, 6500k CXB's will hit the market. Kingbrite was supposed to get a few 6500k CXB3590's. Drive one at 300ma, ludicrous efficiency

 

[Sativied]

Using a finely tuned spectrum is one thing.

Yes, and quality another. A finely tuned R/B (and w/e) spectrum doesn't equal by default quality light specifically in reference to sun/natural light, which has untapped advantages. As the name says:

http://en.wikipedia.org/wiki/Color_Quality_Scale
"the measure is a possible answer to the criticism of the widely used color rendering index."

However I'm not really that convinced that CRI plays a critical role in horticulture lighting.

Me neither, especially not about it playing a "critical role". Lights designed to approach natural light may have high CRI but not every light with a high CRI is automatically good. It's possible the role is still small because there aren't a whole lot of options available yet. If you can choose a higher CRI without sacrificing efficiency... you probably aren't going to notice a huge difference or any on a small scale going from 80 to 90 or so either way. Unless tested in an isolated scenario it's hard to measure differences especially on a small scale.

 

[heckler73]

Well that point would be true if CRI meant everything, or something so significant the rest becomes irrelevant, not just anything.

You're going to give me grief over my subjective use of grammar?

And even then CRI alone means very little without spectral distribution and ctt. CRI 98 still isn't going to produce great light and realistic colors for photography if the temp is too low for example.

PRECISELY! That was my takeaway from the analysis.
I'm interested in E = p^2/(2m), not "how does my chzbrgr look under this light".
However, I was under the impression the calculations work well for any temp under 5000K, which is what it is normalized to, in the first place. It's when going over 5000K which causes the equations to breakdown.

Although, who cares? There are better things to ponder than this...like designing drivers for secret LED limits testing. There are boundaries which need exploring. New life, and new civilizations...to boldly go where no plant has gone before.

 

[Rahz]

I associate high CRI with more deep red, so not sure it would be beneficial to veg. Would be beneficial to flower but there's an efficiency loss to figure in.

 

[churchhaze]

I associate high CRI with more deep red, so not sure it would be beneficial to veg. Would be beneficial to flower but there's an efficiency loss to figure in.

I was going to say the exact same thing. When talking about high vs low CRI with cxb and vero phosphor, the higher CRI versions all have more deep red at the expense of less amber.

 

[churchhaze]

Only difference is that I would think the deep red is more beneficial to veg than flowering while more amber is better for flowering.

 

[AquariusPanta]

Well here is the thing, Church ERR I mean Sativied, 4000K-5000K is associated with being the preferred spectrum/array when growing from seedling UP to, and not past, budding. This seems to be a generally accepted consensus, which took place on a recent thread. I'm interested in the 5600K array and wonder if it would be better than the mentioned arrays.

If we, including yourself, agree that this is the case, and we know that 4000-5000K arrays carry with them more blue than red, then why consider deep red, from high CRI, being worthy of our attention? I'm under the impression that the higher CRI tends to bring down the amount of other 'colors', including green and blue.

I'm merely looking to reinforce what I believe to know and to possibly learn more, all the while chatting with you .

 

[alesh]

Well here is the thing, Church ERR I mean Sativied, 4000K-5000K is associated with being the preferred spectrum/array when growing from seedling UP to, and not past, budding. This seems to be a generally accepted consensus, which took place on a recent thread. I'm interested in the 5600K array and wonder if it would be better than the mentioned arrays.

If we, including yourself, agree that this is the case, and we know that 4000-5000K arrays carry with them more blue than red, then why consider deep red, from high CRI, being worthy of our attention? I'm under the impression that the higher CRI tends to bring down the amount of other 'colors', including green and blue.

I'm merely looking to reinforce what I believe to know and to possibly learn more, all the while chatting with you .

Neither 4000K nor 5000K LEDs don't carry more blue than red.

 

[JimmyIndica]

4000 or 5000?

I noticed on the datasheets that efficiency doesn't jump much between 4000-5000 or anything higher, so pointless to choose 5000 based on efficiency.

5000 for veg and 4000 for full cycle,3000for straight flower.

 

[Doer]

Seems to me bigger plants carry bigger buds, and since I only want an 8 week veg period, warmer light makes the plants bigger, faster.

 

[AquariusPanta]

Neither 4000K nor 5000K LEDs don't carry more blue than red.

Ok, maybe I overlooked (or forgot) this graph.

Yes, Alesh, it would appear that there is more red (600-700nm) than blue (400-500nm) but does the frequency of each nm make a difference? Are there not differences in how plant matter absorbs lower and higher wavelengths? I know you have demonstrated your knowledge over this matter and have even gone as far as uploading your work, which I cannot find at the moment; you simply know more about this stuff than I do.

 

[alesh]

View attachment 3402351

Ok, maybe I overlooked (or forgot) this graph.

Yes, Alesh, it would appear that there is more red (600-700nm) than blue (400-500nm) but does the frequency of each nm make a difference? Are there not differences in how plant matter absorbs lower and higher wavelengths? I know you have demonstrated your knowledge over this matter and have even gone as far as uploading your work, which I cannot find at the moment; you simply know more about this stuff than I do.

You have to count area under the graph not to compare peaks.
If we treat each wavelength equally (as SPD does) then typical 5000K (CX/Vero) has almost same output of red (about 27%) and blue (about 25%) with the rest being green. If we were to talk quantal-wise (distribution of photons) then there would be even more red and less blue.

 

[AquariusPanta]

You have to count area under the graph not to compare peaks.
If we treat each wavelength equally (as SPD does) then typical 5000K (CX/Vero) has almost same output of red (about 27%) and blue (about 25%) with the rest being green. If we were to talk quantal-wise (distribution of photons) then there would be even more red and less blue.

Yes, the area under the graph tells all although I don't know how to tally each wavelength besides eyeing it.

 

[alesh]

Yes, the area under the graph tells all although I don't know how to tally each wavelength besides eyeing it.

That requires a little bit of work. I use the software DigitizeIt and then Excel for 'trimming'.

 

[Devildenis69]

Hi guys,

I am about to build a veg light, so I'm very interested in this

the deep red seems to be important during veg, less stretch, more roots ... but I'll get it from 660nm led, not higher cri ...
otherwise, the 4000/5000k seems to be the ticket

I've read about 15W/sqft, to use at the end of the veg, if you could give some examples of intensity used at different stages, it would be nice

 

[JimmyIndica]

OK, now take[/QUOTE]

Hi guys,

I am about to build a veg light, so I'm very interested in this

the deep red seems to be important during veg, less stretch, more roots ... but I'll get from 660nm led, not higher cri ...
otherwise, the 4000/5000k seems to be the ticket

5000. I am using x t e cool white for veg. I believe they are 5500.works very good. If your using it straight veg your good.they don't stretch much. Tight nodes!

 

[AquariusPanta]

Hi guys,

I am about to build a veg light, so I'm very interested in this

the deep red seems to be important during veg, less stretch, more roots ... but I'll get it from 660nm led, not higher cri ...
otherwise, the 4000/5000k seems to be the ticket

I've read about 15W/sqft, to use at the end of the veg, if you could give some examples of intensity used at different stages, it would be nice

I just want to verify with you that the Vero/CXA-B standard (W/sq. ft) is right at 30W/sq. ft, while the PAR W/sq. ft standard is around 15 PAR W/sq. ft.

I believe @churchhaze claims 12 PAR W/sq. ft works for him but he may have more to share in regards to that claim.

 

[Rahz]

Only difference is that I would think the deep red is more beneficial to veg than flowering while more amber is better for flowering.

I was under the impression that the Emerson effect would affect all stages of plant growth.

In regards to color temp, high CRI actually has more blue as a ratio, also has enough 730 for Emerson effect. 3000K 92-3 CRI might be ideal for veg and 2700K for flower... but the efficiency takes a nose dive. I'm pretty sure it's not worth it for that reason.

Of course if efficiency wasn't a concern and someone didn't mind packing in the watts...

 

[Devildenis69]

I just want to verify with you that the Vero/CXA-B standard (W/sq. ft) is right at 30W/sq. ft, while the PAR W/sq. ft standard is around 15 PAR W/sq. ft.

I believe @churchhaze claims 12 PAR W/sq. ft works for him but he may have more to share in regards to that claim.

I'm speaking about Watts, no PAR Watts ... I can't remember the right process for vero18 ...
I'm running about 30~40W/sqft of those for flowering , so I think for veg the standard should be way lower ...

Rahz: I believe church was speaking about phytochrome here.

 

[AquariusPanta]

I was under the impression that the Emerson effect would affect all stages of plant growth.

In regards to color temp, high CRI actually has more blue as a ratio, also has enough 730 for Emerson effect. 3000K 92-3 CRI might be ideal for veg and 2700K for flower... but the efficiency takes a nose dive. I'm pretty sure it's not worth it for that reason.

Of course if efficiency wasn't a concern and someone didn't mind packing in the watts...

Sailor claims that 3000K is good for all-around growing (seedling through budding) with respect to marijuana.

I, however, tend to think otherwise but this view of mine is based on little experience and instead speculation.

I thought the Emerson effect was for flowering only? Are you proposing it be used during vegetation? If so, I'd like to read what your thoughts are on this.

Here is an interesting breakdown on the subject: http://www.reddit.com/r/Head2HeadMG...red_light_the_emerson_effect_and_phytochrome/

I included the above link just for anyone who hasn't read it or needs a quick reminder .