Opinions On Best LED White Lights

[NealCassady]

Hey everybody

Just wondering what types of white lights you guys think are best to include and in what ratios for
a) vegging
b) flowering
c) combo

If this has been discussed/answered and I just can't find it, you could just help me find it and I will be grateful. Otherwise I would love to hear your thoughts

thanks

 

[Hosebomber]

That is a very broad stroking question for a very complex subject. Are you referring to panels or COB's? The best COB's on the market currently are the Bridgelux Vero and Cree CXA series. In nearly all cases using warm white returns the best results. I've found nearly zero use for neutral white diodes.

 

[NealCassady]

Thanks for your response Hosebomber. I know you know your stuff - I have learned a lot from reading many of your earlier posts.

I realize I didn't give enough info. I am designing my own spectrum for a couple of LED lights with 50 x 3 w leds. I am wondering what type of white leds would be best to include for the three types of light I listed, i.e. what temperature (3500 k or 6500 k etc). I will only be getting two lights, just trying to decide how to configure them for maximum efficiency.

thanks for your help

 

[growgo]

veg more white or cool white which in shades of blue and flower more warm white in shades of red,better with some other spectrum led

 

[SloStoner]

hosebomber i'm sorry if i don't have as much exp as you but, i believe that using normal white (4k-5k) leds is very useful, or even better that using only red and blue led's witch, for me, don't really make sense. Let me explain.. white led's have ALL the colours in the spectrum,
but don't have a high peak in a colour. And this is the magic of white led's.. they give you all the colour temperature you need. But i am still not sure if i would use only neutral white for growing, would probably go 1/3 NW and 2/3 CW for veg and then add WW led's for flower and still keep the other colours to have a nice blend.

 

[Hosebomber]

All white LEDs have a blue peak and a red/amber/orange peak. If you break down the spectral distribution of the neutral whites, you will see a very low relative intensity for the red and blue with over 70% of it's light distribution in the green and yellow range. Feel free to test it yourself. I suggest the Cree XM or XP series or the Rebel ES series for the test. I've done both, which is why I made my previous statement.

 

[SloStoner]

so this means that neutral led's should be used only for supplemental lightining?

 

[Hosebomber]

Again, I would avoid green light almost entirely. This is a great doctoral thesis on green light. Read over that and the test results for all stages of growth. Green light inhibits leaf area, promotes shade avoidance and causes cell elongation/ internode length.

 

[SloStoner]

hosebomber, what mix of warm white and cold white led's would you reccomend for flowering?

 

[SloStoner]

and anonther question for you, Hosebomber. Would you reccomend growing with (2x2x8 box) 4x bridgelux vero 18 (30w) + 2 to 4 x 55w 6500k pl-l's ?

 

[Hosebomber]

If you're going for larger output higher amperage diodes, I'd use the CXA 3070's from Cree 2700k Z2 or Z4. They are much more efficient. Running 4 of those @ ~ 1.5A with a 10 or so 660nm a couple 730nm and maybe 1 Vero10 50c or a few lower blues 430/455.

 

[ecofrog]

I use t5 HO's for veg, 100% cool white. Ive been doing it for years and have never found a better system watt for watt and temp issues. I use virtually 100% HPS in flower as i have been doing it for years and have never found a better system watt for watt but temp sux. I found that the the shock of cool white to HPS helps in overall quality. TopLED and others will work ok but only if there is a heat issue whereas HPS has issues. I can only assume this changes in the near future but im sure i will revert back to HPS once summer heat issues pass, at least for this next season.

Im currently testing some cool white LED's with what seems like good results. They seem sufficient to replace t5's if the fixture design and spread can be worked out. And in the next few years with LED improvements coming down the line, specifically in white, less expensive and more output ought to bode well for using them in veg with less heat and watts than t5's.

Also in the big box stores, they are selling white LED's screwin's for ~ $1/watt and with a cheapo focus hood for just a few bucks, Ive just put a few into production this last week but they seem to be working ok.

But i have tested t5's in flower with warm, cool... doesnt matter as a HPS will blow them away with yield and quality watt for watt.

Thus i would say cool white is great for veg but as hose says, you gonna need alot more spectrum shift and power in the reds, even warm white's for flowering successfully.

One more thing, Ive also tested neutral white and have found them to way underperform cool or warm whites.

 

[ecofrog]

Again, I would avoid green light almost entirely. This is a great doctoral thesis on green light. Read over that and the test results for all stages of growth. Green light inhibits leaf area, promotes shade avoidance and causes cell elongation/ internode length.

I can only assume that gro light designers used green because of NASA reports. But now looking back and reading the follow up science, its obvious why G helped NASA... as hose has said many times, 2 or 3 colors aint enough to do all what a plant needs to do. Even adding G to B/R spectrum will help because there is so little there to begin with. This is the fallacy of doing a few tests and extrapolating out to the whole.

Hortilux spectrum has virtually no green but a crapper load of yellow and red, called 'redshift'. Also its my understanding that reflected yellows will generally fall into reds vs blues will fall into greens and yellows, perhaps this is another reason why HPS does so well.

topLED has too much green in their lights IMO. Its hard to kick old habits.

 

[Hosebomber]

If you re-read the NASA study, they didn't test green light at all. The statement from the study is the addition of green or white supplemental lighting would help the visual appeal of the produce and addition of white would help add in the identification of plant and nutrient problems that might not be noticed under red and blue only. It had nothing to do with growth rates.

TopLED does not have any green in their panels at all other than that released from the few whites. I can verify this 100% from their production schematics that I do have a copy of.

 

[ecofrog]

If you re-read the NASA study, they didn't test green light at all. The statement from the study is the addition of green or white supplemental lighting would help the visual appeal of the produce and addition of white would help add in the identification of plant and nutrient problems that might not be noticed under red and blue only. It had nothing to do with growth rates.

TopLED does not have any green in their panels at all other than that released from the few whites. I can verify this 100% from their production schematics that I do have a copy of.

Thats funny, your right now that i think about it about NASA report. I never read the actual report nor the years after followup but only read the summery which talks about appeal and id of problems.

TopLED lights have what appears an aquamarine (490 ish) and a yellowish green (580ish). Their website spec doesnt mention these spectrum on their fixtures. I guess the white and blue just 'look' green because the other diodes scatter the spectrum leaving only a small amount of green spectrum from the white and 470nm diodes which is what we see when we look at the them? cool physics...

Im considering getting some cool white SMD 5050 light bars and seeing how they stack up. I like the low wattage as it will be intercanopy and veg lighting. Are they even worth it? what kind of output should I expect?

Has anyone tried SMD 5050 white strips?

 

[guy4]

I am no expert but with the LED light I have, (veg-flower) there is no green at all, but a funny thing happened to me when I turned on a bright LED flashlight. The flashlight is white of course but under the LEDs at full spectrum it looks green even to the point of looking directly at it. I believe it's because of my eyes seeing all the other colors and not green so as it's a fundamental color in nature I see it as green. It's probably just an illusion but seems odd. It's pretty cool though! The flashlight does show how green the plants are and how bright the light system is. The flashlight is a 1W white LED and all I can see when pointed at the plants is a small very green spot on the plant right in front of the closest plant.