D
daylighting
For veg, what ratio of the following would you pick? How about for flowering? Why?
620-630nm, 650-665nm, 440-450nm, 460-470nm.
620-630nm, 650-665nm, 440-450nm, 460-470nm.
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I wouldn't use Blue LED's. Accessory pigments in plants used for photosynthesis enjoy a broader range. You should consider full spectrum coverage, imo.
White LED's actually have a Blue chip that is covered with phosphor, much like how a fluorescent tube's inner surface is coated with a phosphor layer and has Mercury vapor inside it which is excited by the voltage across it emitting UV light. In turn, the phosphor layer is excited by UV-Blue/Green wavelengths and converts that energy into other colors. Some of the Blue light escapes, however, not all of it is converted in the process.
What I'm saying is you can achieve coverage of the 440-470nm range (and others) with White LED's. Warm White and Cool White LED's often have ~455nm chips, whereas Neutral White LED's can sometimes have ~445nm chips. A mixture of Warm White and Neutral White should cover all bases.
That said, many Warm White LED's don't have as much 630-670nm as we'd like. Supplementing with Red and Deep Red could be advantageous.
This sounds reasonable to me.
5 x Warm White (~2700k)
2 x Neutral White (~4500k)
2 x 630nm
1 x 660nm
I would use the same panel for veg and flowering, unless you have two grow spaces already. In which case you could go with:
4 x Warm White
2 x Neutral White
2 x Cool White
1 x 630nm
1 x 660nm
White LED's actually have a Blue chip that is covered with phosphor, much like how a fluorescent tube's inner surface is coated with a phosphor layer and has Mercury vapor inside it which is excited by the voltage across it emitting UV light. In turn, the phosphor layer is excited by UV-Blue/Green wavelengths and converts that energy into other colors. Some of the Blue light escapes, however, not all of it is converted in the process.
What I'm saying is you can achieve coverage of the 440-470nm range (and others) with White LED's. Warm White and Cool White LED's often have ~455nm chips, whereas Neutral White LED's can sometimes have ~445nm chips. A mixture of Warm White and Neutral White should cover all bases.
That said, many Warm White LED's don't have as much 630-670nm as we'd like. Supplementing with Red and Deep Red could be advantageous.
This sounds reasonable to me.
5 x Warm White (~2700k)
2 x Neutral White (~4500k)
2 x 630nm
1 x 660nm
I would use the same panel for veg and flowering, unless you have two grow spaces already. In which case you could go with:
4 x Warm White
2 x Neutral White
2 x Cool White
1 x 630nm
1 x 660nm
D
daylighting
Interesting. I currently use a lot of warm and cool CFLs, so maybe I'll just add some additional 630 and 660nm LED light to even things out. Thanks. 
EDIT: having a 12x3W LED bulb made for me; 2:1 ratio of 630:660. I think that should help even out the far red side of things!
EDIT: having a 12x3W LED bulb made for me; 2:1 ratio of 630:660. I think that should help even out the far red side of things!
SupraSPL
Member
WeedisGod has a point. Even though blue LEDs have a very high radiometric efficiency, if you are using neutrals and warms in the veg room they likely are already providing all the blue that is necessary so you could scrap the blues. If you can get you hands on the XML2 and run them a 1 amp or less you will have a cutting edge vegging lamp (42% efficient at 1amp, 45% at 700mA)
I would throw in some deep reds and maybe a few reds but 3000K warm white LEDs have peaks in the 630nm range and 2700K have peaks in the 640nm range, so I suspect adding deep red would be the most beneficial.
I would warn against having a lamp made for you. The LEDs used are of unknown bins and we should assume a very low radiometric efficiency, probably less than half that of the top bin deeps reds available (Luxeon ES/Oslon SSL). Also I suspect they will have a high junction temp. The efficiency of reds will really suffer as junction temps rises. I aim for 50-55c. Good luck with yr lamps!
I would throw in some deep reds and maybe a few reds but 3000K warm white LEDs have peaks in the 630nm range and 2700K have peaks in the 640nm range, so I suspect adding deep red would be the most beneficial.
I would warn against having a lamp made for you. The LEDs used are of unknown bins and we should assume a very low radiometric efficiency, probably less than half that of the top bin deeps reds available (Luxeon ES/Oslon SSL). Also I suspect they will have a high junction temp. The efficiency of reds will really suffer as junction temps rises. I aim for 50-55c. Good luck with yr lamps!
D
daylighting
You guys really know your stuff! I only know about Cree LEDs through one of my other obsessions (flashlights).
Dang, if I'd known it was all about the deep red, I would have gone with all 660s. Ah well! The light is only $15 or so so it's no major worry, and they are supposed to work fairly well. Time will tell!
For future reference, any suggestions for Chinese-based suppliers that use top quality BINs?
Dang, if I'd known it was all about the deep red, I would have gone with all 660s. Ah well! The light is only $15 or so so it's no major worry, and they are supposed to work fairly well. Time will tell!
For future reference, any suggestions for Chinese-based suppliers that use top quality BINs?
D
daylighting
After looking at the curves for 2700 and 6500 CFLs, I now wish I'd got 12 x 660nm 3W LEDs. Ah well, maybe I'll pick up another one.
