Now ...For the "W&R school " DIYers ...
It's good to keep in mind several basic " facts ",when building a W&R led horticultural light ....
-Modern white leds ( "Phosphor Conversion " and not " RGB chip " ) are not made for plant cultivation .
They are made to serve different applications ,regarding human vision and only .
So ,there is not such a thing as the "perfect white led for plant growth " .
Different kinds of White pc leds ,have to be used to achieve a plant cultivating light spectrum ...
-Some amount of red leds ,at the region 640-660 nm ,has to be used ,in order to supplement ,
the "deep red" part of the white light ...( Thus turning it also into pinkish -peach colored ).
Less while vegging ,more while flowering/ fruiting ....
The basic White leds that can be used for horticultural purposes :
Neutral White 4000-5000 K .
If of low-mid CRI type ( 60-80 ) ,then this led ,most probably is made out of a blue die at 430-450 nm and a broadpeak green/yellow or yellow phosphor .
Basic provider of blue & green wls ,useful at vegging stage of a plant .Different bins/ temperatures ,provide more or less blue .
If of High CRI (>90) type ,then this led is most probably made out of a blue die at 440-460 nm and a mix of two phosphors ( green + red ) .
Still a basic provider of blue and green ,but now it provides some red wls also ..( usually at 620-640 nm range )..
But with a cost in efficiency ... (Slightly less efficient -radiometrically always - than low-mid CRI NWs ..)
Warm White 3000-2700 K
If of low-mid CRI type ( 60-80 ) ,then this led ,most probably is made out of a blue die at 440-460 nm and a broadpeak yellow or yellow /amber phosphor .
Basic provider of yellow/amber (580-620 nm ) ,probably useful at both vegging & flowering stages, of a plant .
Different bins/ temperatures ,provide more or less blue .( and yellow/ambers of course ..)
If of High CRI (>90) type ,then this led is most probably made out of a blue die at 440-460 nm and a mix of two phosphors ( green + red ).
Basic provider of red,deep red & far red wls ,useful at flowerin/fruiting stage of a plant .Different bins/ temperatures ,provide more or less red/deep red/ far red wls .Also,slightly less radiometrically efficient than low-mid CRI WWs ...