As far as mmj adapting without 660> yes, it will adapt, BUT, it will be somewhat diminished. I doubt it could be able to synthesize what those spectrums 'feed' the plant, but it will learn to live without them
Wisely put ....
It happens with almost all wavelengths ...
Most plants will adapt ,even to some "extreme" or "odd " light configurations ...
Our " goal " here ,is not to examine each and every case of possible configuration ....
Furthermore ,in order to do so ,probably you need "guns" like the Heliospectra L4A ....
Neither the goal is to set the plant under "extremes " and see /note what happens then.....
(Plenty -if not most- of commercial "led grow lights " fall into that case /category ...
Their light ,in plenty of cases ,is ...kinda ...."extreme" ...
Either in power/'density' or spectrum ....
Or worse ? ...At both .... )
The goal is rather complicated ....
........
An
electrical energy efficient led fixture ,as
user -friendly as possible ,
designed to work in humid ( & hot >25°C ) environments ,
for
prolonged periods of timeand having such a
spectrum(s) in analogy with it's output power ,
so to be able to grow plants from start and being able to set the
"fundamental energetic & photomorphogenic basis" required ,
for a plant population ,in order to yield it's genetic "max potential " ......Or as close to that ,as possible .....
Along with the 'goal ' of "beating" the efficiencies of every other "conventional " light source ,used in horticulture ...
A 'secondary goal',somewhat .....
Mainly set by mj growers,all around the globe ....
As also ....
'Mainstream ' big greenhouses and horticulture industry ,demand some other "goals ",along with that ...
Slightly different ....
As the Sun still remains the primary light source in that field ...Production-wise ....
Leds just "aid " or " manipulate " ......
Seldom to Never ,are set to fully grow plants and produce crops ,by themselves ,as the only & solely light source .
And a lot of "confusion" and "misunderstandings " are born ,when this two ,totally different led applications ,'collide '...
( Leds used in
Growth Chambers -aka tent/room/cabinet/box/etc - vs Leds used in big scale
greenhouses )
They seem "identical " or even "same ' ....
Well,truth is ,that they are not ....
In plenty of ways ....