[whatshisface]

Bad old farming: put plants in sun

Good new farming: put solar panels in sun, connect lightbulbs to solar panels, put plants under lights.

(Although it's not totally as daft as I make it sound, because it's theoretically possible to do frequency conversion in a way that makes all the energy of sunlight available to plants instead of everything but green.)

[shawn-butler]

That equation doesn’t balance out.

[whatshisface]

The physical limit to frequency conversion efficiency, whatever it is, is much higher than the efficiency of today's cost-effective solar panels plus cost-effective purple LEDs. So it may happen some day.