It's also possible to control a plant's life cycle, and harvest multiple times per year.
On the other hand, it's rare that the economics favor artificial light. Until energy becomes truly cheap, farms are mostly better off with the big fusion reactor in the sky.
Agriculture LEDs are designed to only emit 'growing' wavelengths. But the efficiency losses in converting sunlight to electricity via solar (20% typical) and from electricity to LED light (better, but not great) don't make it any better than growing in a glasshouse.
They try to make solar panels absorb across as broad a spectrum as possible, but they don't absorb everything by default. It's an ongoing research goal to add spectrum without increasing cost.
Would it be practical to make a vertical farm that takes advantage of the sunlight available, and just supplements it in the obscured areas? A vertical greenhouse kind of thing?
On the other hand, it's rare that the economics favor artificial light. Until energy becomes truly cheap, farms are mostly better off with the big fusion reactor in the sky.