It's been a few years since I've followed vertical farming, but I have recalled an argument being made that an artificial light source can be made efficiently b

It's been a few years since I've followed vertical farming, but I have recalled an argument being made that an artificial light source can be made efficiently by using a single-wavelength, super-efficient LED with a specific color that stimulates photosynthesis. On the other hand, I've also read (old, long-lost) sources that state that the energy cost per loaf of bread is about $10 for indoor farming, vs $5 for outdoor farming. These specialized lights won't save vertical farming today, but I will keep following the progress. If nothing else brings value to vertical farming, the fact remains that local food independence is valuable; growing food in a dense apartment or a dense city will pay dividends in the event of large-scale famine or civil unrest.