Vertical farming, the best solution to support an ever growing population or just a scam?
IMHO it has a lot of potential but not being able to grow grains really is something that should be tackled sooner rather than later. But I could see this being used by self sustaining communities to provide lots of food while using very little space. And it's technically more environmentally friendly than just using vast stretches of land to produce the same amount of food.
You could, for instance, shut down at the end of a cycle and do a thorough cleaning without using pesticides. Using steam, heat, and high-powered ultraviolet light, you should be able to effectively kill any pests or eggs that pests are leaving. Yes, pesticides are certainly less expensive in the short run, but in terms of long-term health for the entire planet, they're super-bad.