You're mixing up Boric acid and Diatomaceous earth. Boric acid works by the overloading the roach's weak digestive system, it also kills ants. They key is to ge

You're mixing up Boric acid and Diatomaceous earth. Boric acid works by the overloading the roach's weak digestive system, it also kills ants. They key is to get pure, do not get the formula with the 'attractant'. Diatomaceous earth needs to be 'food grade' there is a much more dangerous form for pool filters. But that stuff is more for out doors as a perimeter defense and maybe garages and say exterior basement stairs. Boric acid works well but the true solution to urban roaches is exhaustive sealing all your walls, baseboards, electric recepticals, any entrance of piping and weatherstripping your exterior door. I keep boric acid on my apartment door stoop. Boric acid is great in they cant evolve against it and they eat their dead so one east some and it takes out 5-10 others back in the nest. But the key is the effort to seal your walls, and I've encountered very challenging situations with metal cabinets in a friend's place. I got this experience living upstairs from an South Asian Deli in Manhattan. But I'd say I've been roach free 19 out of 20 years here. Two outbreaks, one I broke down and got an excellent exterminator, which I'd normally move heaven and earth to avoid. But we get less than about 6 per year total. as their hiding spots are death traps and we do keep our kitchen shelves and cabinets cleaned out periodically.