We've tried introducing plates a few times, but he just plays with the plate and then tries to throw it. Occasionally, we can get him to eat out of a bowl (in fact, sometimes the only way he will eat is if we let him pick the food out of a bowl). But for the most part, he still eats all of his food right off the tray (or off the table if we're at a restaurant). At what age did your LO start using a plate at mealtime?