The planters are about 20" tall. There is quite a bit of discussion on the web concerning the safety of using metals for edible planter beds. The consensus is that we're talking about iron and zinc (if using galvanized steel). Both of which are found naturally in soil. I would be more concerned about the plant seeds and/ or plant starts you use. More specifically: what is their origin, are they gmo or were chemicals used to cultivate them? I would ask similar questions concerning the soil you use with your edibles.