A vertical tine tiller that includes a chassis, an engine attached to the chassis, a handle assembly extending from the chassis to allow an operator to control the tiller, and at least two vertically oriented tine assemblies. Each of the tine assemblies include a plurality of tines attached to a plate, wherein the tine assemblies are rotatable about a vertical axis such that the tines of each tine assembly provide a grinding path and adjacent tine assemblies have at least partially overlapping grinding paths. The tines are removably connected to the plate.