A hopper spreader for installation on a vehicle has a flow regulator configured to regulate flow of particulate material from the container. The spreader has a conveyor mechanism for conveying particulate material to a spinner that distributes the particulate material to the surface over which the vehicle moves. The spreader also includes a flow regulation mechanism located between the particulate material in the hopper and the conveyor mechanism which is configured to regulate flow of material from the hopper to the conveyor mechanism.