A particle feeder is provided for feeding small particles at a uniform low feed rate. In some embodiments, the particle feeder includes a primary reservoir, a secondary reservoir, and a valve. The primary reservoir encloses an internal volume for holding particles and defining a hole through a bottom surface thereof. The valve includes a rod enclosed within and extending through the volume defined by the primary reservoir. The rod is movable between an open position, wherein particles can flow through the hole, and a closed position, wherein the rod blocks the hole. The actuator controls the movement of the rod between the open position and the closed position. The secondary reservoir has an internal volume, and a conduit for connecting the internal volume of the secondary reservoir with the internal volume of primary reservoir, such that particles can flow from the secondary reservoir into the primary reservoir.