Disclosed herein are handheld seed harvesters comprising: an elongate handle housing a driveshaft; a motor engaged with the elongate handle and the driveshaft; a reel rotatably and demountably engaged with the elongate handle and driveshaft by way of a quick-release system at an end opposite the motor, the reel having a plurality of filaments for removing seeds from plants extending outward therefrom; a hopper partially housing the reel for collecting the seeds; a handle assembly secured to the elongate handle and the hopper; and a shoulder strap securable to the elongate handle for carrying the harvester.