A combine attachment for harvesting radish seeds and the like includes a fixed lower harvesting roll and an upper roll spaced vertically therefrom and mounted for spring-biased movement toward and away from the lower roll. The rolls are spaced a distance sufficient of split seed-containing pods, but not so close as to crush the seeds. The upper and lower rolls are carried by a frame mounted to a forward portion of the combine rearward of a pick-up belt and forward of an auger. The frame is detachably mounted to the frame by fastening means for easy attachment to and detachment from the frame. The split pods are conveyed to a thresher which separates the seeds from the preconditioned pods.