A seed singulator (900) for use with a vacuum disk (200, 500) having a seed face (204, 504) and a shoulder (230, 530). The seed singulator has a first member (906) and a second member (922) supported by biasing members (926, 932). The first member has upper lobes (908, 910, 912) disposed at a radius of curvature slightly less than the outside radius (R2) of a row of apertures (208, 508) on a seed plane (222, 522) of the vacuum disk (200, 500). The second member has lower lobes (914, 916) disposed at a radius of curvature slightly greater than the inside radius (R3) of the row of apertures (208, 508). The biasing members permit the lobes to move with the seed plane and the shoulder as the vacuum disk rotates thereby maintaining their position with respect to the apertures.
