A seed meter comprises a plastic casing defining a volumetric compartment and a singling compartment. The casing has three basic parts including the singling side, the volumetric side and the center portion. The basic parts are held together by integrally molded fastening assemblies. A slidable gate is mounted to two channels in the center portion for selectively directing seed into one of the two compartments. A metering drum having a volumetric section located in the volumetric compartment and a singling section located in the singling compartment is rotationally mounted to the casing. The metering drum is also plastic with each section comprising two identical pieces that can be mounted around a drive shaft.