Abstract: A chemical dispenser is provided for hay balers and it comprises a hopper for the temporary storage of particulate chemicals. The hopper has a rounded bottom with a plurality of openings therein. The openings are selectively opened by 1/4 increments by a slider. The slider has an indicator which cooperates with 1/4 increment indicia printed on the front wall of the hopper for indicating the degree of opening thus permitting the operator to predetermine the quantity of particulate chemicals to be dispensed. For round hay balers, the dispenser has a blower and chemical directing lines.