Abstract: A batch of seed materials is film-coated with a gas- and water-permeable, thin, adherent, uniform non-phytotoxic continuous surface film of a polymeric film-former, by (a) establishing and continuously maintaining a unit compact volume of moisture-containing viable seed materials in a state of continuous agitation and (b) continuously spraying and coating this unit compact volume of seed materials with an adjusted essentially steady predetermined flow rate of a liquid solution or suspension of a polymeric film-former, while simultaneously (i) continuously positively drying the coated seed materials by continuously directing a predetermined flow rate of a gaseous feedstream thereagainst that is at a controlled temperature less than that would adversely affect the viability thereof, (ii) continuously monitoring the temperature within the unit compact volume of seed materials in a state of continuous agitation and (iii) continuously maintaining a moisture content in the final product coated seed materials essent