What is described herein is an aqueous dispersion for coating water-soluble granules of a water soluble active agricultural chemical to substantially increase the rain fastness of the active. The dispersion includes by wt. (a) at least 0.1% of a polymeric anionic dispersing agent, (b) 5 30% of a water-insoluble, natural or synthetic inorganic or organic polymer, and (c) to 100% of water.
