Abstract: A method of forming a methylol urea prepolymer and a particle coated in with the prepolymer. The method involves providing a source of methylol urea and a source of aldehyde and reacting the urea and the aldehyde in the presence of an excess of urea to form the methylol urea prepolymer. The coated particle is preferably a controlled-release fertilizer particle. The particle is a substrate coated with a substantially uniform coating comprising a total nitrogen content ranging from about 39N to about 42N. The coating includes a low molecular weight methylene urea compounds.