Wetter conditions in recent years have led to more questions about polymer-coated urea. Polymer-coated urea is a urea granule that is coated with a polymer that slows the release of urea into the soil. The most widely available polymer-coated urea product on the market for production agriculture is ESN. The most important thing to understand about polymer-coated urea is that it is not an inhibitor like nitrapyrin or DCD.