Abstract: A process for producing polyurethane coated fertilizer granules having core granules in a rotating drum, wherein the drum has an inlet and an outlet and n application zones arranged along the longitudinal direction of the drum between the inlet and the outlet, n being an integer of at least 2 and wherein each of the application zones is followed by a curing zone. The curing zone after each application zone is arranged to allow an interval of 2-15 minutes, preferably 3-5 minutes, before the application in the successive application zone, wherein the polyol and the isocyanate are applied in the first application zone at a ratio of 0.5-4 wt %, preferably 1-3 wt % of the core granules.