Method for coating bulk material comprises: starting a coating apparatus (1; 101) according to a start procedure on a discrete load of bulk material to be coated; operating the coating apparatus (1; 101) in stationary mode, by introducing a continuous flow of uncoated bulk material into the coating apparatus (1; 101) and obtaining at the outlet of said coating apparatus (1; 101) a continuous flow of coated bulk material having a predetermined stationary coating weight gain (W %); in which the coating apparatus (1; 101) comprises a first rotatable tubular container (2; 102) provided with a first dispensing device (5; 105) for dispensing coating material on the bulk material (M) in a plurality of internal successive adjacent spray zones between a first inlet and a first outlet of the first container (2; 102); a second rotatable tubular container (6; 106) arranged to receive bulk material (M) coming from the first container (2), the second rotatable tubular container (6; 106) being provided with a second dispensing device (9; 109) for dispensing coating material on the bulk material (M) in a plurality of internal successive adjacent spray zones between a first inlet and a second outlet of the second container (6, 106); conveying means arranged to convey the bulk material (M) from the first container (2; 102) to said the second container (6, 106); and in which the start procedure comprises in succession: dispensing coating material onto the load, maintaining the coating material inside the first container (2; 102) until coated bulk material is obtained with said predetermined stationary coating weight gain (W %); a transition phase to the stationary mode in which a flow of the load of coated bulk material is transferred from the first container (2; 102) to the second container (6; 106) and is supplied with an equal flow rate of bulk material to be coated to the first container (2; 102); dispensing coating material on the same flow rate of bulk material to be coated ente