A method for depositing granules (48) onto a substrate (14) comprises providing a hopper (36) for granules with a discharge slot (46), moving a gate (50) across the slot to open and close the slot so that when the slot is open granules fall from the hopper and when the slot is closed granules are prevented from falling from the hopper, and detecting the speed of the substrate and controlling the extent of opening of the slot by the gate to meter the granules falling from the hopper in response to the speed of the substrate.