PROBLEM TO BE SOLVED: To provide a method for reducing a period of a harvest interval in strawberry cultivation, and retaining a yield of strawberry.SOLUTION: A method for promoting floral bud differentiation of strawberry includes using, as a nitrogen component to be given by basal fertilizer, slow acting coated urea fertilizer suppressing initial elution, planting a seedling permanently followed by putting into a condition of supplying the nitrogen component as little as possible for a specific period to maintain an internal nitrogen concentration of strawberry in a low state, and inducing floral bud differentiation of calyx such as primary axil calyx, in an early stage. Meanwhile, elution of the nitrogen component of the slow acting coated urea fertilizer is allower to start from a period when differentiation comes near so as to promote growth of stock and the calyx immediately. Furthermore, calyx differentiation is auxiliarily promoted by decreasing a culture medium temperature in a high temperature period and suppressing the temperature rise of a culture medium by using as fertilizer the slow acting coated urine fertilizer and absorbing heat when urine dissolves in water.
