A fertilizer composition is adapted to stage the controlled release of nutrients such that the composition need only be applied once in a plant's growth cycle, but with individual nutrients releasing at predetermined, staged intervals targeted to the precise needs of plants. Timed release particulate materials are blended to form the composition. The nutrients include a magnesium source (Mg), a potassium source (K), a nitrogen source (N), and a phosphate source (P). The composition is adapted to release each fertilizer nutrient over a period most beneficial to plants' physiological growth.