A granular fertilizer product having at least two sources of boron having different solubilities to tailor boron availability during the entire growing season of a plant, while reducing the risk of boron toxicity. A first source of boron can include a sodium-based or highly water soluble boron compound such as sodium tetraborate and/or boric acid, while a second source of boron can include a calcium-based boron compound such as colemanite (CaB3O4(OH)3.(H2O)) (e.g. when the carrier fertilizer is N- or K-based) and/or boron phosphate (BPO4) (e.g. when the carrier fertilizer is P-based). The solubility of the first source of boron is higher than the solubility of the second source of boron such that the sources of boron have different release rates into the soil.