The present invention relates to a fertilizer comprising at least one basic L-amino acid, such as arginine or lysine, wherein a substantial portion of the basic L-amino acid content is present as its monophosphate. The basic L-amino acid phosphate may be combined with a binder and/or provided with an outermost layer acting as a coating. The invention also relates to a method of enhancing the growth of a plant by making a basic L-amino acid phosphate available to the plant.