NPK

NPK is an abbreviation for the three basic fertilizer components: nitrogen (N), phosphorus (P), and potassium (K). The three numbers listed on the fertilizer label indicate, in order, the percentage content of nitrogen, phosphorus, and potassium, usually expressed as P₂O₅ and K₂O. This designation provides information about the product’s composition, but it does not specify the correct application rate or whether the fertilizer meets the needs of tomatoes. Fertilizer selection should be based on soil fertility and the stage of plant development.