NPK

Letters which are commonly used to refer to the Nitrogen (N), Phosphorus (P), and Potassium (K) content within a fertiliser. A percentage figure will be given for each nutrient to indicate how much is present within the fertiliser. Sometimes a fertiliser might also be referred to just three figures which relate to the NPK ratio; for example, 15:5:10; meaning the fertiliser contains 15% Nitrogen, 5% Phosphorus (as the oxide Phosphate though) and 10% Potassium (as the oxide Potash though). See Fertiliser Labelling as this explains the difference between the letters for the oxides and the elements which appear on a fertiliser product.