Fertilisers are usually designated by three numbers printed on their packaging. The three numbers refer to the percentage of the product in the container that is nitrogen (N), phosphorus (P), and potassium (K). The numbers are always in the same order: N;P;K. For example, if a 14 kilogram bag of fertiliser lists the N;P;K as 10:7:3, these numbers are the respective percentages of nitrogen, phosphorus and potassium. You should use a fertiliser with all three elements, but check with your local garden centre for some help with both the selection and calculations for applying fertiliser. If you are not satisfied with the results after fertilising your lawn, consult a turfgrass expert. There are many reasons why grass does not grow properly, and lack of sufficient nutrients is only one possible cause. You may be wondering why fertilisers are mostly N, P, and K, when there are 13 other elements needed for good turf growth. Two of these elements are carbon and oxygen, and these are taken from the air. Generally, the other 11 elements exist in sufficient quantities in most soils. In addition they are not needed in as great a quantity as N, P, and K.
