We all know fertilizer is food for grass. But not everyone knows how it works or what the three numbers on bags of fertilizer mean, or what the components of fertilizer do for your grass. The three numbers on fertilizer labels show the percentage of each of the three most important plant nutrients. Those are nitrogen (N), phosphorus (P) and potassium (K). So a 35-5-10 blend is thirty-five per cent nitrogen, five per cent phosphorus and ten per cent potassium. Nitrogen improves plant growth. Phosphorus stimulates the growth of new roots and helps with the strength of roots. Potassium strengthens the blades of the grass. It helps the grass resist traffic and disease pressure, and reduces moisture lost from evaporation. Polyon ultra high slow-release granular fertilizer is included in all of LawnSavers packages and can also be purchased separately .