Work out lawn fertiliser quantity instantly with clear inputs, formula shown and shareable results.
Fertiliser is dosed on nutrient, not product: divide the nitrogen target by the product's nitrogen percentage to get the product weight. A 25 g per square metre annual nitrogen target from a 12% product means about 208 g of product per square metre, split across the season.
Fertiliser rate
product = area x nitrogen target / (N content); split across the number of applications
A single heavy dose burns the grass and leaches into groundwater. Three to four light feeds through the growing season give steadier growth and less loss.
Percentages by weight of nitrogen, phosphorus pentoxide and potassium oxide. A 12-4-8 product is 12% N, so it takes 8.3 kg to deliver 1 kg of nitrogen.