Although the Purdue University Turf Program publishes information about how to fertilize your turf with nitrogen (N)-based fertilizers including standard rates and timings, there are many factors that influence these rates and timings. It is important that each turf area be fertilized according to its needs. For example, some areas require more nitrogen fertilization because they are highly trafficked and need additional nitrogen fertilization to promote growth and recovery. In another example, some older, well-established lawns may need less nitrogen fertilization because they have more organic matter in the soil (a natural source of some N fertilization). See the table below for more of these examples and make sure to customize your fertilization program to fits your turf needs.