Applications of lawn fertilizers and other lawn chemicals may directly run into the lake when it rains. Before conducting any fertilizer applications take a soil sample and determine what nutrients are necessary for a healthy growing lawn. These services are often offered at low or no cost through the local soil and conservation service or agricultural extension. Many companies are now offering phosphorus free fertilizers that are becoming ever popular in lake communities. To tell if the fertilizer you are using is phosphorus free, look at the N-P-K ratio, this tells you how much nitrogen – phosphorus – potassium is in the fertilizer. A ‘zero’ in the middle will indicate you have found a lake-friendly (phosphorus free) fertilizer.