Fertilizing is complicated. One slip and you can turn a lush lawn into a dirty desert. That's why you don't want to overfertilize or fertilize at the wrong time. Take nitrogen, a main ingredient in most fertilizers. Too much can burn the grass brown. Some nitrogen fertilizers release quickly into the ground. Others release slowly. Make sure you get the right type for your lawn.
Fertilizers also contain salts, which in small amounts help grass to grow. But too much salt, as we talked about in that first entry, can damage roots and eventually kill the grass [source: Clark]. If you're going to fertilize, only do it twice a year in the spring and fall. You might want to add a bit of dolomitic lime every few years. That's because watering and fertilizing can turn the ground acidic over time. Lime restores the pH level while adding important minerals.