The best time to fertilize your lawn is in the spring, when the grass begins to grow again. Look for a fertilizer that contains nitrogen, phosphorus, and potassium (NPK), and follow the directions on the package. Be sure not to overfertilize, as this can damage your lawn.

In the spring, you can apply fertilizer to your lawn when it starts to green up. You should also wait until after the last frost, which typically happens in late April or early May in most parts of the United States.