In the late fall, early winter, apply a well screened compost to your lawn to protect and nourish your grass in the spring months. Spread the compost using the back of a rake until the compost is about 1/3 of an inch in depth (any deeper and you may smother your grass). It should settle on the soil between the blades throughout the winter, and once spring comes, the rains will spread the nutrients throughout your grass, fertilizing it in the coming months.