Picking up leaves
Abundant in moist, heavy soils, earthworms are a natural component of healthy lawns. Their diet of dirt, organic matter, and excrete plant litter in the form of a rich digestive by-product called castings. These small, hardened piles are scattered across the ground. While initially felt underfoot, castings will eventually break down, providing your lawn with a dose of natural fertilizer. You can also buy worm castings for this purpose.
In addition to providing nutrients for plants, earthworms aid in thatch decomposition, improve soil aeration, and increase water penetration through their extensive burrowing.