The displaced soil then disintegrates, topdressing your lawn. The cores can be broken down into your yard by irrigation, rainfall, or your lawn mower. Prepares grass for winter dormancy and a green spring.Before your cool-season grass goes dormant, make sure it’s in tip-top shape by pairing fall with fall fertilization. Aerating prior to fertilizing will help the nutrients soak in more effectively. Benefits pH modification.Applying lime or sulphurafter core aeration promotes the change of pH deeper into the soil profile.