This neutralizes the ammonia so that the grass can fill in. Bluegrass can fill in quickly but fescues will have to be reseeded. If you have dogs, check out the Crown III product information. It really saved me personally from a terrible dog path beside my deck. Keeping your lawn a bit long will produce stronger, healthier grass with fewer pest problems.
Longer grass has more leaf surface to take in sunlight.
This enables it to grow thicker and develop a deeper roof system, which in turn helps the grass survive drought, tolerate insect damage, and fend off diseases. Longer grass also shades the soil surface keeping it cooler, helping it retain moisture, and making it difficult for weeds to germinate and grow. You may have to readjust your mower most are set too low. It's also important to mow with sharp blades prevent tearing and injuring the grass. And it's best to mow often, because grass adjusts better to frequent than infrequent mowing.