If the grass has grown tall, however, it is best to shorten it gradually. For example, if the grass is taller than 5 inches, cut off about an inch when you first mow. Then, mow again a few days later, cutting the grass to a final height of 3.5 inches. Whenever you mow, never remove more than one-third of the grass height. Fertilization As far as fertilization, timing is critical.
Fescue is a cool-season grass and grows most actively during the cooler periods of the year.
That is when it needs fertilizer the most. November before the weather turns severely cold. Fescue cannot utilize fertilizer during warm weather, but disease organisms can and will. Having soil tested is the best way to determine the rate and grade of fertilizer to apply. The standard recommendation for fescue is one pound of nitrogen per 1000 square feet, but most fertilizers also contain phosphorus and potassium.