The fescue grass in my yard is not doing well. I suspect that I may be cutting it too short--especially in the summer heat. I have cut it to a length of three inches for several years now. How tall should fescue grass be before and after cutting?
Taking into account the below couple of questions you've asked here on SE:
Q. Is a cool-season lawn "Fescue" the right type of lawn for your location?
See here: Selecting a Lawn Grass via South Carolina - Clemson University Cooperative Extension
Growing grass in a shady location, especially one shaded by tress, is going to be difficult. Period. Why?
See here: Growing Grass in Shade via South Carolina - Clemson University Cooperative Extension
Below quoted information comes via, What's an organic way to discourage crabgrass from a large “lawn”?
You may want to take the time to read the complete answer, as all the information within is based on a "Tall Fescue" lawn.
If cutting to a final cut height of 3inches (75mm) hasn't been working for you, try raising the final cut height to 3½ to 4inches (87.5 to 100mm).
You may also wish to have a browse through the following information from, South Carolina - Clemson University Cooperative Extension: