The cutting height of fescue will mirror in the dept of the root system. If you cut fescue 1.5 inches ,you will get a 1.5" deep root system. If you cut 4 inches,you will get a 4 inch root system. Its easy to understand why your lawn can quickly go brown in the summer during poor rainfall if you cut the grass close. In eastern virginia,if you want short green grass in the summer be prepared to water frequently. Its better on the environment with runoff issues and water consevation issues to maintain your lawn at 3 to 4 inches.