Hi - I purchased a house about a year ago and the termite inspector recommended I put a 12" gravel barrier around my house to prevent termites. There are no existing issues and the house foundation is dry. There currently is mulch and I think this needs to go. If not gravel - then what? Just dirt? The house is a brick rancher in Columbia Maryland. The termite guy said the mulch was the same as putting blood in the water for sharks.