How thick should the mulch be?

Contrary to common practice, you should use only enough mulch to cover the fabric, usually one to two inches. Thin mulches are desirable for several reasons. By using a thin layer, you can save enough money to pay for the fabric. You will have fewer weed problems since the layer is light enough in weight that aggressive weeds from below cannot punch through. Thin mulch will dry out rapidly, thus extending its life by stopping the rotting activity. Best of all, weeds that are spread into the top mulch by airborne seeds (by far the biggest weed problem) and germinate will be killed when the mulch dries out, thus relieving the need for hand removal.