Why landscape fabric is not necessary in your mulch beds
When using mulch in your landscape, there is no need for the use of artificial weed barrier such as plastic or landscape fabric. These materials do not work and are not weed barriers. They are only necessary under stone. That is to prevent the soil from mixing with the stone. When mulch is maintained at an even depth between two and four inches it will properly serve as a weed barrier. Also, the mulch will naturally break down and incorporate with the soil through matters such as earthworms, microorganisms, and other insects. This adds nutrients and organic material to your plants and the surrounding soil which is very important to sustaining the health of your landscape.
In many cases when artificial material is used under mulch you can clearly see a night and day difference between what is above the plastic and what is below. The material above the plastic is soft, rich, dark, and full of nutrients. The soil below is hard and grey with virtually no nutrients. It looks as if it is suffocated. It also provides no protection against weeds proven by the fact that we see weeds everyday growing through thick layers of concrete and blacktop on commercial property. In the event that weeds do occur in your mulch they are much easier to pick out and maintain when there is not a layer of thick plastic holding them in the ground.