Landscape fabric can kill grass if used properly. Gardeners can use landscape fabric to kill large areas of grassy weed growth without employing herbicides that may harm surrounding plants. However, improper use of the fabric results in weed growth sprouting underneath or on top of the material, according to Washington State University.
Landscape fabric is a material that has tiny holes for air and water to pass through, according to the University of California. Before landscape fabric, gardeners used black plastic to kill weeds. However, black plastic doesn't allow air circulation. Gardeners place landscaping fabric over grassy weed areas. Heat generates underneath the fabric and kills weeds and weed seeds. It typically takes several weeks for weeds to be burned up by the heat generated underneath the fabric.
Landscape fabric used improperly is not effective against weeds. It is important to cover landscape fabric with an inorganic mulch to generate enough heat and prevent weed seeds from germinating on top of the fabric, according to the Washington State University. Also, some weeds will make it through the fabric, which damages the material when it is removed. Furthermore, landscape fabric is not a permanent solution. Sunlight degrades landscaping fabric over time, especially if mulch was not spread on top.
To install landscape fabric, lay the fabric down next to the weedy area. Cut the fabric to the size of the area. Secure the fabric over the area with landscaping pins. Press a landscape pin every 1 to 2 feet around the perimeter of the landscape fabric. Cover the fabric with an inorganic mulch, such as gravel, pebbles, crushed brick or sea glass. Apply at least 1 inch layer of mulch over the top of the fabric.
Remove any weeds that grow through the landscape fabric with a herbicide, as suggested by the University of California. You also can hand pull weeds if you do not want to use a chemical spray. Monitor the fabric to ensure that your inorganic mulch has not revealed any fabric that can degrade. Patch any holes in the fabric with leftover material. Remove the fabric in six to eight weeks after weed seeds and weeds have been killed.