Landscaping fabric can only help to prevent weed growth in the short term. It's not an ideal long-term solution because dirt will eventually make its way on top of it, causing weeds to sprout. These fabrics can also leave microplastics in the environment for many, many years, so pulling weeds using one of the methods in this guide as soon as you see them is a better long-term prevention strategy.

Technically, dandelions aren’t bad for your lawn, and they don’t directly kill grass. In fact, they appear in areas that are nutrient-deprived, and their long taproots can loosen the soil and bring nutrients closer to the surface. 

However, dandelions do spread quickly, and they can take over your lawn, eventually crowding out grass. This is why a healthy lawn is the best defense against dandelions.

Some of the particular herbicides that work best to get rid of nut grass without killing the grass include Halosulfuron-methyl, mesotrione, sulfentrazone, and metsulfuron. A herbicide like glyphosate would kill nutgrass, but it will kill nearby plants, too.

Herbicide application, manual removal, and landscape fabric are common approaches.