Mulches reduce the growth of weeds, when the mulch material itself is weed-free and applied deeply enough to prevent weed germination or to smother existing weeds.

• 覆盖物可以减少杂草的发生，覆盖物本身不含杂草，覆盖足够的厚度，可以阻止杂草的萌发，既有的杂草也可以被覆盖而消亡。