Inorganic mulches such as polyethylene rolls are sold in hardware or garden supply stores by the yard or foot. The most common width is 3-4 ft. In row gardens, lay the plastic between rows leaving enough space free to plant. Alternatively, place the polyethylene over rows with slits cut for planting. An x- shaped cut in the plastic mulch provides just the right opening to plant directly into the soil.
Plastic helps to warm up the soil, providing a jump-start for early gardens.
Use these inorganic mulches only during the growing season of your garden, removing them soon thereafter. Plastic is often placed over organic mulches or may be used alone. Cover raised beds completely with one sheet or section of polyethylene, especially if the beds have been built to accommodate the dimensions of the plastic. Organic mulch includes materials such as manure, newspaper clippings, grass clippings, leaves straw, and much more. Remember as a rule of thumb that organic mulch is some form of material that will decompose as nature intended, back into the soil.