Some gardeners layer pieces of carpeting, roofing paper or newspapers to insulate the soil.
But purists cringe at the idea. The smart mulches, she says, are natural or organic materials that eventually break down to improve soil texture and drainage. Mulch reduces weeds and conserves water by slowing evaporation. Whether you spread around freebie coverings or buy commercial products, you'll get the best results if you match mulches to the needs of particular garden areas. Don't leave any soil exposed.