Grass trimmers not only maintain the edges of the lawn, providing a clean separation between the pavement and the lawn, they also keep weeds under control and ensure bushes and shrubs are not choked by weeds or the encroaching lawn. Different sizes of grass trimmer lines accommodate different types of grass as well as different size jobs.
Light work includes the regular grass trimming normally done on a front lawn and even a small backyard. This kind of work is done with home-use electric or gas-powered grass trimmers that use spooled line. For light work, a 0.08-inch round line spool is standard. Trimmers that use this type of line include the Black & Decker Grass Hog Electric String Grass Trimmer and Edger. These spooled lines can deal with most types of grass and many types of weeds but are fragile and break easily. Fortunately, the spool can be unwound when the line breaks providing an easy replacement.
Larger backyards, front yards and small commercial landscapes require something more heavy duty than 0.08 inches. These grass trimmers use spools of 0.105-inch square line and 0.095-inch five-sided line not only because the line is thicker and stands up more readily to thick brush, but also because the angular construction provides a cutting edge. Pre-cut lines are also available for medium work, including a 0.099-inch serrated line. This type of line can slice into thick weed stems, but can also easily cut the hand or slash a leg; so proper safety equipment is required. Trimmers designed for this medium work include the Poulan Pro PP125 25-cc 2-Cycle Gas Trimmer.
Heavy work includes industrial landscaping, very large yards, golf courses and other large areas where the line is expected to stand up to a large amount or variety of grasses and weeds. Pre-cut lines for heavy work include the 0.130-inch square line and the 0.168-inch serrated line, while the spooled-line varieties include a 0.130-inch twisted line and a 0.170-inch square line. Again, these lines all have edges designed to cut more easily through difficult grasses and weeds.