Trimming means cutting horizontally. It usually is done around trees, fences, and other obstructions to prevent a ridge of long grass from growing up around them.
Edging means cutting vertically. It keeps the edges of the lawn next to walks and garden beds looking crisp and neat.
Traditionally, these jobs have been done with grass shears, the wheeled multi-toothed rotary edger, or the semicircular turf edger. In recent years, however, electric and gas-powered tools have become more popular. Although some tools are designed to do only one job, many can be used for either trimming or edging. Which type of tool you choose depends largely on the size of the job, how fast you want to accomplish it, and whether you want to invest in the more expensive power tools. If you want to “trench” the edge, you’ll need equipment with digging capacity.
For nylon string trimmers and edgers, see Nylon String Trimmers and Brush Cutters.
Sitting on the grass and trimming with hand shears may be laborious, but it affords a certain satisfaction. There are two basic types of hand shears: the traditional sheep-shearer design, in which the shears are simply squeezed together, and spring-activated shears, with vinyl-covered handles and a vertical squeeze. The latter is more comfortable for extensive trimming. In addition, sheep shears are easier than most garden tools to cut yourself with. In both types, the blades must be kept sharp to be efficient.
Battery-operated shears are a boon for those who like to trim by hand but just don’t have the strength. All you need to do is point these shears in the right direction and turn on the switch. They will cut for 30 to 40 minutes at a time and fully recharge in 24 hours. However, they are good only for trimming grass and very light weeds. Heavy material will cause the engine to strain and lug down, possibly burning out the tiny motor. Shears often have replaceable blades. They cost only a couple of dollars and can be replaced each year, which saves you the bother of sharpening blades.
Semicircular Turf Edger
This tool looks like a hoe that has been straightened out and trimmed to a half-moon shape. With its curved edge that is beveled on one side and kept sharp like a hoe, the tool will cut through soil as well as grass. It is used primarily for cutting the lawn next to a sidewalk and straightening up crooked edges.
It doesn’t work for regular edge trimming, however, because it takes off a little soil each time. Therefore don’t use it too often or your lawn will get smaller and smaller. Once or twice a year will do for trimming. You can also use it to cut out sections of turf. Its construction is very similar to that of a hoe.
When the wheels roll along the surface next to the lawn, the rolling action drives the multi-toothed rotary blades. These blades cut and trench flush with the outer edge of the flower bed, sidewalk, or driveway. Models come with either one wide wheel or two wheels (the latter provide more control and balance).
On some models, the rotary blade can be adjusted to two or three different cutting depths. Before you buy this feature, consider whether you really need it.
The electric cord limits the reach of these 1/2- to 1-horsepower edgers, but many homeowners like the instant power and quiet, largely maintenance-free motor. With extension cords, these edgers can work from 50 to 100 feet from a power source.
The diameter of the edging blade ranges from 6 to 8 inches and leaves a trench varying from 0 to 2 inches deep. If depth adjustment is available, it normally is made with a lever on the handle. The power button is built into the top of the handle.
As a safety feature, on some models this button cannot be locked in the “on” position; the power is cut immediately when the switch is released. On other types, an automatic blade-brake stops the blade within seconds after the power is cut. Because the power edgers can send rocks or chips of concrete flying, goggles or other eye protectors are highly recommended.
Gasoline-powered edgers come in a wide variety of engine sizes. Which to choose depends on how much edging you must regularly do. The four-cycle engines range from 2 to 4 horsepower. Most models have two wheels at the rear for stability, and another in the front for guidance and ease in maneuvering over curbs.
Since they are more powerful than electric models, they can support blade lengths up to 10 inches to make cuts from 0 to 4 inches deep. Depth adjustments are made by a lever on the handlebars.
Some models convert into trimmers when a lever that tilts the blade from vertical to horizontal is pulled. Some models offer nine different blade angles within a range of 120 degrees. The trimming width matches the overall blade length.
The edger has a blade guard that prevents debris from being tossed toward the operator; when the edger is used as a trimmer, the blade guard keeps the blade from striking walls or tree trunks. Despite this safety device, however, goggles or other eye protectors are recommended.
All edgers, whether hand-operated or powered, should be kept clean, rust-free, and lightly oiled.
Grass shears Because shears, like scissors, are somewhat self-sharpening, they don’t need to be sharpened too often. If you do want to touch them up, however, use a smooth file or a whetstone and carefully follow the existing bevel on the outside of the blade. Never touch the inside edge where the blades cross each other or you will create a small gap that ruins the effectiveness of the cutting.
If the shears are already fairly sharp, hone them on a bench stone. Set the edge of the shears on the stone at the correct bevel angle and pull the blade toward you, as if you were trying to slice off a thin layer of the stone.
Battery-operated shears These reciprocating-action blades are not normally sharpened. Just replace the blade.
Rotary edger With most models, two steel honing blades built into the housing lightly grind each tooth on the rotary blade as the blade passes. Thus it is self-sharpening. If you find it increasingly difficult to make the edger do the job right, touch up each tooth with a file every month or two.
Semicircular turf edger Sharpen this tool just like a hoe. Place it in a vise and follow the bevel with a mill file in one long motion.
Electric and gas-powered edgers When the edger blades become dull, remove and sharpen them. Use a bastard file and follow the existing bevel. If the bevel is worn away, file the new edge at about 75 degrees in order to keep a lot of metal behind the edge. To maintain and tune edgers with gasoline or electric engines, see Caring for Power Equipment.