The Basics
Back when baby boomers were kids, suburban lawns were mostly clean-shaven thanks to the convenience of lawn mowers; backyard landscapes, on the other hand, lacked meticulous grooming of perfectly edged sidewalks, driveways, lawns and flowerbeds unless manual hand trimmers were utilized. In the early 1970s, the first string trimmers appeared on the scene, changing the face of the suburban landscape and becoming one of the most important pieces of outdoor power equipment in any garage or tool shed.
The string trimmers of the 1970s were limited in terms of both selection and performance. But trimmers, along with baby boomers, have matured. These days it's easier than ever to find a trimmer that can tackle your particular landscape needs. A string trimmer can cut stretches of grass your mower can't reach, trim around trees and flowerbeds and tidy uneven edges. A growing number of trimmers can even clip hedges, prune, sweep, cultivate and blow, thus saving you the trouble and cost of buying and storing multiple garden tools.
Trimmers can be divided into three categories: gasoline-powered, electric corded or electric battery-powered (cordless). Though their power sources may differ, they all generally have a long shaft -- a major component of the trimmer -- with a power source on one end and a trimmer head on the other. (Some electric models have both the motor and trimmer head at the bottom end of the shaft.) The type of trimmer head can vary, depending on how it dispenses the string. Despite their differences, though, all trimmers are designed to spin a plastic line at a high speed, thereby turning the string into a super sharp cutting instrument that slices through tall grass and weeds.
With so many different shapes, sizes and brands from which to choose, the task of selecting a particular string trimmer can seem overwhelming. Prices, too, can vary depending on the power source and features. Expect to spend anywhere from around $25 for low-powered electric corded model to $500 or more for a professional-grade gas-powered unit. If you're constantly confronted by really tough jobs, you may want to consider investing in a more expensive, high-impact trimmer with a metal blade capability; for simple tasks, an inexpensive model may be more sensible. If you do opt for a super-cheap model, however, make sure it cuts grass rather than simply bending it down.
Gas-powered trimmers are great for rural landscapes, large lawns and heavy-duty tasks such as tall grass and tough weeds. Since they don't have cords, they can go anywhere with a run time that will likely last as long as you do. On the down side, they typically weigh more (10-14 pounds) and require more maintenance than electric trimmers. Also, pollution, noise and occasionally difficult starting are other factors to consider.
Electric corded trimmers are typically the least expensive trimmers. They are easier to start, quieter and lighter (generally 4-6 pounds) than their gas-powered counterparts, and thanks to new design technology and more efficient motors, the best corded units are often on par with or better than some gas trimmers. Still, many corded trimmers are typically not as powerful. As such, they are better suited to smaller yards and light trimming and edging. Run time is unlimited, but you are tethered to within 100 feet of a power outlet.
Electric battery-powered trimmers give you the best of both worlds: the free range of gas trimmers and the eco-friendly features of corded models with a clean battery power source. Cordless units are easy to start and use, require no fueling, produce no exhaust emissions and run extremely quietly. Their performance has generally not been on par with gas trimmers, but once again, new technology and more efficient motors have raised the power levels of some cordless models to those of their gas-powered counterparts. Cordless trimmers are great for lawns with many trimming areas, and the best can even tackle your tallest grass and toughest weeds. Run times can vary from 15 minutes to an hour or longer.
Semi-automatic heads are among the most popular and prevalent among trimmers. Also known as tap-and-go heads or bump-and-feed heads, this head type advances a pre-measured length of line when you tap the trimmer head on the ground during operation. Unfortunately, dirt, debris and continual banging can cause the line on these heads to jam. Automatic heads, conversely, release new line whenever it is needed without any assistance from the operator, thus offering added convenience when they work well. Manual heads require you to turn the machine off and manually pull or unwind the string inside the head. A fixed-line head holds two precut lengths of string that you replace as they wear, thus eliminating jams and the need to bump in order to advance the line; you do need to stop the machine in order to replace the lines, but it usually takes just seconds to reload as there is nothing to take apart or wind.
String trimmers are available in a variety of cutting widths. A smaller cutting width -- 8-12 inches -- works well for smaller areas or less frequent trimming tasks; a cutting width of 14-15 inches is better for moderate use; and trimmers with a cutting width of 15-18 inches work best for large areas and heavy-duty use.
Trimmers are typically offered in curved- or straight-shaft models. Curved-shaft models are well balanced and generally lightweight, thus making them easier and more comfortable to use. Straight-shaft models usually have a longer reach, making them a great fit for taller users. The longer shaft length also makes this type of trimmer better for reaching under decks and trimming beneath shrubs and low branches. A split-shaft design increases the versatility of the trimmer with a variety of multi-task attachments such as blowers, tree and hedge trimmers and tree pruners.
Many of these machines are designed with only trimming in mind, but if you want to keep the borders along sidewalks, driveways and flowerbeds well manicured, then opt for a unit that lets you switch between trimmer mode and edger mode. Some models can convert into edging mode by turning the cutting head 180 degrees with the touch of a button.
How to Shop
The first step in buying a trimmer is deciding on whether you want gas-powered, corded electric or cordless electric model. Advances in technology have enabled manufacturers to design gas-powered trimmers that are much quieter and cleaner than models introduced only a few years ago. Most gas models are equipped with a two-stroke engine, though four-stroke engines are often the norm on near-pro and professional models. Two-stroke engines burn on a mixture of gas and oil, whereas four-stroke engines add the oil automatically, so all you need do is pour in the gas. Two-stroke engines weigh less than four-stroke engines, though four-strokes are quieter and cleaner, cutting toxic emissions by 50 to 75 percent over two-stroke units. If you want a cleaner running two-stroke, look for a CARB-compliant model that meets California's higher emissions standards.
Gas-powered units today are easier to start than before, using a simplified 1-2-3 starting system -- you only need to push the primer bulb, flip the choke lever and pull the cord. For even simpler starting, look for models with a spring-assisted advanced starting system that makes it easier to pull the cord. Four-stroke gas engines are designed for easier starts and significantly less vibration than two-stroke engines; this can help reduce hand fatigue, especially if you'll be using the trimmer for more than 15 minutes at a time.
Regardless of the power source, a trimmer needs to be comfortable to use. Hold the trimmer in the cutting position and make sure the weight is evenly distributed or only slightly heavier at the top. Some electric models have the motor and trimmer head at the bottom end of the shaft and, therefore, may be uncomfortable to use due to the lack of balance. Cordless units featuring a battery pack on a belt or a strap are easier to use when tackling tougher tasks, since the weight is shifted from the trimmer.
Trimmers with a large gap between the cutting head and the end of the shaft can slow or stall the engine -- the smaller the gap, the less chance there is that tall grass or weeds will wrap around the cutting head. Also, make sure that changing the line spool is easy for you; some models require you to hand-wind the new line around the spool, which may not be something with which you are experienced or comfortable. Some models even feature a removable cartridge, which makes changing lines even easier -- just remove the spent cartridge and snap a new one in place. With a little research and a hands-on approach to shopping, selecting and using your trimmer will be a breeze.
