Gas, electric, or cordless?
There are three options when choosing a string trimmer: gas-powered, electric, or cordless.
Gas-powered trimmers are more powerful and lack awkward power cords, but they’re more expensive and require skill and strength to pull the start cord. A gas trimmer is noisy enough to warrant ear plugs, and although tougher federal laws have helped decrease emissions from gas trimmers, electric trimmers remain the more planet-friendly choice.
Lighter-weight, less expensive gas trimmers have a two-cycle (or two-stroke) engine, which needs a gas-oil mixture. If you have serious brush to tame, check out trimmers with four-cycle engines. They’re the most expensive, but they’re smoother, quieter, easier to start, and they run only on gas—no mixing in oil. Four-cycle engines weigh more than two-cycle engines; many come with harnesses for better weight distribution.
Electric trimmers are less powerful and less expensive than gas trimmers. They have an electrical cord that limits how far you can move away from the outlet (usually about 100 feet). There’s always a risk that you might slice through the cord, and depending how well the trimmer is designed, the cord tends to come unplugged from the machine.
Cordless trimmers are sufficient for light trimming chores. The battery charge lasts for about 30 minutes, so use them only for small jobs—or buy a second battery so you can recharge one while you’re using the other. Some cordless trimmers weigh as much as gas-powered trimmers.
Try your trimmers
Before buying a trimmer, spend some time at the store handling various models to see which one feels right for you. Here are some factors to consider:
Choose the right shaft. Trimmers with a straight shaft can get beneath shrubs and decks more easily and, depending on the design, are less likely to spray grass clippings. Curved shafts often weigh less, get closer to fences and other obstacles, and are better for people with limited upper-body strength and for use during shorter periods of time.
Check the weight. Hold various string trimmers in your hand to get a feel for how heavy they are. Electric trimmers start at about 5 pounds, with cordless trimmers weighing slightly more and gas trimmers weighing 15 pounds or more.
Get a feel for balance. The weight should feel evenly distributed or slightly heavier at the top. Remember, you will be moving the trimmer around your yard for 30 minutes or more. Gas-powered trimmers have their engine on the top—a plus for balance. Most electric and cordless trimmers have the motor at the bottom, which makes them more unwieldy, though some models have top-mounted motors to solve this problem.
Check the controls. They should move smoothly and be easy to reach. Make sure a gas-powered trimmer has a deflector that channels hot exhaust away from the body, rather than toward.
Think about string. Trimmers use a spool of string that slowly disintegrates with use. Depending on a machine’s design, it may release more string automatically (an obvious advantage) or you may have to tap the trimmer head on the ground to release more. Either way, eventually a trimmer runs out of string. Check out how easy it is to replace the spool before purchasing your trimmer. Tangled string is a chronic problem, but better design has made this less of an issue. Some models, for example, have a fixed-line head that uses two short, precut pieces of cutting line instead of an easily tangled spool.
Look for accessories. Most string trimmers also bill themselves as edgers and may even have a rotating head that moves into a vertical position for easier edging. But their ability to edge may be limited. Cordless and electric models are better for touch-up edging—that is, trimming stray pieces of grass throughout the season after using a more powerful, bladed machine to edge in the spring.
Some models are designed with a special shaft that comes apart so you can replace the trimmer head with an edging blade, a leaf blower, or a number of other power tools. As a rule, the more powerful the trimmer, the more effective these tools will be. If your trimmer is relatively underpowered, any attachment will be underpowered, too. Also check to see how easy it is to attach the parts.
Choosing a string trimmer
Our buyer’s guide to getting what you need.
Gas-powered trimmer (Photo 1)
Advantages: More powerful than electric and best choice for cutting brush and woody material. Highly portable and long-running.
Disadvantages: More expensive than electric and cordless. Almost always heavier than electric—10 to 15 pounds or so—a problem if your upper body strength isn’t good and if you want to use it for long periods of time. Starts with a pull-cord, which can be a hassle. Much noisier than electric. Produces emissions.
Cost: $70 to more than $300, with most selling for $100 to $150.
Electric trimmer (Photo 2)
Advantages: Unlimited run time. The most lightweight trimmer, usually weighing about 5 pounds. Good ability to cut—nearly as good as gas-powered models. Quiet compared to gas. Easy to start.
Disadvantages: Limited by cord length—usually around 100 feet. Less power than gas, making very tall grass and weeds difficult, if not impossible, to cut.
Cost: $15 to $75.
Cordless trimmer (Photo 3)
Advantages: Lighter than gasoline-powered, inexpensive, a snap to start. No awkward cords. Perfect for small yards.
Disadvantages: Even though they’re generally lighter, some weigh 10 pounds, so choose carefully. Most hold their charge for just 15 to 30 minutes, yet take hours to fully recharge. Lack of power makes them inadequate for all but the lightest trimming chores. Most have the motor at the bottom of the shaft, which can make them awkward to handle.
Cost: $25 to $100.
Veronica Lorson Fowler is a garden writer living in Ames, Iowa.