A string trimmer gets into places that a lawn mower can’t and can also tackle tall weeds or grass that might choke a mower. It’s the ideal tool for keeping the edges of your garden or walkway neat and tidy and for manicuring around fence poles and tree trunks.
To choose the right string trimmer for your yard, you need to answer two basic questions: Which type of shaft do you want—curved or straight; and which power source is most convenient—gas, electric, or battery? Here’s how to decide.
String trimmers have either a straight shaft or a curved shaft, the latter of which is bent about halfway between the handle and the spinning trimmer head. A straight shaft is often better for taller users because it’s longer, and the design lets you trim without kneeling or bending to keep the trimmer head close to the ground.
Shorter users may prefer a curved shaft because it’s a little easier to hold and maneuver, and its design makes it more convenient to keep the cutting head perpendicular to the ground. If you’ve never used a string trimmer, try one of each at a home center or hardware store to see which feels more natural.
Power Source
A string trimmer can be powered by gasoline, by a battery, or with a traditional power cord plugged into an outdoor outlet. In our tests we find that all three types can cut well, depending on the model.
Corded electrics are the cheapest but only a good option if you have an outdoor outlet and a long extension cord—you’ll rarely find an outdoor cord longer than 100 feet, so if you need to trim an area more than 100 feet from an outlet, choose another type.
Battery-powered models often cut as well as gas, start instantly, and run quietly. If you have a battery-powered lawn mower, the smart move is to buy a string trimmer from the same brand because you’ll be able to use the batteries interchangeably and always have one fully charged. Otherwise, expect to trim for about 30 minutes on a single charge.
Gas-powered string trimmers are the most common. They’re loud, so you’ll need hearing protection, but they can go anywhere and run indefinitely, provided you keep adding fuel. Models with a four-cycle engine run on regular gasoline, but be sure to add fuel stabilizer to the gas before prolonged storage—the ethanol in gas can gum up the engine, making it difficult to start.
Two-cycle models are cheaper than most four-cycle models, but they emit more pollutants and require you to mix gas and oil in specific proportions, usually 40:1 or 50:1, before adding fuel to the tank. You can also buy cans of premixed gas and oil for string trimmers (and other outdoor power equipment) at the home center. It costs more than mixing fuel yourself, but a single $7 can is likely to last an entire season.
Should You Buy a Powered Base?
With both gas- and battery-powered string trimmers, you’ll have the option of buying a stand-alone tool or a powered base. The latter is basically an engine or a motor designed to accept different attachments, and it’s typically sold with a string trimmer head. For most models, you can also get a hedge trimmer, pole saw, edger, and brush cutter, and even a cultivator attachment. It’s a good option if you need a string trimmer and any or all of the additional tools, and you don’t have the space for multiple tools, or the money, to buy each separately.
Mind the Gap
Before you buy any string trimmer, look at the cutting head, where it meets the shaft of the trimmer. If there’s a large gap, be warned that tall grass will probably get wrapped around the shaft in that spot. Instead, look for a model with a minimal gap, or one with an easy-to-remove cutting head, so you can quickly pop the head off and get rid of weeds.
Safety First
String trimmers can easily break through skin and send debris flying while they cut. They have a shield to deflect most debris, but even so, you’ll want to wear gloves, protective eyewear, boots, and long pants, in addition to hearing protection for gas models.
Let your lawn and landscape dictate which type of string trimmer you buy.
The best choice for large properties, a gas-powered string trimmer goes anywhere and can run indefinitely. This type is also the most common, so you’ll have the most options when shopping if you go this route. Look for models with an adjustable handle and a translucent gas tank, so you can see when fuel is low. Models with a four-cycle engine run cleaner and use regular gas but cost more. Models with a two-cycle engine cost less, but you’ll need to add oil to your gasoline. All the gas-powered string trimmers in our tests are loud enough to require hearing protection for the user.
Cost: $100 to $190
While corded yard tools may seem outdated, a corded string trimmer can perform really well for a certain subset of homeowners. If you have a small yard and don’t need to trim more than 100 feet from an outlet, these are ideal. Most have a short cord and require a long outdoor-rated extension cord—you can typically find these cords in lengths up to 100 feet. Corded-electric string trimmers tend to be the cheapest, plus they start instantly and run indefinitely, and you don’t need to worry about buying gas or charging a battery.
Cost: $90 to $110
You’ll pay a slight premium for a battery-powered string trimmer, as compared with a gas model, but if you have a modest property, it may be worth it. In our tests, the best battery-powered models trim as well as gas, produce no emissions, and run quietly. They also start instantly every time, without fussing over the choke or yanking a pull-cord. They require far less maintenance, plus their batteries can typically be used in other outdoor power tools from the same brand, including lawn mowers, hedge trimmers, leaf blowers, and chain saws. The lifespan of the lithium-ion batteries used to power these tools is still a big unknown, so look for a long warranty that specifically applies to the battery. Expect to cut for about 30 minutes on a single charge. Most batteries take about an hour to recharge once they’ve fully drained.
Cost: $130 to $190
Shopping for lawn gear can be overwhelming. Here’s the help you need to get the job done.
The shaft transfers power from the engine or motor to the lines that do the cutting. Models with a straight shaft offer a longer reach, and they tend to be better for tall users and for reaching beneath bushes and other shrubs. Models with a curved shaft (shown) tend to be lighter and easier to handle.
On some models, the cutting head can be swiveled to a vertical position for edging. This feature is especially useful because the trimmer can otherwise feel unwieldy if you have to maneuver it 90 degrees—and hold that position—for several steps as you edge your lawn where it meets a driveway or sidewalk.
All manufacturers tell you which size replacement line fits your trimmer. Be sure to use what’s intended for your trimmer. Line that’s too thin can compromise cutting power, while line that’s too thick can bog down a trimmer’s engine or motor. Trimmers with two lines cut more grass with each revolution than single-line models, so they can typically handle heavier growth.
A bump-feed releases line from a spool when you bump the trimmer’s head on the ground, but more models are using fixed-line heads with short lengths of line to help eliminate the jams and tangles associated with loading new line. You thread in a piece of line as needed—though you’ll have to do that relatively frequently. Fixed-line heads are also available as aftermarket items. Auto-feed heads come pre-wound and release line on their own as needed.
Spring-assisted starting makes pulling the starter cord of a gas-powered trimmer easier. And a relatively foolproof sequence of pushing the fuel-primer bulb and engaging the choke delivers the proper fuel mixture to a cold engine for faster starts. Trimmers that have the stop switch within easy reach let you quickly stop the engine or motor if you need to.