Greenworks 21342 40V Review

My Honest Take on the Greenworks 21342 40V Cordless String Trimmer

I’ve been using the Greenworks 21342 40V cordless string trimmer for the better part of a season now, and I feel like I have a solid handle on what it does well and where it falls short. As someone who edits reviews for a living, I know how easy it is to get swept up in marketing hype. So I’ll keep this real: this trimmer is a solid tool for the average homeowner, but it’s not a miracle worker. Let me walk you through everything I’ve learned from using it on my own lawn, which has a mix of easy grass, some weedy patches, and a few stubborn areas near the fence line.

How I Tested It

To give you an honest assessment, I didn’t just run this trimmer around a perfectly manicured lawn for five minutes. I put it through a series of real-world tests over several weeks. My property includes a standard quarter-acre lot with a mix of Bermuda grass, clover, and some thick crabgrass along the edges. I also have a few overgrown spots near the compost pile and a stone wall where weeds get out of control.

I tested the Greenworks 21342 in three main scenarios. First, I used it for routine edge trimming along sidewalks, driveways, and flower beds. Second, I let the grass and weeds grow for an extra week in one section to simulate a slightly neglected yard. Third, I deliberately tackled a patch of tall, thick weeds and brambles near my back fence to see how it handled heavy brush. I timed each session, noted battery life, and paid close attention to how the trimmer felt after 20 minutes of continuous use. I also compared it side by side with a gas trimmer I’ve used for years, just to keep perspective.

Performance

Lightweight and Easy to Maneuver

Right out of the box, the first thing I noticed was the weight. The Greenworks 21342 is genuinely light. I’m not a big guy, and I’ve used trimmers that left my arms tired after 15 minutes. This one, at about 7.5 pounds with the battery, feels almost like a toy in comparison. That’s a huge plus if you have a large yard or if you’re someone who dreads the physical strain of yard work.

Maneuverability is excellent. The handle is adjustable, and I found it easy to tilt and pivot around garden beds, trees, and fence posts. The shaft is straight, which helps with reach under bushes, and the head pivots easily for edging mode. I could trim along a curved flower bed without feeling like I was fighting the tool. For anyone with a lot of obstacles or tight corners, this is a big win.

Good Power for the Price

I’ll be honest: I was skeptical about a 40V cordless trimmer’s ability to cut through anything beyond thin grass. But the Greenworks 21342 surprised me. On standard lawn grass, it cuts cleanly and quickly. The 13-inch cutting path is wide enough to cover ground efficiently, and the line speed feels adequate for daily maintenance. I didn’t have to go over the same spot twice unless I was dealing with a clump of damp grass.

For the price point, the power is impressive. It won’t match a 40cc gas trimmer, but it doesn’t need to. For 90 percent of what a homeowner does, it’s more than enough. I could trim around my driveway, edge the sidewalk, and clean up under the deck without any bogging down. The motor maintains consistent speed even when I pushed it into thicker patches of crabgrass.

Automatic Line Feed

This is one of those features that sounds minor but makes a huge difference in real use. The automatic line feed on the 21342 works reliably. I didn’t have to stop and manually bump the head to advance the line. When the line gets short, it feeds itself a little more. I only had to replace the spool once during my testing because I wore down the original line, and that was after heavy use.

The only caveat is that the line is a bit thin (0.065 inches, if I recall correctly). That’s fine for grass and light weeds, but if you hit a rock or a thick root, it can snap. The auto feed compensates by advancing more line, but you do burn through it faster in rough conditions. For normal trimming, it’s a time saver.

Quiet Operation

If you have neighbors close by, or if you just hate the roar of gas engines, you’ll love how quiet this trimmer is. It’s not silent, but it’s a low hum compared to the screaming two-stroke motors I’m used to. I could trim in the early evening without feeling like I was disturbing anyone. My wife, who usually goes inside when I fire up the gas trimmer, actually sat on the porch while I worked. That’s a real benefit for suburban yards.

Battery Runtime Is Average

Now for the part that’s not as glowing. The Greenworks 21342 comes with a 2.0 Ah battery, and in my testing, I got about 25 to 30 minutes of continuous trimming on a full charge. That’s enough for my property if I’m just doing edges and light trimming, but if I have a lot of overgrowth or need to do the entire yard, I run out of juice before I’m done. I had to stop, recharge, and wait. That’s frustrating.

If you have a larger yard, you’ll almost certainly need a second battery. Greenworks does sell larger capacity batteries (like a 4.0 Ah), but they cost extra. As tested, the runtime is average at best. It’s fine for small to medium lawns, but don’t expect to trim a half-acre on one charge. The charger itself is reasonably fast, taking about 60 minutes to top off the battery, but that’s still a pause in your workflow.

Not Ideal for Thick Brush

I knew going in that a 40V trimmer wouldn’t be a brush cutter, but I wanted to test its limits. When I took it to the overgrown patch near my fence, which had 2-foot-tall weeds, blackberry vines, and some small saplings, the Greenworks 21342 struggled. The line snapped repeatedly, and the motor bogged down. I had to switch to a different tool for that area.

This trimmer is designed for grass and light weeds. If you have a lot of thick brush, brambles, or woody growth, you need something more powerful, likely a gas trimmer or a brush cutter attachment. It’s not a knock on the tool; it’s just a reality of cordless electric trimmers in this price range. Use it for what it’s meant for, and you’ll be happy. Push it too hard, and you’ll be frustrated.

Build and Value

Build Quality

The Greenworks 21342 feels well made for its price class. The plastic housing is sturdy, and the telescoping shaft is metal, which gives it a solid feel. The handle is rubberized in places, which helps with grip, and the trigger is comfortable to hold for extended periods. The head swivels for edging, and the lock mechanism feels positive. I didn’t notice any wobble or play in the shaft after several uses.

That said, it’s not a commercial-grade tool. The plastic parts, while durable for home use, might not survive a drop from a truck bed or years of heavy abuse. The line spool is easy to replace, but the cover is a bit finicky to snap back on. I had to align it carefully to get it to click. Minor annoyance, but worth noting.

Value for the Money

When I look at what you get for the price, the Greenworks 21342 is a strong value. It’s a complete kit with the trimmer, battery, charger, and a spare spool. You don’t need to buy anything else to get started. Compared to a gas trimmer that costs more, requires mixing oil and gas, and needs maintenance, this is a much simpler, cheaper option. The automatic line feed and quiet operation are features you’d pay more for in other brands.

But value also depends on your needs. If you only have a small yard and don’t want to deal with gas, this is a great deal. If you have a large property or heavy brush, you might end up spending more on extra batteries or a more powerful trimmer later. For the average homeowner with a standard lawn, the value is solid.

Who Should Buy It

This trimmer is perfect for a specific kind of user. If you have a small to medium sized lawn (up to a quarter acre or so), you value quiet operation, and you don’t want to mess with gas and oil, the Greenworks 21342 is a great choice. It’s also ideal if you’re physically not up for a heavy gas trimmer, because the lightweight design makes it easy to handle. I’d recommend it to neighbors who want a low maintenance tool that just works for weekly trimming.

It’s also a good option for anyone who already owns Greenworks 40V tools. The battery is interchangeable with other tools in their lineup, so you can share batteries between a blower, chainsaw, or mower. That adds a lot of value if you’re already in the ecosystem.

On the flip side, if you have a large yard, thick brush, or you’re a heavy user who needs to trim for more than 30 minutes straight, this isn’t the tool for you. You’ll be frustrated by the battery life and the line limitations. Also, if you’re a professional landscaper or someone who needs to tackle overgrown lots, look elsewhere. This is a homeowner grade tool, and it’s best used within those limits.

My Verdict

After weeks of testing, I can say the Greenworks 21342 40V cordless string trimmer is a solid, reliable tool for its intended purpose. It’s lightweight, easy to use, quiet, and powerful enough for routine lawn maintenance. The automatic line feed is a genuine convenience, and the price is reasonable for what you get. I genuinely enjoyed using it for my weekly trimming and edging tasks.

But it’s not perfect. The battery runtime is average, and it won’t handle thick brush. If you push it beyond its limits, you’ll be disappointed. For me, it earned a permanent spot in my shed for light duty work, but I still keep a gas trimmer for the rough stuff. If your yard is mostly grass and you want a hassle free experience, this is a great buy. Just be honest about your needs before you pull the trigger.