I tried Karcher's cordless grass trimmer - it transformed my lawn from scruffy to sharp in minutes

Karcher dominates the world of power washers, but also offers a limited range of power tools. Their LTR 18-30 cordless garden trimmer, £169.99 at Amazon, is their more expensive garden trimmer, but there are only two to choose from.

As the name might suggest, the LTR 18-30 is a cordless grass trimmer. This means you won’t be limited by extension cables and power sockets when trimming your lawn. During testing, the battery life was very good, and despite having a battery pack, the LTR 18-30 is pretty lightweight.

While the LTR 18-30 grass trimmer is designed for lawns, during testing I took it to hardier weeds too, and was impressed with the performance. Most testing was carried out at my parents-in-law’s farm – it offered loads of different types of grass and weeds to put the LTR 18-30 to the test. I tested it on lawns and long grass alike, checking for how easy the grass trimmer was to use (very) even for gardening novices.

In a nutshell

The Karcher LTR 18-30 is ridiculously easy to use, with initial setup taking around 15 minutes. Once the battery is fully charged, it’s easy to operate this grass trimmer.

It’s designed to trim grass as well as do edging, and it has a flexible head so you can change the angle of how you’re cutting.

During testing, the Karcher LTR 18-30 performed well on grass lawns as well as long grass.

Although you don’t get as neat a finish as you would with a lawn mower, this is great for neatening up edges and quick, small jobs. Although not especially bulky, the Karcher LTR 18-30 isn’t super compact for storing, as the arm doesn’t fold in very far.

Specifications

• Measurements: (H)31.5 cm x (W)31.2 cm x (L)132.5 cm
• Weight: 2.5kg
• Type: Battery
• Battery voltage: 18 V
• Runtime: 30 minutes
• Charging time with fast charger: 44 mins for 80% / 83 mins for 100%
• Material: Plastic
• Safety switch: Yes
• Cutting modes: 2 (edging and trimming)
• Cutting width: 30 cm
• Cutting speed: 7800 RPM
• Extra battery? No

How I tested

Zoë Phillimore

Zoe is a freelance journalist and content strategist with almost – gulp – 20 years of experience. She's worked for the BBC, STYLIST, Marie Claire, heat, Wallpaper*, InStyle, The Sunday Times Style, Ocado, Christie's and more. Zoe started product reviewing in 2021 and has since tested around 1,000 products to find the best. She now regularly writes about home appliances, interiors and sleep – what she doesn't know about gadgets and mattresses isn't worth knowing. In her spare time, Zoe can be found trying to entertain her three active children and documenting her journey on social media.

I spent two weeks testing this grass trimmer out in various places, including weeds in my garden, lawns, long grass and very overgrown weeds at my parents-in-law’s farm, and I even tackled some weeds in the streets outside my house (not sure this is allowed - sorry to my local council if not). I was sent the Karcher LTR 18-30 to test, but I remained impartial in my review.

Unboxing and setting up

The Karcher LTR 18-30 trimmer comes in a smart cardboard box with Karcher’s hallmark bright-yellow branding. Inside, all the components are packaged in individual plastic bags - this seemed slightly unnecessary to me. There’s a front handle to attach to the body - this was easy to do. Then the string guard clicks on, too.

You have to screw this in place with a Phillips-head screwdriver. There’s a battery pack that clicks reassuringly into the handle, and a charge pack. Everything is pretty self-explanatory.

It took me less than 15 minutes to set the whole thing up. It’s worth noting that my battery came 60 per cent charged – this is fine for small jobs, but if you’ve got a big area that needs doing, then you’re going to want to build in charge time before you use the Karcher LTR 18-30 grass trimmer.

Design

The Karcher LTR 18-30 is relatively lightweight, so you don’t need a huge amount of upper body strength to use it. However, it does require the use of both hands while using it, so you can guide it along without clipping any precious plants or garden furniture.

As someone who is a bit intimidated by petrol-fuelled garden tools, this trimmer felt like a nice alternative. Perhaps it doesn’t have the gusto of a petrol version, but it also doesn’t have the fumes or weight of one either.

The Karcher LT 18-30 grass trimmer isn’t exactly compact - the telescopic shaft doesn’t retract all that much. This means you’re probably going to want a shed or decent other outside storage to pop it away in. I wouldn’t fancy storing it indoors, as after a trimming session it’s pretty mucky.

As the operating time is 30 minutes, the Katcher LT 18-30 is great for those with small or even medium-sized lawns. Anything bigger than that, and you might get frustrated at having to charge your battery.

Of course, you can always buy spare battery packs to overcome this issue. I liked that there’s a display on the battery to show how much more battery life is left, so I could calculate what jobs I could or couldn’t get done without charging it.

The LT 18-30 is designed for lawns and the edges of lawns using the string cutter. You can swap out the string head for a lawn-trimmer blade (sold separately), which is designed for hardier weeds. During testing, I did take it to nettles and long grass just using the string cutter, and it performed fine. However, it struggled with brambles, so if your garden is a big jungly, it’s probably best to invest in the lawn-trimmer blades.

Performance

Trimming

I found the LTR 18-30 so satisfying for trimming grass. It made light work out of all types of grass, slicing neatly through it. However, if you want very neat and even grass, then this is perhaps not the tool for you – unless you have a very steady hand.

You’re not going to get Wimbledon-worth lawns using this trimmer, but that’s not really what it’s for. I found that it was really great for around plants and over lumpy ground such as tree roots, which regular lawn mowers might struggle with.

There is a plant guard on the LTR 18-30. This piece of metal snaps down when you want it to, protecting the trimmer head from getting too close to anything directly ahead of it.

This was great when going around the base of trees. I did notice, though, that it’s not foolproof (me being the fool here), and you can still get quite close to plants on either side of the guard if you’re not paying attention.

The head is flexible, so you can get under overhanging plants or even garden furniture. This feature would be hugely helpful for those awkward bits of lawn that are hard to reach. I found it really handy for under heavy wooden garden furniture that I struggle to move on my own.

I was able to do a significant amount of lawn trimming - a medium-sized garden - in one charge. I thought this was really impressive. If you have a day of trimming planned, you are going to need to charge the battery, though – after 20-30 minutes of trimming, my battery pack said it still had 50 per cent juice left, which is more than Karcher suggests in their specs.

The automatic line feed means that the spool automatically releases more cutting line and cuts it so it’s the optimal length for grass trimming with zero effort from you. I really liked this, as it meant I didn’t have to faff about with the thread myself.

Edging

You can twist the trimmer head so the string cuts horizontally. This allows you to get neat edges on your lawn around flower beds. This is a great option so long as you don’t have flower beds that spill out or are planted right up to the edge.

A few leaves on some plants came a cropper during testing when I cut the edges of my lawn this way. However, it did leave very neat edges that would take ages to do with a pair of sheers. So as long as you’re more careful than I, the LTR 18-30 grass trimmer is a convenient tool for trimming the edges of your grass.

Weeds

I took the LTR 18-30 to some seriously long grass and nettles that had grown in my parents-in-law’s garden. The LTR 18-30 made light work of the long grass and nettles, bringing down a hefty clump in minutes. This was hugely satisfying.

However, the LTR 18-30 with the line head, I found it couldn’t handle thick brambles and other heavy-duty weeds. You might find Karcher’s lawn trimmer is better suited to this, but I didn’t have this, so I couldn’t test it out.

Cleaning

There’s very little cleaning required with this trimmer. Karcher recommends you give it a once-over with a damp cloth and remove any trimmings, which is so easy to do as it’s not a fiddly tool with loads of nooks and crannies. Other than that, you just have to make sure the charge pack doesn’t get dusty, and that’s it.

Storage and Maintenance

The LTR 18-30 grass trimmer’s downside is that it’s quite large to store away. Karcher doesn’t make a compatible wall mount for it, so I ended up laying it down in my shed. Annoyingly, it takes up a lot of room this way, simply because it’s so long (although not hugely bulky or heavy, thankfully).

The battery charger and pack are not too bulky - you could store them in a shoe box or a standard carrier bag and tuck them away somewhere.

How does it rate online?

People who own the LTR 18-30 grass trimmer love its simplicity to use, remarking on how lightweight it is to use despite it being cordless. Indeed, many people seem to have converted from a corded grass trimmer to the LTR 18-30 and have loved how much easier it is to use. Many are also pleased with how well it tackled weeds and cleared overgrown paths, despite being merely a grass trimmer.

However, there are many reports of faulty batteries that don’t hold a charge. It seems Karcher has dealt with the complaints swiftly, replacing faulty batteries. This isn’t a problem that I encountered during testing.

How does it compare to similar models and its predecessors?

Karcher produces a similar product called the LTR 18-25. This offers a shorter cutting diameter of 25cm. This is better suited to closer cuts and tighter spaces. Other than this, both models offer very similar features and the LTR 18-25 is slightly cheaper.

Competitor models include the Stihl FSA30, £144 at Just Lawnmowers, which has blades rather than a line. It is battery operated too, but has a shorter run time than the Karcher LTR 18-30 of under 20 minutes. At time of writing it is a bit cheaper than the Karcher grass trimmer I tested here.

The Powerbase 550W electric grass trimmer, £59.99 at The Range has the nice design feature of wheels to help make edging easier and neater. It reviews well as an efficient grass trimmer, but it is quite heavy and is corded, which will mean you are tethered to a plug socket. It does come in considerable cheaper though.

Should you buy the Karcher LTR 18-30 grass trimmer?

I am really impressed with the Karcher LTR 18-30 - it’s so lightweight and easy to use. I loved the automatic line feed, plant guard and how easy it is to switch between edging and trimming.

I wouldn’t want to cut a huge lawn with it - you’re better off getting a lawn mower for that – but if you have weeds, long grass or a smaller lawn to tackle, then I’d definitely recommend the Karcher LTR 18-30.