The best grass trimmers can make tidying up the garden a breeze, while the worst can leave you with chewed-up lawn edges and a battery that's dead within minutes.
Use our expert advice to help you decide whether you need a petrol, electric or cordless model – and then check our reviews to ensure you don't end up taking home a dud.
There are three main types: petrol, cordless and electric.
These are designed for cutting large areas of long grass and stubborn weeds. But because they're so powerful, they can be tricky to use for light tasks such as lawn edging.
They're best suited to gardeners working away from the house for longer periods of time, for example in a meadow or on an allotment – all you need is a can of petrol and you can trim for hours.
Most petrol trimmers can also double up as brushcutters for cutting brambles.
Cordless models are typically more expensive, as you're paying for the convenience of not having a power cord – perfect if you don't have easy access to a power source.
They're usually lighter than corded and petrol models. However, you will need to factor in the extra time needed to charge the trimmer in between doing large garden jobs – the worst batteries can take more than four hours to charge.
You can get cordless models for both light and heavy-duty gardening tasks.
Generally the cheapest option, electric trimmers need to be plugged into the mains.
They are designed for general, light tasks around the garden such as trimming around the fence and edging the lawn.
Nothing – a strimmer is just a shortened version of grass trimmer. Trimmer is the generic term, while strimmer (and any other distinctions) are typically coined by manufacturers for the same thing.
The only exception is a brushcutter, which is a highly powered machine designed to cut tougher foliage and small trees. You can convert most petrol trimmers into brushcutters by swapping the line-trimmer head for a metal blade.
The cheapest grass trimmers are corded electric models, which you can buy for as little as £20. However, in our tests we've found that buying a very cheap grass trimmer is often a false economy.
You can get a Best Buy electric grass trimmer for around £50, so you don't need to spend much more to get a decent model.
If you're just planning to cut your lawn edges, look at buying long-handled shears instead. These are better for the environment and much quieter in use. They're also easier to cut a straight line with than some grass trimmers.
Cordless models are more expensive. The cheapest Best Buy is around £80, and this is suitable for lighter tasks around the garden. However, for a more powerful grass trimmer with a longer-lasting battery, you can expect to pay around £200.
The most expensive cordless grass trimmers are designed for cutting down long grass and tough weeds, and have a long shaft and a fixed head. These are more heavy duty and often cost more than £300, including the battery and charger.
Petrol grass trimmers cost more than both cordless and electric models, with the cheapest starting at around £100. They're best suited to heavy-duty tasks, and it's worth paying a bit more for a top-scoring petrol model.
The most common problem is the line or blades breaking or running out. You'll be able to buy new ones from garden centres and diy stores - contact the manufacturer if you have difficulty finding them.
More expensive brands, such as Stihl, can be taken to a garden-machinery specialist for repairs if the trimmer breaks. Cheaper plastic trimmers may wind up in landfill if they break.
Manufacturers often have one or two standard batteries and chargers that are compatible with a wide range of tools. Before you buy, check to see if any of your existing tools have a battery and charger that you can use with the tool you're planning to buy, as this could save you a considerable amount of money.
Alternatively, you may see it as a good chance to buy a second battery for your tools. Batteries are sometimes cheaper when bought with a tool, and it’s often useful to have a second one charged and ready to go when you’re carrying out jobs that will take some time to finish.
If you're want a grass trimmer for simple tasks, such as tidying the edges of the lawn by a fence or neatening straggly grass around a rotary drier, then you won't need a model with lots of features. But for anything more, the following additions could prove invaluable:
All grass trimmers cut using either a string-like line or small plastic blades.
Trimmer line is designed to break if it hits something too hard to prevent it getting wrapped around the object. It also wears down gradually and will snap when it becomes too thin. As a result, you'll need to feed out more line, and this is done by one of three different systems:
In each case you need to remember to feed out more line regularly, or it can become too short and disappear back inside the head.
Most grass trimmers have a double line. This lets you cut more quickly, but threading the line on the spool is slightly trickier.
Line can cost as little as 20p a metre, but it will all depend on the quality and the amount you buy at one time.
Plastic line shreds when used and scatters small pieces of plastic. There are some lines that are claimed to be biodegradable. These aren't widely available though and aren't suitable for all machines.
Bladed grass trimmers avoid all the problems of line-feed systems, as it's easy to replace the blades on the trimmer head.
However, they're not really designed for tough jobs such as tackling long grass and weed patches, and often break on hard surfaces such as fences and garden furniture.
They can also be expensive, costing up to £1.40 per blade in some cases, so you'll need to factor this into the overall cost of owning a grass trimmer. However, some manufacturers offer free blades for the life of the grass trimmer.
Plastic blades can deposit broken plastic on to the garden if they get damaged while in use.
For super tough weeds such as brambles, or for areas of brash, a brushcutter is a better tool. This replaces the grass-trimmer line head with one that has a triangular metal plate that spins at high speed. This is longer-lastting than a plastic blade or line and shouldn't leave waste in the garden.
Use these with extreme caution. Alternatively, employ a professional gardener to carry out this work for you.
Below we've listed the key specs and features for some of the most popular grass trimmers.
This relatively pricey Bosch cordless trimmer is more powerful than most. It's intended for cutting long grass, which is typically more suited to petrol versions. But does its extra oomph mean it's too hard to use for lighter garden tasks such as edging the lawn?
The Qualcast Corded Grass Trimmer 600W has the largest motor of the brand's range of corded electric grass trimmers, and it's also one of the cheapest trimmers we've reviewed. In fact, there's only a handful of cheaper models on our website.
Does a bigger motor mean better trimming?
This large petrol grass trimmer is designed to tackle tough brambles and rough foliage. It uses a double line to cut, and you can turn it into a brushcutter by swapping the trimmer head with a blade. The Stihl FS94 C-E has bike-style handles that are meant to help when cutting larger areas, but how easy is it to use in practice?