Grass Trimmers Buying guide
Grass trimmers are essential for keeping the edges of your lawn tidy and for trimming those areas your lawnmower just can't reach.
Trimmers don't use a blade. Instead, they spin a nylon line at an incredibly fast speed. This makes it strong enough to cut through grass and plants, but allows you to use it against driveways, fences, sheds and more without fear of damage.
Trimmers that use a blade are known as brush cutters. These are used for cutting back thick, heavy plant vegetation rather than for general use around your lawn.
Let's explore the various trimmer types available, so you can make the best choice for your garden.
Electric, cordless or petrol
Trimmers are either powered by mains electric, cordless battery or petrol. Each type has its benefits and drawbacks. Brush cutters are normally petrol powered, but electric models are also available.
Electric trimmers are an affordable, lightweight choice for small to medium lawns. They're mains powered, so you'll need to ensure the cable is long enough to reach the closest plug socket. If not, you'll need an extension cord.
Cordless models are battery-powered, so your movement isn't restricted. They're still fairly light, but make sure you pick one that carries enough charge to allow you to complete your work. Otherwise you'll have to stop to recharge.
A petrol trimmer gives you more power and endurance to deal with large areas and thicker grass. This is why most brush cutters are petrol powered. But they are heavier and noisier than other models and will also require more servicing.
Line feeds - and why they're important
As already mentioned, trimmers cut with a line instead of a blade. This makes them safer to use, but does make them vulnerable to wear and tear.
Because of this, most trimmers include a whole reel of line contained within the head. What you see when you look at the head is only the ends of the line. As the line wears out, more can be released so you can continue trimming. Eventually, the line will run out, at which point you'll need to purchase a replacement.
It's important to understand how each trimmer releases the line during use, as this impacts how you use your trimmer.
For manual feed models you'll need to stop the trimmer during use and pull out more line yourself. These models tend to be inexpensive and allow you to control how much line you use. But releasing the line can take a bit of effort.
When the line starts becoming short, a bump feed system allows you to simply tap the head on the ground to release more line. This means you can continue uninterrupted, but care is needed to prevent damage when you 'bump'.
Automatic feed systems simply feed more line when it's needed. This means you can trim uninterrupted, but it doesn't allow you to control exactly how much line you use. Automatic feeds can also be harder to repair if damaged.
Brush cutters are the heavy-duty cousin of grass trimmers. They use a spinning blade made from either metal or plastic to tackle thick growth and vegetation.
They're not made for careful tasks, so they're not ideal for tidying your lawn. Brush cutters are best for areas such as under bushes, grass verges, steep banks, around ponds or streams, or for cutting back wild grass so it doesn't encroach on your lawn.
They are, however, perfect for tackling lawns that have become seriously overgrown. You can use a brush cutter to cut back the grass to make it more manageable for a lawnmower.
One drawback of brush cutters is that because the blade is solid and more exposed, it can be easily chipped or broken if it strikes something hard. But replacement blades are available and easy to attach.
The essential specs
Now you've an idea of the different types available, it's time to look at the essential specs you'll need to compare before making your choice.
Single or dual line
Grass trimmers come with either one or two lines. Two lines provide faster cutting, but smaller, single line trimmers are fine for trimming grass on small, tidy lawns.
The more powerful the motor, the more trimming power. Electric motor power is measured in watts, cordless battery power in volts and petrol motors in CCs.
Generally speaking, for small lawns or for light use, not much power is needed. Electric models from 250Ws - 400Ws or cordless models with 14 volts and above will be suitable. But for larger lawns, with difficult areas, more force will be required.
This decides the cutting range of the trimmer. Larger cutting widths will make cutting large areas quicker, but may be restrictive for small, hard-to-reach areas. Here's a general guide to the cutting widths you should consider:
- 20 to 30cms for light grass trimming for small-to-medium lawns
- 35 to 38cms for thicker grass and medium-to-large lawns.
- 40cm and larger for heavy work, like thick grass and undergrowth
For electric trimmers you'll need to know how far the power cord reaches so you can determine whether an extension cord is required.
Running time & charging
If choosing a cordless model, ensure the battery will last long enough to do all the work, and check how long it takes to recharge after.
You could be carrying your trimmer for a long time if you have lots to do. Check your choice is light enough to carry comfortably for the duration. Some heavy models and usually brush cutters, will come with a carry strap.
Adjustable shaft (handle)
You'll need to be able to use your trimmer comfortably, ideally without having to bend. Check the trimmer height and whether it has an adjustable shaft or telescopic handle.
Two or four cycle motor
Petrol motors come in two types. A two cycle motor requires a mix of oil and petrol for fuel, while a four cycle motor requires only petrol. It's essential to know, as adding the wrong fuel will cause damage.
These are all features that can make using your grass trimmer that bit easier.
Many trimmers come with a guard that allows you to trim against trees, fences and other objects safely without the line coming into contact.
An adjustable head will rotate or tilt to help you to get the right cutting angle.
A model with reduced vibration will help take some of the strain and effort out of mowing.
Some trimmers can convert into an edger to give you a perfect cut across your lawn's edges.
This allows you to trim at a low angle, helping you to get under benches, chairs and other furniture.
Petrol trimmers and brush cutters have a pull start motor, which can make them tough to get going. A fast start mechanism usually involves a simple switch or twist key mechanism that starts the motor instantly.