How To Use a Grass Trimmer

The grass trimmer is a versatile machine that can become a very handy companion in keeping your lawn looking its best. Trimmers come in many different shapes and sizes based on the propulsion system, however with all types, the principles are the same.

How Does A Grass Trimmer Work?

A grass trimmer is a garden tool that uses a nylon line instead of a blade to cut the grass. The propulsion system spins the wire at such a speed it is able to cut through the grass with ease. Using the principle of centrifugal force, the line becomes stiffer the faster it is spun, making it easier to cut through garden debris. The user is protected from the cutting line and any debris thrown up by a shield that covers the head of the grass trimmer.

Grass trimmers can be powered by a number of different sources. Petrol powered trimmers are usually the most powerful as the internal combustion engine is able to spin the wire much faster. As a result, this type of machine works best for the densest patches of grass. For smaller jobs, an electric or battery grass trimmer would work well, as they won’t need to work as hard. Electric trimmers will come with a cable to plug into the mains power sockets. These cables can be 10-12m typically, so you will need to size up your garden before you commit to purchasing the machine.

Although cheap to replace one of the drawbacks with this type of machine is that breakages to the line can occur. Reason for this includes;

  • Close Contact – The most frequent cause of breakage is with harsh contact with something in the garden. Usually breakages occur when the head is taken too close to garden objects like stones, walls and paving edges which causes the line to snap.
  • Incorrect Parts – It may not be ideal but breakages can be attributed to incorrect parts. You should check the manufacturers instructions for advice on the correct parts.
  • Wear and Tear – Unfortunately wear and tear can also take its toll on the trimmer. Even a product in great condition can suffer the test of time. Cold temperatures in wintertime can affect the nylon line making it brittle and hard. You should store the nylon line out of the cold and somewhere warm in the cold winter months.

To prolong the life of your grass trimmer you will need to make sure it is clean. A freshly cleaned trimmer will always perform better than a dirty one. Dirt and debris can build up in the trimmer head and can clog up the line mechanism, which means it isn’t as efficient at spinning the cutting line.

Spin Direction

Understanding the direction of the spin is very important when it comes to getting the most from your grass trimmer. If the line spins in an anti-clockwise direction, it will eject the grass debris from the left hand side and cuts better with the right side.

Therefore, if the spin is anti-clockwise, and you are moving along a fence or curb keep the right side of your body closer to where you are working. This will mean the head is positioned so that the grass is ejected to the left – otherwise it will be ejected onto the cut path you are trying to clear. This can then cause problems as the trimmer can get bogged down.

cutting technique

Cutting Techniques

Parallel cutting

This is the most common method of using the grass trimmer. By holding the grass trimmer level, the angle of the line creates a simple and straight cut. Keeping an even footing means as you transfer the weight of the trimmer it doesn’t affect the height. This can be great for fences or walls, however a small slip up can result in an uneven height.


Tapering is a handy technique that involves tilting the trimmer so that it is at an angle and the leading edge of the line is used to cut the grass. By cutting the grass at an angle it can create a cleaner and angled look to the fenced edges.


Edging is a great way to add some neat touches to the sides of the lawn. Normally this would be done for the grass by flowerbeds or driveways. It enables you to create crisp edges to the lawn by removing any overhanging blades of grass or debris.
This can be done with a grass trimmer by simply turning the line so that it is perpendicular to the grass enabling the cut to be made vertically. This can be easier with some Flymo models that have rotating heads. With most Flymo products, the head can rotate 90 degrees so that edging is easy along the extremes of the lawn.


If your grass is longer, this can be a good way to cover large areas quickly. You will need to swing the grass trimmer in a circular U-shaped motion around you. If you keep yourself in a steady position, you will get a nice and even cut.

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