A string trimmer, sometimes called a weed whacker, makes trimming lawn edges and flower beds easier and more precise, allowing you to reach areas a lawnmower can’t. However, using this powerful tool requires proper technique and safety precautions. In the video, This Old House landscape contractor Roger Cook demonstrates the correct methods for using a string trimmer effectively and safely. Here, we’ll offer some additional information about safe and effective trimming.
Safety First: Protecting Yourself While Trimming
The high speed of the spinning nylon string allows the trimmer to cut through plants easily, but can also cause safety hazards. Thus, proper protective gear and precautions are essential to prevent injuries to yourself and others.
Essential Safety Equipment
- Closed-toe shoes: Opt for sturdy footwear to protect your feet from flying objects and accidental contact with the trimmer.
- Eye protection: Wear safety goggles to shield your eyes from flying debris.
- Hearing protection: Use earplugs or earmuffs to protect your hearing from the loud engine noise.
- Long pants: Wear sturdy, long pants to protect your legs from debris and potential contact with the trimmer line.
Gasoline Safety and Storage
If you have a gas-powered string trimmer, it makes sense to keep some gasoline around. However, to make gasoline shelf-stable, you need to add a stabilizer while it’s fresh or it’ll degrade. Only store gasoline in approved, closed containers and store them on the ground out of the sun.
If your string trimmer has a two-cycle engine, you’ll need to mix oil with the fuel as recommended by the manufacturer. The best way to get the correct ratio is to add the recommended amount of oil to the gas storage container and then pump in one gallon of gasoline. Shake thoroughly before adding the mixture to the trimmer’s fuel tank.
Additional Safety Precautions
When using a string trimmer, always be aware of your surroundings. Keep children and pets away from the work area, and be mindful of nearby objects that could be damaged by flying debris. Additionally, avoid using the trimmer in wet conditions to prevent slipping and potential electric shock with corded models. Always check the condition of the tool and confirm all safety guards are in place before starting.
Proper Technique for Effective Trimming
Mastering the correct technique will keep you safer and make trimming your lawn quicker and easier.
Trimming Along Obstacles
Hold the trimmer head parallel to the ground to trim grass along obstacles such as rocks, fences, or walls. This ensures an even cut and prevents damage to the trimmer line or the obstacle itself. Move the trimmer slowly and steadily along the edge for the best results. Remember, a steady hand produces a precise cut, reducing the need for repeated passes.
Edging Flower Beds
Creating a clean edge along flower beds requires rotating the trimmer vertically, holding the trimmer head perpendicular to the ground. This allows you to create a straight line between the lawn and the bed. Move the trimmer slowly to achieve a clean cut and avoid damaging plants in the bed.
Protecting Trees
Exercise caution when trimming around trees. The monofilament line can easily damage tree bark, potentially harming or even killing the tree. Instead of trying to awkwardly shimmy the trimmer right next to the trunk every time you cut the grass, create a mulch ring around the tree or use hand tools for close trimming. This approach protects the tree and enhances its health by retaining soil moisture and regulating temperature.
Maintaining Your String Trimmer
Regular maintenance will help your string trimmer last. Here are a few tips to help you get the most out of your device.
Replacing the Trimmer Line
You’ll need to replace the trimmer line when it breaks or wears down. If your trimmer requires manual restringing, follow these steps:
- Remove the spool from the trimmer’s head.
- Cut an 8-foot-long piece of new trimmer line.
- Feed one end of the line through the hole in the spool and pull the ends even.
- Wind the line around the spool in the direction indicated by the arrow on the spool.
- Secure the line ends in the notches on the spool’s edge.
- Reattach the spool to the trimmer, ensuring the line ends feed through the holes in the spinning head.
- Tug on each line to release it from the notches.
For self-winding heads, simply feed the line through the spool and rotate the head to wind it automatically.
Maintaining the Engine
For gas-powered trimmers, regular engine maintenance not only extends the life of your trimmer but also leads to safer and more efficient operation. This includes:
- Checking the spark plug: A functioning spark plug is essential for engine startup and operation, so check it every year and replace it as necessary.
- Cleaning or replacing the air filter: Trimmer air filters get dirty quickly from all the dust. A clean filter improves engine efficiency by ensuring a proper air-to-fuel mixture.
- Cleaning the muffler: Carbon can build up on the muffler or spark suppressor, so check it and clean it occasionally. Do the same for the cooling fins.
- Greasing the gearbox: Straight-shaft trimmers feature a gearbox that requires periodic checking and refilling.
- Regular oil changes: Fresh oil reduces friction and ensures the engine runs smoothly. If your trimmer doesn’t require oil mixed in with the fuel, you must change the oil separately.
- Replacing the fuel filter: Consult the manual, but typically, you’ll need to replace the fuel filter every two to three years.
Types of String Trimmers
String trimmers are primarily classified by their power source, each with its own advantages and limitations.
Gas-Powered Trimmers
Gas-powered trimmers are known for their power and mobility, but they burn fossil fuels and require you to have gas on hand. They are ideal for larger yards and more demanding jobs. They come in two shaft designs:
- Curved shaft: More maneuverable and often lighter, suitable for smaller yards. These are easier to handle and ideal for beginners.
- Straight shaft: Offers better reach and is ideal for taller users. It’s suitable for trimming under obstacles like bushes and benches.
Electric Trimmers
Electric trimmers are quieter and more environmentally friendly than gas models, though they tend to offer less power. They are perfect for smaller yards and lighter tasks. They come in two varieties:
- Battery-powered: Offers cordless convenience but may have less power and limited runtime compared to gas models.
- Corded: Provides consistent power but limits mobility due to the cord length. They are lightweight and require access to electrical outlets. You’ll need to provide your own extension cord.
- Multi-task: Saves space by offering multiple lawn tool functions. Some manufacturers make battery-powered bases that can attach to different tool heads including string trimmers, pole pruners, power cultivators, and leaf blowers.
Note that electric string trimmer technology has improved substantially in recent years. In fact, high-quality cordless models perform nearly as well as some gas-powered trimmers. Modern battery-powered trimmers are highly efficient and include interchangeable batteries for extended use. However, they may still be challenging to use for yards larger than about half an acre.
Propane-Powered Trimmers
Propane-powered trimmers offer a balance between power and environmental consciousness. They burn cleaner and run quieter than gas models while providing comparable power. These trimmers use small propane tanks similar to those used for camp stoves, offering about two and a half hours of runtime per tank. Propane-powered trimmers are gaining popularity due to their efficiency and reduced emissions.
Choosing the Right Trimmer
Selecting the right trimmer depends on your specific needs:
- For large areas with thick grass or hardy weeds, a gas-powered trimmer is ideal.
- For small to medium-sized yards, use an electric or battery-powered trimmer.
- If you are environmentally conscious and need a balance between power and efficiency, a propane-powered trimmer is a great option.
