How to Weed Eat Your Lawn Like a Pro

close-up of the underside of a string trimmer, with cut grass stuck to the underside

Getting a professional-looking, crisp edge on the lawn is the one thing that will make your lawn stand out from the pack. We can tell you how to weed eat like a pro, and then all your neighbors will be trying to find out your tips and tricks.

How to weed eat your lawn 

We’ll assume that you’re using a string trimmer (not an edger with a hard metal blade) for this discussion.

1. Mow the lawn

close-up of the back side of a lawn mower sitting on grass
Phil Roeder | Flickr | CC BY 2.0

Many pros prefer to mow, edge, and then blow — in that order. After you set the mower blade at the proper height, the mowed grass serves as a guide for how high to weed eat around the perimeter and flower beds after you’re through.

2. Gear up and prep

You wouldn’t get in a car without a seatbelt, so don’t edge your lawn without proper safety equipment.

Protective gear:

  • Long sleeves and pants
  • Gloves
  • Safety glasses or a face shield
  • Closed-toe shoes
  • Ear protection

These machines spit out grass and other lawn debris at speeds that can cause real damage if you are not properly outfitted. So, gear up before you go out.

If you want professional results from your gear, you’ll need to pay for professional gear, or at least buy a gas or propane-powered machine. The corded electric and battery machines aren’t as powerful and won’t give you professional-level results. 

Straight shaft vs. curved shaft weed eaters: Similar to the performance of gas vs. electric machines, straight shaft machines perform at a higher level than curved shaft machines. Curved shaft machines weigh less and are better for small lawns with light weed-eating needs. They are also good for inexperienced beginners. Straight shaft models also offer a longer reach and more versatility for cutting weeds underneath bushes and doing heavier work. 

Think of the curved shaft models as the cost-effective residential choice. Straight shaft models are the pricier, commercial workhorses that run all day and can do almost any job a weed eater is designed to do.

String length on your trimmer: If you keep the debris guard on the machine, it will always trim the string to the perfect length for that machine. If you take the guard off, you can use the bump cap to extend the string to whatever length you want. Once you start the engine, bump the cap on the ground a few times to extend the string to your desired length. Six or so inches is common for pros who take off the debris guard and use the string to edge along the lawn.

Holding the trimmer: Most pros use the handle to hold the trimmer whether they are weed eating with the line parallel to the ground or have the line vertical for edging. The handle provides a comfortable handhold and keeps the machine stable. Many folks find it comfortable to rest the handle against their hip for better control. Alternatively, you can use a strap or sling to help decrease the weight of the machine.

3. Weed eat your lawn

Man using a weed eater on his lawn
Jared Muller | Unsplash

Weed eating is essential for lawn maintenance, and it’s a DIY project that anyone can do. Don’t be too hard on yourself if your lines don’t look perfectly straight the first time. It may not be difficult, but it takes practice to edge like a pro.

There are many ways to use a weed eater around your lawn. Weed eaters have two main functions: weed eating and edging. Weed eating means cutting down grass and weeds in areas where the lawnmower won’t fit. Edging means creating or maintaining an edge between two surfaces.

If you haven’t already done so, remove all hoses and other obstructions from your work area.  

How to start your gas weed eater (for a cold gas engine):

  • Put the weed eater on the ground. 
  • Prime the engine bulb 5-10 times.
  • Close the choke and pull on the starter cord a few times until the engine starts to turn over.
  • Put the choke on half choke. Pull the starter cord until the engine starts to run.
  • Close the choke. If the engine turns off, repeat this process.

If your engine is warm, start with the choke on half choke and go from there.

Electric-powered machines require a cord, and battery-powered machines only require a battery. From there, pull the trigger and safety to start the engine.

How to weed eat around trees and flower beds:

  • Pull the trigger (and safety) to start spinning the line.
  • Hold the line parallel to the level of the mowed grass. Move the weed eater across to the taller grass. Keep moving the line back and forth. (Move the head left to right if your head spins clockwise and vice versa if it spins counterclockwise.) 
  • Walk around the tree or flower bed until all the grass is even. Don’t get too close to your trees; you don’t want to damage the bark. (The flip down edge guard and the debris shield on the trimmer will keep your line short and keep you from hitting objects beyond the guard.)

Pro Tip: If your beds are filled with rocks, use a concrete or other hard border around the beds. When you weed eat, you won’t risk flinging rocks at yourself.

How to edge between the grass and paved surfaces:

  • Flip the trimmer upside down so the line is vertical. 
  • Start the engine. Pull the trigger and safety to start spinning the line.
  • Hold the weed eater line at 90 degrees to the pavement. Walk along the edge.

Your first pass may be slow, but with practice, your edging will be faster and more precise. 

Edging around the pool deck: Weed eating around a pool is the same as weed eating around your driveway, but you want to prevent the clippings from blowing into your pool. A simple way to do this (easiest with a friend) is to tape together a few cardboard boxes and use them as a shield between the pool and the weed eater. You also can have your friend face you with the blower while you edge.

If you have a screened-in pool, you also have the issue of not cutting into your screen as you weed eat. Many weed eaters come with flip-down edge guards that extend out a few inches at the front of the weed eater. (This is in addition to the debris shield, which keeps your string line cut to a safe length.) As long as you have the edge guard at the front and the debris guard at the back, your line will not be longer than these guards and you’ll avoid cutting your screen.

Another option is to add an ornamental bed next to your screen with landscape fabric and mulch to keep the weeds at bay. This way, you may only have to remove weeds from this area a few times per year instead of every week.

Creating an edge vs. maintaining an edge: If you need to maintain an edge around flower beds, driveways, etc., a string trimmer with a nylon line is fine. If you need to create an edge between the driveway and the grass or around flower beds, use an edger. A manual edger is sufficient for small lawns, and a powered edger works well for larger jobs. 

To clarify: Weed eaters and edgers are different tools. Weed eaters maintain an edge (and do many other things around the lawn), but edgers are used to establish an edge between grass and other areas. 

Pro Tip: There is much debate about which way you should walk when you’re edging. People whose trimmer line runs counter-clockwise should walk right to left because that’s the way the head is spinning. If you walk left to right, you’ll have much more drag to deal with. If your trimmer spins clockwise, walk left to right

For safety reasons, avoid trimming along beds with rocks, and hold the weed eater at a normal distance. Don’t stand back so far that you are bending over to keep it further away or so close that your feet are right up to the line of the concrete.

4. Clean up

Finally, blow the small bits of grass clippings into the lawn to give your work a professional finish. Don’t underestimate the benefits of leaving grass clippings on your lawn. A year’s worth of clippings left on the lawn as you mow is equal to one fertilizer treatment. 

Other uses for weed eaters

Weed eaters do more than mow down weeds or create edges. Here are a few other ways you can put your weed eater to work:

  • To cut very tall grass before you mow 
  • To take down tall grass along slopes and in ditches
  • To use as a multi-purpose machine: Some weed eaters are designed as dual-duty weed eaters and brush cutters. These machines accept standard string trimmer lines and a variety of different rotating blades for heavier work.

FAQ

1. Why are there so many different names for weed eaters?

We can’t say for sure. Some seem to be regional, but whatever the reason, here are some of the many names for this humble workhorse: 
Weed whacker (or weed wacker)
Weed trimmer
Trimmer
String trimmer
Whipper snipper
Weed whipper
Strimmer
Line trimmer

2. Is the guard on my weed eater necessary?

It serves a useful purpose, but it’s not necessary. There are pros and cons to keeping it on.

Pros:
✓ Safety: Protects you from flying debris
✓ Cuts string to the manufacturer’s recommended length
✓ Less string means less strain on your machine
✓ Keeps string from hitting fences, trees, and other objects

Cons:
✗ Shorter string
✗ Less visibility
✗ Not as easy to maneuver

3. What other tips will give my lawn a professional look?

Any homeowner can create a great edge around his lawn, but not every homeowner has a great lawn to edge. A well-edged lawn that is short and thin doesn’t stand out nearly as well as one that is tall and dense. To create a nice edge, you need to start with a tall, full lawn. If you’re new to lawn care, let us guide you through how to grow a full lawn you’ll be proud to edge. Check out our articles on lawn health:

Mow
Water
Fertilize
Aerate
Overseed

If you prefer to leave the professional finish to the experts, contact one of our local lawn care pros. They’ll have your lawn looking sharp in no time.

Main Photo Credit: Hedwig Storch | Wikimedia Commons | CC BY-SA 3.0

Sarah Bahr

Sarah is a writer who has previously worked in the lawn care industry. In her spare time, she likes to garden, raise chickens, and mow the grass with her battery-powered lawn mower.