Metal lawn edging, available in steel and aluminum, is one of the most durable ways to define garden beds, pathways and driveways. According to the University of Illinois Extension, metal edging is the longest lasting material you can choose for landscape borders. This guide walks through the practical differences between steel and aluminum, what to expect during installation, and how to avoid common problems like frost heave. If you are still comparing materials, our metal lawn edging category page and the broader lawn edging materials comparison can help you weigh your options.
Steel vs. aluminum: what the University of Illinois Extension says
Rhonda Ferree, a horticulture educator with University of Illinois Extension, explains that metal edging, including steel and aluminum, outlasts other common materials. Steel edgings have been used for more than 30 years, but they are relatively expensive and difficult to install properly. The Extension notes that steel edging has problems with frost heaving in the winter. Because of its strength, steel is best used where a great deal of side-strength is required, such as along driveway edges. For projects like driveway edges, that rigidity is a real advantage.
Aluminum edging, by contrast, is easier to work with during installation. The trade-off, according to the Illinois Extension, is that the silver color appears unnatural in many landscapes. If the look of bare aluminum does not fit your garden design, you might need to consider how it will blend with plants and hardscaping. Both steel and aluminum can create clean, neat lines that minimize hand trimming and help contain mulches within bed areas, as long as they are installed correctly.
How metal edging helps retain shape and ease trimming
The Royal Horticultural Society (RHS) advises that installing wood or metal edging helps to retain the shape of a lawn edge and makes edge trimming easier. A well-defined lawn edge with a decent drop down to the border also helps keep mulching material in place. The RHS recommends broad, sweeping curves over intricate shapes because they are easier to maintain. If you are planning a curved border, our guide on curved lawn edges offers additional layout tips.
When you install metal edging, you are essentially creating a permanent barrier that stops grass from creeping into beds. The RHS notes that a crisp edge prevents lawn grasses from encroaching into adjacent borders. This means less time spent hand-trimming and more time enjoying a tidy landscape.
Digging the trench and calling 811
Any metal edging project starts with digging a trench. The RHS outlines a straightforward method for creating a lawn edge: mark the shape with a string line for straight edges or a garden hose for curves, then cut along the line with a half-moon edging tool or a flat-backed spade. The RHS suggests marking a depth of 7.5cm (3in) on the spade blade to keep the cut consistent. After cutting, you remove the unwanted grass and check that the line is neat from both ends.
Before you put a shovel in the ground, the national 811 service reminds every homeowner to contact 811 a few business days before any digging. The Common Ground Alliance, which runs the 811 program, describes not calling before digging as the #1 cause of utility damage. You will need to provide the address, county, nearest cross street, and the type of project. After you contact 811, wait a few days for utilities to mark their lines, then dig carefully around the marks. This step is just as important for a metal edging trench as it is for planting trees or installing a mailbox.
Preventing frost heave with proper installation
Frost heave is a known challenge with metal edging, particularly steel. The Illinois Extension states that most frost heaving can be stopped by using grooved or lip-style edging, steel anchoring stakes, and proper installation procedures. The edging itself should be set firmly in the ground so that freeze-thaw cycles do not push it upward. While the Extension does not prescribe a specific depth for metal edging, it does mention that a hand-edged bed 4 inches deep and wide can contain bluegrass. That gives a rough sense of the scale needed to keep grass roots from traveling under the barrier.
When you install metal edging, take extra care to drive anchoring stakes deep enough to resist movement. The combination of a lip or groove that locks into the soil and sturdy stakes helps the edging stay level through winter. For more detailed steps, see our straight lawn edges installation guide.
Edging tool safety: what the Lawnmaster manual says
Once your metal edging is in place, you will likely use a string trimmer or a dedicated lawn edger to maintain the crisp line. If you use a powered edger, always follow the safety rules in your tool’s manual. The Lawnmaster 21V cordless lawn edger manual, for example, emphasizes several key precautions. Always wear eye protection, and use non-slip safety footwear and heavy-duty gloves. Keep children and bystanders at least 15 meters away from the operating area. Remove debris like small stones and sticks from the work area before you start, because the blade can throw objects. The manual also says to avoid operating on wet grass, not to expose the edger to rain, and not to use it in explosive atmospheres.
These safety principles apply broadly to any power edging tool. If you use a manual edger, you still need to wear sturdy shoes and gloves, and keep the blade away from your feet. For more on tool choices, visit our lawn edging tools overview.
Maintaining metal lawn edges
Metal edging requires little upkeep once it is properly installed. The RHS points out that a well-maintained edge prevents lawn grasses from encroaching into borders. You can touch up the edge with a half-moon edger or a string trimmer as needed. The Illinois Extension notes that even hand-edged beds need to be touched up once or twice a year, and the same periodic attention keeps a metal-edged border looking sharp. Check that anchoring stakes have not loosened after winter, and tap them back down if necessary. If you notice any sections heaving, re-set them before the problem worsens.
Because metal edging is long lasting, you will not need to replace it as often as plastic or wood. The main task is simply keeping the adjacent grass trimmed so the metal line remains visible. For seasonal care tips, our seasonal lawn maintenance page can help you plan a routine.
Frequently asked questions
Is steel or aluminum better for a driveway edge?
According to the University of Illinois Extension, steel edging is best where a great deal of side-strength is required, such as driveway work. Aluminum is easier to install but may not provide the same rigidity under the weight of vehicles. If you are edging along a driveway, steel is the more practical choice.
Will metal edging stop grass from spreading into my flower beds?
Yes. The Illinois Extension explains that edging forms a clean, neat line between planting areas and turf, and helps contain mulches. The RHS adds that a well-defined lawn edge with a decent drop down to the border keeps mulching material in place and prevents lawn grasses from encroaching. When installed at an adequate depth, metal edging acts as a physical barrier that grass runners cannot easily cross.
Do I really need to call 811 before digging a trench for metal edging?
Yes. The 811 service, managed by the Common Ground Alliance, states that you should contact 811 a few business days before any digging, even for shallow projects. Some utilities are buried just inches below the surface, and failing to call is the leading cause of utility damage. The call is free and helps you avoid hitting gas, electric, or communication lines.
For a broader look at how metal compares with plastic, stone and other materials, visit our lawn edging types section.
