How to Install Steel Garden Edging

How to Install Steel Garden Edging

A crisp, clean edge along your garden bed or landscape border adds a polished, professional touch. Rather than struggling to keep grass and weeds from encroaching on your planting space, steel garden edging provides a sturdy, straight boundary that not only keeps plants neatly contained but gives your garden an extra visual structure.

While flexible plastic and aluminium edging can work for a time, nothing maintains straight lines and right angles like steel. Steel garden edging is durable, hardy, and when properly installed will retain its form for many years.

Installing steel edging does take some upfront work, but the long-lasting results are worth the effort. Here’s everything you need to know to successfully add steel lawn edging to your garden.

Tools and Materials You’ll Need

Installing steel lawn edging requires a few specialized tools to get the job done right:

  • Tape measure - for accurate measurements
  • Metal snips - for cutting the steel edging to size
  • Sledgehammer - for securing the edging in the ground
  • Stakes - these will help hold the edging in place during installation.
  • Shovel - for digging the trench to sink the edging into
  • Gloves - to protect your hands while working the steel
  • Safety glasses - when hammering and cutting the edging

You’ll also need to purchase steel edging strips in the appropriate length and thickness for your project. 6mm thick edging is best for straight runs, while 3mm can work for curved sections.

How to Prepare Your Garden Bed

The first step in any new edging project is preparing the garden bed or border area to receive the steel barrier.

Clearing the Area

We recommend removing any existing edging materials, gravel or plants from the planned edging installation area.

Clear at least 8-12 inches of space on the outside of the planned edging line to have room to work. Identify any sprinkler lines, cables, or other subsurface elements so you can avoid them when digging.

Take the time to weed the garden bed thoroughly. This will prevent weeds from growing through the edging later on and ensure a neat appearance.

Marking the Boundary

Use stakes and string to clearly mark the outline of where you want the new steel edging to go. The string line should be placed about a centimetre away from the visible face (with no fixings) and level with the top of the edge. Outline curved beds as precisely as possible.

This string line will be your guide for digging the trench and installing the edging. Get this step right and the finished product will have clean, smooth lines.

Digging the Trench

Using a shovel or garden spade, dig a trench at least 4-6 inches wide and 5-6 inches deep along the string guideline. The steel edging must be buried sufficiently deep to prevent frost from pushing it up. We recommend burying one-third of the edge in the ground or in driveways where it may be driven over, and burying at least half of the edge below ground level for added stability.

Maintain straight trench sides and a consistent depth for the most professional result. Use a level or a long straight board to ensure that your trench is even and straight.

How to Measure and Cut Steel Garden Edging

Once your bed is prepped, it’s time to customize the steel strips to fit.

Measure the length of each side of the garden bed from end to end. For straight runs, measure in one continuous length rather than each section between corners. Transfer these measurements to the steel edging strip and mark the cut lines with a marker or chalk.

Use metal snips to cut the edging to size at the marked lines. Wear gloves to protect your hands from sharp edges. Steel edging can also be cut with a hacksaw or angle grinder.

Repeat this measuring and cutting process until you have custom edging strips for each side of the bed.

How to Install Steel Garden Edging

With your trench dug and edging cut to size, it’s time for installation.

  1. Start by staking every 2-3 feet along the marked boundary line. The stakes will temporarily hold the edging upright in the trench as you anchor it in place. We recommend leaving a portion of the stakes above the top of the edge until you are happy with the overall line. This will make it easier to remove them and to make adjustments if required. 
  2. Position your first steel edging strip into the trench, lining it up against the stakes for straight, even spacing. When lawn edging, we recommend setting the top of the edge at soil level so the grass and thatch layer is above the top of the steel, this works well aesthetically and ensures mowers do not hit the top of the edge.
  3. Use a sledgehammer to gently tap the edging down into the earth. Continue hammering along the strip until it is firmly anchored at the bottom of the trench. The stakes will prevent the edging from shifting while hammering.
  4. Check that the edging remains straight and at the proper height as you work. Make alignment adjustments as needed.
  5. If forming a stand-alone curve, begin at the end by inserting stakes into the two end sleeves before attempting to bend the steel (a stake in a single sleeve allows the edge to pivot around the stake, while two stakes should provide enough grip for the edge to begin bending round). If you're forming a curve as part of a larger run, simply start curving the steel to the desired arc and knocking the stakes in as you go.
  6. Once the edging is fully secured in the trench, backfill the soil on the outside to cover the buried portion. Pack the soil firmly around the edging with your shovel to hold it in place.
  7. Repeat this process to install edging along each side of your garden bed or border. Join pieces together end-to-end by overlapping them in the trench.
  8. Remember to leave unfinished edging ends unsecured until adjoining pieces are installed. This allows room to adjust fit and join ends neatly.

Mild Steel Garden Edging

How to Join Two or More Lengths Together

Because of the strength of our joining system, you can attach up to four lengths of our edging at once while laying flat next to its final position; this saves time and is easier than joining individual lengths of edging vertically in its final position, especially on curves.

Please take care not to overbend the edge if doing this. While our joining system is one of the most robust in the industry, joins are still the most vulnerable part of the edge. Small movements of the edge all along its length are the best way to get it into position.

How to Bend Steel Garden Edging

For curved garden beds, you’ll need to bend the straight steel edging to shape. If you prefer sharp angles, we offer 90-degree internal and external corner pieces which allow you to join steel edging strips seamlessly. If you need to permanently bend the steel edge to form tight curves or angles, this can be done with a few simple steps and tools:

Our 3mm thick edge can form a complete circle with a diameter of around 2 metres without deforming, and the 6mm thick edge can form a circle with a diameter of around 4 metres (the 200mm and 300mm heights can achieve a 5-meter diameter circle). Be careful not to overbend to the point where it cannot return to the straight position, as this will result in a kink.

You'll get a feel for how the steel reacts, so keep checking to make sure you have a smooth curve or straight line. Small adjustments make a big difference, and it's important to get it right during installation because the ground around the edge and stake will settle and firm up over time, making it difficult to adjust.

3mm Steel Garden Edging

For our thinner 3mm edging, you can bend it by hand. Start by marking bend lines on the edging where you want the curve to start and stop. Bends look best when smooth and gradual.

We recommend laying a plank or similar perpendicular over the top of the steel with the point you want to bend protruding, then standing on the plank, pulling the steel up and bending it just beyond the angle you're attempting to achieve.

To make tight curves in the 3mm edge, repeat the process but bend the steel in small increments 2-3cm apart. These slight bends at regular intervals will together form a nice even curve.

It does take some skill to bend the steel just enough each time to create the desired curve. Most people overextend themselves, so be cautious. Feel for when the steel simply gives and stops. A little tip is to look for surface crackling. If you overbend, simply flex the edge in the opposite direction until you feel it give. Any incorrect bends can be removed by hammering them out over a hard flat surface, such as concrete.

6mm Steel Garden Edging

Thicker 6mm edging requires more force. The 75mm and 100mm high can be bent using the method described above, but the 150mm will most likely require the assistance of another person. We don’t recommend trying to permanently bend our 200 and 300-mm edging, although it will still flex to form curves.

Tips for Maintaining Steel Garden Edging

Properly installed steel garden edging should retain its crisp edges for many years. But a little seasonal maintenance will keep it looking its best.

  • Check for loosening each spring and after any ground freezing or heaving. Re-hammer any stakes to keep edging snug.
  • Touch up any scratches or paint chips. This prevents rust from forming and spreading under the finish.
  • Keep grass and weeds from growing over the exposed edging, which ruins the clean lines.
  • Avoid using weed whips along the edging, which can damage the galvanized surface leading to premature rust.

With its durability and longevity, steel is one of the best options for edging garden beds and creating crisp boundaries in your garden. Follow these steps for a professional-looking installation that will keep your landscapes neatly contained for many seasons to come.