Edging creates a clean border that keeps mulch in place and makes your beds look finished

Edging is a border you cut or build between your garden bed and the lawn or hardscape around it. It stops mulch from spilling into the grass, prevents grass roots from creeping into the bed, and gives the whole yard a sharper, more intentional appearance. You can edge with a shovel before you lay mulch, or install a permanent edging material like plastic, metal, or wood that stays in place year after year.

The simplest approach is to cut an edge with a flat-bladed shovel the day before you mulch. A more durable option is to install edging material—usually 4 to 6 inches tall—that sits partially underground and creates a lasting barrier. Most homeowners use one of these two methods or combine them: a permanent edging material with a fresh cut edge each spring.

Key Takeaways

  • A clean edge prevents mulch from washing or spreading into the lawn and stops grass from growing into the bed.
  • You can cut an edge with a flat-bladed shovel by slicing vertically along the bed line, or install permanent edging material like plastic, metal, or composite.
  • Permanent edging should sit 2 to 3 inches above ground and 3 to 4 inches below so it holds mulch in but remains mostly hidden.
  • Spring is the best time to edge—either by cutting fresh or installing new material—because the soil is workable and you are about to refresh mulch anyway.
  • Edging lasts longer and looks cleaner if you maintain it each year, either by re-cutting or by clearing debris that collects along the line.

Cutting an edge with a shovel

A shovel edge is the fastest method and costs nothing if you already own a flat-bladed spade. Stand at the edge of your bed where the mulch will meet the lawn. Hold the shovel blade vertical—not angled—and push it straight down into the soil about 4 to 6 inches deep. Work along the entire perimeter of the bed in one direction, keeping the blade perpendicular to the ground so the cut is clean and straight.

The blade cuts through grass roots and soil, creating a defined line. You do not need to remove soil; the cut itself is the edge. If the bed is against a hardscape like a driveway or patio, you can skip this step along that side. After you cut, lay your mulch right up to the line. The edge will settle and soften over the season, so plan to re-cut it each spring or after heavy rain.

This method works best on beds that are not too large and soil that is not compacted or full of rocks. If your soil is very hard or rocky, soak the area the day before so the shovel cuts more easily.

Installing permanent edging materials

Permanent edging sits in a shallow trench along the bed line and creates a barrier that lasts several years. The most common materials are plastic landscape edging (the cheapest), metal edging (aluminum or steel, more durable), composite edging (wood-plastic blend, longer-lasting than wood), and real wood (cedar or composite boards, most attractive but shortest lifespan).

To install edging, dig a trench about 4 to 6 inches deep along the bed line. The trench should be as wide as the edging material. Lay the edging in the trench so that 2 to 3 inches stick above ground—enough to contain mulch and look intentional—and 3 to 4 inches sit below ground to anchor it and stop grass roots from creeping under. Backfill soil on both sides and tamp it down firmly. find metal or plastic edging with stakes or spikes every 2 to 3 feet, following the manufacturer's instructions.

Plastic edging is the least expensive option and works well for straight beds, but it can crack in cold climates and may bow outward over time if mulch weight is heavy. Metal edging is more rigid and lasts longer but costs more and can rust if not powder-coated. Wood and composite edging look more finished but require more maintenance and replacement sooner.

Preparing the bed line before edging

Before you cut or install edging, walk the perimeter of your bed and mark where the edge should go. Use a garden hose, chalk line, or spray paint to outline the edge so you can see it clearly. Step back and look at the line from different angles—it should follow the shape you want and look balanced from the house and yard.

Clear any debris, dead grass, or weeds from the line itself. If grass is overgrown into the bed, trim it back first. Remove any rocks, sticks, or roots that would prevent a shovel from cutting cleanly or edging material from sitting flat. If you are installing permanent edging, loosen the soil along the line so digging the trench is easier.

Timing and maintenance

Spring is the ideal time to edge, usually in late March through May depending on where you live. The soil is moist and workable, grass is actively growing so the cut edge is visible, and you are usually refreshing mulch at the same time. Edging in spring means the line stays sharp through the growing season.

If you cut an edge with a shovel, plan to re-cut it each spring and after heavy rain or watering, which can soften and blur the line. If you install permanent edging, inspect it each spring for settling, debris buildup, or damage. Clear leaves and mulch that collect along the top so water can drain and the edge stays visible. Replace any cracked or rusted sections.

Over time, permanent edging can shift or sink as soil settles. Tamp down any sections that have heaved or tilted, and add soil underneath if gaps appear. Most plastic and metal edging lasts 5 to 10 years before it needs replacement; wood and composite last 3 to 7 years depending on climate and maintenance.

Edging curved versus straight beds

Straight beds are easier to edge because you can cut or install in one direction and the line is naturally clean. Use a chalk line or string pulled tight to keep the cut straight, or install edging in long sections and find it firmly so it does not bow.

Curved beds require more patience. Mark the curve with a garden hose or chalk, then cut or install edging in short sections, following the curve as closely as possible. Plastic edging bends easily around curves; metal and wood edging may need to be cut or scored to follow tight curves. Step back frequently to check that the curve looks smooth and intentional, not jagged or uneven.

Frequently Asked Questions

Can I edge after I lay mulch?

Yes, but it is harder. You will have to remove mulch along the line, cut or install the edging, then replace the mulch. It is faster and cleaner to edge first, then lay mulch right up to the finished line. If you are edging an existing bed, remove the top layer of mulch along the perimeter, edge, and then replace the mulch.

How deep should I cut or dig when edging?

For a shovel cut, 4 to 6 inches deep is enough to sever grass roots and create a visible line. For permanent edging, dig a trench deep enough so that 2 to 3 inches of the material sits above ground and 3 to 4 inches sits below. This depth anchors the edging and prevents grass from growing under it.

What if my bed is against a house or deck?

You do not need to edge the side against the house or deck. Edge only the sides that border lawn or hardscape where mulch could spill or grass could creep in. This saves time and looks intentional—the house or deck itself acts as the boundary.

Do I need to edge if I use landscape fabric under the mulch?

Landscape fabric stops weeds from growing up through mulch, but it does not stop mulch from spreading into the lawn or grass from creeping into the bed. Edging and fabric work together: the edge contains the mulch, and the fabric blocks weeds. You benefit from both.

How often should I replace permanent edging?

Plastic and metal edging typically last 5 to 10 years before cracking, rusting, or bowing. Wood and composite edging lasts 3 to 7 years depending on climate and how much moisture it absorbs. Inspect your edging each spring and replace sections that are damaged or no longer holding their shape.