A clean landscape border starts with a straight trench, the right edging material for your yard, and proper compaction — skip the prep and you’ll be resetting edges all season.
A crisp lawn-to-bed border separates purposeful landscaping from yard neglect. The install itself isn’t complicated, but the difference between edging that’s still straight two years later and edging that’s heaved and wavy comes down to three things: trench depth, base compaction, and stake spacing. Here’s the order that works for plastic, metal, stone, and composite edging alike.
What You Need Before You Dig
Trench depth depends on your edging material. Plastic edging needs a trench about 4 to 6 inches deep so roughly half the strip sits underground. Stone and paver edging works in a shallower 2 to 3 inch trench with a level sand bed underneath. For metal edging, plan on burying 3 to 4 inches of the height to keep it stable against mower vibration. You’ll also want 1 to 2 inches of compactible base material — crushed rock or sand — in the bottom of the trench, especially in soft soil or regions with freeze-thaw cycles.
1. Mark Your Line
Lay a garden hose, rope, or string line along the intended border and adjust it until the curve or straight run looks right. Mark the line with spray paint or a shallow cut with a half-moon edger.
2. Cut and Remove the Sod
Cut along your marked line with a flat spade or power edger, then lift the sod on the bed side. For stone edging you want a clean vertical face on the lawn side; for plastic edging you can let the trench wall be slightly sloped.
3. Dig the Trench to the Right Depth
Excavate to the depth your edging material requires — 2 to 6 inches depending on the type. Keep the trench width just slightly wider than the edging base so the material fits snugly. A trench that’s too wide lets the edging tilt sideways when backfilled.
4. Level and Compact the Base
Spread 1 to 2 inches of sand or crushed rock in the trench bottom and compact it with a hand tamper or the end of a 2×4. Check the slope with a level; a settled base prevents sinking and tilting within the first season.
5. Set the Edging at the Correct Height
Place the edging into the trench. Aim for the top edge to sit about half an inch above the finished grade on the lawn side. That small lip stops grass rhizomes from crawling over the top while staying low enough that a mower wheel can ride over it without damage. Use connectors and couplers that came with your edging —
6. Anchor With Stakes or Spikes
Drive stakes or spikes through the edging’s pre-molded holes or beside it, spacing them 18 to 24 inches apart on curves and up to 3 to 4 feet apart on straight runs. Plastic edging stakes should be driven at a slight angle (pointing away from the lawn) for better holding force. Tighter spacing on curves prevents the edging from springing back toward its coiled shape. For materials that handle heavy clay or rocky soil,
7. Backfill and Compact
Scoop the excavated soil back into the trench on both sides of the edging, then tamp it firmly with your foot or a tamper in 2-inch lifts. Loose backfill is what allows edging to shift after a heavy rain. After tamping, top the bed side with mulch, decorative rock, or gravel and lay landscape fabric underneath for an extra weed barrier.
What Can Go Wrong and How to Avoid It
The three most common failures are trenching too shallow (the edging heaves), failing to compact the base (it settles unevenly), and setting the top edge level with the lawn (grass overgrows it within weeks). On metal edging, leaving small gaps at the connector points is actually correct — the gaps allow for thermal expansion on long runs, preventing buckling in summer heat. Plastic edging gets more flexible if you let it sit in the sun for an hour before installing. Always use a rubber mallet rather than a regular hammer to drive stakes — a metal hammer can crack connectors or deform the edging’s top bead.
FAQs
How deep should the trench be for different edging types?
Plastic and composite edging typically needs a 4 to 6 inch trench so half the height is buried. Stone or paver edging works with 2 to 3 inches of depth plus a level sand base. Metal edging should be buried 3 to 4 inches deep — enough to anchor it but shallow enough that the visible face provides your clean edge.
Do I need landscape fabric under gravel edging?
Yes, placing landscape fabric under decorative rock or gravel prevents the stones from sinking into the soil and blocks weed growth that would require annual weeding along the border. Install the fabric after backfilling and before spreading the top layer of gravel.
Can I install edging without removing the grass first?
You can, but the results are rarely clean. Cutting and removing sod along the trench line gives you room to backfill against the edging and stops grass from creeping back into the bed. A half-moon edger makes quick work of the initial cut.