How to Install Timber Garden Edging | Done in 8 Steps

Installing timber garden edging requires digging a shallow trench, laying a gravel base, positioning pressure-treated timbers, and securing them with 10-inch galvanized steel spikes — the whole job takes about a day for a standard bed.

Timber garden edging keeps mulch off the lawn and lawn grass out of the flower bed. It also looks clean. The process is straightforward if you respect the prep work: trench depth and gravel base matter more than anything else. Skip either one and the edging shifts after a wet season. Here’s the exact sequence that holds up through a Midwest winter.

What You’ll Need Before You Start

Standard landscape timbers are 6 to 8 inches wide and about 2.5 inches thick. Buy pressure-treated lumber — it resists rot against moist soil. For a single-layer edge, one timber tall is enough; for taller borders that hold back more soil, plan on stacking two layers.

Tools: shovel or spade, level, measuring tape, mason line and stakes, a circular saw, an impact drill with a wood bit that matches your spike diameter, a sledgehammer, and a mallet.

If you’re deciding between timber styles, our roundup of top-rated garden wooden edges for every bed size can help you pick the right look and budget.

The Trench Depth Rule: Single vs. Double Stack

Trench depth controls stability. For a single-layer timber edge, dig 2 to 3 inches deep. For a double-stack (two timbers high), go 6 inches deep. If your bed has curves or sits on a gentle slope, 3 to 4 inches deep keeps the timber seated — the gravel base under it provides the leveling.

Make the trench about 2 inches wider than your timber. That gap lets you backfill tightly on both sides later, which locks the timber in position.

8-Step Installation Sequence

Step 1: Mark the perimeter. Drive stakes at each corner and run mason line between them. This gives you a straight visual guide for the whole dig.

Step 2: Clear and dig the trench. Remove grass and roots. Dig to your chosen depth, keeping the bottom as level and flat as possible. Pile excavated soil on a tarp so backfilling is easy later.

Step 3: Pour the gravel base. Spread about 2 inches of gravel evenly over the trench bottom. The gravel drains water away from the timber and prevents the wood from sitting in standing moisture — the most common reason edging rots early.

Step 4: Lay the first timber layer. Set the timbers onto the gravel clockwise, meeting at corners. Check level across the top. Shovel gravel underneath a low section rather than shaving soil off a high one — it’s faster and won’t settle as badly.

Step 5: Stack the second layer (if using double-stack). Place the upper timbers counter-clockwise so the joints stagger. Staggering is the difference between a wall that shifts and one that stays put.

Step 6: Drill and drive the spikes. Drill pilot holes through both layers at all four corners and every 4 feet along straight runs. At corners, bore at a 45-degree angle through the top timber into the one below. On straight sections, drill vertically. Hammer the spikes until the head sits flush with the wood surface. Use a sledgehammer for the final few inches — a mallet often bounces.

Step 7: Backfill. Tamp soil or gravel into the gap between timber and trench wall.

Step 8: Trim excess stake tops. Your edging is now set.

Common Mistakes That Ruin Timber Edging

The first and worst mistake is skipping the gravel base. Direct soil contact accelerates rot. Second: not staggering joints on a double stack — aligned seams create a single long weak point. Third: driving spikes without pilot holes. Full disclosure: even with the right drill bit, hammering spikes into dense pressure-treated timber is hard work; if the spike bends, pull it and try a slightly wider pilot hole. Leveling errors along a long run are another frequent problem — check every 5 feet as you go.

One more detail worth getting right: run landscape fabric behind the timber before backfilling. It blocks weeds from sneaking through the gap between wood and soil, and you won’t have to spray along the edge every summer.