How to Use Landscape Timbers for Borders | Sturdy & Simple Edging

Landscape timbers create durable, natural-looking borders for flower beds and pathways when installed with a gravel base, galvanized spikes, and pressure-treated wood rated for ground contact.

A border made from landscape timbers gives a garden bed a finished look without the cost of stone or poured concrete. The key is doing the prep work right — digging a shallow trench, laying a gravel base for drainage, and securing every timber with galvanized spikes driven through pilot holes. Here is how to do it so the border stays straight and solid for years.

Planning and Material Prep

Start by marking the border line with a garden hose, string, or landscape paint. This lets you adjust the shape before digging. Standard timbers are pressure-treated 4x4s (actual dimensions run about 3.5 inches thick) rated for ground contact — never use untreated lumber, which rots in two seasons. For a typical flower bed border, you will need one timber per 8 feet of edge, plus galvanized spikes or rebar, a bag of pea gravel or crushed stone, and landscape fabric. Lowe’s installation guide recommends 10-to-12-inch spikes for edging and 12-to-16-inch spikes if you stack timbers for a low wall.

Digging the Trench and Setting the Base

Excavate a trench 2 to 4 inches deep and as wide as the timber. This recess keeps the border flush with the grass or slightly above it, which makes mowing easier. Lay landscape fabric in the trench, then pour in about 2 inches of gravel or crushed stone. The gravel bed stops water from pooling against the wood and prevents frost heave in cold climates — a common cause of crooked borders after one winter.

Position the first timber partly below grade and check it with a level. If it rocks, pack more gravel under the low spots until it sits solid.

Cutting, Drilling, and Securing Timbers

Cut timbers to length with a circular saw fitted with a wood-cutting blade. A handsaw works but takes longer. For inside or outside corners, either notch the timbers with a saw or use galvanized corner braces — the brace method is easier for a first-time installer.

Drill 3/8-inch pilot holes every 4 to 5 feet along the timber and always near corners. Drive a 10- to 12-inch galvanized spike into each pilot hole using a sledgehammer. For corners, bore the pilot hole at a 45-degree angle through one timber into the one below it — this locks the joint better than a straight vertical spike. Rebar cut to 1-foot lengths and driven through 7/8-inch holes is an alternative many old-timers prefer, but spikes are faster and just as strong.

If you are stacking a second layer, offset the joints from the first layer by at least 4 inches (like brickwork), and secure each layer with heavy-duty structural screws rather than spikes for a tighter bond.

Backfilling and Finishing the Border

Once all timbers are driven in place and level, backfill the outer and inner edges with the original soil or more gravel. Tamp it down firmly with your boot or a hand tamper so no gaps remain. Water the fill lightly to settle it, then top off with more gravel or soil. The border should be stable enough to stand on without shifting. If you left end grain exposed, seal it with a waterproof sealant — the end of a pressure-treated timber soaks up moisture faster than the sides and will crack sooner if left bare.

When you are ready to buy materials, see our tested picks for landscaping wood borders — these are the products that hold up best in wet clay and sandy soils alike.

Common Mistakes to Avoid

• Using untreated lumber. Untreated pine or fir rots within 18 months. Only buy timbers stamped for ground contact.
• Skipping the gravel base. Timbers laid directly on dirt heave with frost and settle unevenly after rain.
• Weak corners. A single vertical spike at the corner pulls loose under pressure. Drive a spike at 45 degrees through the corner overlap or use a corner brace.
• Neglecting safety. Pressure-treated wood contains preservatives. Wear a dust mask and gloves when cutting, and wash up afterward.