A dry-laid brick border for flower beds is made by marking the shape, digging a level trench, compacting a gravel base, and setting bricks in sand with polymeric sand joints.
A brick border gives flower beds a clean, permanent edge that lawn mowers can’t chew up and grass can’t cross. Here is the step order that works for straight runs and gentle curves alike.
Marking and Planning the Border Line
Skip the layout step and you will dig a wavy trench that forces bricks into a crooked line. Lay a garden hose or rope along the intended edge and step back to check the shape from every angle — adjust until the curve looks right. This Old House recommends measuring the bed perimeter with the rope, then dividing by the actual brick width and adding 10% for cuts and mistakes.
Digging and Preparing the Trench
Dig a trench along your marked line with straight sides, making it several inches wider than the bricks so you have room to adjust each one. The typical trench runs 3 to 6 inches deep depending on your paver thickness and sub-base — at least 2 to 3 inches of that depth is for the compacted base layer. Tamp the trench bottom firmly with a hand tamper or the end of a 2×4; a loose, uneven base guarantees wavy edging that will need resetting after one winter. For drainage on heavy clay soil, slope the trench bottom very slightly away from the garden bed so water runs off instead of pooling against your flowers.
Setting the Bricks and Filling Joints
Add 2 to 3 inches of paver base or a 6:1 mix of stone dust to Portland cement (the mix This Old House uses for extra stability), and compact it again. Lay each brick on the prepared base and tap it level with a rubber mallet — never a steel hammer, which will chip or crack the brick every time. Check the height against both sides of the trench so the brick sits flush with the lawn and the soil edge. On curves, cut bricks into wedge shapes with a masonry chisel or angle grinder, or use split keystone bricks if available. Once every brick is set and level, sweep sand or polymeric sand across the surface to fill the joints, then lightly mist it with water (polymeric sand instructions ask for a gentle wetting to activate the binding agents). Backfill the outside edge of the trench with soil to lock the bricks in place and prevent grass from creeping underneath.
If you want to skip the measuring guesswork and see which brick shapes, sizes, and edging kits save the most installation time, check the best brick border products for flower beds — it covers the actual dimensions and material options that work for this method.
Common Mistakes That Cause Early Failure
The three errors that send people back to the garden center within a year: skipping the base compaction (bricks settle unevenly after rain), using a regular hammer (brick shatters on the third tap), and leaving joint gaps unfilled (weeds take over and ants excavate the sand).
| Step | What to Do | What to Avoid |
|---|---|---|
| Mark the line | Use rope or hose, adjust the curve visually | Digging without a plan — results in a crooked edge |
| Dig the trench | Straight sides, several inches wider than bricks | Narrow trench that leaves no room to adjust bricks |
| Add base layer | 2–3 inches of paver base or 6:1 stone dust mix | Skipping compaction — causes wavy, unstable edging |
| Set bricks | Rubber mallet, check level after each brick | Steel hammer — cracks and chips the brick |
| Fill joints | Sand or polymeric sand, brush in and wet lightly | Leaving gaps — invites weeds and erosion |
| Backfill edge | Soil or leftover base material against outside | Leaving the edge exposed — grass creeps under |
FAQs
Do I need mortar for a brick flower bed border?
No — a dry-laid system using compacted paver base and sand joints is the standard DIY method and actually performs better in freezing weather because the bricks can shift slightly without cracking.
How deep should the trench be for brick edging?
Plan for 3 to 6 inches total, with at least 2 to 3 inches reserved for the compacted base layer. The exact depth depends on the brick thickness and whether you need extra drainage gravel for heavy clay soil.
Can I install brick edging on a curved flower bed?
Yes — use a garden hose to mark the curve, then cut bricks into wedge shapes with a masonry chisel or angle grinder as you reach the bend. Some manufacturers make tapered keystone bricks specifically for curved layouts.
References & Sources
- This Old House. “How to Edge a Garden Bed with Brick.” Complete DIY guide with trench dimensions, base mix ratio, and brick-setting technique.