One option when installing a garden bed or flower bed is to raise the bed above ground level. To do this, you must build a retaining wall around the bed to contain the soil. Retaining walls can be constructed of wooden timbers, stone or bricks. If you need to build a retaining wall for the bed that's curved, you can use precast curved concrete blocks to build the wall. These blocks are cut in at an angle on the sides, which allows you to place them in a straight or curved formation.
Lay the blocks on the ground along the outer edge of the bed, following the contours of the bed.
Drive an edging shovel into the ground an inch away from the blocks on both sides to create a score line. Remove the blocks.
Dig a trench between the score lines that is half the height of the blocks. Level the soil in the trench and tamp it down.
Place the first block into the trench. Place a level across the top of it side-to-side and front-to-back, tapping down on the block with a rubber mallet to level it if needed.
Set the second block into the trench next to the first brick. Lay the level across both blocks, and lightly tap the second brick with the hammer to even it out with the first block if you need to.
Continue laying blocks into the trench until the first course is done.
Fill the gaps between the blocks and the sides of the trench, and any gaps between the sides of the blocks, with dirt and tamp them down. Partially burying the first course helps strengthen the wall.
Apply a thick bead of masonry adhesive on top of two of the blocks, running the adhesive from the centre of one block to the centre of the next block in a zigzag motion. Place a block on the adhesive so it spans the two blocks in the first course. Staggering the rows like this makes the wall stronger.
Continue laying the second course of blocks until it is complete.
Lay a third course of blocks, if desired, using the same technique you used for the second course.
Call 811 before you dig the trench to get the utility lines in your yard marked.
Tips and warnings
- Call 811 before you dig the trench to get the utility lines in your yard marked.
Things you need
- Precast curved concrete blocks
- Edging shovel
- Rubber mallet
- Masonry adhesive