Raised Bed Mailbox Garden Upgrade

For a professional look, mark the layout of the raised bed. You can lay out straight lines with landscape stakes and string. A garden hose works well for curves. Use a shovel to transfer the layout to the ground. Dig up and remove any turf from the bed area.

Using the layout marks on the ground as a reference, dig a trench about 12 inches wide by 4 inches deep. Adjust the depth as needed to account for any slope in the ground. Remove the loose soil. Compact the bottom of the trench with a tamper. Check for level, adding and removing soil as necessary and tamping the bottom of the trench firm.

Add a couple of inches of all-purpose gravel to the bottom of the trench. Use a garden rake to spread it evenly. Tamp it down and repeat until you have a level base compacted to a depth of 4 inches. A firm, level base is key for building the walls of your raised bed.

Begin placing the first row or course of block. Check for level as you go, side to side and front to back. Add a bit of paver base to raise a block or tap it with a rubber mallet to lower it. If the blocks aren’t level, they create problems for the other rows. You might need to cut the block to fit your layout. Practice on a spare block. You can use a chisel and a small sledgehammer to mark and cut a few blocks. Use a rafter/speed square if you need to mark straight lines for precise cuts. If you have many blocks to cut, you might want to use a power saw. See our article, How to Cut Bricks, Patio Blocks and Pavers, for step-by-step instructions. Take safety precautions when cutting blocks. If using a hammer and chisel, you need safety glasses and work gloves. If using a power saw, you need hearing protection, safety glasses and a respirator. 

Once you have the first course of block down, brush off any dirt or debris.

Begin laying the second course of block. Apply generous beads of construction adhesive to the top of the first row as you go. Stagger the joints on each row so a block spans a joint in the row below. You might need to begin the second course with a partial block. Check for level as you go and press each block firmly into the adhesive to create a strong bond. Brush off the row.

We only need two rows of block for our project, but if you need a third, lay it using the procedure above to apply adhesive and lay and level each block. For this project, we’re not using retaining wall caps, but if you choose to use them, brush off the final row of block, apply adhesive and place the caps, cutting them as necessary. Be sure they span the joints of the final row of block. Backfill around the first layer of block with gravel as necessary to allow drainage and tamp down. Top with soil.

Fill the bed with premixed raised bed soil to make it easy for the plants to get a good start. You can use landscape fabric to block weed growth. Add your plants. Shrubs, long-lasting perennials and colorful flowers make a good mix. See our guide to planting a shrub if you’re adding a new shrub to your landscape. If you’re installing a new mailbox, take a look at our mailbox project. 

If necessary, add a few plants outside of the bed to continue the look around the installation area. Be sure to check plant tags for tips on planting and care. Finish with a layer of mulch to help retain moisture in the soil, but pull the mulch back an inch or so from the plant stems.