A garden that's on a slope is in danger of topsoil erosion. Water running down a hill may wash away nutrient-rich soil from the surface. Build a retaining wall out of paving stones to prevent this issue. Placing the stones properly will prevent the wall from collapsing. If the wall is more than 4 feet high, consider using a different kind of stone and having the wall professionally installed.
Dig back into the existing dirt wall 2 feet to make room for the new retaining wall.
Set two stakes on each end of the dirt wall using a mallet. Stretch a string between the two stakes. Place a string level on the string and adjust until even.
Dig down 6 inches along the length of dirt wall to make room for gravel.
Pour 6 inches of gravel into the trench. Compact the gravel with a tamper.
Add 2 inches of stone dust to the trench and tamper down.
Place the first row of paving stone onto the stone dust. Gently tap the stone with a rubber mallet to make the stones even. Check the line with a level.
Fill behind the first course with crushed stone. Do not tamper down.
Set the second row of paving stone onto the first, staggering the stones back 1/4 of the paving stone width onto the crushed stone behind the first course. Staggering back aids in water drainage.
Fill behind the second course with crushed stone. Continue this process until the wall is at its correct height.