How to Build a Garden Wall With Interlocking Blocks

Clear the area where the garden wall will go by digging a trench. Use a shovel to remove dirt, rocks and grass.

Compact the soil with a tamper. Hold the tamper over the area and tamp or hit the ground with its flat bottom.

Add a layer of sharp gravel or rock dust. This will prevent settling.

Place a stake at one edge of the wall's intended location. Place a stake at the other edge. Connect the stakes by tying a string to them. Place a block down at one edge. Use the level to make sure the block is balanced from front to back and side to side. Adjust the block by adding more gravel or digging deeper. Adjust the string so that its height is exactly the same as the block's.

Continue laying blocks in a straight line along the string. Make sure the tops of the blocks are not higher than the string.

For the second layer of blocks, lay them in a staggered fashion so that joints occur over the centers of the underlying blocks. Periodically check that the blocks are straight and level using the string and the level.

Cut blocks using a brick chisel and a sledgehammer. Use the chisel to score blocks that need to be cut. Place the chisel on the scored line and strike it with the sledgehammer. There may be mark on the back of each block to indicate the center.

Fill in gravel and dirt behind the garden wall. Place gravel next to the blocks and dirt behind it. Use the tamper to compact each layer. This will provide support for the wall.