Landscaping blocks are designed to easily dry stack for borders, retaining walls and raised beds. These inexpensive blocks can be quickly assembled for simple weekend projects. However, when installing boarders, beds and retaining walls, care must be taken to provide adequate drainage and a level surface for landscaping blocks to prevent future problems in your landscaping.
Lay out the course where the landscaping blocks will rest by pouring flour onto the ground in a line. Flour is an environmentally friendly alternative to spray paint for marking the ground.
Dig a level trench approximately 1 ½ times wider than the concrete blocks and as deep as the frost line for your area. If you are landscaping a hillside, your trench may have to be composed of a stair-step arrangement. Tamp the dirt down using the tamping tool. Add a 2 inch layer of sand and tamp again.
Drive stakes into the ground at the ends of your wall using a rubber mallet. Tie a piece of string between the two stakes, taking care that the ends are tied at exactly the same height and the string is taut.
Lay your first course of landscaping blocks, using the string to ensure that each block is set at the same height.
Cut a block in half with a chisel. You will begin your second course with this block to ensure that the blocks are staggered with the first course. The lip of each block should fit against the back of the foundation course. Lay the blocks on each end first, and place your string at the top of each block so that you can check that each block is set at the same height. Continue to stagger courses until your project is finished.
Cover the back side of the wall with porous landscaping fabric to prevent soil from seeping through the cracks in the wall. If you are building a planter, then fill the space with dirt. For a low retaining wall, backfill with 4 inches of gravel. Then place a French drain pipe on top of the gravel and cover with more gravel and finally with soil.