How to Create Raised Beds Using Interlocking Concrete Blocks

Measure the area where you will build your raised bed, including height, width and depth. Most raised beds have a depth of 3 to 4 feet and can have any length or shape. The height of a raised bed can vary from 6 inches to waist high. If you have a bad back or knees, or if an elderly person will also tend the garden, it's best to go waist high.

Purchase interlocking blocks based on your measurement. For a 4-foot deep by 8-foot wide raised bed, you will need at least 40 to 50 blocks.

Mark off the area for your raised bed, using stakes and string or colored turf marker. Remove grass, roots and other debris from the soil using a shovel or flat spade.

Dig a level trench as deep as the height of one of the bricks. The first course of bricks needs to lay below grade for stability. Using a square shovel makes it easier to level the bottom.

Put commercial grade fabric in the trench. The fabric will prevent dirt from leaking out. Place the excess towards the interior of the bed. Put down 3 to 4 inches of gravel and the first level of blocks on top of the fabric to hold it in place. Use a rubber mallet to settle the blocks to keep them leveled.

Check each layer with a level. This step will define the succeeding courses, so it's important to keep the blocks straight and level, so the next layers of blocks will remain aligned and straight.

Add the next layer of blocks. Match the tongues of the following layers of blocks with the grooves of the lower level of blocks.

Fill the bed with dirt and add weed barrier.

Add plants and mulch.