How to Install an Allan Block Flower Bed

Mark the layout of your flower bed border using a garden hose for curves, then dig out a shallow course with a shovel. Remove the sod and other surface material, and dig a trench 10-12 inches wide and at least 6 inches deep. Check with a level as you dig. Fill the trench up to 4 inches with wall rock. Use a hand tamper to level the wall rock and make it compact.

Place the first course of blocks along the trench. The blocks must be placed with the raised front lip facing up and forward. Use a rubber mallet to level the blocks. Once you have the base course in place, fill in the blocks with wall rock. Also fill the 4- to 6-inch gap behind the blocks with wall rock and compact thoroughly with hand tamper. Sweep the top of the blocks clean and check for level. Fill any remaining area in front of the blocks with on-site soil.

Place the next course of Allan Blocks with the seams offset from the course below by 2 to 4 inches. This will lock each course tightly in place and make the wall stronger. Backfill again with wall rock and compact tightly. Repeat for any remaining courses until you obtain the desired height. The recommended flower bed Allan Blocks have a height of 6 inches and can be used to build walls up to 30 inches high. The tightest curves you can attain will have a 22-inch radius. A full circle flower bed with a radius of 22 inches requires 18 blocks.

Finish the top of the Allan Block wall by filling in the top course with planting soil and planting with border or trailing flowering plants, using the raised front lip as the finished edge and no caps. Alternately, glue AB Capstones to the top of the last course with cement glue for a clean bordered-edge. Cut capstones as necessary with a masonry saw for curves and corners.