To enclose a garden or make a decorative enclosed area you can build a concrete block retaining wall, which is not a difficult thing to do. Let us assume that you want a nice decorative area for an enclosed garden.
The first thing you will need is interlocking concrete blocks which you will know how to buy after you have measured the area you want to retain.
The interlocking concrete blocks will not require any mortar as each block has a lip that will lock into the previous block. These blocks are heavy but they are easy to work with. A concrete or timber retaining wall of this type can be built to be up to thirty inches tall. For a taller wall, you need to prepare the area for water drainage and reinforce the wall for stability.
The first thing you want to do is to mark off your prospective wall area with a line and posts. You can mark the perimeter of the garden wall with a garden hose.
You will need a solid base on which to begin to build therefore, using a shovel dig a trench in accordance with the size of your concrete block. If your property slopes that you will have to dig a trench at each level as you build. Otherwise, after you have built a solid foundation level you can begin to lay the blocks.
After you have laid the foundation you can now start laying in the rest of the blocks. Be sure that the lip of the block you are laying is against the block before it. Continue to build checking carefully that all blocks are set in place levelly.