How to Terrace to Reduce Soil Erosion

Start the first terrace at the bottom of the slope for the easiest construction. Measure out the garden before you start, per your personal preferences. Aim for a 4- to 5-foot-wide and -long garden for simple planting and design, with walls on three sides and the rising slope on the fourth. Put stakes at the corners of the garden to mark them.

Tie twine between the stakes at the bottom of the garden, at the top of the stakes, to mark the line. Repeat with the stakes that make up the sides of the garden. Adjust and measure the twine until it's level throughout. This twine marks your level, and ideally marks the top of your terrace wall.

Excavate trenches for the wall on the bottoms and sides of the terrace. Dig the trenches wide enough to fit the concrete blocks, and 4 to 5 inches deep, along the bottom of the garden. Run the trench along the sides, sloping downward as you go to maintain a level with the twine. The trench should be deeper at the top of the sides than it was at the bottom.

Lay the first set of concrete blocks in the trench, with the holes facing upward. Mix quick-set concrete in a bucket, according to the manufacturer's directions, and shovel the concrete into the holes in the blocks. The concrete gives the wall better security against soil and water.

Repeat this process with a second course of concrete blocks. Lay a third course of blocks, if necessary, to reach the twine between the stakes.

Repeat the process with other terraces up and over the slope, with 2 to 3 feet of space between the raised structures. The tiers interrupt water flow during rainstorms to improve drainage and reduce erosion. Allow the concrete to dry overnight.

Fill the gardens with a mixture of topsoil and organic compost for planting. Put 10-10-10, 12-12-12 or 13-13-13 fertilizer in the soil for vegetable planting, and 5-10-5 or 5-10-10 fertilizer in the soil for flower planting.