Size the trench so there's enough room for the retaining wall block and at least 8 in. of space behind it. Excavate deep enough to completely bury at least one full course, including space for 6 to 8 ...

Dear James: I’m planning a veggie garden on my sloping lot so I need a retaining wall. I have used timbers before, but blocks might hold up better. Which method do you prefer? -- Steve W. Dear Steve: ...

Q. Can you tell me how to build a retaining wall? Are retaining wall blocks a good choice? What critical things do I need to know so that I don't have a collapse or other failure in the years to come?

A yard with a steep slope can be difficult to landscape. Build a block retaining wall to add level tiers to your yard, which prevent erosion and provide a perfect place for a flower garden.