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One of the easiest ways to construct a retaining wall is by simply laying bags of concrete, wetting them, and then letting them cure. After that you can either allowing the bags to fall off and biodegrade over time (about 6 months) or simply remove the bags. You are left with a remarkably sturdy wall that fuses itself together. If you plan on going higher than 4 feet you’ll need steel reinforcement. Some people have gotten very creative with this concrete bag projects and I was stunned by some of their end results. Search the internet for concrete bag walls and see what’s out there for inspiration. The link below will give you some basic instructions for this super simple diy:
