The answer to 'retaining wall installation turning brown' is that a discolored retaining wall is often caused by oxidation or mineral deposits. This can happen when the wall materials, such as concrete or stone, react with water, soil, or other environmental factors. The most common symptoms are a brownish, rusty appearance on the surface of the wall.
In many cases, this discoloration is just a cosmetic issue and doesn't affect the structural integrity of the retaining wall. However, it can be unsightly and detract from the overall landscape design. The best solution depends on the cause - minor staining may be treatable with cleaning, while more extensive damage may require resurfacing or replacement of the wall.