Landscape sleepers are sections of timber, used in garden and outdoor landscaping projects. The idea originally started from traditional railway sleepers that were creosoted and pumped full of nasty chemicals to preserve them. They are now a popular, versatile material for building retaining walls, raised beds, steps, edging, and garden structures. Sleepers are normally made from softwood or hardwood and are available in treated green or brown forms depending on their intended use. (Please note that oak sleepers aren’t treated.)