Abstract: A narrow-trench earth trencher and flexible tube installer, including a relatively large diameter narrow driven sprocket connected by a chain with attached earth cutters to a relatively small drive sprocket. The trencher includes a carriage frame adapted to be connected to a pulling vehicle, with wheels at one end to facilitate horizontal travel. Mounted on the carriage frame are first and second vertically-oriented trencher frame assemblies. The trencher also includes a vertically-oriented tubular member and a crumber for helping place the flexible tubing in the trench.