Abstract: Automatic steering mechanism for use on apparatus for forming beds of uniform widths and rows of uniform spacing. The apparatus is of a type comprising a self-propelled vehicle having a steering apparatus for steering the vehicle, and a ground engaging implement carried by the vehicle for forming an indentation in the ground. The steering mechanism is comprised of a framework structure adapted to be secured to the front end of the vehicle. A boom structure is provided and is mounted on the framework for pivotal movement about a horizontal axis. An arm is also provided and is pivotally mounted on the outer extremity of the boom structure for rotation about a horizontal axis substantially parallel to the first named horizontal axis. An indentation following device is carried by each end of the arm. The indentation following device is capable of following an indentation in the ground made by the ground engaging implement in a previous pass through the field.