Abstract: A plow apparatus for laying cable, pipe, tile and the like underground having a blade with an upwardly extending shank portion for support. A blade holder connects the shank to a plow-pulling crawler tractor and the holder has an opening therein to receive the shank. An arm is pivotally mounted on the blade holder on one end of the arm to press the shank against an interior surface of the holder in the opening. A blade dog pivotally mounted on the holder is also provided to lock the shank in the holder at a selected height by means of recesses formed on the rear surface of the shank at various heights. One of the recesses is engaged by the blade dog in the locked position. The invention permits one machine operator to quickly and easily adjust the cutting depth of the blade without the use of tools.