A lock assembly is provided for a row planter unit to maintain the unit in a raised transport position and to relieve stress on the hydraulic system of the planter unit. The lock assembly includes a lock arm pivotally mounted to the bracket assembly of the row planter unit for selective receipt in a notch or detent on the mounting plate or mast of the bracket assembly so as to retain the row unit in the raised transport position. The lock arm can be disengaged from the bracket assembly notch or detent, such that the planter unit can be lowered to the field use position.