A lawn aerator sulky adapted for attachment to a selflawn vehicle, such as a walk-behind mower or fertilizer spreader. The sulky includes a frame supported with wheels, a first platform on which an operator can stand and ride while not aerating, and a second platform carrying one or more aerator tine assemblies on its underside. The second platform and tine assemblies are moveable by the operator selectively transferring his/her weight to position the tine assemblies in a ground-engaged or ground-disengaged position. The sulky includes a device to support the second platform and its tine assemblies in the disengaged position when the operator steps off the platform, and a latching device to hold the second platform and its tine assemblies in the engaged position when the operator steps off the second platform.