A seed planting unit of an agricultural implement may include a wheel support arm having an upper portion and a lower portion. A wheel may be rotatably supported by the lower portion of the wheel support arm, the wheel configured to contact the soil surface to define a penetration depth setting for a ground engaging tool relative to the soil surface. A depth stop member may be provided in operative association with one of the support structure or the wheel support arm. A depth adjustment member may be selectively movable relative to the other of the support structure or the wheel support arm to vary a relative position between the depth adjustment member and the depth stop member. The depth stop member may selectively abut one of the plurality of steps when the wheel is contacting the soil surface to set the penetration depth setting for the ground engaging tool.
