A planting unit is provided having a seed trench opener that forms a seed trench in a ground surface as the planting unit travels along the ground. A depth regulating member is provided that has a predetermined vertical position relative to the opener. The depth regulating member is operable to ride along the ground and thus predetermined the seed trench depth. A suspension assembly is provided to reduce the shock forces on the planting unit when obstacles are encountered. Furthermore, a suspension system is provided to the seed trench opener, in addition to the depth regulating member.