A planting unit (14) is disclosed. The planting unit (14) has an alignment system for a blocking member (162, 162a) for the transfer of seed (152) from a seed meter (24) with a seed meter housing (30) to a delivery system (400), a blocking member (162, 162a) having a blocking face (1404) adjacent a seed path of the seed meter (24), the blocking face (1404) having an opening to a seed passage, the seed passage extending through the blocking member (162, 162a) to an interface (1400) between the blocking member (162, 162a) and one or more of the delivery system (400) and another housing. In order to facilitate the alignment of the blocking member (162, 162a) with various moving parts it is proposed to provide a blocking member recess (1414) on the blocking member (162, 162a) at the interface (1400)； and a first protrusion (1416) on the other housing, the first protrusion (1416) configured to extend toward the blocking member (162, 162a) at the interface (1400) and to seat firmly in the blocking member recess (1414) when the seed passage is correctly aligned with the delivery system (400).
