The present invention provides a method and apparatus to improve seed distribution to a plurality of seed or row units (30) of an agricultural planter (14). Each row unit (30) is fitted with a seed box (50) having an air/seed inlet (52) and an air outlet through which air is allowed to escape. The present invention effectively closes off or substantially reduces the flow of air out of one or more of the seed boxes (50) to reduce the amount of seed that is fed to the seed boxes (50). Through the use of restrictor plates (60), which may be vented to allow some air flow or solid to prevent air flow, the delivery of seed to the seed boxes (50) can be equalized to provide more uniform seed distribution to the row units (30).
