A method and system enables sectional control for an air seeding system of a farm implement by exposing a main header, or selected ports of the main header, to a purging air flow when product flow through the selected ports is stopped. A plenum of air is fluidly coupled to the main header and provides a purging air flow to any exit port of the main header that has been shut off from product flow. Valves are used to selectively flow couple the exit ports of the main header to the product flow and to the purging air flow.
