The organization now known as GROWMARK started in 1927 when nine of the local agricultural supply cooperatives in Illinois, which had started early in the 1920s, formed Illinois Farm Supply Company. In 1955, the company adopted the FS trademark, which has remained in use by its member cooperatives since then. In the 1960s, the company moved from Chicago to Bloomington, Illinois, merged with Farm Bureau Service Company of Iowa to form FS Services, Inc., then merged Wisconsin Farmco Service Cooperative and Producers Seed Company into itself as well. FS Services and Illinois Grain Corporation merged in 1980 to form Growmark, Inc.
It entered the northeastern U.S. market in 2002 by purchasing Agway's seed and agronomy businesses, including Seedway.