Cooley's main occupation was gathering, processing and shipping Florida arrowroot, a starch made from the root of the coontie plant. Arrowroot was used to make bread dough, wafers and biscuits; its resistance to spoilage made it especially favored for use on ships. Pulp remaining after processing was used as a fertilizer or for animal feed. Favorable conditions for arrowroot cultivation contributed to the presence of several hundred Indians in the area—arrowroot being a staple of their diet. The market price for the starch was (between 17¢ and 35¢ per kg), and the geography of the river and the good performance of his machinery—the output was close to —brought Cooley great prosperity. His good fortune allowed him to dedicate much of his time to exploration of the area as far north as Lake Okeechobee and brought him increasing political influence. It is likely that he married Nancy Dayton, a former Indian captive, on December 2, 1830.