Phosphate and the Port of Tampa — Tampa, Florida

Phosphate gave Tampa a bulk export to sit beside its cigars. The University of Florida's Ingraham Expedition notes record that in the late 1880s Tampa became a major commercial city, exporting cigars and phosphate amongst other goods. The City of Tampa's own history ties the timing to the mines: when phosphates were discovered nearby in the late 1880s, the resulting mining and shipping industries prompted a boom of growth and wealth that lasted through the 1890s.

That boom ran through two Tampa waterfronts. The first was Port Tampa, Henry B. Plant's rail and steamship terminal on the Interbay Peninsula. The second was Seddon Island, a dredged island in Hillsborough Bay at the foot of downtown, where phosphate elevators worked from 1908 into the late 1960s. Neither shoreline handles phosphate today. Seddon Island is now Harbour Island, and Port Tampa became a neighborhood of the City of Tampa in 1961, yet Port Tampa Bay still calls fertilizer a cornerstone of its export business.

The rock came from the Peace River valley, inland and southeast of Tampa Bay. According to the Southwest Florida Water Management District, Captain J. Francis LeBaron of the U.S. Army Corps of Engineers found phosphate in 1881 while surveying the Peace River south of Fort Meade. More deposits turned up in 1886, found by John C. Jones and Captain W.R. McKee, who formed a company and began mining. Within a decade more than 200 companies were mining phosphate in central Florida, and the price of an acre of Peace River land had soared from $1.25 to $300.

Early crews dug with picks and shovels; later the companies strip mined with steam shovels. The district's numerous fossils earned it the nickname Bone Valley; the water management district illustrates it with a company store near present-day Mulberry around 1920. A 2023 report carried by WLRN and WUSF adds that Bone Valley is not a valley at all but a high point whose mine pits only make it look like one, and that ground and river pebble mining began around 1888. The same report describes a 1919 strike by miners at Mulberry that put a chokehold on the worldwide fertilizer trade for months. The City of Tampa dates the shipping boom that this rock fed on Tampa Bay to the late 1880s and the 1890s.

Port Tampa was a deepwater railhead, not the downtown riverfront. The Ingraham Expedition page places it about nine miles south of the city of Tampa and says it was developed in large part by Henry Plant as a transportation hub for the Plant System's railway and steamboat lines. Plant had the channel deepened, extended the docks and built up the port's infrastructure. In the early 1890s his South Florida Railroad ran twice daily train service connecting Port Tampa with the rest of the country by way of Sanford and Jacksonville, and Plant steamships sailed weekly to Key West, Havana, Mobile and New Orleans.

Plant paired the docks with hotels. The Tampa Bay Hotel opened in 1891, and the Port Tampa Inn stood on the pier itself to serve rail and steamer travelers. The community history kept by American Legion Post 138 says the inn was built on stilts over the bay so guests could fish from their rooms. Settlement of the surrounding Interbay tip, then called Black Point, began around 1885, and port expansion produced a separate town: Port Tampa City received a charter from the state legislature on June 30, 1893, with its own elected officials and ordinances.

The growth showed in the census. The Ingraham notes give the population of the Tampa metropolitan area as 5,532 in 1890 and say it tripled by 1900, helped by Tampa's role in the Spanish American War. Members of the 1892 Everglades exploring party described on the same page rode Plant trains from the Sanford region to Port Tampa and boarded the Plant System steamship Tarpon there for Fort Myers, a small record of how the pier linked rail and sea.

The downtown phosphate docks sat on land that did not exist until 1906. Writing in Tampa Magazine in May 2020, Hillsborough County historian Rodney Kite-Powell explains that the Army Corps of Engineers cut a shipping channel through Hillsborough Bay toward the Hillsborough River, slicing through a mangrove islet called Little Grassy Island. The dredged sand was piled on the east side of the new channel to make a larger island for port use. W. L. Seddon, an engineer for the Seaboard Air Line Railroad, the main beneficiary of the dredging, directed the work, and the island took his name.

Garrison Channel, dug at the same time, separated Seddon Island from mainland downtown Tampa. Seaboard freight trains reached the island over a steel Scherzer rolling lift bridge put in place in 1908, and the port's first phosphate shipment followed the next year. From then until the 1960s the docks, wharves, warehouses and phosphate elevators along the downtown waterfront stayed busy; Kite-Powell writes that millions of pounds of phosphate were shipped out from Seddon Island from 1908 to the late 1960s. The island also held lumber yards, and Kite-Powell describes the whole waterfront from the Hillsborough River down to the estuary, today's Water Street district, as industrializing with Seddon Island at its center.

Both early terminals lost their phosphate role as the main harbor grew. The Post 138 history states that Port Tampa became less important when several dredging projects made the Port of Tampa accessible to all shipping. The pier was not abandoned: ships carrying bulk products and petroleum still dock there, and it remains the main entry point for fuel for Tampa International Airport and MacDill Air Force Base. Port Tampa City kept its charter until May 11, 1961, when it was annexed by the City of Tampa, and the former First Bank of Port Tampa City building now serves as the neighborhood's library.

Downtown, Mayor Curtis Hixon began a cleanup of Tampa's industrial waterfront in the 1950s, according to Tampa Magazine. By the late 1970s the empty Seddon Island, with burnt out docks and feral pigs, looked like a redevelopment site rather than a port. In 1981 Beneficial Corporation announced the mixed-use plan that became Harbour Island, and from 1985 to 1999 the Harbour Island People Mover shuttled riders between the island and the Fort Brooke Parking Garage across Garrison Channel.

It does, though it no longer leads. On its current about page, Port Tampa Bay says mountains of fertilizer have moved out through the port ever since phosphate was first discovered in Central Florida in the late 1800s, and calls it a cornerstone of port export activity. The same page says energy has taken the baton from phosphate as Tampa Bay's top cargo, with nearly 15 million tons of petroleum products delivered each year. The port's modern cargo sites sit at Hooker's Point, East Port, Port Sutton, Pendola Point, Port Ybor and along Channelside, not at Seddon Island or Port Tampa.

The industry's corporate center is also in Tampa. The June 30, 2023 WLRN report notes that Mosaic, headquartered in Tampa, reported net income of $3.6 billion for 2022, and that Florida's phosphate miners unearth some 10 million tons of phosphate rock a year, supplying nearly a quarter of global demand. The City of Tampa still lists phosphate shipping among the trades of a port it calls the seventh largest in the nation, a line that traces back to the Peace River finds of the 1880s.