A highly anticipated new report from the University of Florida argues there isn’t enough research to determine whether seasonal fertilizer bans help stop pollution from dumping into Florida waterways.
It’s a claim that questions a tool that scores of local Florida governments, including nearly two dozen in Pinellas County, have used for years in an effort to improve water quality.
The state-commissioned report by the university’s Institute of Food and Agricultural Sciences, born from a lobbying effort by the TruGreen lawn care company, also suggests a widespread, potentially yearslong study is needed to evaluate the effectiveness of fertilizer bans.
Environmental groups fear that possible study could be the reason lawmakers may push to extend an ongoing pause on any new fertilizer bans, which was approved last summer and runs until July 1 this year.
“The assumption that residential fertilizer restrictions will reduce pollution to waterbodies and improve water quality remains largely unclear,” the report reads. “To fully understand the effect of fertilizer ordinances and other strategies to mitigate nutrient pollution and improve water quality, thorough study of the topic is required.”
But one of the scientists whose research was cited in the report told the Tampa Bay Times that it omits one of her study’s findings — that applying fertilizer less frequently was significantly correlated with lower nitrogen pollution.
“I think the report missed the forest for the trees. They focused so much on the lack of peer-reviewed literature that they missed the real-world application,” said Leesa Souto, whose 2019 research evaluated the effectiveness of local fertilizer ordinances in the Tampa Bay area.
“I don’t see how they couldn’t be effective,” she said of whether fertilizer bans improve water quality. Souto, the former executive director of the nonprofit Marine Resources Council, is now the operations director of Applied Ecology Inc., an environmental services business.
Five current and former local government officials from across Florida told the Times fertilizer bans are helping their communities decrease pollution that can fuel harmful algal blooms like red tide or toxic blue-green sludge.
John Allocco, a Republican county commissioner representing Hernando County, helped his community adopt a summer fertilizer ban in May. That was just weeks before lawmakers halted counties from passing new bans until July 2024 while the University of Florida used $250,000 from the legislature to review whether they work.
“Minimizing the amount of nitrogen that rolls directly into our waterways makes sense, and until they can prove that they don’t work, local ordinances that restrict fertilizer are the low-hanging fruit that local governments need to go after,” Allocco told the Times in an interview.
Lee Constantine, a Seminole County commissioner, put it this way: “I don’t know how many studies need to be made for them to say that when harmful chemicals get into our water, they pollute it.”
Across Florida, roughly 100 municipalities have adopted summer rainy-season fertilizer bans. Pinellas County’s fertilizer ordinance became law in 2010. One of the county’s main legislative priorities this year is to support efforts to keep counties in charge of their fertilizer bans, according to spokesperson Tony Fabrizio.
The county believes the ordinance is an effective way to curb nutrient pollution from entering waterways like Tampa Bay, Fabrizio said.
In responses to questions from the Times, Michael Dukes, director of the University of Florida’s Center for Land Use Efficiency, said there is a “knowledge gap” about whether fertilizer bans work.
“Our role is to provide the latest science-based information for decision makers to set policy,” Dukes said in a written response. “We simply don’t have the studies to say definitively whether fertilizer ordinances work at mitigating pollution and under what conditions. Fertilizer ordinances may be effective, but we don’t know without proper study that takes into account the many variables.”
Dukes said there is currently no cost estimate for the long-term study on fertilizer bans suggested by the report. Without including the cost to taxpayers for the suite of studies the University of Florida team recommended, “it is impossible to start any discussion of the funding for such research,” said Cris Costello, the senior organizing manager for Sierra Club Florida.
Jon Thaxton led the charge to make Sarasota County one of the earliest counties in Florida to adopt a fertilizer ban when he served as a commissioner there in the mid-2000s.
Thaxton said he fears the report will be used as a tool against local control.
“People are going to look at this and say, ‘Hey, look, there’s no evidence that these bans are improving water quality, and therefore the state should prevent them from happening,’” said Thaxton, who also sat on the Florida Consumer Fertilizer Task Force, which the Legislature created in 2007 to offer recommendations on state policies dealing with fertilizer.
The new report tries to divert attention away from fertilizer bans in favor of other pollution-cutting measures, like removing septic tanks, when local governments should be doing both, Thaxton said.
“Fertilizer bans are not going to fix all of the problems,” he said. “It’s one tool in the toolbox — but it’s an important tool.”
This story was produced in partnership with the Florida Climate Reporting Network, a multi-newsroom initiative formed to cover the impacts of climate change in the state.
