Scientists have long known that the nitrogen that makes your lawn green also chokes the oxygen out of water, making it hard for fish, crabs, shrimp and other marine life to breathe.
Nowhere is that more true than in the Tampa Bay area, where the state has declared many water bodies "impaired" because of high nitrogen levels.
That's why local governments are considering a law to restrict fertilizer use.
The Tampa Bay Estuary Program, a public-private agency that works to increase sea grasses in the bay, developed the model ordinance. The estuary program estimates residential runoff, including fertilizers, comprises about 32 percent of the total amount of nitrogen carried to the Bay, said Nanette O'Hara, a spokeswoman for the estuary program.
The program estimates the amount of nitrogen flowing into Tampa Bay could be reduced by 4 percent a year, or 84 tons, if 50 percent of households in Hillsborough, Manatee and Pinellas counties complied with the ordinance.
A Controversial Proposal
But fertilizer restrictions are controversial in Florida, where lush, emerald-green lawns are intrinsic to the state's image. A key part of the ordinance, a ban on applying nitrogen-based fertilizers during the summer rainy months, is opposed by the lawn-care and turf-grass industries.
The industry groups reject claims by environmental groups and government agencies that rain washes fertilizer off lawns and into stormwater drains. It then flows to the nearest river or bay.
"It is scientifically shown that the turf and mulch capture those nutrients and don't allow them to move," said Erica Santella, regional technical manager for TruGreen, a lawn-care company.
Opponents of the ban also say summer is a critical growing period when turf grasses need nitrogen the most. They dispute claims by environmental agencies that other, safer soil additives can keep a lawn green in summer.
Concerned About A Ban
But in Sarasota County, where a fertilizer summer ban was enacted more than a year ago, no ill effects to grass or ornamental plants have been seen, Commissioner Jon Thaxton said.
"We have some groups doing leaf and root testing, to test the health of the plants, and we're not seeing stressed lawns or die-off," Thaxton said.
Hillsborough Commissioner Al Higginbotham, who chairs the county Environmental Protection Commission, said he worries about the summer fertilizer ban.
"I'm real concerned about using the word ban," Higginbotham said. "If there is a way we can fix this rather than ban the sale of a product, I'd like to see it."
Higginbotham has invited University of Florida agriculture scientists to Thursday's EPC meeting to discuss how much nitrogen grasses need during the summer.
Though the ordinance would include fines for non-compliance, proponents say its main purpose is to educate homeowners and lawn-care companies about proper fertilizer use.
"This is one of those situations where we don't have the ability to hire new enforcement agents to go out and tell people they can't," said Hillsborough Commissioner Mark Sharpe said. "We're going to have to try to get people to want to do that."
Turf War?
Tampa, Hillsborough and Pinellas counties are considering an ordinance restricting lawn fertilizer use. Key elements include:
- Banning application of fertilizers containing nitrogen from June 1 through Sept. 30.
- Designating a fertilizer-free zone 10 feet from waterways.
- Creating a licensing and certification program for lawn-care professionals.