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Sanibel’s seasonal ban on fertilizers to go into effect

By Staff | Jun 30, 2020

DANA DETTMAR Snowy egret forages in a cyanobacteria bloom caused by fertilizer runoff.

With the arrival of the rainy season comes a blackout period for certain fertilizers on Sanibel.

From July 1 through Sept. 30, a city ordinance prohibits the use of fertilizers containing nitrogen or phosphorous, along with additional guidelines, to prevent excess nutrients from entering waterways. Nutrients fuel algae and high enough levels can lead to blooms like blue-green algae.

Residents, along with lawn service companies, are reminded to give fertilizer routines a summer vacation and to abide by the ordinance in an effort to minimize nutrient pollution in area waterways.

“It’s a pretty well-known fact that fertilizers, when used improperly, can add to our water quality issues,” Environmental Specialist Dana Dettmar, with the city’s Natural Resources Department, said.

She noted that the ordinance limits the type and amount of fertilizer used, plus its application.

DANA DETTMAR Impact on island wildlife from algae blooms.

“It limits the opportunities for an excess amount of fertilizer to get into the water,” Dettmar said.

She added that the ordinance goes into effect for the rainy season because fertilizer, say in granular form, applied prior to a big rainstorm rolling through will likely get washed away immediately.

“Before it even has a chance to break down and be used by turf grass,” Dettmar said.

To abide by the ordinance, the first step is eliminating the use of nitrogen or phosphorous.

“So, no applying fertilizers that contain nitrogen and phosphorus,” she said. “Our fertilizer ordinance is really about controlling those two nutrients in particular because algae like to specifically eat those.”

DANA DETTMAR Sunshine mimosa

Fertilizer should be cleaned up from impervious surfaces, like sidewalks and streets.

“If we have a rainstorm, that gets washed directly into a stormwater drain,” Dettmar said.

Outside of the ordinance, the city also has some year-round fertilizer guidelines. Ones containing nitrogen and phosphorus cannot be applied within 25 feet of a water body, including lakes, ponds and wetlands. Plus, there are limits on how much can be applied each year and in a single application.

“Fertilizers that they apply can only contain 20 percent nitrogen or less and 2 percent phosphorus or less, and of the 20 percent nitrogen content 50 percent has to be in slow-release form,” she said of property owners who choose to use fertilizer containing those nutrients outside of the backout period.

Further specifications and guidelines can be found on the city’s Website.

“Those are really the big ones that we like to remind people of and that will have the most impact,” Dettmar said.

As for the ordinance, it applies to lawn and landscape companies servicing the island, too.

“We do have a requirement that anybody applying fertilizer on Sanibel has to take our fertilizer endorsement competency course,” she said. “They learn the Sanibel-specific regulations.”

As part of the course, there is an introduction on how fertilizers can impact water quality.

“As an applicator (of fertilizer), they have responsibilities,” Dettmar said, explaining that one thing companies have to do is keep track of their nitrogen applications at each property they service.

The course also involves a proficiency exam that must be passed. When applying fertilizer to a property, at least one company staffer must be present who possesses the competency card.

During the rainy season, there are alternative fertilizers available for use.

“They can apply any nutrients aside from nitrogen and phosphorus,” she said. “They would be iron, potassium, magnesium. Those are elements that the lawn also needs.”

Dettmar noted that iron helps to keep a lawn green.

“It just doesn’t cause it to grow at such a rapid pace,” she said.

Another method is to leave mower clippings on the lawn, rather than bagging them.

“They will break down and provide the nutrients that the lawn needs,” Dettmar said.

There is also the option of eliminating fertilizers – completely.

“There’s always the option to not fertilize and let your lawn take a natural course,” she said, explaining that fertilizers are typically applied to maintain turf grass and that there are alternatives to turf grass.

“There are plenty of native groundcovers that grow well on Sanibel, but don’t need the same type of maintenance that turf grass does,” Dettmar said, adding that they can be mowed like turf grass.

Two types are sunshine mimosa and matchweed.

“They are both very low-growing sprawling groundcovers,” she said.

For more information, visit www.mysanibel.com/Departments/Natural-Resources and click on the “Fertilizer Information Website” link. People can also call Natural Resources at 239-472-3700.

For additional details or best management practices on transitioning to a no-fertilizer or more eco-friendly yard, visit the Sanibel Communities for Clean Water at sanibelcleanwater.org. Those interested can also check out the Florida-Friendly Landscaping Program via ffl.ifas.ufl.edu.