With the arrival of the rainy season in Southwest Florida, the city of Sanibel is reminding property owners of the seasonal blackout period for certain fertilizers on the island.
From July 1 through Sept. 30, the city's annual ordinance will be in effect. It prohibits the use of fertilizers containing nitrogen and phosphorous, plus sets additional year-round guidelines.
"In an effort to protect water quality on Sanibel and in our surrounding waters, city council adopted the fertilizer ordinance in 2007, which limits the timing of fertilizer as well as the application of certain fertilizers," Natural Resources Department environmental biologist Dana Dettmar said.
During the rainy season, nitrogen and phosphorous can impact water quality.
"The reason that we have the blackout period during the rainy season is to be protective of water quality. Most fertilizers, especially those applied in residential areas, are in granular form," she said, explaining that strong rains after applying them can wash the fertilizers directly into waterbodies.
"It's to limit the likelihood that they'll get washed off the landscape," Dettmar added.
She noted that all life needs the nutrients nitrogen and phosphorous.
"So we put those on plants and turf grass because they need them to grow, but that's also true for algae," Dettmar said. "So when you have fertilizer getting into waterbodies, it's an unnatural human induced acceleration of nutrients. It kind of gives algae a buffet and can create the algae blooms."
While those containing nitrogen and phosphorous are banned, alternatives are available.
"There are other fertilizer blends that exist that you can use during the summer months that contain other macronutrients," she said, citing iron, potassium and magnesium as examples.
Rather than cleaning up grass clippings, let them sit to break down and provide nutrients.
"Mulching your grass as you mow it instead of bagging it is another way to get nutrients back into the soil," Dettmar said, explaining that the clippings will decompose and return the nutrients to soil.
If near an open body of water, however, do not blow clippings into the water.
"Because that can add to the nutrient issue," she said.
By skipping the turf grass altogether, people can reduce or eliminate their reliance on fertilizer.
"We would recommend going fertilizer free because that's better for the environment here on Sanibel," Dettmar said.
Property owners can choose not to fertilize and take the "mow what grows" tactic or they can replace turf grass with native groundcovers, such as sunshine mimosa, matchweed or frogfruit, and bacopa.
"Native groundcovers are low-growing and can be mowed like turf grass," she said.
In addition to the seasonal blackout period, the ordinance states:
– Fertilizers cannot be applied within 25 feet of a body of water, including lakes, ponds, canals, wetlands and the Sanibel Slough.
– Fertilizers cannot be applied to impervious surfaces, such as roadways, driveways and sidewalks. Any spills should be cleaned up immediately.
– Fertilizers cannot be applied to stormwater conveyance systems or catch basins, which includes roadside swales.
Also for year-round, the ordinance restricts fertilizer content and application rates.
For the fertilizer content, those being applied must contain 2% or less of phosphorous and less than 20% or less of nitrogen. Additionally, 50% of the total nitrogen has to be in a slow-release form.
For the application rates, no greater than 1 pound of nitrogen per 1,000 square feet per application. Additionally, no more than 4 pounds of nitrogen per 1,000 square feet within a calendar year.
The island is encouraged to give fertilizer a summer vacation.
"It's well known that overfertilization can have negative environmental impacts," Dettmar said. "Sanibel relies very heavily on our water for both recreation and economic well-being, so we want to protect water quality and make sure that we're not adding to the overall problem that the state of Florida is experiencing."
"We want to do our part to keep our water healthy here on Sanibel, and adhering to the fertilizer ordinance is a really easy step that citizens can take to do their part," she added.
For more information, visit https://www.mysanibel.com/402/Sanibels-Fertilizer-Information.
For questions, contact the Natural Resources Department at 239-472-3700.
While the purpose of the ordinance is to be protective of water quality, property owners can further protect water quality by implementing best management practices in their backyard and neighborhood. Visit Sanibel Communities for Clean Water at https://www.sanibelcleanwater.org/ for more details.
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GIVE FERTILIZER A SUMMER VACATION
– It is a violation of Ordinance 07-003 to apply fertilizers containing nitrogen and phosphorous during the rainy season, from July 1 to Sept. 30.
– Fertilizers cannot be applied within 25 feet of a body of water, including lakes, ponds, canals, wetlands and the Sanibel Slough.
– Fertilizers cannot be applied to impervious surfaces, such as roadways, driveways and sidewalks. Any spills should be cleaned up immediately.
– Fertilizers cannot be applied to stormwater conveyance systems or catch basins, which includes roadside swales.
Source: City of Sanibel
