Give Fertilizer a Summer Vacation: Sanibel’s Seasonal Ban Begins July 1

As the rainy season arrives in Southwest Florida, the City of Sanibel is reminding residents and property owners that its annual fertilizer ban goes into effect from July 1 through September 30. This blackout period helps protect Sanibel’s delicate water ecosystems from harmful nutrient pollution caused by fertilizer runoff.

What’s Banned?

During this seasonal ordinance, fertilizers containing nitrogen and phosphorous are strictly prohibited. These nutrients, while essential for plant growth, can lead to harmful algae blooms when washed into surrounding waterbodies.

“Fertilizer applied right before a rainstorm can easily be swept into canals, wetlands, and the Sanibel Slough,” explains Dana Dettmar, Environmental Biologist with Sanibel’s Natural Resources Department. “That runoff becomes an unnatural buffet for algae, fueling blooms that damage water quality and marine life.”

Alternatives You Can Use

Don’t worry—there are eco-friendly options available:

Use fertilizers containing iron, potassium, or magnesium, which are allowed during the summer months.
Mulch your grass clippings as you mow; they naturally break down and return nutrients to the soil.
Consider going fertilizer-free altogether by adopting the “mow what grows” approach or replacing turf grass with native groundcovers like sunshine mimosa, matchweed, frogfruit, or bacopa.

Additional Year-Round Fertilizer Rules:

Even outside the blackout period, Sanibel’s fertilizer ordinance enforces best practices all year:

Do not apply fertilizer within 25 feet of any waterbody, including lakes, canals, and wetlands.
Do not apply fertilizer to hard surfaces like sidewalks or driveways. Spills must be cleaned up immediately.
Avoid fertilizing stormwater conveyance systems, such as roadside swales or catch basins.

Content & Application Limits (Year-Round):

Fertilizer must contain 2% or less phosphorous and less than 20% nitrogen, with at least 50% slow-release nitrogen.
No more than 1 pound of nitrogen per 1,000 sq. ft. per application and no more than 4 pounds total per year.

Why It Matters

Overfertilization is one of the leading causes of poor water quality across Florida. On Sanibel, clean water is essential for both the environment and our island’s economy. By following the ordinance, every resident helps preserve our ecosystems and way of life.

“We rely on clean water for everything—from wildlife and recreation to property values,” Dettmar said. “Adhering to the fertilizer ordinance is an easy, meaningful way to protect what we love about Sanibel.”