Report: Effectiveness of Timing of Seasonal Fertilizer Restrictions on Urban Landscapes

“Effectiveness of the Timing of Seasonal Fertilizer Restrictions on Urban Landscapes, Specific Appropriation 146, Final Report” is now available online.

Download the full report as a PDF.

From the executive summary

Increasing inputs of nitrogen (N) and phosphorus (P) in aquatic systems are primary contributors to the decline in water quality across Florida. While both natural occurrences and human activities contribute to the transport of N and P into Florida’s surface and groundwater, N and P inputs via landscape fertilizers have been a particular focus for local communities.

Since May 2000, at least 36 counties and 98 additional municipalities have established official urban landscape fertilizer ordinances, also called “fertilizer bans”, fertilizer “blackout” periods, “restrictive periods,” or “restricted season.” There is concern over whether fertilizer ordinances are effective at reducing pollution or providing ecological benefits, particularly given their ubiquity throughout the state and the variety of different ordinance types. This concern led to a fertilizer ordinance development moratorium until July 1, 2024, through the Florida Senate – 2023, Bill No. SB 2502, Lines 2455 – 2460. Via this legislation, and from funds in the Specific Appropriation 146, the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) shall “…evaluate the effectiveness of the timing of seasonal fertilizer restrictions on urban landscapes toward achieving nutrient target objectives for waterbodies statewide.”

Therefore, the purpose of this document is to provide a literature review of the most recent and relevant studies linking fertilization of urban landscapes with nutrient export to the environment, and potential subsequent water quality concerns in Florida. As a specific objective, this document discusses the effectiveness of seasonal fertilizer restrictions in decreasing nutrient contributions to aquatic ecosystems. Finally, this report summarizes the published studies, details recommendations regarding the current fertilizer ordinances, and identifies areas where further research is required to understand the effect of fertilizer ordinances on Florida’s waterbodies.

The literature review summarizes and relates studies performed mainly in Florida, with some additional studies from other states when deemed relevant. Download the full report as a PDF.