Keep Water Clean by Following Fertilizer Rules

From June 1 through Sept. 30, it is against the law to use fertilizer that contains nitrogen and/or phosphorus. Hillsborough County's rules on the use of fertilizers containing these nutrients are intended to protect and preserve the cleanliness of local streams, rivers, lakes, and bays. Protecting the county's water reduces the severity of algae blooms, such as red tide. This, in turn, benefits the health of the area's wildlife and residents.

Nitrogen and phosphorous-based fertilizer

Problems from nitrogen and phosphorus fertilizers can become more severe in the summer, when heavy rainfall is common in West-Central Florida. During this time, fertilizer-laden runoff from stormwater and irrigation often flows into local waterways. The impact of fertilizer runoff is greater in areas lacking shoreline vegetation that would otherwise absorb these excess nutrients.

While nutrients are often blamed for red tide, it is a natural event that happens almost every year in the gulf. Blooms usually begin offshore and grow slowly. Wind and currents can carry them toward the coast. If coastal waters have high nutrient levels, the bloom can grow quickly and become more severe. The worst impacts - like fish kills and breathing problems - usually happen along the shoreline.

Algae blooms can reduce the amount of sunlight reaching seagrass and other beneficial aquatic plants, limiting their growth. This can lead to lower oxygen levels in the water, which, along with toxins produced by some algae, may contribute to fish deaths. Larger or persistent blooms may also affect other marine life, such as manatees and dolphins. For example, red tide can release a neurotoxin that may cause manatees to show symptoms similar to seizures when inhaled, and in some cases, may interfere with normal breathing. Dolphins can also experience respiratory irritation from red tide, similar to symptoms seen in people.

Blue-green algae blooms are becoming more common in stormwater ponds within master-planned communities and commercial areas. Their growth is often fueled by elevated nutrient levels. Some types of blue-green algae can produce toxins that are harmful to fish, people, and pets. The only way to determine if a visible bloom is toxic is to identify the algae species involved and test for toxins.

Fertilizer ordinance details

The fertilizer ordinance applies to residents, homeowners, HOA common property management, businesses, governmental entities, and companies that apply fertilizer and provide landscape services to non-agricultural property.

Here are some key provisions of Hillsborough County's fertilizer ordinance: 

• Fertilizers containing nitrogen and phosphorous may not be applied on turfgrass or landscape plants from June 1 through Sept. 30, though the ordinance does not prohibit stores from selling the material during this application blackout
• Fertilizers containing phosphorous may not be placed on turfgrass or landscape plants at any time unless a soil analysis showing a phosphorous deficiency has been performed by a qualified laboratory
• Fertilizers containing nitrogen must be at least 50% controlled or slow-release
• Fertilizer may not be applied, spilled, or deposited on any impervious surface like driveways, sidewalks, or roads. If fertilizer does land on these surfaces, it must be removed and may not be washed, swept, or blown into storm drains, ditches, or water bodies
• Fertilizers containing nitrogen or phosphorous may not be applied when it is raining, within 36 hours of a predicted rainfall of at least 2 inches, during a flood watch or warning, or when a tropical storm or hurricane looms
• Fertilizer may not be spread within 10 feet of any surface water or water body
• Violation of any of the ordinance's provisions is a misdemeanor and can result in a fine of up to $500 and/or up to 60 days in jail

Enforcement and violation reporting

The fertilizer ordinance is enforced by Hillsborough County Code Enforcement. Suspected ordinance violations can be reported online.

Additional information

More information can be found on the Fertilizer Ordinance and Regulation webpage.

Contact Hillsborough County Extension Service for more information at (813) 744-5519.