Reduce Fertilizer Runoff

Fertilizer helps our lawns and plants grow on land but in excess, it can also harm our waterways. By understanding the effects of fertilizer and taking steps to reduce its impact, we can help to protect the health of our waterways, wildlife, and coastal communities.

What is Fertilizer?

Fertilizer is food for plants and primarily provides nitrogen and phosphorus in a form that the plant’s roots can easily absorb. It is used by the agriculture industry to grow food and it supports ornamental and residential landscaping. Residential lawn fertilization is estimated to be the second-largest contributor of household nitrogen in the U.S. (Souto et al., 2019).


Educational Blogs

How to read a fertilizer bag

Have a Florida-friendly lawn year-round

Know how and when to apply fertilizer!

How to Keep Biscayne Bay Blue and Your Lawn Green

Composting for the home gardener

How does Fertilizer Impact Biscayne Bay?

Fertilizer is considered a type of nutrient pollution and can harm waterways. Just like fertilizer feeds plants on land, it also feeds vegetation in our waterways. In the summer, it rains so often that plants on land don’t have a chance to absorb fertilizer nutrients before they are washed away and eventually reach Biscayne Bay.

Floating in the water are tiny aquatic plants called algae, which eat up fertilizer nutrients. When too much nitrogen and phosphorus enter a waterway, the algae blooms and lowers the level of oxygen in the water in two ways:

  1. The bloom itself blocks sunlight from reaching other aquatic plants that need it to grow and photosynthesize. 
  2. These algal blooms eventually die and are decomposed by bacteria. This process takes up a lot of oxygen, which also affects the survival of aquatic life.

Biscayne Bay has lost up to 90 percent of seagrass in some areas, resulting in dead zones where there is not enough oxygen present in the water for marine life to survive. This has led to several instances of fish kill, or mass deaths of fish and other marine species.

In August 2020, Biscayne Bay experienced an unprecedented fish kill that resulted in over 27,000 dead fish on our shores. Two years later, the bay experienced another major fish kill, leading to thousands more dead and dying fish. We are now seeing fish kills more regularly in August and October when the water temperature is at its highest and when we experience king tides – two extraordinary factors that put additional stress on the bay.

Biscayne Bay has already reached this tipping point, so it’s more critical now than ever to prevent excess nutrients from entering our waterways. While nutrient pollution comes from a variety of sources – including fertilizer, septic tanks, sewage leaks, and stormwater runoff – reducing the use of residential fertilizer is one of the many ways that can improve our waterways and help to keep Biscayne Bay blue.

Why is it a problem?

Biscayne Bay is a central feature of South Florida, and as an economic driver in our region, a healthy bay is essential to our communities. The health of Biscayne Bay is tied directly to the health of South Florida’s economy, environment, community, history, and culture.

If we don’t change our fertilizer habits, we risk:

  • The loss of native seagrass habitats in Biscayne Bay.
  • Manatee habitat and ecosystem degradation.
  • The threat of pollution in our waterbodies.
  • Our water-driven economy and livelihoods.
  • More frequent fish kills on our shores.
  • Loss of opportunities for commercial and recreational fishing.

We can't risk Biscayne Bay becoming a dead zone.

What's being done?

Miami Waterkeeper researched, wrote, and advocated for the enactment of what became the strongest fertilizer ordinance in the state by Miami-Dade County. Our fertilizer education campaign resulted in eight municipal ordinances followed by two county-wide ordinances in Miami-Dade and Monroe counties.  However, it is key that the public is informed and engaged about this new ordinance for it to be effective. 

You can do your part to protect Biscayne Bay by learning about and following the guidelines outlined in the fertilizer ordinance.

Your efforts will lead to:

  • Cleaner, clearer water.
  • A vibrant Biscayne Bay.
  • Better water quality for residents and tourists.
  • Healthier manatees.
  • A more stable, secure ocean economy.
  • Resilience against sea level rise.
  • Maintained home values.
  • Thriving urban areas.
  • The satisfaction of doing your part for the environment.

What can individuals do?

Do your part to protect Biscayne Bay by:

  • Learn more about the impacts of fertilizer on Biscayne Bay.
  • Share resources and information with your networks.
  • Follow Miami-Dade County’s fertilizer ordinance:
    • Do not use fertilizer during the summer months (May 15 - Oct. 31).
    • Use only phosphorus-free fertilizer.
    • Use fertilizers with at least 65 percent slow-release nitrogen.
    • Apply fertilizer at least 20 feet away from storm drains and waterways.

What can you do? Model Ordinance Fertilizer Awareness Toolkit Fertilizer FAQs