This summer, skip the fertilizer

There’s one garden project that you should skip this summer: fertilizing. As a resident of the Keys, you may be thinking “I haven’t used fertilizer in years — my yard is a bunch of rocks!” And that may be true. But, maybe you live in a condo with nice landscaping or maybe you frequent a community park with a grassy field. These places are likely using fertilizer. During South Florida’s rainy summer months, fertilizer is more likely to run off into waterways before plants can use it. It is a waste of time and money — and it creates pollution for the environment.

Fertilizers are rich in what are known as “nutrients,” like nitrogen and phosphorus. Plants need these nutrients to grow. But when too many nutrients are used, they can run off into the water, and create prime conditions for algae blooms. Algae blooms can turn the water green, smell bad, and cause harm to people, wildlife, the environment and the economy of the Keys. Some recent research even suggests that excess nutrients may be exacerbating sargassum blooms.

Florida Bay is already feeling the stress from algae blooms. In 2015, about 22,000 acres of seagrass meadows died in the Bay after a drought, which likely helped feed algae blooms that appeared shortly thereafter. Recent studies have shown that nearby Biscayne Bay is at a tipping point for nutrient pollution. That is, Biscayne Bay could shift from a seagrass-dominated bay into an algae-dominated one, which would fundamentally alter the biodiversity and ecosystem services of the Bay. Not to mention, algae can have consequences for our coral reefs — too much algae can cloud the water column and affect the coral’s ability to survive.

We simply cannot afford to put our resources at risk. The Florida Keys supports more than 77,000 residents and approximately 5.5 million tourists — contributing to the $4.7 billion economy. (Office of National Marine Sanctuaries 2019; Key West Chamber of Commerce 2018.) Roughly 60 percent of our economy is tied to tourism activities such as boating, fishing and diving. These industries rely on healthy ecosystems to thrive. Addressing nutrient pollution is an investment in the economy we’ve built. 

While nutrient pollution can come from a variety of sources (including animal waste, sewage spills, decomposing plant matter and agricultural runoff), it can also come from fertilizer use. In fact, the Florida Keys National Marine Sanctuary addresses algae blooms and nutrient pollution as threats to the marine sanctuary specifically in its Restoration Blueprint. Some municipalities have responded to this call to action. The Village of Islamorada has already joined 139 cities and 32 counties across the state that have passed fertilizer ordinances. This summer is the first that will be “fertilizer-free” within village limits in an effort to protect our water quality. In fact, the village is the only municipality in Monroe County that has taken this action to address fertilizer runoff. 

Absent legislation, here are some fertilizing tips you can keep in mind to protect our waters:

●      Skip summertime fertilizer use from June through September.

●      Avoid fertilizers with phosphorus in them — look for 0% phosphorus on the bag!

●      Remember to go slow! Use fertilizers with 50% slow release nitrogen.

●      Never apply fertilizers within 15 feet of a waterway or storm drain.

As a resident of the Florida Keys, I’m committing to go fertilizer-free this summer. Clean water is central to our way of life — and addressing fertilizer runoff is just one piece of a very complex pollution puzzle. I hope you’ll join me — skipping the fertilizer is an easy way to do your part to protect the water you love.

For more information, please visit

Kelly Cox, general counsel for Miami Waterkeeper. CONTRIBUTED

Kelly Cox
General counsel
Miami Waterkeeper