Doing our part for the St. Johns River

The Fourteenth State of the River Report ( was recently released. The report addresses issues affecting the health of the St. Johns River. The report contains information that should be of interest to homeowners with residential landscapes. Nutrient levels in the tributaries leading into river, primarily nitrogen and phosphorous continue to be a concern. While often the solutions to these problems are larger than any one person can undertake, collectively we can take steps to ensure that our landscapes are not contributing to the nutrient load of the river.

Fortunately, the Florida-Friendly Landscaping™ (FFL) program offers several practices that we can adopt that will help us all protect the water quality of the river. These practices fall under four specific FFL principles. They are Water Efficiently, Fertilize Appropriately, Reduce Stormwater Runoff, and Protect the Waterfront.

Watering Efficiently

When you choose the right plants for your landscape you will probably need to water them less. If you group plants with the same watering needs and set your zones up to match, you will avoid some of the disease issues that come with improper irrigation. Additionally, converting shrub beds to micro irrigation reduces water use and disease problems.

While many homeowners have automatic irrigation systems for their lawn, most do not know how much water they are putting out, and how to measure it. To make it easy a simple turf irrigation schedule should apply between ½ to ¾ of an inch of water at each watering. During the hot dry seasons (daylight savings time), this can be done twice a week. During the cooler months (eastern standard time), no more than once a week. If there has been adequate rainfall to achieve this amount of irrigation, no watering is needed.

If you do not know how many inches your sprinkler system is putting out, it is time to calibrate it. This is done using the “catch can “method. By laying out several tuna, or cat food cans, you can easily determine how long it takes your system to apply ½ to ¾ inch of water. Measure the amount of water in the cans after running the system for 15 minutes. For example, if after 15 minutes, you have ¼” of water, it would take 30 to 45 minutes to apply the correct amount of water (1/2 to ¾ of an inch) through your irrigation system. Once you know how much water your system is putting on your lawn, you can set the timer accordingly.

Fertilizing Appropriately

There is no one lawn care practice that has more effect on Florida’s environment than turf fertilization. If fertilizer is mis-applied to the lawn, the excess nutrients can run off, or through soil and pollute our surface waters. In 2007 the State of Florida created a rule that all urban turf fertilizer sold in the state had specific instructions on how to properly apply the fertilizer to turf. This makes it easier for the homeowner to apply the proper amount when the label on the bag is followed.

Before you apply fertilizer to your landscape, get a soil test and fertilize only when necessary. Look for fertilizers with low-release nitrogen and little or no phosphorous. Timing is also important. Fertilizer should be applied when our lawn grasses are most able to take up the nutrients and use them. This is when they are actively growing. One way to think about it is; if you are having to mow it often, then it is growing.

University of Florida recommendations call for applying ½ pound to 1 pound of nitrogen per 1000 square feet of turfgrass per fertilizer application. If you follow the instructions on the turf fertilizer bag, you are in good shape. However, the Florida turf fertilizer rule allows fertilizing in the late spring and summer (when turf is actively growing) with up to 2 pounds of nitrogen per 1000 square feet IF the fertilizer has at least 65% of the nitrogen in a slow-release form.

Reduce Stormwater Runoff

This principle may seem like the hardest to perform but there are some easy recommendations that almost anyone can do. First, if you spill fertilizer on the lawn or on a sidewalk or driveway, sweep it up and put it back in the bag. This way the fertilizer does not get carried away into the storm drain. If you have downspouts, make sure that they empty into a plant bed, or permeable surface instead of onto a sidewalk or driveway. Finally, collecting rainwater in a cistern or rain barrel to use it later in the landscape can save money in your water bill in addition to reducing the stormwater runoff.

Protecting the Waterfront

For those of us that live on any body of water we can do our part by adopting practices that slow down, filter, or eliminate runoff from reaching the water.

Maintaining the part of your landscape that is adjacent to the waterbody as a buffer from lawn and landscape practices can do wonders for water quality. Planting the area with low growing, low maintenance, native shoreline vegetation can help to make it attractive, filter out contaminates, reduce erosion as well as attract native wildlife.

Developing a “maintenance free zone” of at least 10 feet from the shoreline will protect the water from landscape runoff by creating distance from lawn maintenance activities. Make it attractive by installing plants that do not require fertilization, irrigation, or mowing. As always make sure the area remains free of any invasive exotic plants such as torpedo grass.

Grass clippings and trimmings often get blown into or thrown into the water to dispose of them. Allowing lawn clippings to remain by leaving them in place or collecting our grass trimmings and composting them keeps the nutrients contained in the clippings out of the water. Reducing the amount of pet waste that runs off into water bodies can also reduce harmful bacteria levels.

Helping to protect the St. Johns River does not mean you need to sacrifice keeping your lawn or landscape healthy. The Florida-Friendly Landscaping™ principals are based on research to provide our landscape what they need in a way that also helps keep our water resources healthy. For more information on the other FFL principles, or additional help in creating a Florida Friendly Landscape go to


Posted: December 1, 2021

Category: Agriculture, Florida-Friendly Landscaping, Home Landscapes, Horticulture, Lawn, Turf, Water
Tags: Duval, FFL, Nutrients, St. Johns River

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