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Healthy lawns for a healthy Niantic River and Long Island Sound


Published June 24. 2021 9:00AM 

By Judy Rondeau, Special to the Times

This summer, the Niantic River Watershed Committee is asking residents of East Lyme and Waterford to think about how they use lawn fertilizer. Through the Healthy Lawns, Healthy River project, funded through the Long Island Sound Futures Fund program, volunteers from the Watershed Committee will visit neighborhoods along the Niantic River to ask residents to consider how much fertilizer they apply on their lawns and how they time their applications.

Nitrogen, one of the primary components in fertilizer, can impact coastal waterways and the marine habitat. Nitrogen dissolves very easily in water. When it rains, or when a lawn is watered, nitrogen soaks readily into the ground where it feeds the grass. But it also just as easily soaks through the soil into the groundwater table or runs off the lawn and into nearby stormdrain systems.

This nitrogen works its way into streams and rivers like the Niantic River, and Long Island Sound. There, it feeds plants that live in the estuary and Sound, such as seaweeds, plankton and algae. This can cause excessive seaweed growth and algae blooms.

When these plants die, they trigger an explosion in the population of bacteria that decompose the dead plant matter. These bacteria use oxygen, and as they decompose dead seaweed and algae, they can create zones in the water with low (hypoxic) or no (anoxic) oxygen.

These zones are often only detected after events like fish kills are observed.

Research conducted at the University of Connecticut from 2013 – 2015 evaluated sources of nitrogen to Long Island Sound bays and harbors (

In the Niantic River watershed about 29% of nitrogen comes from fertilizer. Other sources of nitrogen, such as atmospheric nitrogen that is deposited on the land and water and nitrogen from septic systems, are difficult to control and require coordination on state and even regional levels.

But controlling how much fertilizer you apply on your lawn is easy! According to turf scientists from the University of Connecticut and other New England universities, mature lawns do not need much, if any, fertilizer.

According to the “New England Regional Nitrogen and Phosphorus Fertilizer and Associated Management Practice Recommendations for Lawns Based on Water Quality Considerations,” if you don’t fertilize your lawn and are happy with the way it looks, there is no need to start fertilizing. If you do fertilize, apply half of the amount recommended on the fertilizer bag.

If you are satisfied with the way your lawn looks, you are applying the right amount. Make sure you apply fertilizer at the right time of the year – before green-up in the spring (around Memorial Day) and around Labor Day when grass is coming out of summer dormancy.

Applying fertilizer too early or too late in the season, or during the hot summer months when grass is dormant, will waste the fertilizer since the grass won’t use it.

Finally, leave your grass clippings on the lawn. Grass clippings break down quickly and will return nitrogen stored in the plant tissue to the lawn, feeding it for free!

Help us sustain a healthy Niantic River by adopting these simple healthy lawn care actions. To learn more about Healthy Lawns, Healthy River, visit

Judith C. Rondeau is assistant director of the Eastern Connecticut Conservation District in Brooklyn and coordinator of the Niantic River watershed. She can be reached at [email protected].