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Keyword: fertilize lawn

lawn chemicalsErin Wisnieski, Natural Resource Specialist
Baltimore County Department of Environmental Protection and Sustainability

It’s the eternal suburban dilemma — how to have a nice lawn but not damage the environment. I think that a lot of people assume that they need to apply chemical fertilizers to their lawn, but that’s not necessarily so.

Lawn Fertilizer and the Chesapeake Bay

If not properly applied, lawn fertilizer can wash off lawns when it rains. Once this polluted runoff enters the storm drain system through a street or yard inlet, it flows quickly to the local stream and down to the bay.

The Problem

Nitrogen and phosphorus are the primary nutrients in lawn fertilizer and are essential for plant growth, but too much of a good thing makes the bay sick … and, in part, dead. Excess nutrients create the bay’s “dead zone.”

In response to high nutrient levels in the water, algae growth takes off. Masses of slimy algae coat beneficial aquatic plants (SAVs), blocking the sunlight and inhibiting SAV growth. As an algal bloom dies and decays, oxygen is robbed from the water, depleting the amount of dissolved oxygen available to fish, crabs, clams and oysters. At times, large fish kills result as fish suffocate. 

According to the Chesapeake Bay Commission, 14% of the nitrogen and 8% of the phosphorus entering the bay comes from urban and suburban lawns. To help address strict new water quality standards for the bay, Maryland passed the Fertilizer Use Act of 2011, which restricts use of lawn fertilizer by homeowners and commercial applicators. The law changes the nutrient composition of lawn fertilizers and provides for enforcement, labeling, and education.

You Can Help

Either “just say no” to fertilizing or strictly limit the addition of fertilizer and other chemicals on your lawn — it will be safer for you, your kids, pets, and the bay. Leave grass clippings on your lawn to recycle the nutrients back to the lawn (a.k.a. grasscycling). Start a compost pile. Topdressing with compost will increase the health of your lawn without using chemicals. Keep your neighborhood storm drains free of grass clippings, leaves, dirt, and trash.

Planting native trees to expand a forested area or converting some of your turf grass to native plant beds helps, too. Once the bed is established, little maintenance is needed. The natural space created will be appealing to the eye, helps protect water quality, and provides food and shelter to native hummingbirds and butterflies.

If you apply fertilizer to your lawn, please carefully read the label for instructions. If you hire someone to do lawn care, find out if they fertilize, what they use and how the spread rate is determined. If fertilizer gets on sidewalks, driveways or other hard surfaces, sweep it back on the grass.


Revised April 6, 2016