We all love the look of lush, green turf grass - but sometimes the methods we use to achieve it can unintentionally harm our local waterways. When lawns receive more nutrients than they need, especially phosphorus, the excess washes away during rainfall. These nutrients enter nearby streams, rivers, and lakes, causing algal blooms that degrade water quality and harm aquatic life.
The good news - you can enjoy a beautiful lawn while protecting the environment. Here are some simple, effective tips for reducing nutrient runoff and keeping your yard—and local waterways—healthy.
Improve soil quality. Lawns with good soil quality reduce the need for watering and minimize the need for fertilizers to stay green. Soil quality restoration (SQR) is the process of improving soil health on new or existing lawns. To perform an SQR, aerate the lawn, evenly spread 1/2”-3/4” of compost, reseed if needed, then water until vegetation is established. You can learn more about the process at this link. The Davenport Compost Facility has another great resource at this link.
Apply fertilizer only when you need to. Most soils in Iowa naturally contain plenty of phosphorus, meaning many lawns don’t need additional phosphorus to stay healthy. The best first step in responsible lawn care is to understand the fertility of the soil beneath your turf. A simple soil test can tell you exactly what your lawn needs - and what it doesn’t.
When reviewing your soil test results, pay close attention to three key nutrients: phosphorus (P), nitrogen (N), and potassium (K). These values will help you decide whether applying fertilizer is necessary or if other lawn‑care practices might be more effective.
After understanding your soil’s needs, make a plan. Instead of immediately reaching for fertilizer, consider actions that improve soil health and reduce runoff, such as applying a thin layer of compost or applying only the nutrients your lawn actually needs.
These practices can significantly reduce contaminated runoff while also saving you money on watering, chemicals, and maintenance.
You can find out more about how and when to use fertilizers by downloading the Iowa State University Extension Service's Lawn Fertilizer Guide at this link.
Soil test kits are available at many local retailers. The University of Minnesota's Soil Testing Lab is another great resource.
If you do need to apply fertilizer,
- Avoid applying before rain
- Apply it sparingly, and
- Remember to sweep up any excess that lands on sidewalks and driveways.
Mulch grass clippings back on to the lawn. Mulching leaves and grass clippings back onto your lawn is one of the simplest ways to nourish your turf naturally. As these materials break down, they return valuable nutrients - especially nitrogen - directly to the soil. Over time, this helps build organic matter and supports healthier, more resilient grass.
Mulching doesn’t just improve soil health. It also provides several practical benefits:
- Helps suppress weeds by covering bare spots
- Retains soil moisture, reducing the need for watering
- Reduces yard waste and eliminates the need to bag clippings
- Supports a healthier lawn without added fertilizers
By recycling what your yard already produces, you strengthen your turf, save time, and help protect local waterways from excess nutrient runoff. Find mowing tips that will help you keep your lawn and our waterways healthy at this link.
Properly dispose yard waste. In accordance with the Clean Water Act and City ordinance, you can be fined for blowing or depositing grass clippings and yard wastes into the street or directly into or near a water body. Grass clippings and yard wastes that end up on streets and in our waterways degrade water quality and can reduce oxygen levels necessary to support aquatic life. In addition, when washed to nearby storm drains during rain events this lawn debris can clog catch basins and contribute to localized flooding. The City offers a number of ways to properly dispose yard waste.
Consider home composting. Reduce yard and food scrap wastes, and have a great lawn? Grass clippings, leaves and food scraps such as apple cores, banana and orange peels, melon rinds, coffee grounds and eggshells can be recycled and put to good use through home composting. Not only will you avoid disposal fees, but you will produce beneficial nutrient rich compost for use in all of your lawn and garden projects without having to purchase the product. Find out more at this link.