Every spring, Minnesotans step outside to perform the same ritual: rake the lawn, plan the garden, and grab a bag of fertilizer to help the yard wake up from winter. What most people don’t realize is how much this last step can affect the water around us.
A University of Minnesota study from a few years back delivered a clear wake‑up: backyard chemicals, especially lawn fertilizers, are a significant source of nutrient pollution in our lakes, rivers, and wetlands.
The problem is bigger than many people may realize. Every year, the Minnesota Department of Agriculture (MDA) tracks off-farm fertilizer and pesticide sales. In 2024, the last year purchase data was published, Minnesotans bought 178 million pounds of fertilizer for residential use. Pesticide purchases were smaller — about 870,000 pounds at last count — but they also contribute to contamination risks.
So, no matter what you apply — fertilizer, weed-and-feed, pesticide — the same rules apply: Chemical products used at the wrong time or in the wrong place can move off your property and into our waters.
But here’s the good news: You don’t have to overhaul your yard or give up a healthy lawn. Just use these products the right way. Here are simple steps that help keep chemicals out of our water resources.
- Use only what you need. Conduct a soil test before you buy or apply any fertilizer to ensure it’s needed. Test kits are available at most garden centers. Spot‑treat weeds and other problem areas, whenever possible. Mow at 3–4 inches to shade out weeds and use mulch in gardens to prevent others from establishing. When using any backyard chemical, always follow label instructions.
- Keep products where they belong. If a powder or granular chemical lands on the sidewalk or driveway, sweep or blow it back into its intended area. Pavement is the fastest route to a storm drain.
- Check the weather before applying anything. Avoid windy days, heavy rain in the forecast, extreme heat, and drought conditions. Weather determines whether products stay put or end up downstream.
Even if you hire a lawn care crew, you still have a say over what happens in your yard. Professional applicators are licensed by the MDA and are required to provide a clear breakdown of what they apply to your yard. You can — and should — ask how they determine what products are used, how they prevent runoff, and whether their practices align with your goals for protecting water quality. A reputable company will welcome these questions.
Minnesotans fish, sail, swim, and brag about our lakes for good reason. And protecting these waters isn’t just the job of farmers, cities, and regulators. It’s on all of us.
This spring, as you step into your yard with a fertilizer spreader or a bag of weed control, please remember: Small changes in how we use backyard chemicals can make a meaningful difference. And when thousands of households make those changes together, Minnesota’s waters stay cleaner, clearer, and healthier for everyone.
Denton Bruening is an agronomist with the Minnesota Department of Agriculture.
