Fertilizer
Green lawns can make green lakes. Fertilizers containing phosphorus cannot be used on established lawns in Minnesota. This statewide ban was passed to help reduce the amount of phosphorus that enters lakes and wetlands. Washed off of lawns by rain and excessive irrigation, phosphorus runoff can end up fertilizing lakes and wetlands, leading to an abundance of algae and green water. This can potentially lead to fish kills and public health concerns for water users. While fertilizer with phosphorus is still allowed in gardens and to help establish new plantings, you should have your soil tested before any application. Many Midwestern soils already contain a high level of phosphorus. A simple soil test will ensure optimum nutrient levels for your flowers and vegetables as well as reducing runoff of excess nutrients. High levels of nutrients can also promote excessive weed growth. Native plants have evolved to thrive with the existing nutrient levels of our soils and are an excellent alternative for a fertilizer-free garden or landscape.
Other Resources:
U of M - Soil Testing Laboratory
U of M Extension - Responsible Fertilizer Practices for Lawns
U of M Extension - Characteristics of Natural and Manufactured Fertilizers for Lawns
