Chemically Treated Grass Clippings in Compost Pile
Two years ago we accidentally added grass clippings from our chemically treated lawn to our compost bin. When we used the compost, all our plants died. The same thing happened again this spring. It couldn't just be the grass clippings. Are there other items we shouldn't add to compost?
What you put in your compost can influence the speed of decomposition and quality of compost produced. Treated clippings are best left on the lawn. They add nutrients and moisture to the soil. Avoid adding black walnut twigs, leaves and fruits. These contain juglone that is toxic to other plants. Once these materials are fully decomposed they are no longer toxic to other plants. Partially decomposed compost can temporarily tie up nitrogen in the garden soil. Mix this into gardens in the fall or wait for the compost to completely decompose (crumbly and brown like soil) before adding it to the garden. Do not add meat or animal products to compost bins. These materials can attract rodents.
Related
Upcoming
Events & Webinars
August 6-16, 2026
Wisconsin State Fair
We Energies Energy Park, West Allis, WI
August 29, 2026
Composting 102
Milwaukee Public Library - East Branch
Register here
Sept. 3, 2026
FREE WEBINAR:
Tree Planting and Care
Register here
Sept. 11, 2026
Illinois State Master Gardener Conference
Rockford, IL
Register here
Sept. 12, 2026
2026 Knowledge in Bloom Conference
Urban Ecology Center, Milw., WI
Register here
Sept. 17, 2026
FREE WEBINAR:
Fall Landscape Care and Planting
Register here
Sept. 26, 2026
Pruning Hydrangeas & Other Shrubs
Pasquesi Home & Gardens, Lake Bluff, IL
Oct. 6, 2026
Upper Midwest Invasive Species Conference
La Crosse, WI
Register here
WATCH ON-DEMAND WEBINARS
MORE UPCOMING EVENT DETAILS


