Do I need to worry about herbicides used on material that is composted? - Ask Extension
Can materials donated to compost sites, that have been treated with herbicides cause problems for your plants when the compost is used in your garden?...
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Do I need to worry about herbicides used on material that is composted? #927478
Asked April 04, 2026, 9:00 AM EDT
Can materials donated to compost sites, that have been treated with herbicides cause problems for your plants when the compost is used in your garden? Or are there organic compost sites near Le Sueur county?
Le Sueur County Minnesota
Expert Response
Hi Tanya,
Thanks for reaching out! This is a great question. Herbicides can carryover from contaminated materials in compost, such as treated grass clippings. The residues can remain in the compost for a year or longer. When added to gardens, the contaminants can persist and damage the plants. This article has additional helpful information: https://yardandgarden.extension.iastate.edu/encyclopedia/herbicide-injury-garden-plants
I did a quick search in Le Sueur County, and it looks like there is an organic compost site in New Prague: https://www.ci.new-prague.mn.us/organics-site It might be helpful to call them for more information.
I hope this helps!
