Persistent broadleaf herbicides are a group of chemicals used to kill weeds and includes both pre-emergent herbicides, applied to the soil to interrupt the germination process, and selective post-emergent herbicides applied directly to the plant to kill broadleaf weeds while not damaging grass. Though they do not kill grass, they can be taken up by grass, consumed by horses or cows, passed through the digestive tract, expelled as manure, and still remain active after composting. Incorporating contaminated compost or grass clippings into your garden can result in damage to broadleaf plants (including many vegetables).
It was created in partnership with the Duke Superfund Research Center Many thanks to co-authors
- Check Your Dirt NC - Tool to identify and address problems related to soil contamination
- Food Safety for School and Community Gardens
- Garden Soil Contaminant Resources and FAQ
- Herbicide Carryover in Hay, Manure, Compost, and Grass Clippings.
- Herbicide Injury – Symptoms and Fact Sheets
- Minimizing Risks of Soil Contaminants in Urban Garden
- Urban Soils
Note: This is not just an urban issue, persistent broadleaf herbicides are used to manage pastures and residual problems and are showing up in rural areas as well.
