Yard & Garden Report


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Know your manure

Know where your manure comes from and avoid contaminating your garden with herbicide.

Horse with manure in pastureMany gardeners add manure to their gardens in fall. Please be sure you know where your manure comes from. Some farmers spray their pastures with pyridine herbicides to control broadleaf weeds. These herbicides include Crossbow, Curtail, Forefront, Grazon, Milestone, Redeem and Surmount.

Manure from livestock feeding on pyridine-treated hay or pasture grass should not be used in gardens. The chemical passes through the animal without decomposing. When gardeners use this manure, they are literally adding a persistent herbicide to their soil. The hearts and hopes of many of the best gardeners in our state have been broken. 

 Tomatoes, potatoes, peas and beans are extremely sensitive. Affected plants will stretch and curl, similar to damage caused by dandelion killers that drift onto plants. Pyridine can persist in manure for a few years—be very careful!

Written by Tom Kalb, Extension Horticulturist, North Dakota State University. Published in the NDSU Yard & Garden Report, October 15, 2014. The photo was made available under a Creative Commons license specified by the photographer: Malene Thyssen.

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