Consider your herbicide program when planting cover crops

Submitted by Sara Berges, Allamakee SWCD

Plan now to facilitate successful cover crop establishment this fall.  Your herbicide program could prevent successful cover crop establishment or may restrict grazing/forage options for your cover crop.  Many herbicides prohibit grazing or feeding within a specified time frame, which would then prohibit cover crops planted on these fields to be used for feed. Make sure that you follow the restrictions listed on the label.  There are several resources available that compile information from herbicide labels regarding establishment of cover crops for grazing/forage.

The Iowa State University Publication “Herbicide use may restrict grazing options for cover crops” was updated in January and splits herbicide use into three categories: products that allow establishment of cover crops for grazing/forage less than 4 months after application, those that allow establishment 4 months after application, and products that allow establishment 4.5 months after application.  According to this chart, products containing metolachlor had the longest restrictions for cover crop establishment.  The University of Wisconsin-Extension has a publication titled “Herbicide Rotation Restrictions in Forage and Cover Cropping Systems” and Penn State has a publication called “Herbicide Persistence and Rotation to Cover Crops.” 

All of these are available online or at the Waukon NRCS office.  The first place to look for information on herbicide persistence, however, should be your chemical label as following the label restrictions is the law.  If you have questions, please contact the Allamakee SWCD/NRCS office by stopping by 635 9th St NW in Waukon, calling 563-568-2246 ext. 3, or emailing Sara Berges at