Some farmers are considering taking prevented planting on some acres this year. Some of these farmers are interested in planting a cover crop this summer. The summer cover crop could help to manage weeds, sequester nutrients already applied, reduce soil loss, and enhance soil quality.

Consider herbicides applied for row crop. If herbicides were applied anticipating row crop establishment, they could negatively impact the establishment and productivity of summer cover crops. Check labels and ensure that cover crops will not be negatively impacted. 

Grass cover crop species. Sorghum sudangrass and pearl millet will establish and grow well in Kentucky and are widely available from most seed suppliers.  Both pearl millet and sorghum sudangrass will produce heavy biomass that could interfere with seed placement in subsequent plantings. Foxtail millet has a lower growth habit and finer stems. It does not regrow once clipped below the growing point. If it is bushhogged in in the late boot stage seed set will be greatly reduced and growth limited.  

Legume summer cover crop species. Cowpea and sunn hemp both will establish well and help cover the soil. Annual lespedeza is another option and will produce the lowest biomass of these three. Seed availability may be more limited for these summer annual legume species.   

Other summer cover crop species. Other species include brassicas such as forage or tillage radish and asters such as sunflower. These species are usually used as a part of mixtures rather than standalone seedings.  Seed availability may be more limited. Small-seeded legumes and forbs tend to be more sensitive to seeding depth and can be harder to establish. 

Monocultures versus multi-species mixtures. If a farmer grows only a grass summer cover crop, then there are herbicide options to control broadleaf weeds should they escape the cover crop. If a farmer grows only a legume, then there are some grass herbicide options to control escape in that crop. Planting mixtures of grasses, legumes, and forbs virtually eliminates the used of herbicides for weed control.   

Multi-species cover crop mixes. Mixing summer annual grasses with legumes such as cowpea or sunn hemp and forbs could provide excellent erosion prevention (from the grasses), add nitrogen to the system via dinitrogen fixation (from the legumes), and provide habitat for pollinators (sunflower).  That additional nitrogen could be beneficial to a crop planted in the fall. Remember that multispecies cover crops eliminate the ability to use herbicides.

Use high quality cover crop seed. The cover crop seed should be of high quality, easy to drill and provide excellent ground cover for most of the summer. “Cheap” cover crop seed that does not meet these criteria will cost too much. If the primary goal is weed suppression, then choose a cover crop with higher biomass potential. If higher biomass will lead to other challenges in the fall, then select a cover crop with less biomass potential. The Grain, Forage, and Cover Crop Guide for Kentucky (AGR-18) provides an excellent overview of the species listed above.

Additional Management Considerations. Summer cover crops should not go to seed and should not become a weed to the fall crop. Termination could occur with grazing, mowing, tillage and/or herbicide.

The Southern Cover Crop Council has a cover crop selector tool https://covercrop-selector.org/ . The farmer can specify their cover crop window, location, soil condition, and goals, and then read about the options that align with their system.

USDA RMA Prevented Planting. According to the United States Department of Agriculture Risk Management Agency (USDA RMA),  the Final Planting date for corn in Kentucky is June 31, 2025 and the End of Late Planting Period is June 15, 2025 (USDA RMA Web Applications). For soybean, the Final Planting Date is June 15, 2025 for single crop and June 25, 2025 for double crop. The End of Late Planting Period is July 10, 2025 for single crop and July 15, 2025 for double crop (USDA RMA Web Applications).  Note: On the USDA RMA website “Nfac” means “not following another crop” and “Fac” means “following another crop”.

Your crop insurance agent should have specific details on the steps taken for Prevented Planting. Consult with your crop insurance agent and the USDA RMA for other questions regarding Prevented Planting and what is allowed with a cover crop. Reach out to your local county extension agent for questions about establishing and managing a summer cover crop.

Resources:

Knott, C., E. Haramoto, J. Henning, C. Lee and R. Smith. AGR-18 Grain, Forage, and Cover Crop Guide for Kentucky. Univ. of Kentucky Cooperative Extension Service. Lexington. https://publications.ca.uky.edu/sites/publications.ca.uky.edu/files/AGR18.pdf

Southeast Cover Crop Council Cover Crop Selector https://covercrop-selector.org/

USDA RMA Web Applications | Final Planting Dates https://webapp.rma.usda.gov/apps/actuarialinformationbrowser/DisplayCrop.aspx

USDA RMA First and Second Crop Rules https://old.rma.usda.gov/en/Fact-Sheets/National-Fact-Sheets/First-and-Second-Crop-Rules

Contributors: Chris Teutsch, Erin Haramoto, J.D. Green, and Hanna Poffenbarger