January 24, 2025

When is the Best Time to Terminate a Cover Crop? 

At our recent Cover Crops and Sustainability Field Day, Eric Brennan, Research Horticulturist at USDA-ARS in Salinas, shared valuable insights on determining the best time to terminate cover crops. Timing is key to maximizing the benefits of cover crops while minimizing potential drawbacks. Here are the factors to consider: 

Maximizing Biomass for Soil Health 

  • Allowing cover crops to maximize shoot growth ensures more above-ground biomass, which provides energy to the soil when incorporated. 
  • Encouraging root growth builds underground biomass to nourish microbial communities and promote overall soil health. 

Timing Matters: Post-Flowering, Pre-Seeding 

  • Terminating cover crops after flowering but before seed production prevents viable seeds from becoming a source of unwanted plants in future crops. 
  • Terminating too early can result in nitrogen loss, as nitrogen remains in a leachable form during early growth stages. 

Considering Seasonal Conditions 

  • In cooler weather, cover crops may grow more slowly and produce less viable seed, extending the window for termination. 
  • Warmer weather or stressful conditions, like low moisture, can cause cover crops to bolt or have stunted growth, potentially limiting their benefits. 

Stay tuned for more information and practical tips from our Cover Crop Field Day series. 

Additional Resource: Free Cover Crop Seeds and Support for Growers 

If you’re a grower in Santa Cruz, Monterey or San Benito County, there’s an exciting opportunity available. Thanks to RCD Santa Cruz and RCD Monterey, growers can receive 4–5 acres worth of cereal cover crop seeds for free. This program also offers access to personalized technical assistance from RCD staff, soil nitrogen quick tests and help calculating nitrogen scavenging credits for Ag Order 4.0 compliance. For more details, please contact Elliot Grant from Sustainable Conservation at [email protected]