Katherine Jarvis-Shean, UCCE Orchard Advisor, Sacramento, Solano and Yolo Counties

Please note that the following are general recommendations intended to help you keep track of regular practices in a busy time; the optimal timing for management practices may vary based on specific location and conditions.

• Harvest timing: Timely harvest is important for nut quality. Delaying harvest can darken pellicles, and encourage mold development and navel orangeworm. Walnut color quality decreases most rapidly in the first nine hours, so try to pick up the same day that nuts are shaken.
• Pest Management: Collect a representative IPM evaluation sample from across each orchard block at harvest to assess your IPM program. Grade sheets won’t always give the detail necessary to decipher the source of damage and what needs to be changed to improve an IPM program. Compare what you see with photos and descriptions in our post on Harvest Damage Evaluation for Walnuts.
• Orchard Renovation: If you’re removing an orchard, October is the time to kill roots with Garlon. It is critical to paint stumps with Garlon within five minutes of cutting trunks, and leave stumps for 60 days.  See our article on Considerations for Replanting Walnut Orchards for more information.
• Cover Crops: If seeding a cover crop, try to seed before leaf drop to get the best stand establishment. If drought conditions continue this fall and winter, supplemental irrigation will be needed for germination and/or optimal growth. Make sure you have an available water source during the winter months before seeding this fall. There’s more information in our blog post: Time to Think About Cover Crops in Walnuts.