Classification
Product TypeRaw Material
Product FormRaw (Dried; In-shell and Shelled Kernels)
Industry PositionPrimary Agricultural Product
Raw Material
Market
Raw walnuts in the United States are a major tree-nut commodity with production overwhelmingly concentrated in California’s Central Valley. Chandler is the most common variety in California, and industry quality language is anchored by USDA voluntary grade standards for both in-shell walnuts and shelled walnut kernels. Harvest is typically in the fall, with commercial supply managed through drying, storage, and year-round distribution by handlers and processors. The sector is supported by research and promotion under the USDA-oversight federal marketing order framework for California walnuts.
Market RoleMajor producer and exporter
Domestic RoleLarge domestic consumption market with significant industrial use (baking, confectionery, snacks) alongside export sales of in-shell and shelled kernels
SeasonalityHarvest is in the fall (typically mid-September to early November), while marketing and shipments can occur year-round due to drying and storage.
Specification
Primary VarietyChandler
Physical Attributes- Sound, well-dried nuts/kernels with low defect incidence (insect injury, mold, foreign material)
- Kernel integrity (e.g., halves/large pieces) and shell condition (for in-shell trade) are core buyer acceptance attributes
Compositional Metrics- Moisture control is a primary quality parameter for storage stability and buyer acceptance
Grades- USDA voluntary grade standards for walnuts in the shell (e.g., U.S. No. 1 / U.S. No. 2 / U.S. No. 3) with specified size and color references
- USDA voluntary grade standards for shelled walnut kernels (e.g., U.S. No. 1 / U.S. Commercial) with specified color categories (extra light, light, light amber, amber) and size classifications
Packaging- Bulk packaging for in-shell walnuts for further handling/processing
- Corrugated cartons for shelled walnut kernels for wholesale and export programs
Supply Chain
Value Chain- Orchard harvest (mechanical shaking) → field pickup → hulling (green hull removal) → drying → storage → (optional) shelling and kernel sorting → grading and packaging → domestic distribution and export shipment
Temperature- Cool, dry storage and temperature discipline support quality retention by slowing oxidation and reducing defect development during extended storage and shipping
Atmosphere Control- Oxygen exposure management (packaging and storage practices) is relevant because walnut quality can deteriorate through oxidation during storage
Shelf Life- Shelf-life is sensitive to moisture control, oxidation (rancidity), and pest/defect incidence; post-harvest handling and storage practices strongly influence marketable quality over time
Freight IntensityMedium
Transport ModeSea
Risks
Climate HighCalifornia’s dominance in U.S. commercial walnut production makes supply highly exposed to drought, irrigation water availability constraints, and heat events that can reduce yields and degrade kernel quality, creating sudden export supply tightness and contract non-fulfillment risk.Diversify sourcing and inventory strategy across handlers and crop years; include contingency clauses for weather-driven shortfalls; prioritize suppliers with documented irrigation and orchard stress-management practices.
Phytosanitary MediumInsect and disease pressure in California walnuts (e.g., codling moth and navel orangeworm damage risk at/around harvest) can increase defects and trigger buyer rejections or intensified destination inspections.Align supplier practices with UC IPM monitoring and harvest-timing guidance; require defect monitoring at intake and robust sorting/inspection prior to packing.
Logistics MediumOcean freight volatility and port-side disruptions can change landed costs and transit times for bulk walnut shipments, increasing contract and quality risk (especially if storage/temperature discipline breaks during extended dwell times).Book capacity early for peak shipping windows; use quality-protective packaging and documented storage/transport conditions; maintain alternate routing/port options where feasible.
Regulatory Compliance MediumProcessed/packed walnut supply chains relying on U.S. facilities must meet FDA FSMA preventive controls and related compliance expectations; gaps in documented hazard controls, sanitation, and supplier verification can lead to buyer delisting or enforcement actions.Prefer suppliers with current third-party food safety certifications (e.g., SQF/BRCGS/FSSC 22000) and demonstrable FSMA-aligned food safety plans; conduct periodic supplier audits focused on preventive controls and corrective-action closure.
Sustainability- Water availability and irrigation management risk in California’s Central Valley walnut orchards (drought and allocation constraints can affect yield and kernel fill quality)
- Pest management and pesticide-residue scrutiny, with emphasis on integrated pest management practices in California production systems
Labor & Social- Farm-labor compliance risk in California agriculture (e.g., heat illness prevention, wage-and-hour compliance) across orchard operations and seasonal work
- Supplier social compliance auditing expectations for U.S. agricultural supply chains (documented policies, grievance mechanisms, and labor contractor oversight)
Standards- SQF
- BRCGS
- FSSC 22000
- HACCP-based programs aligned to FSMA preventive controls expectations
FAQ
When is the typical walnut harvest season in the United States (California)?Walnuts are typically harvested in the fall, commonly from mid-September to early November in California, with product then dried and stored for year-round marketing.
What grade references are commonly used for U.S. raw walnuts in trade?USDA’s voluntary grade standards are commonly referenced for both walnuts in the shell and shelled walnut kernels, including defect tolerances and specified color categories for kernels.
Do exporters need a phytosanitary certificate for shipping U.S. walnuts overseas?It depends on the importing country’s requirements. USDA APHIS provides plant health inspection and issues phytosanitary certificates for plant products when a destination country requires them.