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All seed potatoes entered for certification shall be classified on the basis of production phases as follows:*


The purpose of this program is to provide certification of Seed Potatoes of propagative stock now being produced by tissue culture and/or stem cutting techniques. Annually, new disease free stock is propagated for multiplication. There are restrictions on the number of seasons this seed may be planted back. For complete rules on Washington Certified Seed, see

Our seed potato growers are famous for growing and marketing quality seed. The isolated locations provide vigorous seed and deliver the product to you when you need it. 



  1. The quality of the grading of seed potatoes is the full responsibility of the grower. The Department of Agriculture shall monitor grading activities for compliance with the United States Standards of Seed Potatoes and established state standards for seed potatoes.

   2. Three colors of tags shall be permitted for use:

     (a) Blue tags shall be used for seed potatoes which meet or exceed minimum 

          requirements  of United States Standards  for U.S. Number 1 grade of seed potatoes

     (b) Yellow tags shall indicate a contract between buyer and seller.

     (c) White tags shall be U.S. Number 1 (1 oz. min./3 oz. max.)


(1) Zero tolerance is not intended, nor shall be construed, to mean that the lot inspected is free from the disease. In case of ring rot,        nematode, or powdery scab, it means that the disease was not identified during any visual inspection.

(2) First and second field inspection tolerances, expressed as percentages.

*Tolerance for black leg does not apply

TR = Trace


The purpose of this test is to visually detect virus and virus-like plant symptoms in seed potato samples submitted by the grower. A seed stock that has more than a trace amount of virus disease noted during any field inspection shall not be recertified, unless it has been post harvest tested. All Generation 1 lots except lots that are less than .25 acre and planted back on the same farm, and all seed lots sold for recertification must also be post harvest tested.


WA Seed Potato Isolation District and Quarantine Rule


The Washington Administrative Code (WAC) 16-325 (Isolation District) and 16-482 (Quarantine Rule) were changed based on a request from the WA Seed Potato Commission.


These WAC Revisions became effective September 15, 2023.


The amendments to these chapters include:

  • Expanding the definition of ‘seed potatoes’;


  • Clarifying that the requirement to be enrolled in the certification program includes all plantings for commercial use and adds the option for certified seed to be used for each growing season in commercial potato plantings of one acre or less instead of enrollment in the certification program;


  • Adding a requirement that all lots of potatoes entering the isolation district for planting or further sale, except for those intended for immediate human consumption (example: potatoes sold in grocery stores), must be tested and found negative for Bacterial Ring Rot (BRR) by an approved laboratory at origin;


  • Adding a requirement that shipments entering or transiting the isolation district must be covered in a manner that safeguards pathogen dispersal;


  • Establishing a prior notification requirement for seed potatoes entering the isolation district;


  • Requiring shipments of potatoes be held for 24 hours after delivery to allow the department time to contact the receiver for inspection;


  • Adding a violation section regarding the disposition of potatoes in the isolation district found to be in violation of this chapter;


  • Clarifying in the seed potato quarantine rule (WAC 16-482-010) that all lots of potatoes entering the seed potato isolation district, except for those intended for immediate human consumption, are also subject to the requirements under chapter 16-325 WAC.


Questions or concerns surrounding these changes may be directed to the WA Seed Potato Commission at

Related Links WA State Potato Commission National Potato Council Potatoes USA

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