1. (1) The field isolation requirements for grass seed are as follows:

   1. (a) A seed field eligible for the production of Foundation, Registered or Certified seed must be isolated from any other variety or strain of the same species and all cross pollinated species in accordance with the requirements in the following table:

      Minimum Isolation Distance Required for Fields Producing:
      Symbol for Type of Reproduction	Foundation	Registered	Certified
      Strains at least 80%Apomictic A	60 feet	30 feet	15 feet clean fallow
      Highly Self-Fertile Species—S	60 feet	30 feet	15 feet clean fallow
      All cross-pollinated
      Species—C	900 feet	300 feet	165 feet

   2. (b) A seed field that is eligible for the production of Foundation or Registered seed must be isolated from different classes of the same variety of cross-pollinated (C) species in accordance with the requirements in the following table:

      Class SeedPlanted	Class SeedProduced	Distance Required From Nearest Field Producing:
      Breeder	Foundation	Registered		150 feet
      Breeder	Foundation	Certified		225 feet
      Foundation	Registered	Certified		75 feet

   3. (c) Isolation is not required in fields producing Certified class seed when the isolation zone is less than 10 percent of the entire field being certified if there is a clear (10 feet) line of demarcation between adjacent varieties. The isolation zone is the area calculated by the length of the common border with other varieties by average width of the certified field falling within the 165 feet isolation distance requirement.

   4. (d) A field eligible for the production of Foundation, Registered or Certified seed must be isolated from classes of the same variety of apomictic (A) and self-fertile (S) species in accordance with the following requirements:

      1. (i) A field producing Foundation or Registered seed must be a minimum of 15 feet from a field planted with a different class of the same variety.
      2. (ii) A field producing Certified seed must be a minimum of five feet from a field planted with a different class of the same variety.

   5. (e) If it is not possible to provide minimum isolation distances for fields producing Foundation, Registered or Certified seed exceeding five acres in area, border removal is permitted. Border removal requires removal of the portion of the field being certified that is adjacent to a contamination source. The following requirements apply if the grower uses border removal:

      1. (i) The minimum distances required for border removal are as follows:

         Minimum Isolation Distance Required for FieldsProducing:
         Border to be removed from the field beingcertified	Foundation	Registered	Certified
         0 feet	900 ft.	300 ft.	165 ft.
         15 feet	450 ft.	150 ft.	75 ft.

      2. (ii) The grower must apply for seed certification of the entire field and clearly stake off the border removal portion before inspection of the field by the certifying agency.

   6. (f) The border removal portion of the field may be harvested for uncertified seed under the following conditions:

      1. (i) The entire field must pass all certification requirements except for isolation at time of inspection. The field report will show rejection due to lack of isolation.
      2. (ii) The grower must harvest and deliver to a department approved conditioning plant the seed from the certified portion of the field separately from the seed from the isolation strip. At this time the seed program records will indicate the field has passed certification.

[Statutory Authority: RCW 15.49.005, [15.49].021, [15.49].310, [15.49].370, 15.140.030, and chapter 15.49 RCW. WSR 25-09-035, s 16-302-330, filed 4/9/25, effective 5/10/25. Statutory Authority: Chapters 15.49 and 34.05 RCW. WSR 02-12-060, § 16-302-330, filed 5/30/02, effective 6/30/02. Statutory Authority: RCW 15.49.005, 15.49.081, 15.49.310, 15.49.370(3) and chapter 17.24 RCW. WSR 00-24-077, § 16-302-330, filed 12/4/00, effective 1/4/01.]