Isolation requirements for the production of alfalfa seed crop are as follows:

1. (1) Alfalfa seed crop for certification must be isolated from all other alfalfa varieties or fields of the same variety not meeting varietal purity requirements for certification as follows:

   Class	Fields lessthan five acres	Fields fiveacres or more
   Foundation	900 feet	600 feet
   Registered	450 feet	300 feet
   Certified	165 feet	165 feet

2. (2) Isolation between different classes (generations) of the same variety of alfalfa seed crop must be as follows:

   Class Being Produced	Distance required from fields planted with:	Fields less than five acres	Fields five acres or more
   Foundation	Foundation or Registered	225 feet	150 feet
   Registered	Registered or Certified	115 feet	75 feet
   Certified	Certified	75 feet	45 feet

3. (3) In cases where an adjoining field is planted with a different variety of alfalfa, or alfalfa of a lower class, isolation may be obtained by measuring off the required strip in the Certified seed crop field. This isolation strip may be mowed for hay, or it may be harvested for uncertified seed under the following conditions:

   1. (a) The grower must apply for certification of the entire alfalfa seed field and clearly stake off the isolation strip. 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. (b) 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 isolation strip. After the seed is weighed and lotted in, the weight of the seed from the isolation strip is to be reported to the seed program. At this time the seed program records will indicate the field has passed certification.
4. (4) Isolation is not required in an alfalfa seed field 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-foot 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.

[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 16-302-230, filed 4/9/25, effective 5/10/25. 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, § 16-302-230, filed 12/4/00, effective 1/4/01.]