(1) The size of seed blend permitted is dependent on factors such as quality of seed lots to be blended and the conditioning plant facilities permit. Approval by the department or certification agent is required in advance to blend seed lots. The issuance of certified blend tags is based on each component seed lot's eligibility, qualifying seed tests for the blended lots, and compliance with the provisions of this chapter.

(2) For eligibility of each seed lot of one variety blended to form a larger lot of uniform quality that meets Washington seed standards, the seed conditioner must maintain and provide a file blend data sheet with the certifying agency.

All component lot certification tags must be forwarded to the department within 10 days of completing the blend.

(3) Laboratory analysis of the individual lots used in the blend must be submitted with the blend data sheet request. Tests must have a WA-state noxious weed seed exam and meet Washington certification standards to qualify for immediate eligibility.

(a) Components within the lots requiring interagency certification must have an all-states noxious weed seed exam, and meet another state's or Washington's certification standards, to qualify for immediate eligibility.

(b) All tests must be completed before the blend data sheet is submitted and tags are issued.

(c) If 18 months have passed since the last viability test of any of the component lots, the blend sample must also be tested for viability before tags are issued.

(4) If the blended weight exceeds the sum of the components' poundage by more than five percent, the applicant must submit a written justification and revised blend data sheet for review by the certification agency.

(5) Seed must be blended by a seed conditioner approved by the department under WAC 16-302-125.

(6) A representative of the certifying agency may supervise the blending operation.

(7) A tetrazolium test may be used in lieu of a germination test for issuance of Washington blend tags.

(8) Field run lots of seed may be commingled to facilitate conditioning. The blend fee shall not apply.

(9) Remill lots of seed may be blended prior to testing to facilitate processing.

(10) Individual lots of grass seed shall not contain more than 180 per pound of objectionable weed seeds.

(11) Alfalfa and clover seed shall not contain more than 90 per pound of objectionable weed seeds.

(12) Individual lots must be free of prohibited noxious weed seeds.

(13) Two or more sod quality lots may be blended and tagged as a "sod quality blend." Appropriate tags will be issued and quality sod fee shall be applicable.

(14) Seed lots resulting from a blend of different Certified classes may only be labeled at the lower class.

(15) Fees for blending of Certified seed shall be the most applicable fees established by the department in rule, see chapter 16-303 WAC.