Wash. Admin. Code § 16-302-510
Isolation requirements for the production of red clover seed crop are as follows:
(1) Red clover for certification must be isolated from all other red clover varieties or fields of the same variety not meeting varietal purity requirements for certification as follows:
| Class BeingProduced | Fields less than five acres | Fields five acres or more |
| Foundation | 900 feet | 600 feet |
| Certified | 165 feet | 165 feet |
(2) Isolation between different classes (generations) of the same red clover variety is as follows:
| Class Being Produced | Distance Required from Fields Planted with: | Fields less than 5 acres | Fields5 acresor more |
| Foundation | Foundation or Certified | 225 feet | 150 feet |
| Certified | Certified | 75 feet | 45 feet |
(3) In cases where an adjoining field is planted with a different variety of red clover, or red clover of a lower class, isolation may be obtained by measuring off the required strip in the certified seed field. This isolation strip may be mowed for hay or it may be harvested for uncertified seed under the following conditions:
[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, § 16-302-510, filed 12/4/00, effective 1/4/01.]