Manager, Seed Inspection Program
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| Harvesting seed crop in Skagit County |
If you grow any type of Brassica species, remember that any plants left to bloom and produce seeds are regulated within Washington State. Brassica plants that go to seed must be isolated from other Brassica flowering crops to protect against cross-pollination.
Seed production is an important industry for Washington’s economy and for world food supply. For instance, one-quarter of the world’s cabbage seed comes from Western Washington. More than 15 species of Brassica vegetable seed crops are grown in Washington. To safeguard the purity of these products, crops must be isolated by specific distances to prevent cross-pollination.
Common names for plants within the Brassica family – also known as Crucifer family because the 4 petals of the flowers look like a cross or crucifer – include cabbage, kale, kohlrabi, broccoli, cauliflower, Brussels sprouts, mustard, rutabaga, turnip, pak choi, and others.
When open-pollinated species like Brassica species are allowed to bolt, flower and go to seed, they can spread pollen to neighboring fields and farms, contaminating other Brassica seed crops. This has been happening, especially in northwestern Washington counties.
Why “pin” seed crops?
Growers of Brassica crops intended for fresh market sale may not allow their plants to over-winter and go to seed unless they follow the state’s rules. WSDA regulations require Brassica seed growers to participate in cooperative events that identify (‘pin’) their crop locations. This applies to “seed savers” as well. If you intend to allow a Brassica crop to overwinter and produce seed, you must identify the location of that field on a public map.
‘Pinning’ the locations of cross-pollinated seed crops, which started in Washington State in the 1940s, brings together seed crop growers to mutually map out where crops will be planted with the goal of preventing unwanted cross-pollination. At a minimum, a half-mile distance is required between Brassica plantings of the same species. The distance is greater for different Brassica species.
In Western Washington, pinning days occur the first weekday of March and June at the WSU Mount Vernon Northwestern Washington Research & Extension Center in Mount Vernon. Similarly, pinning of cross-pollinated vegetable seed crops in central Washington takes place at the WSU Grant and Adams Counties Extension office in Moses Lake. This time-honored tradition of agricultural cooperation keeps the reputation of our state’s seed industry as high quality, safe, and productive.
Please do your part to support Washington’s seed industry – be a good neighbor by preventing volunteer Brassica bloom, or take part in the state’s pinning process if you want to produce seed.
If you have questions, contact the WSDA Seed Program or your local WSU Extension office.
In summary: WSDA is reminding farmers of Brassica crops that plants left to bloom and produce seeds are regulated in our state and must be isolated from other Brassica flowering crops to protect against cross-pollination.