The Pacific Northwest Coast & Valleys region includes the Coast Range, Pueget Sound Lowlands, and Willamette Valley.
The Coast Range has warm, relatively dry summers and mild, but very wet winters. Cranberries are grown commercially in Oregon in the Coast Range. High humidity along the coast is also great for mushroom cultivation. Larger cities include Aberdeen, Astoria, Seaside, Tillamook, Newport, Coos Bay, Crescent City, and Eureka.
The Puget Lowlands include the areas adjacent to the Puget Sound in Washington. It is in a glacial trough with many islands, broad rolling lowlands, some plains and low mountains. The climate is mild and because it is affected by the rainshadow of the Olympic Mountains, the rainfall is less than other nearby areas. Farms in this region tend to be small and family-operated. Major agricultural crops are red raspberries, flower bulbs, and seeds (spinach, beets, and Brussels sprouts). Larger cities include Seattle, Tacoma, Bellingham, Mt. Vernon, Everett, and Olympia in Washington.
The Willamette Valley, a broad plain in Northwestern Oregon extending a short distance into Southwestern Washington, is agriculturally rich with volcanic and glacial soil about a half mile deep. The soil was carried by floods during the last ice age caused by periodic rupturing of a large ice dam forming the glacial Lake Missoula. The weather is relatively mild all year with cool, wet winters and warm, dry summers. The growing seasons is long, averaging 150 to 180 days per year. Cloud cover can be more than 70 percent in the winter but less than 15 percent in summer. Because of the productive soils and temperate climate, the Willamette Valley is an important agricultural area. Major agricultural crops include berries, vegetables, nut orchards, grapes, hops, grass seeds, Christmas trees, hazelnuts, and nursery stock. Larger cities include Portland, Gresham, Beaverton, Hillsboro, Salem, Albany, Corvallis, Eugene, and Springfield.
This paper by Oregon State University, includes information about gardening on the Oregon coast and valleys.
Vegetable Gardening in Washington (Includes planting dates.)
Growing Fruits in Washington (Information about specific crops and methods)
Washington Vegetable Gardens (Information about specific crops and methods)
Seattle Tilth Website (An organization dedicated to creating a sustainable local food system.)