The Pacific Northwest is home to fertile soils, wet winters, and warm, dry summers. The geography of Washington State hosts several different climates, but most of the state has ideal growing conditions for a variety of vegetables. In general, cold season crops fare the best in many parts of Washington, but some regions have long enough summers for warm season crops.
Broccoli, cauliflower, and cabbage all take a while to get going, so it's best to start them indoors about two months before transplanting them outdoors. They should go into the garden about two weeks before the last frost date. If you live in the Columbia Basin or southwest of the Cascade Mountains, transplant these vegetables in mid-April. For higher elevations and in eastern Washington, early May is the best time to transplant. Along the Washington Coast and the Puget Sound, the transplants can be planted as early as April 1.
Lettuce, peas, radishes, onions, and spinach can all be directly sown as soon as the ground is workable. Plan to start them about a month before the last frost date. If the soil is very wet, let it dry out before putting in peas because too much moisture can cause young pea shoots to rot. Gardeners in eastern Washington and the Cascades can wait as late as mid-May to plant these vegetables , while soil along the coast and Puget Sound should be warm enough in mid-March. In other regions, plant these seeds in the middle of April.
Mid- To Late-Spring Crops
Chard, early potatoes, carrots, and beets all grow well across Washington state. Sow them directly into the garden the same time that you transplant your broccoli, cauliflower and cabbage, about two weeks before the last frost. For a late carrot harvest, do another planting in the middle of summer. The mild autumn weather in the Pacific Northwest makes the soil an ideal storage place for fall carrots---you can leave them in the ground until you're ready to eat them.
Gardeners on the coast and near the Puget Sound have the most choices for warm-season crops. The growing season is usually about 180 days, with the last frost date in mid-April. Tomatoes, eggplant, corn, squash and muskmelons usually fare well in that part of the state. In the Columbia Basin and southwest of the Cascades, the growing season is about 150 days, with the last frost near May 1, so gardeners in those regions should plant established seedlings of those vegetables, usually when they're 6 to 8 inches high. You can also extend your growing season with cloches or cold-frame greenhouses. In the cooler climates of Eastern Washington and up in the Cascade Mountains, many warm-season vegetables probably won't have enough time to mature, with the exception of fast-maturing beans such as wax or snap beans.