Consequently, because of the associated short growing season, average yields fall well below 400 sacks. Water is relatively available via canals from the Deschutes and Crooked rivers and other sources. Willamette Valley Willamette Valley farmers grow about 2,000 acres, divided approximately equally between the fresh and chip markets. Production is concentrated in the north end of the Valley in Clackamas, Marion, Multnomah and Washington counties. The growing season can be extremely short because of winter rains which sometimes begin in early October and extend through early June.
Soils are typically heavy and are slow to warm and dry in the spring.
Yields average about 365 sacks per acre. The Willamette Valley experiences late blight every season with frequent severe outbreaks. All fields must be routinely sprayed with fungicides. Heavy dews extending well into mid-morning in August guarantee the presence of inoculum even in the absence of rain. With the exception of rainfall patterns, growing conditions in the Vally mimic those of midwestern and eastern U.S. production areas.