Onions are perhaps the Walla Walla valley's most famous crop. However, grapes for wine have become a much larger industry and in some circles may be eclipsing onions. The valley also has large acreage in alfalfa. The ice age flood silts and wind deposited silts combined with irrigation and generally dry air are the right combination for highly productive alfalfa fields. The fact that large tracts of range land are present on the east end of the Horse Heaven Hills and in the nearby Blue Mountains helped establish large acreage in the production of feed for livestock. In the early days of Walla Walla there was good money to be made from raising meat for mines in Idaho.
Ice on a recently irrigated strip of alfalfa
The ice age flood silts will hold a lot of water and alfalfa will grow as soon as the weather begins to warm. Hence, irrigation is a year round project to build up and maintain soil moisture in this otherwise very dry area on the southern half of the valley.
A new type of "farming" can be seen on the ridge line south of the valley. The State Line Wind Farm is one of the largest in the region with wind turbines lining the crest of the Horse Heaven Hills along the Washington-Oregon boundary. These turbines catch the wind rising up and over the Horse Heaven Hills from the Columbia River gorge to the west.