Potatoes are Washington state’s third top commodity, behind apples and milk, valued at $888 million last year, up from $813 million in 2016.

This year’s outlook looks promising, with most of the state’s potatoes grown in Eastern Washington and the Skagit Valley and producing 20 percent of all U.S. potatoes.

“Last year, Washington state produced 165,000 acres,” said Matt Harris, director of governmental affairs for the Washington State Potato Commission. “This looks like a pretty average year. My guess is that we’ll be in the range of 165,000 to 170,000 acres this year, which is about 10 billion pounds of potatoes.”

The state ranks second nationally in potato production, but holds the top spot for highest potato yield per acre, thanks to a favorable climate, rich volcanic soil, water availability and long growing season.

More than 300 farmers grow potatoes in Washington and the annual harvest averages 30 tons per acre, “twice as much as the average yield in the United States,” according to the commission.

Harris’ forecasted 2018 potato acreage is an average because actual numbers won’t be available until later in the year from the U.S. Department of Agriculture’s National Agricultural Statistics Service.

“When we look at a 10-year span, the lowest I’ve ever seen is 155,000 acres and the highest was 175,000 acres,” said Harris, a 13-year veteran of the commission.  “About 10 to 15 percent of the total is fresh and the rest goes to processing.”

Potatoes are annual plants, with fields planted every spring and harvested in the fall. Although potatoes grow underground, they aren’t considered to be roots. Instead, they’re stems known as tubers.

After plants emerge, which occurs between two and six weeks after planting, the fields must be kept thoroughly watered. Irrigation watering, mostly through the use of pivot machines, is sometimes required 24 hours a day during the hottest summer weather.

Some of the state’s potato growers use laser-guided planters, or tractors that navigate fields using satellites, and irrigation equipment that monitors and delivers only the amount of water needed.

Seven categories of potatoes exist for cooking, and more than 100 varieties are sold across the U.S.

Computing the value of potatoes is a complex process, unlike other crops solely sold as fresh product. Several variables are weighed to determine overall value, Harris said.

“It can vary because there are so many different varieties, dug at different times and for different purposes. It also depends on whether it’s a contracted potato, for french fries, chipping potatoes, dehydrated or fresh,” he said.

Potatoes are grown from special potatoes called seed potatoes, which are cut with specialized equipment to make seed pieces uniform in size. The seed pieces are usually treated to prevent infection and rot before being delivered to the field. There, they are loaded into planting machines attached to tractors. Growers plant these like-sized pieces together in a field, which helps grow tubers of approximately the same size in one location.

Dale Lathim, executive director of the Potato Growers of Washington, manages the bargaining unit to negotiate with potato processors on behalf of the growers.

“We have an intimate relationship with the growers and processors,” Lathim said. “We negotiated 2018-19 contracts in January and February of this year.”

The outlook is great, he said, as demand has exceeded the number of available potatoes.

“The acreage will go up slightly because of the new production line at Lamb Weston in Richland,” Lathim said. “Overall, we need about 5 percent more acreage of potatoes to keep the (processing) lines at their current rates of capacity.”

Lamb Weston’s new $200 million expansion of the potato plant on its Richland campus nearly doubled its capacity when it opened last fall. The company can now produce about 600 million pounds of frozen french fries annually across three processing lines.

Lamb Weston said 75 percent of the product produced in the Tri-Cities remains in North America. The other 25 percent gets exported to 100 different countries, many in the Pacific Rim, with Japan being a top importer of frozen french fries.

During the past 10 years, there’s been a surplus of fresh potatoes, Lathim said. As a result, some previously fresh potato growers now contract with frozen processors.

“I’m estimating a net growth of 2 percent to 3 percent in volume,” he said. “The price on (processed potato) contracts, which accounts for about 80 percent of the state’s potato crop, is up about 5 percent for 2018 and 4 percent in 2019. We have very stable pricing right now.”

Starting in 2014, growers gave up some of their profit margins to help processors become more competitive in the world marketplace, Lathim said.

“A very significant number of processors export, so as profit margins came down and cost production went up 3 percent, the growers gave up some money to help processors,” Lathim said. “We’re now back to what we believe is a sustainable level, but would like to see a continued increase. It’s currently very healthy for both growers and processors.”

This year’s increase is “the first we’ve received since 2013,” Lathim said. “We’re very optimistic about the future of our industry.”