Extreme heat and drought are expected to take a major toll on Oregon’s signature seed crops, though the extent of the damage won’t be known until after harvest.

Combines are beginning to roll in the Willamette Valley, home of the “Grass Seed Capital of the World.” Oregon grows 98% of all U.S. orchardgrass seed, 93% of fescue seed and 91% of ryegrass seed, according to the state Department of Agriculture.

But this year could see yields across the region reduced by as much as half due to low precipitation and sizzling temperatures, said Nicole Anderson, an associate professor and field crops extension agent for Oregon State University.

“In this case, we could have both low seed number and low seed weight,” Anderson explained. “It’s kind of a double-whammy effect here.”

Anderson estimated that 75-80% of Willamette Valley seed crops are grown without irrigation, relying instead on normally rainy spring weather.

The period from March 1 to June 1 is especially critical, Anderson said. That’s when the crops start coming out of winter dormancy, soaking up moisture and nutrients to sprout reproductive tillers and fill seed heads.

This year, Anderson said precipitation was down 5.5 inches in most places during that timeframe, hampering the plants’ development. Without enough water, she guessed yields might drop 25-50% based on the conditions.

Looking at OSU records dating back to the 1970s, Anderson said no other year comes close to the precipitation deficit seen this growing season, throwing out any historical comparison.

“This really is something that’s fairly unique,” she said.

Along with the drought, a punishing heat wave with temperatures reaching as high as 117 degrees on June 28 is also putting grass seed growers to the test.

Normally, the first step to harvest is swathing the grass into neatly piled rows. Growers then return to the field in a combine that separates the seed from the straw. If it gets too hot, however, the physical impact of mechanical swathing can cause the seeds to break off the stem — known as “shattering” — resulting in yield losses.

Farmers often swath at night when there’s dew on the ground to avoid shattering, Anderson said. Even that has proven challenging during the scorching weather.

“With these super hot conditions, we aren’t seeing dew at night,” she said. “We expect to see more shatter than normal.”

Bryan Ostlund, administrator of the state Fine Fescue, Tall Fescue, Clover and Ryegrass Growers Seed commissions, said some growers in the northern Willamette Valley have indicated they won’t even attempt to swath for fear of shatter.

“The issues are obvious,” Ostlund said. “That’s just the way Mother Nature throws it at us sometimes.”

Denver Pugh, of Pugh Seed Farm in Shedd, Ore., said he anticipates reduced yields, though he hasn’t started combining yet.

“When you really start looking at the seed heads, it’s going to be an awful light seed, if anything at all,” Pugh said. “Right now, everything looks to be for the most part down.”

Pugh Seed Farm grows about 4,400 acres of primarily annual ryegrass and tall fescue, along with smaller amounts of wheat, radish seed, turnip seed and meadowfoam.

Pugh said the farm was fortunate enough to catch some much-needed rain in May, though the showers were isolated and didn’t stretch beyond a few miles.

Grass seed was Oregon’s fifth-most valuable agricultural commodity in 2019, with a crop worth $517.4 million, according to OSU.

In response to the lower yields, Mark Simmons, executive director of the Oregon Grass Seed Bargaining Association, said prices are “up significantly” over last year, though he declined to provide exact figures.

The bargaining association negotiates prices for perennial ryegrass and tall fescue on behalf of growers. Other seed types, including fine fescue, clover, orchardgrass and annual ryegrass, are sold on the open market.

“I think everyone is sure the Oregon crop is short, but nobody knows how short at this point,” Anderson, of OSU Extension, said. “Time is going to tell, as seed gets into the combine, how bad yield is going to be.”