PROSSER — They may be indoors, but the vendors and shoppers at the Prosser Winter Farmers Market still bundle up.

Merchants of bread, olive oil and beef huddle near space heaters. Shoppers in coats and boots peruse tables of tea, honey and earrings. A rancher displays boxes of steaks stacked on a table with little fear of spoilage, while a quilt vendor wraps one of her goods around her shoulders.

“Some of the vendors were smart enough they brought their space heaters,” said Kristi Polus, owner of the Tea Gallerie in West Richland. The market provides a few but not enough for every table.

Washington is now home to more than 150 farmers markets, but Prosser is one of only eight to operate all year, said Karen Kinney, executive director of the Washington State Farmers Market Association. Another nine run at least eight months, well into the cold season.

Expect more markets to expand their seasons. Many market managers are searching for indoor — or at least covered — digs while growers have been experimenting with altering their planting and harvesting schedules to stretch out the season.

“It’s definitely something that there’s a lot more interest in these days,” Kinney said.

Winter markets typically are smaller than their outdoor counterparts and on the west side of the state, where winters are milder. Port Angeles, for example, sets up outdoors every week on the waterfront under a pavilion that keeps patrons dry — as long as the rain falls straight down, Kinney said. A small market in Tacoma runs only once a month, which works, too, Kinney said.

Yakima and Ellensburg may not be far behind, though managers in those communities need indoor space that can be hard to find, they said.

The Yakima Farmers Market, which fills a block of downtown’s Third Street in the summer, has operated in the winter before, said manager Don Eastridge. Vendors held a market in 2002 and tried again in 2006 inside a vacant building owned by Joe Mann, a downtown retailer and market supporter.

Eastridge has another location in mind but state access laws would require an elevator, he said. He has interest from fruit and vegetable vendors, too.

“I have farmers with hothouses but they don’t grow anything because they have no outlet for it,” he said.

In Ellensburg, manager Eric Miller is courting the owners of a downtown hall often used for concerts for a winter market starting this November. He’s been spreading the word to farmers already.

“Obviously not as easy to do as a summer market,” he said.

Wenatchee has large plans for a winter market starting late 2013.

Later this year, the city’s Pybus Public Market will move into a new home, setting up both inside and outside of an old warehouse. The indoor portion, which includes a market-operated retail store and a commercial kitchen, will stay open all year, according to the market’s website.

In Prosser, vendors have been taking smaller steps.

They talked about a winter market for about three years before finally trying it out in November 2012, said Kathy Aubrey, president of the Prosser Farmers Market board of directors.

“This has kind of been a dream of mine for a long time,” she said.

They set up shop from 9 a.m. to noon the first and third Saturdays of the month at City Park, the same place they run the summer market. The only change is they moved indoors, crowding tables end-to-end inside the park’s concession buildings.

The winter market averages between seven and eight vendors each day, Aubrey said.

A few growers sold fresh apples and vegetables well into December, while recent months have featured baked goods, wine, frozen blueberries, art and even a 13-year-old boy selling seeds he planted and harvested in his parent’s garden.

“I do all the planting and harvesting but I don’t do much of the weeding,” Walker Orr said. “I provide all the seeds for them so it’s not like I’m getting a free ride or anything.”

However, several farmers have promised to stagger plantings even more next year, she said.

Vendors have noticed mixed results.

Connie Crawford of Crawford Farms in Prosser said sales of her frozen blueberries have been slow at the winter market. She has 700 pounds to get rid of before spring.

Dan Peplow, owner of Heirloom Cattle Company in White Swan, said that farmers markets in general are not enough for his business to make a profit.

Market customers are loyal but the community is too small, he said.

Still, his sales at the Prosser winter market surprised him. “It’s been actually worth our while,” he said. “I don’t know if they can sustain it.”

This winter, Kelly Pfeufer-Wiegers, owner of Nature’s Farm and Nursery in Prosser, has sold only English walnuts at her stand, going through between 10 and 20 bags per market. Not a lot, but more than she anticipated, she said.

Pfuefer-Wiegers, a regular at the summer market since 1997, plans to expand for next winter. She aims to plant cold-weather crops such as spinach, cauliflower and cabbage. By May, a heat wave has usually stunted those for the year, and in late fall she can squeeze out one harvest, she said.

The winter market also gives her a head start selling her vegetable and herb starter plugs, which people usually ask for starting in April.

“I can add more months to the growing season,” she said.

Aubrey will find out more about sales figures later this week but even then won’t know what to compare them to.

“Being our first year, I don’t know how to gauge that,” she said.

She figures it will be good news though because vendors continue to set up. Last week, the market had a season high of 14.

“I don’t think our vendors would be coming back if it weren’t good,” she said.

• Ross Courtney can be reached at 509-930-8798 or