Downtown Detroit's pop-up shops have been swarmed with customers this holiday season and ringing up phenomenal sales, a boon for the city and a win for real-life shopping when online shopping is making all the news.

Vendors in the Detroit Downtown Markets, a marketplace of 30 temporary shops near Campus Martius and Capitol Park, reported doing such strong business in late November and early December that the markets' operations were extended by three weeks. This includes the small village of shops inside glass huts.

Downtown Markets will now run through Jan. 28, said Francesca George, director of tenant relations for the Bedrock real estate firm. Bedrock organizes the pop-ups marketplace and, along with other Dan Gilbert-companies in the Quicken Loans family, is behind the "Winter in Detroit" marketing campaign.

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The extension will let vendors remain open for the downtown crowds during the 2018 North American International Auto Show and the popular Winter Blast on the final weekend in January. The marketplace opened Nov. 17 and is substantially bigger than last year.

"The vendors didn't want us to close, and that's why we extended it," George said. "Every single vendor has been doing really, really well. If anything, the biggest issue we have is vendors are running out of inventory."

The pop-up shops are small locally-owned businesses that generally do not have year-round storefronts. Detroit Downtown Markets puts these shops in front of downtown's many weekday office workers and weekend visitors. For their part, the shops provide another reason for people to make a trip downtown.

This year's setup includes a large, temporary indoor lounge in Cadillac Square, the Cadillac Lounge, where food and $9 craft cocktails are served.

In interviews this week, numerous pop-up shop vendors said their sales and customer foot traffic this season surpassed expectations.

"This is busier than I ever anticipated. There's a line out my door every single day," said Ashley Gold, owner of Ashley Gold jewelry, who ordinarily sells her merchandise — all of which she designs — through the Internet or at boutique shows.

"Being down here gives me much better exposure, because everybody comes here — not just Detroiters," Gold said. "I started with 2,000 business cards on Nov. 17 and I just ordered new ones over the weekend, so that tells you something."

Owners of The End Grain Woodworking Co., which sells furniture and objects for the home made from the reclaimed wood of old Detroit buildings, were unsure whether joining the pop-ups would be worthwhile.

But co-owner Sam Constantine said they are now very glad they decided to rent space in one of the marketplace's glass huts.

"We've had some phenomenal days. The last Saturday and Sunday — I can't believe how much stuff we've sold," he said, adding. "The first few weeks that we did it, we surpassed the amount of sales that we did the entire season last year."

Many of the pop-up shoppers buying clothing are looking for unique items that one can't find from big retailers, according to Tee Capel, owner of Fly Behavior Style Lounge, a women's boutique set up in 1001 Woodward that doesn't have a year-round storefront.

"A lot of people are coming down looking for special Detroit-based brands and products and gifts," Capel said. "Prior to this, a lot of my business was online. But being here and being visible, it's been great. The business here has kind of outweighed the online business."

The pop-up shops have been helping suburbanites get back into the habit of shopping in Detroit.

Vanessa Priebe, 31, of Clarkston made her first-ever shopping trip downtown this week with a friend to buy stocking stuffers. One of her purchases was a Vernors-inspired, ginger-scented candle.

"I feel like my friends from out of state are going to love this," she said. "It will be like a nice piece of home for them. It's unique to Detroit, and that's what makes it amazing."

Another pop-up shopper, Jenna DeVries, 24, who lives in Detroit's West Village, walked through the marketplace with a shopping bag carrying the mixed nuts and chocolate bar she bought inside 1001 Woodward, where about 10 pop-up vendors are set up.

"I'd rather support the local vendors than go to the mall," she said.

Some longtime Detroiters were surprised to see how one pop-up vendor, Greystone Gardens, is selling natural Christmas trees, presumably for the city's growing population of downtown apartment-dwellers, even though some high-rises don't allow real trees for fire safety reasons.

Lloyd Michael, whose wife, Debra, owns the Armada Township-based business, said Bedrock contacted them to see whether they had any interest in Detroit this Christmas season. Sales have been going "all right," he said.

"For the first year, it's about what I expected. We sell some trees every single day. We haven't had a day when we didn't sell any," Michael said.

Overall, they noticed little difference between the sizes of Christmas trees people buy in downtown compared to in the suburbs. Many people assumed they would mostly sell very small trees to fit into apartments, he said.

Some of their first customers bought the tallest, biggest $140 trees on the lot for their downtown penthouse. Most of the trees are priced between $40 and $60.

"Our most popular trees have probably been 6 to 8 feet," he said. "So there's really no difference here, I believe, than in the suburbs."

Contact JC Reindl: 313-222-6631 or jcreindl@freepress.com. Follow him on Twitter @JCReindl.