Blama Kollie and his family of four pulled up to the Minneapolis Farmers Market on East Lyndale Avenue one Saturday last month at 5:30 a.m. Vendors were still unpacking, some carefully arranging their goods on tables, others unloading boxes from trucks, all by the light of the full moon.

The Kollies set their gazes upon a stall heaped with freshly picked greens piled three feet high on a folding table.

By the end of their two-hour, $500 shopping spree, the Kollies had filled 10 bags, 40 gallons each, with vegetables to freeze for meals during the winter.

"We are so excited," Blama Kollie said. "If I had like a thousand bucks, I was going to spend everything. We might have to make another trip over here again."

Blama Kollie loads a giant bag of vegetables into his car at the Minneapolis Farmers Market on Sept. 17. Kollie and his wife drove 8 hours from Minot, N.D., to purchase African vegetables from the market. Sam Harper | MPR News

Another trip? All this way -- an 8-hour drive from their home in Minot, N.D. -- and all that money? Just for vegetables?

But those bags weren't filled with just any vegetables. They were filled with the kind of vegetables coveted by African immigrants like the Kollies, who come from Liberia.

"This is place is a gold mine," Blama's wife, Makavee, declared. "We can't get this stuff where we live."

While African crops are hard to find in most American cities, they are increasingly abundant in the Twin Cities, thanks in large part to Hmong-American farmers, many of whom sell their produce only at farmers markets.

Blama and Makavee Kollie inspect habaneros and bitterballs before sunrise at the Minneapolis Farmers Market one Saturday in September. Sam Harper | MPR News

"Most of our customers are from out of state," said May Lee, whose family began selling at the Minneapolis market 20 years ago. "They come from all over: Iowa, North Dakota, Wisconsin. One of our biggest customers comes every two weeks from Seattle."

And every time that customer visits, Lee said, he buys her family's entire crop of bitter balls, a vegetable beloved for its acrid aftertaste, for his African grocery store. Other growers also count ethnic grocery stores across the country among their customers.

Dozens of vendors now offer sweet potato greens for sauteeing into savory stews with chunks of meat and poultry; habaneros, a main ingredient for their spicy dishes; and bitter balls and kittley, essentials for torborgee -- a curious medley of pureed eggplants cooked with fermented palm oil, dashes of baking soda and an assortment of meats.

The Twin Cities metro area has become home to sizable African immigrant populations the past two decades, so the customer base was there. But seizing it proved daunting for some Hmong-American farmers, especially with a significant language barrier to overcome.

Africans' different names for the same vegetable stumped the farmers. Kenyans clamored for mrenda, Liberians craved palaver sauce and some Nigerians pleaded for them to grow ewedu: three names for the same thing — corchorus leaves — a leafy green vegetable similar to spinach but with the consistency of okra, when it's cooked.

Kitley torborgee is stirred at MaMa Ti's African Kitchen in Brooklyn Park, Minn. The Liberian dish uses bitter balls, a popular vegetable in African dishes, as one of its main ingredients. The dish is accompanied by rice, collard greens and potato greens. Sam Harper | MPR News

"We still don't know the real names of the vegetables," said Robert Lor, a farmer who lives in St. Paul.

Determined shoppers brought seeds, stalks and even pictures to Lor and other farmers. Eventually Hmong growers captured this local — and ever-widening — community of customers that had been overlooked by mainstream farmers.

Pat Nelson said the Minneapolis farmers market, which he manages, attracts customers from across the country.

"We have people from New York, Texas, Ohio," he said. "They get a big cargo truck full of bitter balls, kittley — and they haul it back."

Steve Songor's road trip from Tulsa, Okla., to the Minneapolis market took 12 hours, but Songor, who's from Liberia, said it was worth it.

"This is the food of our culture, the food that we're most familiar with," he said, clutching shopping lists from other Liberians in Oklahoma who couldn't make the trip.

When West African cooks outside the Twin Cities can't find someone who's making the trip, their Twin Cities relatives and friends often help out. Jimmy Earley, a Shoreview, resident, said he's shipped produce to eight out-of-towners so far this year.

Fresh picked kittley fill a large bucket on a farm in Andover, Minn. The crop, native to west Africa, has seen a boom in demand. Evan Frost | MPR News

"To my surprise, when I went to the Brooklyn Park post office, there was a huge line of Liberians with boxes of kittley, bitter balls and peppers," he said. This fall, he bought the same batch of vegetables for relatives in California, Maryland and Ohio. "We were all shipping to family members and in different states."

Hmong-American farmers who have made the foray into growing African crops said they are enjoying a surge in sales and customers, despite the fact that, according to a 2015 U.S. Department of Agriculture report, farmers market sales nationwide have plateaued.

"We have a lot of African customers, so business is quite good now," said Chaseng Vang, who sells at his mother's stand most weekends outside the Unidale Mall on University Avenue. "Africans buy more than any other group. It's good for business."

Business is so brisk, growers said, that African crops are gone before markets open most Saturdays.

"The African vegetables sell faster than other vegetables because the people are already over there, waiting in their cars," said Lor, who farms about 10 acres near Marine on St. Croix, Minn. "When you go, you just open the truck and they come right away. They don't let you set up; you have to finish selling the African vegetables before you can set up."

Farmers unload potato greens at the Minneapolis Farmers Market on Sept. 17. Some farmers have started to growing crops like potato greens, bitter balls and habanero peppers. Sam Harper | MPR News

And as the growing season hit its peak this year, shoppers arrived as early as 4 a.m. to beat the competition — and boost their chances of finding enough produce to last the winter.

"It's just amazing to watch," Nelson said.

"Originally it was 5, 6 o'clock but as they compete for these vegetables, they started coming a little bit earlier, little bit earlier. And they wait patiently."

More than 25 Hmong growers who sell in the Minneapolis market now raise African crops, Nelson said. He recalls only two vendors catering to the population five years ago. And he expects more will join them.

But some farmers are reluctant.

"It's hard to convince some of these Caucasian growers to think outside of the box, because they've grown this their entire lives and that's what they're comfortable with, that's what they're familiar with," Nelson said.

Meanwhile, Hmong farmers devote more acres to African vegetables each year, and some say they still can't meet the demand.

May Lee picks a bitter ball on her family farm in Andover in September. "They don't want any that are colored," Lee said of her customers' specific demand for bitter balls, a small variety of eggplant. Evan Frost | MPR News

"This year I don't have enough vegetables for African people," said Lor, who sells at three markets in St. Paul. "We need more land."

Some growers said they are considering nixing mainstream produce altogether to make room.

"Right now we have five acres, and three of them are African vegetables," said May Lee, whose family leases farmland in Andover, Minn. "To meet the demand, we need 10 acres with just African vegetables. I'm willing to get rid of everything else and just focus on the African vegetables. It's what the customers want."

Local ethnic food stores tend to stock limited, frozen and more expensive inventory of these goods. But at farmers markets, they are fresh, affordable and plentiful. Minnesota's short growing season, then, marks a season of shopping — and hoarding — for many Africans immigrants in the Twin Cities. Shoppers said the vegetables they buy at the market are headed for their chest freezers at home.

Habanero peppers at the Minneapolis Farmers Market. Sam Harper | MPR News

"When I come here, I stock up for a whole year's worth," said Beatrice Eze, a native of Nigeria who lives in Minnetonka. "I buy them in bulk, wash them and freeze and use them for a whole year until the next farmers market."

She shops weekly, and spends $100 each trip.

"The money is not the issue," Eze said. "The thing is, we are getting it fresh and it's homegrown and it's something we cannot find elsewhere. I like my pepper extremely hot — the hottest pepper — and I love greens that I just can't find in regular stores."

For Rose Makumbi, the draw is osuga, a leafy green vegetable popular in her native Uganda. The mildly poisonous nightshade is also a delicacy in Kenya, it's called managu there. Makumbi bought a trunkful of the greens every other Saturday to cook for her family.

A farmer handles potato greens at the Minneapolis Farmers Market. Sam Harper | MPR News

"You just steam it and put on salt and pepper," the Bloomington resident said.

Eze said each trip to the farmers market is "like being home. I can still be here and still eat the food I was raised with in Nigeria."

Antoinette Jones, a Liberian who lives in Crystal, completed her winter vegetable shopping weeks ago, but was back at the market recently, serving as a tour guide for the Kollies, friends of hers from Minot. She instructed them to be at market before sunrise.

"The vegetables are fresher and you have more selections," she told them. "If you come too late, the farmers will be sold out of everything."

Heartbreak and disappointment are unavoidable nearly every weekend, especially when the sweet potato greens sell out.

"We got here at 5 a.m., but other people were here before us, already in line for the potato greens," said Evangeline Tarlue, a Liberian who drove with her family from Fargo and was tenth in line at a stand with piles of greens.

Bitter balls sit next to giant bags of potato greens bought by Minneapolis Farmers Market customers one Saturday in September. Many customers will arrive before opening to ensure getting the specific vegetables they want. Sam Harper | MPR News

"The first five people in front bought everything," she said. "The potato greens was mainly the thing I wanted. And I didn't get it. I'll have to come back. Next time, I'll leave Fargo at 11, so I can be here at 3 in the morning."

Steve Songor, from Tulsa, was also too late for the potato greens that day — but he paid a grower in advance to reserve six bags for the following day. Songor stayed the night at a relative's place, grabbed the bundle early Sunday morning and headed back to Oklahoma.

In 12 hours his friends and family in Tulsa would have their winter of supplies of habaneros, bitter balls and, of course, potato greens.