The popularity of farmers markets is sprouting as consumers become more aware of the benefits of eating fresh, leafy greens and shopping locally.

But with the experience of strolling along the stalls on a summer Saturday morning, buying some fresh-picked strawberries, flowers or maybe some meat and cheeses, comes a reality check when it's time to open the wallet.

"The closer you get to D.C., the more expensive it becomes," said Steven Knopp, who operates a 30-acre farm with his father in Severn, Md.

On Tuesday afternoons, Knopp sells his vegetables alongside a handful of vendors behind a West Hyattsville strip mall, where mariachi music streams from the storefronts. A quart of beans gathered the day before sells for $3; summer squash run about 75 cents each, and cucumbers cost 50 cents.

Come the weekend, Knopp's father sets up at the always bustling Eastern Market on Capitol Hill. There, prices can rise by $2 to $3, Knopp said.

And efforts to undercut the competition are met with a friendly lesson on agrarian cooperation.

Knopp's fellow farmers universally agree with his pricing, attributing the markups to the longer distances traveled, the variable costs of renting market space, and a basic principle of capitalism: charging what the market can bear.

On a recent Thursday afternoon, downtown workers sweating beneath suit coats took the markups in stride, enjoying a stroll outside the office even in the burning heat.

"I'm not expecting a better deal financially, but qualitywise, absolutely," Simone Coyle said. "I try to eat locally sourced, organic food as much as possible, especially now that I have a small son."

Even so, the expense is too much for most people to rely on farmers markets for the bulk of their produce, even when it's fresher and tastier.

"The idea is to support local farmers, but when all is said and done, it's too expensive to support them as much as you'd like to," said Jeremy Ford, who comes to the Vermont Avenue market for whatever he forgot at the grocery store. "At Wegmans, sometimes we'll get bigger and better produce for half the price," he said.

The Washington area now has 70 farmers markets, from Dupont Circle to Silver Spring to Cheverly. The number of markets is expanding nationally, too, tripling to 5,274 since 1994, according to the Department of Agriculture. There was a 13 percent increase from 2008 to 2009 alone.

The cost to set up shop at a market is a major factor in how much an apple or tomato costs.

At Hyattsville, vendors pay $10 each week to rent space. In Rockville, where the city helps to subsidize the market, they pay about $100 for the season. At Falls Church, the cost jumps closer to $600 per season. And at the 11 markets operated by FreshFarm, such as Thursday afternoons at Penn Quarter, or Dupont Circle on Sunday mornings, vendors pay about 6 percent of their earnings.

"There's probably some correlation between the price of rent in a neighborhood, and the price of the produce at the markets," said Sara Lipka, who has spent time working small farms and local markets.

But the farmers hardly return home rich.

Lipka ran through the litany of labor-intensive steps between a tiny seed and food on the table: sowing, watering, transplanting, cultivating, weed and pest control (whether the produce is certified organic or not), transportation, gas, space rental, and finally, the sale, maybe for a few dollars.

"I used to flinch at the prices before I worked on a farm for a season," Lipka said. "After working on the farm, I'd get a little indignant at people flinching at the prices."