Michelle Bentzen and daughter Mae, 2½, pick out tomatoes for their CSA share from Groundworks Farm, on Maryland’s Eastern Shore. The farm’s whole-diet CSA provides grains, meats, produce and dairy products in addition to the fruits and vegetables that standard CSAs supply. (Katherine Frey/The Washington Post)

Every Tuesday and Friday afternoon, the open barn at Moutoux Orchard in Purcellville looks like an especially well-stocked natural foods co-op.

Underneath high rafters, produce covers weathered wooden tables from end to end. One day in mid-July finds a rich array: quarts of plump cherry tomatoes, a riot of heirlooms, zucchini, fennel, chard, carrots, cucumbers. Small baskets of varyingly hot peppers. Tomatillos and okra. Crates of peaches, a little blemished because they weren’t sprayed. Bins of flour: buckwheat, rye, oat, barley and wheat. Refrigerators with diagrams of animal cuts taped to their doors and packages of beef, chicken and pork inside. In another cooler, raw milk, exempt from pasteurization laws.

By 3:30 the space is humming with chatter, full of subscribers to Moutoux’s whole-diet CSA, or community-supported agriculture program, who drive to the farm every week to pick up their shares. Most travel 20 to 30 miles each way, trunks loaded with coolers, tote bags and glass bottles; some come from as far away as Arlington and even Alexandria, almost 60 miles to the east.

More than a vegetable supplement, the whole-diet CSA embodies the full extent of community-supported agriculture, in which one farm provides members with the makings of a well-rounded omnivorous diet, year-round.

Like the vegetable CSAs that have become so popular in the United States, whole-diet programs imply risk: Subscribers commit to align their diets with the output of one farm. More than that, some members say, they subscribe to a dietary lifestyle, one tied closer to land and community, in which they swap recipes for the ingredients that give them pause, and seasonal shifts are reflected in the butter as it turns from buttercup to pale blond.

On pickup days at Moutoux, handwritten signs let subscribers know what’s in abundance and what’s not (“Can tomatoes and make pickles this week!” “Don’t be greedy with the chard”); another announces the birth of a calf; say hello. Shopping is by honor code, or “buy what you can eat,” a tack some programs refer to as “free choice.” Depending on the season, the cook and the fullness of the cook’s pantry, the range of options the CSA provides might or might not be enough to prevent a trip to the grocery store that week.

In practice, the whole-diet subscription provides enough food not to eliminate all conventional grocery shopping but to reduce it to a supplement. At a minimum, most subscribers will still buy oils, vinegars, beans, nuts, seeds and some condiments from other sources.

“I think if you wanted to eat exclusively from the program, you could,” says Bonnie Deahl of Sterling, who has subscribed to the Moutoux Orchard CSA since it launched three years ago. “But I think that’s veering into homesteading, and making your own ketchup isn’t for everybody.”

The inherent limitations of the program — what might be seen as a crash course in strict seasonal eating — have freed Deahl, an avid cook, to push boundaries in the kitchen. “It’s been sort of an adventure and an education process,” she says. Each week, as she wrote on her blog last year, is a mission to find out how long she can go without a trip to the supermarket.

The open-shopping format, common among whole-diet programs, provides flexibility not always found in other CSAs. “I didn’t like the limitations of just getting what you get in a box,” Deahl said, referring to the format employed by many vegetable CSAs. (Increasingly, though, vegetable CSAs are offering on-farm and in-town pickups at which subscribers can customize their own share.)

On-farm pickups are standard for most whole-diet CSAs, but a significant urban customer base leads some farms to provide in-town deliveries, too. Margaret Evans and Kevin Brown, owners of Groundworks Farm in Pittsville, Md., moved their farm and CSA in Vermont to a plot of land they bought on the Eastern Shore early this year. They quickly acquired subscribers for their various CSA options, including produce, meat and whole-diet plans, but theirs is a geographically diverse membership, scattered throughout the Chesapeake region and the Washington area.

Just a handful of people come out to the farm for pickup each Saturday, filling their shares using a point system, cutting flowers and picking their own if something is in abundance. But Groundworks also delivers shares weekly to Annapolis, Alexandria and Arlington, where they set up what amounts to a mobile farm shop.

Whole-diet CSAs are designed to be more economical than shopping piecemeal in conventional outlets or through farmers markets, but the prices can be jarring at the outset. Costs range from $3,000 to $4,000 per year for a single subscriber, with discounts for additional family members and lower prices for children.

“There was definitely some sticker shock at first when we realized this is how much we’re going to be spending,” says Stephanie Beckmann, a subscriber to the Groundworks CSA who lives in Alexandria. “But in terms of vegetables and meat, we buy next to nothing at the grocery store, and we’re spending less overall as we’ve gotten really creative about what comes with the CSA.”

Despite demand, whole-diet programs nationwide are scarce, numbering in perhaps the dozens in the United States compared with an estimated 6,000-plus vegetable and meat programs.

Ten years ago, Mark Kimball pioneered the whole-diet CSA model on Essex Farm in upstate New York with his wife, Kristin, who chronicled their early experiences in the 2011 book “The Dirty Life: A Memoir of Farming, Food and Love.”

To sell a whole-diet CSA, of course, a farm has to produce more than just, well, produce. “There’s a reason there aren’t that many completely diversified farms out there, and it’s because they’re so challenging to manage,” Mark Kimball said.

Rob Moutoux, who counts Essex as an inspiration, says the model “definitely takes a certain kind of person. You end up being a jack of all trades, which lends itself to not being a specialist in anything.”

Clearer divisions of responsibility have helped Moutoux excel at more; he now handles animal husbandry, and his partner, Maureen Moodie, whom everyone knows as Mo, manages vegetable production. “We’re in a good spot now,” he says.

Despite the logistical demands, diversified farms are driven by environmental and economic sensibilities. The leftover straw from growing grain can be transferred to barns for animal bedding; manure that accumulates over the winter can be used to fertilize vegetable crops. No middlemen, no paperwork.

“There is a sense of independence in keeping everything in one place and having control over all of these different variables,” Kimball says.

The requirements of a whole-diet program still lead some farms to outsource, or “buy in,” some of what they provide to members. Moutoux found that producing a wide variety of grain required too many resources, so aside from the wheat flour he grows and mills himself, he gets grain for his CSA from a farm in southern Pennsylvania.

At Groundworks Farm, Evans and Brown are buying in beef, lamb and cheese while they develop the on-farm infrastructure to produce those foods themselves. Their dairy and grain operations are still getting going, and they plan to add those to the CSA next year.

About 120 miles northeast, in Duncannon, Pa., Judi Radel will admit that producing everything on-farm demands patience. The whole-diet CSA that Radel, her husband and their four kids provide from their Yeehaw Farm is small, with accommodations for seven or eight families of four, something they began to offer when she realized it might help make their homestead more sustainable.

On a rolling expanse interrupted by shady hillocks, one glimmering pond and a caboose swallowed by wildflowers, they produce milk, butter, cheese, lard, eggs, pork, beef, lamb, chicken, spring and winter wheat, oats, mill corn and barley, in addition to a diversified vegetable crop. The only thing they buy in is buckwheat; occasionally they trade for peaches, blueberries, apples. Radel is apologetic: “We tell our members up front we don’t have a lot of fruit.”

Radel’s predicament is the norm in farming. Her hours are backbreaking and long, the work is relentless, she rarely gets to take a vacation. But when she’s gone for three days, she gets homesick. And providing the whole-diet CSA has given her a connection with members that she wouldn’t trade for almost anything.

“I really love being their farmer,” Radel says.

Back at the Moutoux Orchards pickup, the sun is high and unforgiving, but there’s a cross-breeze in the barn. A wild-looking patch of zinnias splashes color, and a tabby cat is lazing in the sun at the foot of the barn. In a way, it all belongs to the CSA members. They are subscribing for the food first, but they can also satisfy a craving to be closer to the farming process and to the land itself. Along with the totes and coolers, members bring compost buckets full of their past week’s trimmings.

“I feed it to the pigs or put it on the compost heap,” Deahl says, and then laughs at that, a small pleasure. “It helps me be a part of the process in a little way.”

Horton, a Washington food writer, will join today’s Free Range chat at noon: live.washingtonpost.com.