If it’s February, it must be time to feel guilty.

It’s not because I’ve broken any new-year diet resolutions. (I don’t make any.) It’s because I will not join a CSA.

Community-supported agriculture programs, or CSAs, traditionally offer a weekly box of seasonal produce from a local farm. Customers pay upfront so the farmer has the cash on hand to buy seeds and equipment, and a guide for what and how much to grow. (Some plans also require that members put in a few hours’ work on the farm.) In exchange they receive an assortment of whatever is ready for harvest that week. That might mean a lot of greens in early spring and an overload of tomatoes in high summer — or if there’s a blight, no tomatoes at all. The benefit, or so they tell me, is that participation supports local growers and teaches families to cook with what Mother Nature provides rather than the global panoply of foods available year-round at the grocery store.

Maybe. But a model designed to serve the producer and not the customer will never be, well, sustainable. And in my experience, CSA customers get the short end of the stick. If I take a vacation in the summer, I pay for food I never receive. If I want more food one week to throw a party and less the next? Tough luck.

The good news is that farmers and a new crop of food entrepreneurs are getting the message that, at least some of the time, the customer should have options. Flexible CSA models are sprouting up around the country, proving that subscription services can work for farmers and consumers. Some, dubbed multi-farm CSAs, offer produce from a network of small farms for more variety. Others let customers choose what and how much goes into their weekly box or use pre-paid credit at the farmers market or online.

“My customers have a lot of things in their lives, and this can’t be their total focus,” says Karen Pendleton, a farmer in Lawrence, Kan., who started a CSA in 2011. “The goal is to get local food in the hands of people who are less committed to the idea and do it in a way that is comfortable and convenient for them.”

Her business, Pendleton’s Country Market, offers two options to CSA customers. Some pay $15 a week for a standard box, which they pick up at a local day-care center. That makes sense to a lot of customers because they don’t have to make a special trip to get their food; they’re picking up their children at the same time. Others choose to buy a monthly punch card, a kind of limited-expiration gift card, which allows them to spend $60 in pre-paid credit at Pendleton’s farmers market stand. They can buy some produce each week or spend it all in one go if, say, they are canning tomatoes or making salsa to put away for the winter. Shoppers can buy a card every month or only at times when they know they want a lot of produce. The scheme helps busy customers, and Pendleton is saved the trouble of packing bags for individual shares.

Closer to home, there’s Star Hollow Farm. Owners Randy and Chris Treichler have built an online ordering system for their 400 members. Customers pay $300 to join, then choose what and how much they want on any given week. The cost of their order is deducted from their account, and they can add money whenever they need to. In high season, they can order every Wednesday for Saturday pickup at the Adams Morgan farmers market. Or they can skip a week or even several months with no penalty.

The Treichlers have farmed in the Pennsylvania mountains for 20 years. They experimented at various times with the traditional CSA model both near their home town of Three Springs and in the District. Customers loved the food, but the system was too restrictive: “People would say, ‘We go away in July when all the tomatoes come in.’ Or, ‘We don’t like anything in the turnip family,’” Randy Treichler remembers. “In Washington, we’d donate unclaimed shares to a food pantry. And, boy, that makes people feel good once or even twice. But at some point, you want to get your money’s worth.”

The customer-friendly CSA has helped the Treichlers to build their business. They still get money up front. And there’s very little customer turnover. (There is a waiting list to join the program, though new members are admitted every few months.) The Treichlers grow much of the produce they sell. But they also buy from neighbors who want to market their wares in the big city. On a recent week, the site offered, among other things, three varieties of apples, pea shoots and lettuce from the greenhouse, Jerusalem artichokes, eggs, mushrooms, jams and jellies.

Entrepreneurs are building similar models. Richmond-based Farm2Family has a multi-farm CSA that offers meat, dairy, bread and soy products, such as tofu in winter, plus vegetables during the warmer months. There’s no official start date. Customers can sign up for a season at any time (the fees are prorated) and pick up biweekly at Eastern Market or Maret School in Northwest. Similarly, Brooklyn’s Nextdoorganics, offers a winter CSA that serves locally made bread, cheese and pantry items such as jam and granola. Customers can choose what and how much goes in their box, put orders on hold for vacation or cancel at any time. Nextdoor also offers home delivery for a fee. (It’s New York, after all.) Traditional CSAs “are not a sustainable business,” says Kris Schumacher, the company’s co-founder. “We try to make it as easy as possible because we want people to switch from the stuff in the supermarket.”

One of the most innovative models is Kansas City’s Good Natured Family Farms. Customers commit to pay $25 each week for 18 weeks. But they pay only when they show up and get their box, which might include bison meat, milk, squash, tomatoes and zucchini bread. Pickup is on Saturdays at Hen House Market, a local grocery chain, where they can shop for whatever else they need to go with their CSA allotment. Moreover, every item has a certain number of points associated with it. So if a customer doesn’t like beets, for example, they can trade them in for cucumbers or something of equal value.

The CSA, which sources from more than 150 farms, now has more than 700 members. But when it launched in 2006, the scheme had lots of critics, says Otavio Silva, Good Natured’s director of sustainability: “A lot of people said it wasn’t a CSA. And I said, ‘Why not?’ ” It’s not your perceived idea of granola bars and work on the farm. But there are many ways to create community.” And, I might add, to build a better CSA.

2012 list of Washington area CSAs

Black, a former Food section staffer, is a Brooklyn-based food writer who is working on a book about one West Virginia city’s struggle to change the way it eats. Follow her on Twitter: @jane_black.