It was a dreary Friday, the kind of day farmers like Karen Vollmecke and her mother, Jan, use to get take care of paperwork that takes a backseat during the long, fertile spring days.

At the Vollmecke Orchard & CSA, rain cascaded off the roof of an outbuilding and into tanks that hold 1,500 gallons of water, a hedge against a future drought and a sign of the commitment to "green" agricultural practices that characterizes most CSA (community-supported agriculture) farms.

A business model rooted in a community-oriented philosophy, CSAs encourage a direct relationship between farmer and consumer.

In return for buying shares that support the farm's operating budget, members receive fruits and vegetables throughout the growing season.

Chester County has at least 11 CSAs. Most of them are thriving, with many aspiring members on waiting lists.

One example: This spring, the Willistown Conservation Trust inaugurated a CSA in a six-acre plot of land christened Rushton Farm. The lucky 35 members in the pilot venture were chosen by lottery from among the more than 75 who applied.

Encouraged by growing demand, some local CSAs are experimenting with new ideas, such as "winter shares" (based on the shorter growing season), and are working cooperatively with other local farmers to offer products like beef, cheese, honey and yogurt to members.

While a few still have retail operations on site, many sell at farmers' markets, provide produce to restaurants, or stock health food stores.

Daryl Katz, who ran another CSA in the 1990s, recently started Opperman's Corner Organics, a Chester Springs CSA that washes produce and delivers it directly to the buyer.

CSA growers attribute the boom in demand to a "perfect storm" of converging factors that include rising energy and food costs, increased environmental consciousness, and a desire to buy produce from a neighbor rather than from a conglomerate thousands of miles away.

"I also like to know where my food is coming from," said Tim Ferris of Uwchlan's Milky Way Farm.

A born entrepreneur, Ferris is the son-in-law of Milky Way owner and farmer Sam Matthews. The family started the CSA last year as one arm of a multipronged operation on the 103-acre farm already known for its school tours, pumpkin sales, and Chester Springs Creamery.

Ferris sees the CSA as another way of attracting potential new customers to the farm, and introducing them to the charms of the other items the farm sells, which include eggs, beef, chicken, lamb, pork and, very soon, pasteurized milk.

His father-in-law, who has seen Uwchlan Township's population surge from 900 to about 17,000 in his lifetime, is well acquainted with the vagaries of farming life.

For them, the CSA is less about philosophy than about meeting the needs of residents, and keeping the family enterprise going.

It's been about 11 years since the Vollmecke family converted their 37-acre West Brandywine farm into a CSA.

As rain drummed on the roof of the greenhouse Vollmecke recently bought at auction and rebuilt with the help of CSA community members, she reflected on the challenges of growing produce for a "diverse group of eclectic eaters."

Chiefly staffed and organized by Karen and Jan Vollmecke, their CSA maxes out at 150 shares, which Karen Vollmecke estimates may constitute as many as 180 families.

Some members pick up their produce at the farm on Tuesdays or Fridays. Others commit themselves to share "co-op" duties with a group of members, picking up produce at the farm and bringing it back to their neighborhood.

Plants growing in the greenhouse included tomatoes, peppers, eggplant, and variations on other standards. But like other CSA farmers, Vollmecke doesn't shy away from introducing produce that may be a bit of a walk on the wild side for some of her more timid palates.

In a move to help members incorporate less familiar vegetables like celeriac (celery root) and okra into their diets, Vollmecke provides members with panoply of easy-to-fix recipes.

"You start making up your own recipes, and from there, it's really hard to go back to the grocery store," said Vollmecke.

Although getting the CSA certified "organic" by the USDA would be both time-consuming and expensive, she said, she does not use synthetic pesticides, fungicides, herbicides or sewage sludge.

Some CSAs require that members spend time doing farm chores, or have members who provide labor instead of cash. A few local CSAs offer that option.

Vollmecke praises the cooperative spirit of the members who volunteer their time and talents. "The members have formed a community around this farm," she added.

It is that sense of comradeship that continues to inspire her - as well as her sense of stewardship.

"I would like to be respectful of this property, to grow high-quality and nutritious produce for our members, and, in the process, to be as sustainable as we can be," she said.

A few townships away, Ferris ponders the growth of CSAs pragmatically. "People that get their vegetables from the average supermarket are missing out," he said.

Then he walks back towards the fields, where he is in process of building a greenhouse to house the unusual crops of tropical fruit that he hopes will attract more visitors, and buyers, to this historic farm.