MILWAUKEE — Environmentalists recommend buying close to the farm. But actually buying the farm?

A growing number of people around the nation are investing in shares of a local farmer's crop, reducing trips to the supermarket and the cost of shipping food.

"It makes sense that you would save gas on broccoli grown 30 miles away versus California," said Rob Goldman, 53, a doctor from the Milwaukee suburb of Whitefish Bay.

Goldman will participate this summer in a community-supported agriculture program, or CSA. Members buy a share of a farmer's crop, usually for $500 to $600, and receive a box of vegetables and fruits each week during the summer and fall. A box typically feeds three or four people for a week, although many farms offer half-shares for individuals or couples.

The number of CSA farms has grown from about 50 in 1990 to more than 2,000 nationwide, according to a database maintained by LocalHarvest, a California-based group that supports buying locally grown food. The heaviest concentrations are in the Northeast, West Coast and upper Midwest.

Many farmers say they can sell as many shares as they can offer. Elise Margoles, 32, sold the 100 shares she offers at Elysian Fields Farm in Cedar Grove, N.C., in one week and now has a waiting list.

"This is the first time I ever filled up," she said.

The farmer Goldman signed up with, Peter Seely of Plymouth, said he usually sells all of his 500 shares. His CSA serving has grown from 50 shares in 1988, and he's taking more calls than ever this year.

"In general, there has been pretty substantial interest in it," Seely said.

The CSAs tend to draw well-off families who can afford to pay more for fresh vegetables and come up with all the money up front. But a growing number of farms are offering installment plans, Ferschinger said, and the rising cost of produce at grocery stores has reduced the price difference.

"It's not a cheap way to buy foods," Goldman said. "But I think the sort of premium you are paying is sort of reduced because food has gone up, vegetables have gone up, and I think a lot of that is trucking it from California."

CSA farmers and members save on gas by dropping off and picking up produce at central locations.

Mary Leciejewski, 21, a senior at Providence College in Rhode Island, helped organize a drop-off for the college community that will be across the street from her apartment.

"Most of the food you get, a meal would travel like 1,600 miles or something," she said. "But the farm we are getting it from is six miles away."

CSA farmers reap a number of benefits. With money paid up front, they don't have to take out loans to buy fertilizer and seed or worry about demand and prices at harvest time.

"Starting this CSA was probably one of the smartest moves I ever made," said Ken Dawson of Maple Spring Gardens farm in Cedar Grove, N.C.