He's called "Farmer Dave," to distinguish him from four other Davids at Weavers Way Co-op, but don't get all misty-eyed about tractors and grain silos.

His farm is as unlikely and urban as they come - in Germantown, in the heart of the city.

In January, David Zelov, 28, became the member-owned co-op's first full-time farmer, a sure sign that this free-spirited fixture in Mount Airy is getting serious about organic agriculture.

Weavers Way has quadrupled the amount of land it's been cultivating for the last seven years - to a full acre off Washington Lane, about two miles from the co-op. It's invested $80,000. And it's taken on two goals: to grow what Zelov calls "cute vegetables" that co-op members will be willing to pay a premium for, and to make a profit in five years.

The cute stuff includes things like purple kohlrabi and dwarf gray sugar peas, "Tom Thumb" lettuces and - 'Scuse me while I kiss the sky - "Purple Haze" carrots.

"It's awesome," says Zelov, a lanky, good-natured fellow from Sussex County, N.J., who farms about 10 hours a day with help from students and "cooperators," as co-op volunteers are called. Members have to work six hours a year, either at the farm or the store, at Greene and Carpenter Streets.

Zelov's jeans are perpetually muddy, and he gets an occasional blister or sore back. But he seems to relish his days in the dirt.

"It's a lot of work," says the Rutgers University graduate with a "green" resume. "I sleep very well at night."

The farm's fields are leased for $1,200 a year from Awbury Arboretum across the street. It's a peaceful place, with mature trees and rich bird life.

"You kind of feel like you're out in the country," Zelov says.

But then the city asserts itself with a distant police siren or the whoosh of the R7 headed into town or . . . a break-in. After someone pilfered the lawn mower, hand tools, and weed whacker from his shed, Zelov installed bars on the windows and chains on the doors.

And shrugged it off.

"I know there aren't many opportunities like this," he says. "This is going to be so cool."

The farm is officially known as the Mort Brooks Memorial Organic Farm, named for the retired factory manager and longtime "cooperator" who died a decade ago. In 2000, Brooks' widow, Norma, proposed using his memorial fund to get the project started.

The fledgling farm found a home on about one-quarter acre of arboretum land and was staffed by a part-time farmer and volunteers, mostly for educational purposes. The other three-quarters acre was recently transformed from an overgrown mess to a farm-ready field.

"It's going to be great," Norma Brooks says.

It's also going to reflect, more or less, a fledgling farming concept called SPIN, which stands for "Small Plot INtensive."

"Small plot" means an acre or less. "Intensive" means three to four short-season, high-value, rotated crops per bed per season, rather than onetime large plantings of row crops like corn.

"We're trying to open up farming to a lot of different people that might not have seen it as possible for them," says Wally Satzewich, who developed the SPIN concept in his backyard gardens in Saskatoon, Saskatchewan, in central Canada.

Traditional farming brings to mind vast rural acreage with start-up costs to match, work crews, heavy equipment, and delivery trucks. Not so with SPIN, says Satzewich.

"We haven't reinvented the wheel - you can't really do that in agriculture - but I think we offer a really fresh perspective," he says.

SPIN farmers plant densely in long narrow beds for efficient access. Satzewich straddles his to plant, harvest and weed, timing himself with a stopwatch "to get a better feel for the work flow."

He blends his own organic fertilizer, using alfalfa pellets, molasses, coffee grounds, bone and blood meal. He handpicks potato bugs and other pests.

Zelov is not a strict organic constructionist, but close enough. He mixes compost with a Fertrell organic fertilizer, uses natural insecticides when handpicking fails and believes strongly in building up the soil over time.

And in making money. It's possible - and this is where SPIN comes in - even with a relatively small plot.

Somerton Tanks Farm in the Far Northeast, started in 2003 by the Philadelphia Water Department and the city's nonprofit Institute for Innovations in Local Farming, ran on SPIN principles. It aimed for $50,000 in gross sales by 2008.

Barely three years into this half-acre experiment, the goal was passed. Last year, with help from an unheated hoop house to extend the growing season, gross sales hit $68,000. (Zelov sees a hoop house in his future, too.)

"If we extend the growing space to maybe just under an acre," institute director Roxanne Christensen says of Somerton Tanks Farm, "we might get within shouting distance of $100,000."

But the Somerton farm is closed for now. Its farmers moved away, and the Water Department needs to paint the property's giant water-storage tanks.

At the 3,200-member Weavers Way Co-op, "Farmer Dave" has just arrived, but produce manager Jean MacKenzie already calls him "exactly what we need."

He knows how to farm. He has excellent people skills. "And he cares about the cooperative concept," she says.

Zelov's mission - and the viability of "the small organic farm" - were on the mind of member Hannah Roberts of Chestnut Hill as she shopped in the co-op with her toddler, Martha, last week.

"It's the right thing for every reason," she said, placing an organic garlic blossom and a fluffy head of lettuce into her cart.

Virginia A. Smith blogs about gardening at http://go.philly.com/kisstheearth.