PORTLAND – The Libra Foundation, which is well-known for helping to re-energize downtown Portland during the 1990s, now is putting on its straw hat and overalls as it seeks to revitalize farms around Maine’s largest city.

The foundation has resurrected two working farms within the former state-owned Pineland Center into dairy, sheep and organic egg operations.

Now, a subsidiary of the nonprofit foundation that promotes economic development projects is expanding its reach to fields and forests between Portland and Lewiston-Auburn with hopes of bringing new strength to farms across the state.

Libra has purchased eight other farms and assembled 3,000 acres in New Gloucester, Gray and Pownal. Much of the land is wooded, but about 1,000 acres are in some form of agricultural production, making Pineland Farms among the largest farms in southern Maine.

On 106 acres of prime farmland eyed last year by homebuilders, farmworkers tend pumpkins, corn, strawberries, peas and tomatoes.

Cows graze on a pasture at another farm. The pasture will expand next year to support hundreds of head of cattle raised for natural beef.

Libra’s project also involves an embryo transplant venture with black Angus beef cattle that holds the potential for a lucrative return on investment. A $750,000 hydroponic greenhouse has computer-controlled tubes that drip nutrient-rich water, growing 2,500 pounds of tomatoes each week from vines that reach to the ceiling.

A research project seeks to create a better strain of sheep and a planned cheese factory.

Libra hopes to make its farming ventures national models. The well-tended farms are prompting comments from some farmers that the rich foundation is buying up the countryside to make fussy hobby farms.

“There may be some people who feel that way, but they’re shortsighted,” said Erick Jensen, manager at Wolfe’s Neck Farm in Freeport, the operation that produces pesticide- and hormone-free beef. “The fact is, they have the resources to do this. The state can’t do it.”

Jensen said the farming community should embrace Libra’s innovations.

The Libra Foundation has had a continuing interest in preserving open space from development, and learned that one way to accomplish that is to keep land productive through agriculture.

Owen Wells, the foundation’s president, said it has become increasingly difficult for farmers to stay in business, and Maine’s dairy farms are a case in point.

Libra’s farm projects can help support Maine’s working farms by serving as a model, processing some of their products and furnishing new techniques to help keep farms viable.