Maine farmers may be able to expand their growing seasons thanks to Springworks' technique. Credit: Micky Bedell

A farm in Lisbon that grows lettuce indoors year-round using a technique combining water and fish waste has raised one-third of the total $1.6 million in equity funding it is seeking.

Springworks Farm Maine Inc., started three years ago by Bowdoin College student Trevor Kenkel, 22, raised $535,838, according to a U.S. Securities and Exchange Commission filing. About $150,000 of the proceeds will be used to pay debt held by company officers, while the rest will be used for expansion.

“We are still operating at full capacity, and production will increase as the weather gets colder,” said Duncan Pfaehler, director of horticulture and research at the company.

Aquaponics, which uses processed waste from fish to fertilize lettuce growing on floats in large water tanks in greenhouses, promises year-round fresh greens. Maine farmers have been seeking methods to expand Maine’s growing season, including vegetables more tolerant to cold.

Aquaponics uses about 90 percent less land and water than soil agriculture but potentially could generate three to four times more food, according to a report from Industry ARC, a Hamilton, N.Y., consulting and research company.

Springworks currently has one greenhouse, and has plans for a second, but it is looking at vendors now to build it, Pfaehler said.