ST. PAUL — The former Hamm’s brewery complex in east St. Paul has been transformed into an urban farm, the home to thousands of tilapia and racks of leafy green vegetables.

The six-story building is now occupied by Urban Organics, an aquaponics farm. Aquaponics is a method of raising fish and vegetables in a system where the fish waste helps nourish the vegetables, and the plants purify water that gets recycled back into the fish tanks.

The building had fallen into disrepair after it was abandoned in 1997, but $1 million in renovations helped restore it to usability. Its thick walls and concrete floor were perfect for a business that requires consistent temperature and heavy fish tanks.

The first floor, once used to ferment beer, is now filled with six rows of floor-to-ceiling shelving. The shelves hold tubs of water containing trays of plants including kale, chard, cilantro and parsley.

Because the vegetables are grown indoors, the business can be productive even through the harsh Minnesota winters.

The vegetables are sold in a handful of stores, and Urban’s owners hope to eventually harvest about 450 pounds of fish per month for sale at local restaurants.

Four huge tanks hold about 1,500 fish each, and thousands of feet of pipes circulate the wastewater from the fish tanks to the various grow tubs.

Urban Organics will soon have some company in the former Hamm’s site. A brewery and distillery are both slated to move in within the next few months.