ALBANY — A greenhouse on a former vacant lot in one of Albany's most troubled neighborhoods shows us how sustainable we could be.

On this damp November afternoon in the city's South End, the Radix Ecological Sustainability Center is blooming with tomatoes hanging from the loft. The basil is fragrant and the watercress has a sharp bite. Tilapia swimming in a tank brimming with plant life wait to be harvested.

On a sunny winter day, you can wear your T-shirt in here.

The Radix Center at 153 Grand St. is a living classroom. There are lessons here for kindergartners, such as that banana peels and apple cores, when composted, turn into great dirt. And there is something to learn for older students, like the role of nitrogen in the life cycle of fish and plants.

Scott Kellogg and Stacey Pettigrew founded the center, which is a not-for-profit, in 2010. Now they're looking to expand their educational outreach, to get more schoolchildren in the doors through a fundraising campaign that will support ecological literacy workshops for young people. Radix has hosted groups from elementary school all the way through college, and is looking to increase the number of young people who come to learn about how an urban environment is an excellent place to farm.

Kellogg said children have held a chicken for the first time in their lives at Radix. He said one child did not know that fish sticks came from an animal until she looked through a window on the aquaponic tanks of catfish and sunfish.

"If all you do is go to the supermarket and pick up frozen foods and processed foods, you have no idea where that's coming from," he said. "It teaches them that just because you live in the city doesn't mean you can't have a relationship with food."

School groups regularly take field trips to farms. But Radix is something else entirely. It's a self-contained ecosystem in the middle of a city and in a place that can benefit from a source of fresh food because there are no grocery stores in walking distance. At Radix, silkworms are raised on mulberry leaves to feed fish, whose waste products are used to feed plants that in turn are used to feed chickens that produce waste used to feed other plants.

Kellogg, who has a master's degree in Environmental Science from Johns Hopkins University, sprinkles his explanation of the systems he and Pettigrew have created at Radix with phrases like "Cartesian dichotomy." Where others see buildings and parking lots, he sees arable space and rain collection areas. He hopes to turn a nearby vacant property where people dump trash into another garden. He said the future plans for Radix are to show that it can be replicated in other neighborhoods and other cities and even provide jobs when it generates enough food to supply stores and food co-ops.

Kellogg said schools are increasingly focused on science, technology, engineering and math. At Radix, they can touch the systems they read about in the classroom.

"The way to get kids excited is to get them to see the end point," he said. "Then they'll have motivation to study those different fields."

swaldman@timesunion.com • 518-454-5080 • @518Schools