In the darkest days of winter, Julie Rappaport has a wish of growing greens.

Rappaport's the founder of Seeds Feeds, a small but expanding hunger-fighting nonprofit. The group distributes fresh, healthy food to families in need and cultivates growing skills in its clients at 10 gardens throughout St. Louis Park.

But when harvest passes and the season turns, Rappaport said, "the gardens close in Minnesota, and we can't really do fresh stuff. Our people are like, 'if we could just get makings for salad, it'd be so nice if we could get this throughout the winter.'"

Four engineering students from the University of St. Thomas just wrapped up two semesters of work on a project that aims to give Seeds Feeds — and maybe some of the individual families it serves — an inexpensive way to grow leafy vegetables and herbs year-round.

"We were surprised at how fast the plants grew," said Noah Drehmel, an electrical engineering major who was part of the St. Thomas group. In recent months, he and his colleagues were quickly growing leafy greens and herbs using the system they built in a laboratory on the school's St. Paul campus.

"We found they were growing about twice as fast as they say it takes to grow these plants in soil," said Drehmel, 21, from Apple Valley.

Greens grown indoors and year-round, including by several Minnesota companies, are a growing segment of the nation's vegetable market. Though still dwarfed by greens grown outdoors in the southwest United States, indoor operations using hydroponic, aeroponic and aquaponic technology are on the rise amid supply chain disruptions, spikes in the price of food, and concerns over that region's long-term water supply.

Beyond the commercial potential of indoor vegetables, food security groups in cold-weather climates like Minnesota see a way to keep fresh greens among their offerings while avoiding the higher cost and complication associated with shipping produce cross-country.

Seeds Feeds, which Rappaport said distributed about 20,000 pounds of food this year, had experimented in small ways with hydroponic growing but found commercial systems both expensive to buy and finicky to operate. The organization had previously connected with St. Thomas students for whom community service projects are a degree requirement, so when Rappaport learned that engineering students were part of that group, she made a pitch.

What she wanted, Rappaport said, was a hydroponic system that could be assembled and operated by non-experts and that would cost less than $500. The group hopes to be able to install the system on a larger scale at its St. Louis Park warehouse, and to both sell and donate small units for home use.

"You know the old saying: you don't give a man a fish, you teach him how to fish?" Rappaport said. "We teach people how to grow food in their habitat. So if you're an apartment dweller, how do you grow fresh food? We hope with this."

The student team studied commercial systems as they embarked on the project. They came up with a growing unit that allows its users to measure temperature and humidity, PH levels and nutrients, and sets off an alert in the event of water leaks.

"It's designed for people who aren't mechanical engineers to be able to use," said Dagmawe Mamo, a 21-year-old mechanical engineering major. "We think the potential capabilities of this thing are huge. It's exciting to think you worked on something that could be used in homes and factories."

The other two engineering students in the group are Timara Williams and Caleb Willeford. They dropped off their system with Seeds Feeds earlier this week, complete with user manual and trouble-shooting guide. Rappaport said she's enlisted the help of an expert on greenhouse systems to implement it for regular use.

While boosting fresh produce offerings for clients is job one, Rappaport is hopeful that the nonprofit might be able to sell the machines commercially. The organization's budget has grown during the pandemic thanks to several large federal grants, she said, but that necessitated moving the operation out of her home and into rental space.

"Hopefully this helps us both feed people and maybe also pay the rent," Rappaport said.