U of I graduate student tackles food insecurity through sustainable indoor farming

Having grown up in Bangladesh, Zarin Subah knew food insecurity was a major challenge and was interested in developing solutions to address it.

After earning her bachelor’s degree in environmental science, Subah began a master’s in water resources development where she studied how natural disasters like flooding can impact food security.

While pursuing her master’s degree, she had the idea to further her research and develop systems that could help people grow food in a resilient way in any part of the world.

“I wanted to work on how to farm more sustainably with limited resources,” Subah said.

Her interest in sustainable farming led her to pursue a doctorate in environmental science at University of Idaho.

Idaho and agriculture 

It’s no secret that in Idaho, the agriculture industry is a major driver of the economy.

According to a recent U of I report based on 2024 data, $44.5 billion in annual sales and 17.2% of the state’s total economic output can be attributed to agriculture.

Developing solutions to complex issues, like food insecurity, can sometimes require an interdisciplinary approach where multiple areas of expertise are needed.

The environmental science doctoral program at U of I provides Subah with the tools to develop more sustainable farming solutions using limited resources.

North to south

After studying on the Moscow campus for a year, Subah moved to Boise to continue her doctoral program at the University of Idaho Boise and was able to complete coursework online.

She also began her research project under the direction of her major professor, Jae Ryu, a professor in the Department of Soil and Water Systems within the College of Agricultural and Life Sciences.

Subah’s research is centered around aquaponics and hydroponics, where she grows plants without soil, and instead, uses the nutrient-rich water from an adjacent aquatic system that houses mature rainbow trout.

Each week, she carefully monitors and cares for a variety of robust leafy vegetables and seventeen adult rainbow trout, which are cold-water fish that flourish in cool lakes and streams.

Subah’s lab at U of I’s Idaho Water Center in downtown Boise received USDA organic certification in 2024.

“The unique part of my research is that I specifically focus on the organic side and on cold-water aquaponics,” Subah said. “I grow rainbow trout in a low-cost, fully controlled organic aquaponic environment, which is still quite novel in this field.”

Sustainable indoor farming

Through detailed computer modeling, Subah studies how a controlled cold-water ecosystem works and finds ways to make it more sustainable.

In most aquaculture systems, the solid fish waste is discarded, but she has developed a solid waste re-mineralization approach.

This is where waste is captured and converted back into usable nutrients for the plants, which means the system is cycling and transforming the nutrients instead of losing them.

“I like to describe it as a nutrient-transforming system rather than a nutrient-removing one,” Subah said. “This is what makes it truly a closed-loop, zero-waste system, which I think is where the real potential lies for sustainable indoor farming.”

She hopes her research on sustainable farming helps address food insecurity globally and is making significant strides toward accomplishing her goal.

These systems, like the one she has built in downtown Boise, can operate in places where traditional farming is not possible — such as in deserts, areas with harsh winters or places with water scarcity.

“Zarin's research is a genuinely innovative approach to feeding urban dwellers across the Treasure Valley with fresh, local food while designing for zero waste in an era of abrupt climate change,” Ryu said.

Just as importantly, it offers the wider aquaculture industry a practical blueprint for exploring alternative business models as cold water availability becomes increasingly uncertain under shifting snowpack conditions, Ryu said.

Sky’s the limit

Subah has also had the opportunity to conduct education-based research and develop her own teaching philosophy by assisting Ryu with his drone education outreach for middle and high school students.

Through this outreach experience, she not only explored experiential learning and how to make STEM topics fun and engaging for students, but she also gained valuable remote sensing skills.

“Having access to Dr. Ryu’s multispectral and hyperspectral drones, I had the opportunity to analyze drone imagery and crop vegetation indices and create maps for agricultural fields,” Subah said. “This gave me hands-on remote sensing experience alongside my aquaponics work.”

Subah has published eight peer-reviewed articles in different disciplines during her doctoral program and plans to graduate in fall of 2026. Once she graduates, she hopes to continue her research and keep building on the systems she’s developed while also inspiring tomorrow’s scientists.

“Eventually, I would love to be in a position where I train the next generation of researchers and help scale these systems, so they have a real impact on food security,” Subah said.