Hydroponic plant factories enable continuous urban edamame harvest

by Riko Seibo
Tokyo, Japan (SPX) Nov 13, 2025
Researchers in Japan achieved year-round indoor cultivation of edamame using hydroponic nutrient film technique and LED lighting. Controlled plant factories allow crops to grow independently of outdoor climate by regulating light, temperature, humidity, carbon dioxide, and nutrients. This approach bypasses the usual challenges of open-field farming for legumes, which include lengthy growth cycles and limited storage times.

The study, led by Professor Toshio Sano of Hosei University and Associate Professor Wataru Yamori of The University of Tokyo, measured edamame yields and quality across three hydroponic systems. Plants grown with the nutrient film technique developed stronger stems, expanded leaf surfaces, and higher biomass compared to those raised with rock wool or mist cultures, as well as standard outdoor farming.

Edamame produced using the nutrient film technique formed more pods and seeds, with yields exceeding traditional methods. "Recent global warming and extreme weather events have raised concerns about reduced yields in open-field crop production. Our hydroponics technology offers a promising model for urban agriculture that is independent of climate conditions," said Professor Sano.

Chemical analysis showed edamame grown hydroponically with LED lighting contained greater amounts of sucrose and isoflavones, while maintaining health-relevant amino acids. The research team suggested that LED light may stimulate synthesis of bioactive compounds, leading to improved nutritional profiles. Taste analysis also indicated sweeter kernels from the hydroponic system.

Scalability further distinguishes this indoor method for high-protein crops. Edamame can be grown in vertically stacked layers, optimizing space efficiency and supporting expansion in urban environments where agricultural acreage is limited. With production untouched by outdoor seasons, plant factories may extend edible crop cultivation into cities, deserts, and even settings beyond Earth, providing stable food supplies.

"Our results demonstrate that growing delicious edamame anytime, anywhere is no longer just an ambitious idea but an achievable reality," said Professor Sano.

Research Report: Sustainable Edamame production in an artificial light plant factory with improved yield and quality