Comparative Study on Resource Efficiency and Environmental Impacts in Vertical Hydroponic Controlled–Environment and Crop Evapotranspiration–Based Drip Irrigation Systems for Bok Choy Cultivation ( <scp> <i>Brassica rapa</i> </scp> subsp. <i>chinensi

ABSTRACT Conventional farming systems face significant challenges due to resource depletion from climate change and population growth. Alternative techniques like soilless culture (hydroponics) can produce high yields using limited space, water and no soil. This study evaluated the efficacy of a nutrient film technique (NFT)–based vertical hydroponic system for cultivating bok choy, comparing it with conventional soil‐based cultivation. The experiment was conducted in a controlled greenhouse at the Centre for Protected Cultivation Technology, Indian Agricultural Research Institute, New Delhi, India. The hydroponic system used a standard Hoagland solution, while soil‐based cultivation applied a recommended dose of fertilizer (76:46:83 kg N:P:K) and 100% crop evapotranspiration (ETc) via drip irrigation. Results showed the vertical hydroponic system outperformed conventional methods, with shorter growth periods, better growth parameters and higher photosynthetic activity. Over the 2022–2023 two‐season cycle, hydroponics yielded 3.5–4 times more production and 3 times greater nutrient efficiency. Its water use efficiency (WUE) was 69% higher, significantly reducing water use. Additionally, it required 65% less space than traditional farming. This study demonstrates that vertical hydroponics is a sustainable, space‐efficient solution for urban agriculture, offering higher yields, reduced water usage, improved efficiency and space savings compared to conventional methods.