Internet of things-enabled plant factories in controlled environment agriculture for resource-efficient and climate-resilient urban farming

Plant factories represent an advanced form of controlled environment agriculture (CEA), enabling year-round, resource-efficient crop production through precise environmental control. As global food security faces challenges due to shrinking arable land and water scarcity, developing innovative, climate-resilient and resource-efficient agricultural systems is crucial. This study evaluates the productivity, resource efficiency, and economic viability of pak choi cultivation across three production systems: soil-based (SB), greenhouse (GH) and IoT-enabled plant factories (IoT-PFs) over three growing seasons (2022-2024). Among these, IoT-PF demonstrated superior performance, maintaining optimal temperature (18-23°C), relative humidity (55-65%), and CO₂ levels (250-800 ppm), thereby optimizing photosynthetic efficiency and biomass accumulation. Its advanced nutrient management stabilized pH (5.5-6.5) and electrical conductivity (1.81-2.49 dS m⁻¹), improving nutrient uptake. IoT-PF also recorded the highest antioxidant activity (45.84%) and glucosinolate content (3.06 µmol g⁻¹), while minimizing nitrate accumulation, thereby enhancing nutritional quality. Economically, while SB incurred the lowest fixed costs, it yielded a moderate benefit-cost (B:C) ratio of 1.42. GH improved profitability with a B:C ratio of 2.20 but required higher investment. Despite its higher initial and operational costs, IoT-PF delivered the best economic returns, driven by superior resource-use efficiencies, including nutrient-use efficiency (76.14 kg kg⁻¹ fertilizer) and water-use efficiency (59.86 kg m⁻³). These findings highlight IoT-enabled plant factories as a climate-resilient and resource-efficient CEA solution capable of enhancing yield and sustainability through precision control. Wider adoption will depend on cost-effective design, renewable energy integration, and scalable system architectures.