Enhancing resource-use efficiency and crop productivity in vertical farming: strategies of crop diversification, density optimization, and dynamic lighting

Vertical farming (VF) enables climate-independent urban food production with high efficiency in land, water, and fertilizer use. However, adoption is constrained by high capital and energy costs, with lighting often accounting for up to 80% of consumption. This research evaluated strategies to improve productivity and resource-use efficiency through crop diversification, optimized planting density, and dynamic lighting. Expanding VF beyond leafy greens and herbs to fruiting and staple crops, lettuce achieved the highest annual marketable biomass (73.2 kg FW m⁻² y⁻¹), 46% higher than arugula and 35% higher than basil, and the highest energy use efficiency (EUE, 46.7 g FW kWh⁻¹)—3.5- and 58-fold greater than tomato and corn, respectively, and up to 1.8-fold higher than arugula and basil. Optimizing planting density for lettuce and basil showed that the highest density (680 plants m⁻²) enhanced fresh yield, leaf area index, light use efficiency, and light-energy use efficiency compared to the lowest density (123 plants m⁻²). Lettuce increased +207% (FW), +227% (LAI), +142% (LUE), and +206% (L-EUE), while basil increased +312%, +316%, +291%, and +309%, respectively. Dynamic LED lighting experiments revealed that 25% and 38% blue light increased lettuce fresh yield by 50–60% without affecting dry weight, improved leaf hydration, enhanced light-use efficiency by up to 63%, and reduced lighting costs by 40%. Overall, lettuce is the most energy-efficient VF crop; high planting densities enhance area-based productivity without significant quality loss; and optimized blue-light management can save 20–40% of energy with minimal yield penalty. Overall, lettuce is the most energy-efficient VF crop; high planting densities improved area-based productivity without major quality loss, and dynamic blue-light management can achieve 16–40% energy savings with minimal yield penalty. These results provide practical, evidence-based strategies to enhance the sustainability of vertical farming systems.