A Comprehensive Review of Lettuce Cultivation in Unconventional Systems: Pioneering Sustainable Food Production

As global populations surge toward 9.7 billion by 2050, traditional agriculture faces mounting pressures from climate change, land degradation, and water scarcity. Lettuce (Lactuca sativa L.), a high-value leafy crop, is at the forefront of innovative cultivation systems designed to address these challenges. Unconventional systems-such as hydroponics, aeroponics, aquaponics, and vertical farming-offer transformative solutions to enhance yield, resource efficiency, and food security. This review investigates the current global status of lettuce cultivation in these systems, emphasizing their potential to revolutionize urban agriculture and sustainable food production. Literature was sourced from peer-reviewed journals (e.g., PubMed, ScienceDirect, MDPI), conference proceedings, and institutional reports published between 2018 and 2025, using keywords like "lettuce," "unconventional cultivation," and "controlled-environment agriculture." A systematic analysis of 87 studies revealed that hydroponics and vertical farming significantly outperform traditional soil-based methods, yielding up to 6.88 kg m?² in controlled environments. Key parameters, including nutrient delivery, lighting, and environmental control, were correlated with growth outcomes, highlighting the synergy between technology and biology. These systems reduce water usage by up to 90% and eliminate soil-borne diseases, making them critical in water-scarce and urbanized regions. However, challenges like high energy costs and microbial risks in organic systems persist. This review proposes integrating AI-driven monitoring and renewable energy to optimize these systems, suggesting future research into cultivar-specific responses and low-cost solutions for small-scale farmers. By redefining agricultural paradigms, unconventional lettuce cultivation can play a pivotal role in ensuring global food resilience.