Editorial: Plant Biology for Indoor Vertical Farming: A Multi-Discipline Approach to Controlled Environment Agriculture

Paul PG Gauthier^1,2*Leo FM Marcelis³

• ¹The University of Queensland, Brisbane, Australia
• ²Queensland Alliance for Agriculture and Food Innovation, Saint Lucia, Australia
• ³Wageningen University & Research, Wageningen, Netherlands

Phosphorus, a crucial nutrient for plant growth, can become a limiting factor in CEA systems due to its potential for leaching. Westmoreland and & Bugbee (2022) demonstrated that excessive phosphorus application in Cannabis sativa did not improve yield or quality but significantly increased nutrient runoff, raising environmental concerns. Similarly, He et(2023) al. investigated nitrogen metabolism under varying light conditions, demonstrating that increased light intensity enhances nitrogen assimilation but also increases nitrate reductase activity and total nitrogen content. Nitrate Reductase is known to be a lightdependent enzyme (Deng et al 1991, Lillo 1994) and its positive response to increasing light intensity confirms its role in modulating nitrogen assimilation in photosynthetic leaves. These findings underscore the necessity of light-optimized fertigation strategies to maintain a balance between photosynthetic efficiency and nutrient use efficiency.Microbial solutions offer promising approaches for nutrient recovery and leachate utilization. Tan et al. (2022) explored the role of Trichoderma harzianum in phosphorus and nitrogen uptake, revealing that its efficacy is highly dependent on light conditions. Under high-light conditions, Trichoderma enhances nutrient uptake, but under low-light conditions, it may shift toward parasitism (further discussed after), competing with the plant for resources. These findings highlight the need for strategic integration of beneficial microbes within hydroponic nutrient management systems to optimize nutrient cycling and minimize inefficiencies Chloride, often viewed as a stress factor, is also critical for photosynthesis, osmotic balance, and ion homeostasis (White & Bradley 2001, Raven 2017 but see Li et al 2017). Fitzner et al . (2023) investigated chloride accumulation in halophytes and found that light regimes and salinity levels significantly influence chloride uptake and stress responses. Their results suggest that improper chloride management in hydroponic solutions can disrupt plant water relations and nutrient balance in salt-sensitive crops. Given the complexities of nutrient interactions in high-density CEA systems, adaptive fertigation models that integrate real-time nutrient monitoring (Lim et al 2024 but see Ahamed et al 2025), advanced mass balance (Langenfeld et al 2022) or microbial cycling strategies are necessary for optimizing plant growth and sustainability. Light management is a fundamental component of vertical farming, influencing plant growth, development, and resource use efficiency. The spectral composition, intensity, and duration of light exposure regulate key physiological processes, including photosynthesis, photomorphogenesis, and secondary metabolite production (Kaiser et al 2024) The spectral composition of light affects both photosynthetic efficiency and plant morphology. Van de Velde et al. (2023) demonstrated that far-red supplementation in butterhead lettuce enhanced light-use efficiency by promoting leaf expansion and photon capture rather than directly increasing photosynthesis. However, excessive far-red exposure led to reduced chlorophyll content and increased stress markers, indicating the need for precise control of spectral tuning. Similarly, Saito & and Goto (2023) investigated upward lighting strategies, showing that redistributing light within dense canopies improves net photosynthetic rates and carbon assimilation efficiency. These findings highlight the potential of spectral and spatial light optimization in mitigating shading effects in high-density cultivation.Light intensity and duration also impact nutrient assimilation and overall crop productivity. He et al . (2023) examined the effects of different light intensities and durations on Portulaca oleracea, demonstrating that increased light exposure enhanced nitrogen metabolism, root and shoot biomass accumulation, and nitrate reductase activity. However, continuous light exposure negatively affected photosynthetic efficiency, emphasizing the need for optimized photoperiod management. Fitzner et al. (2023) investigated spectral effects on halophytes and found that light quality significantly influenced pigment accumulation, stress tolerance, and overall metabolic stability under saline conditions. These findings underscore the necessity of dynamic, responsive lighting systems in vertical farming as highlighted in Kaiser et al (2024) and Abedi et al (2023). Precision spectral tuning, optimized light distribution, and adaptive photoperiod management can enhance resource-use efficiency, improve crop quality, and maximize productivity while minimizing energy expenditure. Integrating plant-microbe interactions in CEA presents a promising opportunity for improving nutrient efficiency, enhancing stress resilience, and optimizing plant health. Beneficial microbial inoculants, including fungi and bacteria, can promote plant growth through nutrient solubilization (Shahwar et al 2023), root architecture modification (Galindocastañeda et al 2022), and systemic resistance induction (Elnahal et al 2022). However, the success of microbial applications depends on environmental conditions such as light intensity, nutrient availability, and plant species specificity. Tan et al. (2022) examined Trichoderma harzianum in Nicotiana benthamiana under different light conditions, revealing that microbial symbiosis is a dynamic process influenced by environmental cues. Under high-light conditions, Trichoderma enhanced plant growth and nutrient uptake, but under low-light conditions, it became parasitic, reducing plant growth and phosphorus assimilation. These findings emphasize the importance of maintaining optimal light environments to preserve mutualistic relationships between plants and microbes.Microbial interactions also play a key role in nutrient cycling and leachate management in hydroponic systems. Trichoderma has been shown to improve phosphorus solubilization, aligning with Westmoreland &and Bugbee (2022)'s findings on phosphorus leaching in Cannabis sativa (see also HershkowitzHershkowitz et al 2025). Leveraging microbial solutions for phosphorus recycling could enhance sustainability in closed-loop hydroponic systems. The future of vertical farming lies in the continued refinement of multidisciplinary approaches that integrate plant biology, lighting optimization, nutrient recycling, microbial interactions, and automated environmental control. While current advancements have demonstrated the feasibility of high-efficiency indoor agriculture, several challenges remain in achieving widespread scalability and sustainability. The integration of artificial intelligence and machine learning for real-time climate control, precision fertigation, and automated plant phenotyping represents one of the most promising directions for improving system efficiency and reducing resource waste. Data-driven models combined with processbased models, like described by Abedi et al (2023) that predict plant growth responses to dynamic environmental variables could enable farms to fine-tune lighting, nutrient delivery, and CO₂ supplementation in ways that maximize yield while minimizing energy consumption.One area of interest for future research is the deeper exploration of plant-microbe interactions in controlled environments and hydroponic cultivations. While studies have shown that beneficial microbes such as Trichoderma harzianum can enhance nutrient uptake and stress resilience, their efficacy is often contingent upon environmental conditions. In some caseslike the one described by Tan et al (2022) -the mutualism can become parasitism. A more detailed understanding of the response of these interactions to varying light spectra, humidity, and nutrient availability will be essential in optimizing microbial applications for vertical farming.Additionally, environmental sustainability will be a key driver in the future of controlled environment agriculture. Future research should focus on drastic improvements in energy (light) use efficiency. Furthermore, integrating renewable energy sources such as solar or geothermal power into vertical farming operations could help mitigate the high energy costs associated with artificial lighting and climate control (Kaiser et al 2024). Closed-loop water and nutrient recycling systems will also play a crucial role in minimizing waste and improving overall efficiency. Advances in real-time sensor technology will allow for precise monitoring of plant physiological responses, enabling a level of control that enhances productivity while reducing environmental impact. This special issue of Frontiers in Plant Science showcases cutting-edge research that advances our understanding of plant biology in indoor vertical farming systems. It highlights that vertical farming research is not limited to plants grown in vertical farms but extends to the knowledge gained from plants cultivated under artificial conditions. Furthermore, it underscores the inherent complexity of integrating and interpreting multi-parametersincluding light, nutrients, biophysics, and microbiome interactions. This complexity makes vertical farming challenging to operate but presents an unprecedented opportunity to optimize our food system by maximizing resource efficiency and crop productivity.By integrating multi-disciplinary research, vertical farming can evolve into a truly sustainable, high-efficiency food production system. Advancements in nutrient optimization, light management, and plant-microbe interactions provide a foundation for future innovations. The incorporation of real-time monitoring technologies, precision fertigation, and adaptive climate control will be essential in driving the next generation of controlled environment agriculture, ensuring food security in a changing global landscape.