3.2.1. Automated Vertical Farming Systems
Automation in vertical farming addresses challenges posed by high labor costs, a lack of skills, and the demand for increased efficiency. The reduction of human involvement not only cuts disease risks but also enhances safety and productivity in vertical farming systems [43,117]. Various automation applications play pivotal roles in shaping the future of vertical farming, including seeding, transferring seedlings to vertical beds, automated watering, lighting, fertilization, crop monitoring via visual systems, automated harvesting, and bed cleaning and reloading [118]. These technologies contribute to cost reduction, provide essential data for optimized solutions, and facilitate IoT-connected farming for precise monitoring of and feedback on growth conditions.Automation in vertical farming addresses challenges posed by high labor costs, a lack of skills, and the demand for increased efficiency. The reduction of human involvement not only cuts disease risks but also enhances safety and productivity in vertical farming systems [31][83]. Various automation applications play pivotal roles in shaping the future of vertical farming, including seeding, transferring seedlings to vertical beds, automated watering, lighting, fertilization, crop monitoring via visual systems, automated harvesting, and bed cleaning and reloading [84]. These technologies contribute to cost reduction, provide essential data for optimized solutions, and facilitate IoT-connected farming for precise monitoring of and feedback on growth conditions.
The emergence of mini vertical farm systems, suitable for home or small business use, highlights the integration of automation. These systems autonomously manage climate, hydroponics, LED lighting, and growth via apps. However, the reliance on manual harvesting and planting currently limits full automation and potential yield optimization [119]. Conversely, fully automated vertical farming systems cover a range of processes, including sowing, planting, light control, fertilization, harvesting, and cleaning, demonstrating the capability of intelligent software-driven setups [120].The emergence of mini vertical farm systems, suitable for home or small business use, highlights the integration of automation. These systems autonomously manage climate, hydroponics, LED lighting, and growth via apps. However, the reliance on manual harvesting and planting currently limits full automation and potential yield optimization [85]. Conversely, fully automated vertical farming systems cover a range of processes, including sowing, planting, light control, fertilization, harvesting, and cleaning, demonstrating the capability of intelligent software-driven setups [86].
The challenges of traditional agriculture have driven the rise of high-tech greenhouses and indoor vertical farms. These developments have led to the adoption of smart technologies using sensors, big data, robotics, and AI for efficient cultivation. In vertical farming, automation varies from manual to advanced systems, impacting labor and energy efficiency. The StackGrow technology of iFarm, Helsinki, Finland [122] cuts labor by 30% and energy by 33%. Around 28.4% of vertical farms use IT-driven automation, with more adoption planned [131]. Vertical farms face challenges in profitability due to their higher electricity usage for lighting, while greenhouses demand increased costs for climate regulation and have more land requirements. Vertical farms require heating and cooling systems for precise environmental control, giving them an edge in product quality and consistency over greenhouses.The challenges of traditional agriculture have driven the rise of high-tech greenhouses and indoor vertical farms. These developments have led to the adoption of smart technologies using sensors, big data, robotics, and AI for efficient cultivation. In vertical farming, automation varies from manual to advanced systems, impacting labor and energy efficiency. The StackGrow technology of iFarm, Helsinki, Finland [87] cuts labor by 30% and energy by 33%. Around 28.4% of vertical farms use IT-driven automation, with more adoption planned [88]. Vertical farms face challenges in profitability due to their higher electricity usage for lighting, while greenhouses demand increased costs for climate regulation and have more land requirements. Vertical farms require heating and cooling systems for precise environmental control, giving them an edge in product quality and consistency over greenhouses.
3.2.2. Robotic Vertical Farming Systems
The integration of robotic systems in vertical farming is increasingly essential due to the physical and economic limitations of human labor. The high-density cultivation and physical constraints of vertical structures make human labor impractical and inefficient. Robotic systems are skilled at complex tasks like precise harvesting, maintaining a controlled environment, minimizing human error, and providing the consistency needed for optimal crop yields and quality. Robotic vertical farming systems address the challenges with precision and efficiency, particularly in mitigating the reliance on human labor. As labor costs constitute a significant portion of total expenses (25–30%), robots emerge as efficient, consistent, and precise performers across various tasks, effectively mitigating both fixed and operational costs. Incorporating smart technologies enhances automation and robotics, offering improvements in resource efficiency, productivity, and sustainability in controlled-environment agriculture.
Autonomous robotic platforms equipped with versatile sensors on vertical farms can be crucial in advancing these goals [115], while robotic applications for planting and harvesting are present but not fully effective due to some challenges. Many vertical farming systems still rely on manual labor due to robot limitations in handling diverse crops and complex canopies. Existing robots are slow, damage crops, and struggle with recognition, and their safety alongside humans must be ensured while preserving plant integrity [43]. Autonomous robotic platforms equipped with versatile sensors on vertical farms can be crucial in advancing these goals [82], while robotic applications for planting and harvesting are present but not fully effective due to some challenges. Many vertical farming systems still rely on manual labor due to robot limitations in handling diverse crops and complex canopies. Existing robots are slow, damage crops, and struggle with recognition, and their safety alongside humans must be ensured while preserving plant integrity [31].
Avgoustaki et al. [115] demonstrated how low-altitude multispectral images can be used to spot plant growth and quality, thereby curtailing nutrient and water consumption. This noninvasive visual technique is ideal for autonomous robots on vertical farms. This method could greatly ease the automation of herb and vegetable cultivation on indoor vertical farms, substantially cutting labor-related production expenses. Marchant and Tosunoglu [137] suggested a robot for planting and harvesting on the CityCrop automated indoor farm. A camera that detects ripe crops is mounted on a manipulator that also plants, controlled by a proposed algorithm. A leading Dutch vertical farm, Future Crops, uses data-driven technology and a “plant whisperer” approach [138] to optimize growth conditions. It employs automation, powered partially by 16,000 rooftop solar panels, to regulate factors like humidity, temperature, and light. With 8000 mAvgoustaki et al. [82] demonstrated how low-altitude multispectral images can be used to spot plant growth and quality, thereby curtailing nutrient and water consumption. This noninvasive visual technique is ideal for autonomous robots on vertical farms. This method could greatly ease the automation of herb and vegetable cultivation on indoor vertical farms, substantially cutting labor-related production expenses. Marchant and Tosunoglu [89] suggested a robot for planting and harvesting on the CityCrop automated indoor farm. A camera that detects ripe crops is mounted on a manipulator that also plants, controlled by a proposed algorithm. A leading Dutch vertical farm, Future Crops, uses data-driven technology and a “plant whisperer” approach [90] to optimize growth conditions. It employs automation, powered partially by 16,000 rooftop solar panels, to regulate factors like humidity, temperature, and light. With 8000 m 2 of potent of potential cultivation space, it is set to become one of Europe’s largest and most globally significant vertical farms [23].
3.2.3. Vertical Farming with Drones
The convergence of vertical farming and drone technology marks a new era of agricultural innovation, redefining the possibilities for crop cultivation in controlled environments. In the face of global challenges in food security, resource scarcity, and environmental sustainability, the fusion of these two cutting-edge fields offers immense potential to revolutionize how we grow and manage crops. The space-efficient and climate-controlled setups of vertical farming complement the capabilities of drones, which provide aerial precision and data-driven insights. This transformative synergy addresses critical agricultural challenges while opening new frontiers in sustainable food production.
i
al cultivation space, it is set to become one of Europe’s largest and most globally significant vertical farms [35].
3.2.3. Vertical Farming with Drones
The convergence of vertical farming and drone technology marks a new era of agricultural innovation, redefining the possibilities for crop cultivation in controlled environments. In the face of global challenges in food security, resource scarcity, and environmental sustainability, the fusion of these two cutting-edge fields offers immense potential to revolutionize how we grow and manage crops. The space-efficient and climate-controlled setups of vertical farming complement the capabilities of drones, which provide aerial precision and data-driven insights. This transformative synergy addresses critical agricultural challenges while opening new frontiers in sustainable food production.
iFarm
[132][91] is effectively experimenting with computer vision technology to enable the monitoring of plant-growth stages on vertical farms using UAVs. Their research focuses on methods to assess plant weight through images and determine optimal lighting modes based on power consumption and leaf-growth speed. They are also exploring the use of autonomous drones to enhance data-collection speed and improve the capabilities of the neural network
[142][92]. Corvus Drones
[143][93] has introduced an innovative autonomous drone tailored for horticulture, specifically designed for tasks like seed germination and flower detection. Growers can easily program flight routes via a web app, assign tasks to drones, and enjoy autonomous execution, including recharging without human intervention. This technology offers rapid reporting, cost savings, improved labor planning, and reduced crop risks.
3.3. AI-Based Research Trends
3.3. AI-Based Research Trends
AI is an efficient computational tool that enables machines to learn from experience, adapt to new data, and execute tasks similarly to humans
[146][94]. The success of vertical farming is intricately tied to technology, with automation and AI at the forefront of transformative innovations in food cultivation
[147][95]. AI, powered by machine-learning algorithms, is employed to analyze information and render decisions. In the context of vertical farming, AI has the capability to monitor plant growth, optimize environmental parameters, and maximize resource usage, including water and fertilizers
[146][94]. By examining data from physical and imaging sensors, AI identifies patterns and forecasts plant health and development, empowering growers to make informed decisions and maximize crop yields
[148][96].
The adoption of emerging technologies is essential for vertical farming in order to mitigate costs and reduce environmental impacts. Vertical farms are embracing innovative solutions to address these challenges
[95][66]. AI plays a significant role in monitoring crop growth in vertical farming, leading to improved production outcomes. For instance, in vertical farming using artificial lighting, color images are utilized for plant phenotyping, enabling continuous monitoring and optimization of crop development
[102][73].
To assess leaf stress levels, Story et al.
[151][97] utilized a machine-vision system to detect calcium deficiency in lettuce cultivated in greenhouses. They applied a gray-level co-occurrence matrix (GLCM) to capture textural characteristics and dual segmented regression analysis to distinguish nutrient-deficient plants from healthy plants. Hao et al.
[152][98] developed a multiscale hierarchical convolutional neural network (MFC-CNN) architecture and evaluated its performance across different stress levels.
Utilizing advanced deep-learning techniques, Wu et al.
[155][99] employed DeepLabV3+ models with various backbones, and they achieved an impressive 99.24% pixel accuracy in segmenting abnormal leaves (yellow, withered, and decayed) in hydroponic lettuce. Hendrawan et al.
[156][100] explored water stress in cultured Sunagoke moss by inducing different conditions in a growth chamber, and they compared deep-learning models for classification. The most effective model, ResNet50, trained with a RMSProp optimizer, achieving 87.50% accuracy.
4. Global Industrial and Market Trends
4.1. Global Status
Vertical farming has gained momentum globally as an innovative and sustainable approach to agricultural production. Offering the unique ability to cultivate crops in vertically stacked layers, this cutting-edge technique is reshaping traditional farming practices and making significant progress in meeting the growing demands of a rapidly changing world
[173][101]. Global food consumption and population growth are driving the need for innovative food-production methods. Vertical farming, with its ability to produce crops efficiently in controlled environments, is addressing this demand, contributing to the growth of controlled-environment food production
[174][102].
Globally, there is a growing number of companies engaged in small-scale vertical farming ventures. In Europe, Asia, and North America, countries have adopted commercial vertical farming for high-yield crop cultivation in controlled indoor settings
[27][103]. Unlike traditional methods, vertical farming involves monitoring and controlling all aspects, including artificial lighting, to maximize space efficiency
[14,175][10][104]. These farms, which can be found underground, on rooftops, or in abandoned spaces of urban areas, employ distinct technologies for specific microenvironments, with a focus on leafy vegetable production
[176][105]. The regions leading the adoption of vertical farming are East and Southeast Asia and North America, including China, Japan, Singapore, South Korea, the USA, and Canada
[33][19].
4.2. Industry and Market Trends in Asia
Vertical farming has gained significant attention in Japan as a solution to the country’s agricultural challenges. In 2015, Japan’s smart agriculture market was valued at less than USD 90 million, but it is predicted to exceed USD 450 million by 2026
[177][106]. Over 200 vertical farms in Japan are growing vegetables like tomatoes, bell peppers, lettuce, and broccoli. In 2019, Japan led the world in plant factories equipped with artificial light (PFALs). Tokyo-based companies like Spread Co., Ltd., Kyoto, Japan and Mirai Co., Ltd., Gifu Prefecture, Japan produce thousands of heads of lettuce daily. Techno Farm Keihanna, operated by Spread, uses fully automated labor and yields 30,000 heads of lettuce daily. Mirai utilizes 17,500 LED lights to produce 16,000 heads of lettuce daily. These farms are reducing food waste, boosting the domestic vegetable supply, reducing imports, and aiding disaster-stricken regions while exporting their technology.
In China, there are approximately 250 active vertical farming sites, and the number is steadily rising
[181][107]. SANANBIO, a prominent leader in Chinese vertical farming, has successfully cultivated over 300 varieties of leafy greens, fruits, medicinal herbs, and edible flowers within their facilities
[182][108]. AgriGarden, established in 2002 as a modern agricultural supply-chain service provider in Beijing, offers comprehensive support, from project consultancy to operations, for urban agriculture and vertical farms
[176][105]. JingDong Group partnered with Mitsubishi Chemical Holdings in 2018 to create a vertical farm in TongZhou, Beijing, that conserves water and has achieved zero emissions. BEO Technology Group, known for electronic components, has a 4500 m
2 artificial light-based plant factory in Beijing that utilizes AI technology for smart cultivation and monitoring
[183][109]
4.3. Industry and Market Trends in the USA
The vertical farming market in the USA is on a strong growth trajectory, projected to reach approximately USD 3.21 billion in 2023 and expand to USD 5.37 billion by 2028. This growth corresponds to a compound annual growth rate (CAGR) of around 10.80% during the forecast period of 2023 to 2028
[191][110]. The US vertical farming market employs various growth mechanisms, including aeroponics, hydroponics, and aquaponics. It includes various structural approaches, such as farms within buildings and vertical farms housed in shipping containers. Additionally, a wide range of crops are cultivated, from fruits and vegetables to herbs and microgreens, flowers, ornamentals, and various other crop types
[191][110].
4.4. Industry and Market Trends in Europe
In Europe, the term “vertical farm” is preferred over “plant factory” to describe a facility that uses vertically stacked or inclined shelves for intensive plant cultivation
[200][111]. European vertical farms have witnessed rapid growth in recent years, despite starting on a small scale. Several factors are driving this expansion, including reduced costs for LED lighting; growing consumer demand for fresh, healthy, locally grown produce with minimal environmental impact; and the repurposing of vacant office buildings from the 2007–2008 financial crisis. The supply sector supporting vertical farms has also expanded, with both startups and established greenhouse-industry suppliers contributing to this growth. However, there remain uncertainties regarding the cost effectiveness, scalability, and environmental sustainability of intensive vertical farming
[201][112]. The initial investment in vertical farming can be as much as 10 times higher per square meter compared to high-tech greenhouses, while operational costs per square meter are estimated to be two and a half to five times higher than those of Dutch greenhouses
[35][23].
4.5. Innovative Concepts for Upcoming Vertical Farms
Numerous proposals for multistory vertical farms remain conceptual due to economic infeasibility. Nevertheless, certain companies are earnestly pursuing visionary concepts and are nearing implementation. Vertical farming, a dynamic and constantly changing industry, has witnessed bankruptcies, like Urban Farmers (Netherlands) in 2018 and Plantagon (Sweden) in 2019, while some businesses have launched or expanded their operations
[35][23].
Sasaki Architects
[208][113] envisions a groundbreaking 100-hectare Sunqiao Urban Agriculture District in Shanghai, China, as a pioneering national agricultural zone. The plan elevates the district’s significance by integrating food networks, vertical farming, research, education, civic areas, and markets. This innovative integration fosters hyperlocal consumption, allowing residents to procure produce from their own buildings, which promotes sustainability. In that regard, Despommier
[27][103] suggested that such buildings adopt circular economy features like rainwater harvesting and solar panels, which would reduce water use and waste, particularly in consistently sunny regions.
5. Conclusions
Vertical farming is a modern agricultural approach that offers exceptional space efficiency, in contrast to conventional farming methods that often result in water wastage and land degradation. The key advantages of vertical farming include the recirculation of freshwater to minimize waste, the optimization of growth conditions for steady year-round harvests, and the ability to sidestep seasonal limitations. These urban-based farms employ advanced technologies to reduce costs by decreasing the need for transportation and labor expenses. However, it is crucial to acknowledge that the realization of vertical farming within urban domains is accompanied by a set of intricate challenges that require careful consideration and strategic resolution.
Figure 146 provides a concise overview of the prospects and challenges associated with vertical farming in sustainable food production.
Figure 146. Prospects and challenges of sustainable food production in an urban area.