Approximately one-quarter of the Earth's surface, accounting for nearly 27%, comprises habitable land, while the remaining vast majority is covered by water, totaling about 73%. Of this habitable land, only three-quarters are deemed productive, with the rest consisting of challenging terrains such as high mountains and deserts. Human activity has already repurposed around 57% of this productive land for agriculture, often at the expense of forests and grasslands, which make up the remaining 43%.(1)

Urbanization is a rapidly increasing global phenomenon, with forecasts suggesting that over 60% of the world's population will inhabit cities by 2030. Concurrently, the global population is anticipated to rise from 7.6 billion to 8.6 billion by 2030, and further climb to 9.8 billion by 2050, ultimately reaching 11.2 billion by 2100. This accelerated urbanization is exacerbating the strain on the limited available land resources, leading to a gradual yet continuous reduction in cultivated land worldwide. (1)

Given the circumstances outlined above, the concept of year-round cultivation of substantial amounts of nutritious food through vertical farming in confined spaces presents itself as a groundbreaking approach. Vertical farming typically entails the cultivation of crops, predominantly vegetables, ornamentals, and herbs, on layered indoor shelves utilizing artificial lighting and nutrient solutions, with minimal reliance on natural sunlight and soil.The availability of cultivable land has emerged as a limiting factor, with land prices soaring in recent years. The transportation of food from rural production areas to urban centers exacerbates this issue, particularly for perishable and semi-perishable goods, notably horticultural crops with shorter shelf lives. One potential solution to mitigate these challenges is to produce food within cities themselves, utilizing residential buildings, rooftops, public spaces, and similar areas. While current advanced agricultural practices strain finite resources, including land, water, and energy, the innovative technology of vertical farming is anticipated to alleviate much of this pressure. (2)

A Brief History of Vertical Farming

While indoor farming has made rapid inroads in recent years, its history stretches back millennia.

Ancient Prototypes: The hanging gardens of Babylon, mentioned by the ancient Greeks, date back 2,500 years and are considered the prototype of vertical farming.
Early Concepts: In 1915, geologist Gilbert Ellis Bailey first used the term "vertical agriculture," though his concept differed greatly from the contemporary view, involving the use of explosives to plant crops deeper in the ground.
Mid-Century Development: Austrian engineer Othmar Ruthner built several greenhouse towers utilizing hydroponics in the 1960s.
Modern Breakthrough: The concept struggled to gain widespread traction for a long time due to the high energy and maintenance costs involved. However, VF finally gained a foothold in the early 2000s with the development of multi-layered plant production systems using artificial lighting in America and Japan. Awareness and popularity have since grown rapidly worldwide.

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Engineering Components and Growing Principles

Vertical farming structures must prioritize safety, efficiency, durability, aesthetics, affordability, and ecological sustainability. These structures rely on critical engineering components to provide controlled microclimates.

Environmental Control: Key components include HVAC (heating, ventilation, and air conditioning) systems, which are necessary for humidity control but can be expensive and energy-intensive. CO2 distribution and environmental uniformity are also crucial.
Lighting: Intelligent LED lighting is vital for optimal crop-climate interaction, with factors like photoperiod, light intensity, and spectrum playing key roles in growth and quality. However, the energy-intensive nature of lighting and HVAC systems constitutes a substantial portion of operational costs.
Growing Media: Traditional field soils often fail to meet the requirements for container plant production. An effective growing medium often involves a mixture of coco peat, vermiculite, and perlite in a 3:1:1 volume ratio. To reduce costs, standardizing locally available inert media is essential.

All vertical farming systems utilize one of three main soilless growth principles:

Hydroponics: This is the most widely used principle, involving growing crops without soil. The plant roots are suspended in a precisely controlled, nutrient-rich solution. Hydroponics features low water consumption, precise nutrient addition, and low disease impact.
Aeroponics: A variant of hydroponics, this term was coined by NASA. Plants grow in air or mist that is sprayed onto their roots frequently (several times an hour). Aeroponics provides better root aeration, potentially allowing plants to grow faster. However, aeroponics requires precision sensor technology, a strict dosing regime, and is highly vulnerable; plants can die within an hour if irrigation fails.
Aquaponics: This system combines aquaculture (cultivation of organisms in water) and hydroponics. Fish are grown, and their waste is converted into food for the plants. While aquaponics is water-efficient and diversifies the revenue model, it requires a broad knowledge base (aquaculture, hydroponics, microbes, and nutrient levels) and a long start-up phase for microbial stabilization.

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Upcoming Vertical veggie ventures: In India

Mushroom Production:

Mushrooms thrive without extensive light and serve as a nutritious food source that efficiently recycles organic waste. Mushroom producers have been pioneers in vertical farming, predating plant producers (3).

One such example is Ayush and Rishabh Gupta from Agra who were studying overseas when the COVID-19 outbreak hit them. The duo chose to return home and establish A3R Mushroom Farms and Gupta Organic Farms, which today produces 40 tonnes of organic mushrooms per month and earning 7.5 crores yearly (4).

Garden Wall:

Garden walls, a form of vertical farming, enjoy global popularity, including in India. Vertical gardens adorn public spaces such as airports, metro pillars/stations, river bridges, and elevated roads in many Indian metro cities. These gardens typically feature multicolored evergreen foliage plants, with some also incorporating flowers and leafy vegetables. (5). Bangalore Airport has implemented a garden wall as part of its innovative sustainability initiatives. The garden wall, adorned with lush greenery and vibrant plants, serves multiple purposes beyond aesthetics. (6)

The architectural and engineering components involved in vertical farming.

Vertical farming structures must ensure safety, efficiency, durability, aesthetics, affordability, and ecological sustainability. These structures should address the physiological and behavioral needs of the intended organisms, providing controlled microclimates and access to appropriate nutrition. Critical engineering components include HVAC systems, environmental uniformity, CO2 distribution, shelf design, and intelligent lighting for optimal crop-climate interaction. Factors such as photoperiod, light intensity, and spectrum play vital roles in crop growth and quality, with LED lighting being particularly significant. However, the energy-intensive nature of lighting and HVAC systems constitutes a substantial portion of operational costs. The design of growing beds aims to maximize space utilization while facilitating ease of irrigation and other essential operations.The crucial element in vertical farming is the depth or limited volume within containers. Traditional field soils often fail to meet the requirements for container plant production. A mixture of coco peat, vermiculite, and perlite in a 3:1:1 volume ratio has been identified as an effective growing medium. However, in order to reduce costs, it is essential to standardize locally available inert media. (7)

Perspective on Vertical Farming in India.

Status and Challenges:

Currently, vertical farming technology in India remains expensive, resulting in higher produce costs compared to conventional geoponic agriculture. Consequently, it faces challenges in competing with market prices. However, there is a significant market for vertical farming produce, primarily in Indian metros, particularly among high-end hotels and affluent individuals.

Research and Development (R&D) and human resource development, crucial for any successful venture, are still in their infancy concerning vertical farming technology in India. There is ongoing debate over whether the produce should be classified as 'organic' or 'inorganic'. Major food crops are not yet feasible for vertical farming due to various limitations. (8)

Why is it a feasible alternative for a country like India?

Despite these challenges, vertical farming has the potential to yield ten times more produce per unit area compared to traditional agriculture. It offers the prospect of integration into present and future food production and consumption lifestyles. Additionally, it is a sustainable technology with several benefits, including reduced land, water, fertilizer, pesticide usage, and other inputs. Vertical farming can be implemented in various settings, including lakes, and even kitchens (for microgreens), making it adaptable to diverse human living and working environments. (7)

Vertical farming presents a compelling solution for a country like India due to its potential to enhance agricultural productivity while conserving resources. With over 95% water efficiency compared to traditional methods, it promises significant water savings, crucial for a nation facing water scarcity with only 4% of the world's water resources (9). Methods like cocoponics, which repurpose agricultural residues into compost, not only contribute to sustainability but also create new revenue streams, particularly benefiting farmers in marginal rural areas.

Furthermore, the absence of pesticides in vertical farming leads to healthier produce, positively impacting public health. This approach not only ensures fresher and safer food but also aligns with India's ambitious goals of achieving carbon neutrality in food production. Additionally, vertical farming has the potential to generate employment opportunities and foster innovation, particularly for agricultural students. By leveraging this technology, India can unlock new pathways for economic growth and agricultural development while addressing pressing environmental and social challenges.(9)