More than half the world’s population
(approximately 4 billion) live in urban areas. As people continue to migrate
from rural to urban areas, the global urban population is anticipated to reach
around 7 billion people by 2050. The growing urbanization activities could pose
a threat to food security since they are likely to reduce the availability of
valuable croplands, which are necessary to produce an adequate amount of fresh
food for the rising population. According to a study, the global urban expansion
would result in approximately 1.8-2.4% loss of global croplands and a 3-4%
reduction in crop production by 2030. Besides, changing climatic conditions
could put a strain on Earth’s resources, creating a serious demand-supply chain
issue. Therefore, sustainable development and growth of the urban population
require a great need for innovative farming methods to meet the demand for more
food and more land to grow food. Vertical farms are at the forefront of the
controlled environment agriculture segment and rapidly take over traditional
farming methods for producing eco-friendly products in metropolitan areas.
Vertical
farming (VF) or
high-rise farming essentially means indoor farming in vertical greenhouses with
regulated growing conditions, offering a favorable environment for crops to
thrive, regardless of the weather conditions outside. This kind of agriculture
practice has the potential to produce food year-round and thus maintain a
steady flow of products for consumers as well as ensure consistent income for
growers. Besides, vertical farming provides an array of advantages such as
urban water recycling, fewer farm inputs, low crop failure risks, restored
farmland, energy conservation, reduced soil erosion and air pollution, urban
beautification, and ecological sustainability. Due to the significant benefits
of vertical farming over traditional methods of agriculture, many countries
have started implementing the innovative farming system on a large scale.
How Does Vertical Farms Work?
In vertical farming setup, plants are arranged
in layers that can reach several stories high. For this purpose, multi-story
buildings (also known as farm scrapers) are utilized to produce vegetables in a
space-saving manner. Modern technologies like artificial intelligence, machine
learning, and Internet of Things are utilized to provide adequate conditions
for crops and every parameter that affects the growth of crops is closely
monitored. Workers take preventive measures to eliminate the risk of pest
infestations that could damage crops. Smart sensors monitor technical variables
such as temperature, light, carbon dioxide, oxygen, humidity, precipitation,
nutrient concentration, pest control, and irrigation whereas advanced imaging
technologies measure plant growth, temperature, and other factors. All these
modern technologies are a part of controlled environment systems (CES), which
have proven beneficial to grow leafy greens, herbs, microgreens, and vegetables
like pepper, tomatoes, etc. Some of the essential components of controlled
environment systems include:
Dosing systems are utilized in
vertical farms to provide optimal nutrients to the plants and monitor nutrient
solutions. Automated dosing systems are connected to peristaltic pumps that
suck the required dose of nutrients and dispense them into the reservoir, which
further supplies a precise amount of nutrients to each plant. Probes placed
inside the reservoir continuously provide information about pH and EC levels,
nutrient concentration, water temperature, etc. More control over nutrient
solution with automated dosing reduces the risk of plant shock or stunted
growth.
The crops grown in vertical farms
need to comply with international food safety regulations. Hence, adopting rigorous
sterilization and disinfection strategies in indoor farming is necessary to
ensure the production of pesticide-free crops throughout the year. Common
sterilization methods include chemical disinfection, UV sterilization, and
ozone sanitation. Chemical disinfection involves sterilizing floors,
transporting equipment, and other tools with hypochlorite and hydrogen
peroxide. UV sterilization is a chemical-free method involving UV emitting
light to destroy micro-organisms invisible to the naked eyes, such as fungi,
viruses, and other pathogens. Ozone sanitation is performed to clean air in
indoor farms, killing fungi and other microorganisms.
Artificial light used in vertical
farming is the crop’s sole source of illumination, so the grower needs to do a
great deal of research to control the light, intensity, and duration to ensure
plant growth and generate a good yield. Every stage of plant growth requires
different lighting; thus, many companies provide light formulations to vertical
farmers to increase biomass production and enhance flavor. Generally, three
kinds of lights are used for vertical farming such as LED lights, high-pressure
sodium lights, and fluorescent grow lights. LED lamps are one of the most
common choices since they generate less heat than high-pressure sodium (HPS)
grow lights, lasts long, and conserve energy. HPS grow light promotes flowering
and fruiting but can slow down plant growth during the early stage of
development and affect output. Also, HPS lights emit a lot of heat since they
contain mercury, which can prove to be hazardous for health. Fluorescent lights
are highly efficient since they produce less heat and are specially designed
for indoor farming.
Vertical farmers need to maintain the ideal CO2
concentration (1000 parts per million) in the indoor farming set up to promote
rapid plant growth and increase plant productivity. Some common type of CO2
enrichment techniques involves CO2 gassing, compressed CO2, and misting aqueous
CO2 through delivery solutions. CO2 gassing is a conventional method of
producing carbon dioxide gas by burning propane or natural gas into the plant
growing area. Another method is to transform compressed CO2 into gaseous form
and inject it into the growing chamber for a certain time frame. CO2 delivery
systems are one of the cost-effective methods of infusing gas directly as
microdroplets into the plant’s leaves via an overhead misting system. Besides,
vertical farms must maintain proper airflow, reducing the build-up of heat and
humidity in the growing area to reduce the risk of infection. Generally,
airflow transducers are used and located at the farm’s entrance and exit points
to assess air velocity continuously and transmit data to the terminal.
Additionally, dehumidifiers and dehumidification systems are utilized to
eliminate excess moisture and maintain optimal humidity in the growing area.