This report has examined how Urban farming has become a
major part of the global agricultural industry, as populations increase and the
food sector is required to generate new systems which can keep up with the
demand. The report established that there are several growing systems that
already exist, however critically analysed their suitability to certain procedures.
It examined the appropriateness of three horticultural crops which have the
ability to be grown in an Urban Farming Environment, highlighting that certain
crops are suitable for certain systems based on their yields, production cycles
and commercial value. The report concluded that the Urban Regeneration site in
Birmingham would grow Strawberries using the Nutrient Film Technique.
Within the next 40 years, the global food system will
face pressures to increase food production to meet the needs of nine billion
people by 2050. Producing food sustainably is becoming progressively difficult
as of the competition for land, climate change and the intensification of water
and energy. As globalization will continue, economic and political pressures
will be exposed within the food system (Foresight: The Future of Food and
Farming, 2011). It is estimated that 54% of the world’s population now live in an
urban area which is set to grow (Beacham et
al., 2017), increasing the interest in urban farming and generating what
researches have called “the third green revolution”.
Urban Agriculture is the growing, processing and
distribution of food within cities and to the local area (Frost and Sullivan, 2017). It has the
ability for cities to become somewhat self-sufficient in the future along with addressing
the issues of food security and food quality while not degrading the
environment and the accessibility of different varieties of food available to
the consumer. Expansion in the popularity
of this farming method has led to large commercial companies inventing
innovative approaches which meet the challenges that the worlds food industry
is going to face (Beacham et al.,
The fresh produce sector was worth $51.8 billion in 2014,
accounting for 12.4% of the European Unions agricultural output, giving it a
significant role in the UK’s economy (Cicco, 2016). The
value of the fresh produce sector is increasing year on year (DEFRA et al., 2016); 12.4% of farmers grow fresh vegetables
as they are a high value product in comparison to arable crops like wheat (Cicco, 2016). Consumer
demand of high value products has lead Urban Farmers to advance the systems present
in the industry, ranging from growing crops in city parks to rooftops with
highly technical systems
(Beacham et al., 2017).
Urban farming is rapidly
developing around the world, with innovative ideas becoming reality in areas
including China, America and the across the EU. In the UK, GrowUp farms are the
largest commercial set up for aquaponics, growing tilapia fish, along with pea
shoots, baby watercress and a variety of microgreens. The high value products
are sold to restaurants in London and high end catering outlets across the UK (Stewart, 2017). In comparison to Growup, Aerofarms in New
Jersey are using Aeroponics to create artificial conditions in a cloth medium
to grow 250 varieties of leafy greens. Aerofarms are taking precision farming
to the next level, using LED lighting and converting the plants
photosynthesized wavelengths into chemical energy for future use
Technical Evaluation of Growing
Hydroponic growing systems are a subset of hydroculture.
Plants are grown without soil, using a nutrient solution which provides
accurate quantities of minerals. The systems create a controlled environment by
using innovative technology, allowing growers to stabilize the conditions. Ideal
growing environments are created by altering the supply of oxygen, temperature,
light, humidity and supply of nutrients, nourishing plant growth until harvest.
There are many Hydroponic systems, including Aquaponics, Nutrient Film
Technique, Deep Water Culture and Substrate dripping; all of which will be
discussed below (The Hyrdroponic Grower, not dated).
Aquaponics is a highly complex system shown in figure 1,
which uses three biological systems; fish, plants and nitrifying bacteria.
Fish, often Tilapia, are intensively produced using pond culture and plants are
produced without soil, using hydroponics (Suhl, et al., 2016). The single recirculating aquaponics system (SCRAPS),
is the basic structure. It allows waste to be recycled in a sustainable,
recirculating and connected system (Grzyb, not dated). Dissolved nitrogen waste
and solid waste are released by the fish which is then converted
to nitrates which
are toxic. The plant crops clean the water with the bacteria living in their
rooting zone which is nitrification, allowing it to be recirculated back into
the fish rearing tanks with an accumulation of non-toxic nutrients and organic
matter (Suhl, et al., 2016). The
nitrates that the plants absorb protect the fish from the poisonous waste as
well as rapidly improving their growth rates (Grzyb, not dated). Double
recirculating aquaponics system (DRAPS) is the intensive aquaponics system
which enables optimum conditions of both fish and plant to be met, including,
pH, nutrients and water quality. The fish and plant cycles are separated
allowing the adaption of conditions, improving production rates so commercial
companies can produce products on a large scale (Suhl, et al., 2016). Recirculating aquaculture systems (RAS) use 90-99%
less water than conventional systems and address the environmental issues of
fresh water usage and increased nutrient release into the water systems (Suhl, et al., 2016). However, the operation of aquaponics needs to be
precisely calibrated and constantly monitored for successful growth of both
plants and fish (Kyaw and Keong, 2017).
Film Technique (NFT)
The Nutrient Film Technique uses nutrient
solution which is pumped through plastic channels in a thin film, providing the
roots with nutrients while using no solid planting material. Figure 2
demonstrates the channels are built on a slight gradient ensuring uniformity of
water flow, however, localised depressions of even a millimetre will obstruct
the flow. The root mat develops into the recirculating solution, so it is
crucial that the nutrient film is constant, preventing the roots being exposed
to oxygen deprivations which they are very sensitive to (Morgan, not dated).
Deep Water Culture grows
plants with their roots submerged in a nutrient solution which is 8-10 inches
in depth (Hyrdroponic Systems, not dated). Figure 3 shows that the system
incorporates an air infusion pump, an airline and an air stone which create a
supply of bubbles, targeted at the root zone. However, the system requires
several elements and large volumes of water which makes it heavy and immobile. The
bubbles are effective at supplying the roots with a plentiful source of oxygen
to ensure the roots get adequate levels. Increased oxygen levels lead to
greater water absorption and cell growth improving root development and overall
plant growth (GroWell, not dated).
Substrate dripping systems were originally created for
outdoor cultivation systems, then where later adapted for indoor hydroponics.
The system is highly controlled as it regulates the water and nutrients that
are given to the plants through the network of feeder lines. As shown in figure
4, each individual plant has a designated drip emitter which can be altered
according to the requirements of the plant. There are two variations of drip
systems, recirculating and non-circulating systems. The recirculating system
recovers the water which is not initially absorbed and it then flows back
through the system again. The wastewaters pH and nutrient level will have to be
monitored to ensure there are at adequate levels, making this system suitable
for smaller producers. The non-circulating system disposes of its wastewater;
however, larger commercial systems have the means to set up sophisticated systems
which keep run-off to a minimum (Green and Vibrant, 2017).
Vertical farming is a method
of growing crops indoors, making it suitable for areas that do not have the
correct ground or climate to grow plants, including abandoned warehouses and
apartment high rises. The crops can be grown hydroponically in a nutrient
solution or aeroponically which mists the roots with nutrients and water, in an
environment which is strictly controlled, using artificial lighting, temperature
controls and fertigation. As shown in figure 5 the structures which are used in
vertical farming are multiple stacks of shelves or benches, resulting in large
volumes of plants being grown in a small area (Ungbarsky, 2016).
Bench structures vary greatly including,
Corrugated Asbestos Cement benches, Flat Cement-Asbestos benches, Wooden
benches and Welded Wire Mesh benches. The design structure chosen will be based
on whether the system is commercial or for home growing, as each structure
varies in price, weight and mobility. Every bench system as
displayed in figure 6 elevates the plants vertically above ground level, making
it more convenient for those monitoring the growing process. The increased air
levels which the plants are exposed to dries them out enabling the quantity and
timings of water application to be monitored. Air movement around the plant roots
minimises root and foliar diseases, as well as improving plant growth because
of warm conditions (Walker and Duncan, not dated).
Technical Evaluation of Crops
There are many varieties of crops that are suitable for production
in an urban greenhouse, however, I’m going to focus on Cos lettuce, Strawberries
and Spinach based on their production cycle and suitability to greenhouse
Cos lettuce is a leafy salad vegetable which is well suited
to a soilless systems including nutrient film technique or floating structures
because of the varieties small size and light weight. It can be grown all year
round, but typically between May and November with a very short production cycle
of around 6 weeks, and once harvested it grows back, reducing labour costs. The
average yield of Cos lettuce in the UK was 7.2 tonnes per acre in 2015 (Statistics
There are three different varieties of strawberries
including, perpetual fruiting which crop twice a year, alpine which are generally
wild and summer fruiting. If the conditions within the greenhouse are ideal,
strawberries can be planted and harvested within 50 days, generally between
June and September for harvesting. As shown in table 2 the acreage for
Strawberries is 2.7 tonnes (Statistics Norway, 2015), however if both June
bearing and everbearing strawberries are grown, there will a crop to harvest
most months of the year (Trabish, 2012).
Spinach is a very versatile crop which can be grown all
year round at an average of 4.85 tonnes per acre (Takele, 1999). Varieties
include, summer cultivators which will be picked May-October or winter
cultivators which would be picked between October and April. Spinach production
in urban greenhouses allows for multiple short-duration production cycles of
30-48 days which enables high economics returns Saha and Eckelman, 2017).
Table 1- Summary Technical Evaluation of Growing Systems
Waste is recycled
Non-toxic nutrients and
organic matter build up improving plant growth.
Optimal conditions for fish
and plants (pH, nutrients and water quality).
RAS use 90-99% less water
than conventional systems.
Constant monitoring to
ensure optimum conditions are maintained for fish and plants.
Provides roots with optimal
quantities of nutrients through nutrient solution.
Uniform water flow while
using minimal quantity of water.
Roots could be exposed to
oxygen shortages if the nutrient film is not kept constant.
Deep Water Culture
The plant roots are exposed
to very high levels of oxygen
Large quantities of water
Individual emitters per
If uncontrolled the plants
Volumes of wastewater have
to be disposed of.
Plants are exposed to
greater air levels so reduced root and foliar diseases.
Convenient for monitoring
Suitable for areas which
don’t have the correct ground and climate for growing plants.
High energy demands leads to
high value products.
Limited to certain
Table 2- Summary Technical Evaluation of Crops
(Tonnes per acre)
Setting up an Urban Farm is an expensive process to
construct and operate. For it to be commercially viable the products grown need
to be high value, including cos lettuce, strawberries and spinach, which can be
sold at a premium price on and off season (Ackerman et
al., 2013). The three fruit and vegetables shown in figure 7, all have
relatively short production cycles of under 50 days, making several harvests
possible within the one year. Gaining more than one crop from a single
planting, reduces labour costs and so becomes more economically valuable for
The most valuable field crop variety in the UK is lettuce,
averaging at £17 million in 2015 (National Statistics, 2016), with a wholesale
price valued at £0.52 in 2016 (Statistica, 2016). Spinach is another
horticultural crop that has a high value of £0.98 per kilo gram in 2016
(Statistica, 2016). Strawberries averaged at £2.73 per kg (Statistica, 2016),
making them more valuable than the field crop cos lettuce. Temecula Valley
Strawberry Farm (US) has taken advantage of this high value crop and developed a
strawberry farm in March 2017. It grows strawberries vertically using
hydroponics, yielding 130,000 pounds per acre, generating an annual revenue of
$390,000. TVSF demonstrates that with lack of land and water, technology can
increase yields per acre and still be environmentally friendly and economically
viable (Trabish, 2012).
Growing Strawberries within the city of
Birmingham at the regeneration site gives the company many strengths to play
off when marketing the product. Dring, (2016) from the successful company
Growing Underground states that urban farming is, “Feeding the City From within
the City”. This statement encapsulates urban farming into a phrase which covers
the advantageous qualities of its prospects. Strawberries will be supplied
across Birmingham in a sustainable manor, without effecting the environment that
they have been produced in.
Figure 7 demonstrates the
packaging designs that supermarkets have adopted, however figure 8 illustrates a
quirky packaging design from Growing Underground which I feel matches
individuality of the strawberries that are going to be grown in the centre of Birmingham.
The design is clear and unique, exhibiting a high-quality product which will be
reflected in the price. The strawberry farm will be Red Tractor Farm Quality
Assured which is very highly regarded by UK consumers. Displaying this label on
the Strawberry packaging gives consumers something they can relate to, and
inevitably they can have greater trust in the innovative brand.
Urban farming is currently an expensive business which has
a niche customer market who have more to spend on the luxurious products. In my
opinion if urban farming is going to accelerate forward into the future,
companies need to engage a wider demographic, beyond the current niche. A
company who has already taken this into consideration is GrowUp in London. They
have addressed two issues including the need for cheaper products and involving
young people. Growup have developed training and educational programmes for
young people, in the hope that they carry their expertise into the future
(Lovett, 2016). By engaging the younger demographic as agriculture progresses, there
will be young enthusiasts already involved in the industry, making Urban
Farming an exciting prospect for the future. Secondly, GrowUp have introduced mixed
salads into their product range which are retailed at a lower price. Giving a
wider range of consumers the opportunity to purchase urban farmed produce will
encourage the uptake of this modern technology.
A company called ‘Except’ in the Netherlands
is currently developing architecture and city planning which incorporates
sustainable urban farming. As shown in figure 9, the ‘Polydome’ is a concept
that integrates both animals and crops into an eco-system, with estimates that
they could supply enough food to sustain a large population (Schesinger, not
dated). Although it is a working concept, as we work our way into the future these
projects may become prominent to address food security and environmental
I think it would wrong to rule out the possibility of Urban
Farming becoming a large part of our Agricultural sector, taking into
consideration the technological advances and money that is being spent in the
area. However, based on the evidence I think that within my lifetime there will
not be a food revolution towards Urban Farming as the work being completed at
the minute is all in its early stages and a lot of development still needs to
For the regeneration site situated in Birmingham I am
choosing to grow a strawberry crop using the Nutrient Film Technique (NFT). Strawberries are a
very high value crop and can be grown very quickly, multiple times a year
within the one growing system. I am going to use strawberry plugs instead of planting
seeds which will quicken the growth process and improve overall efficiencies.
The plugs will be firmly placed into net pots as shown in figure 10. The net pots
will be placed into the NFT channel shown in figure 11, ensuring that the
bottom of the net pot reaches the nutrient solution, allowing the roots to
The greenhouse will a highly productive
growing space as the channels will be stacked into two tiers, allowing the crop
to fall over the edges resulting in a convenient harvest. The Nutrient Film
Technique is capable of being stacked vertically as it is a very light system
that doesn’t hold large volumes of water. Using this soilless structure ensures
that no soil borne pests will be introduced into the system, resulting in no
pesticides needing to be applied.
The small use of pesticides and fertilisers reduces the
emissions of fossil fuel and the damage to the environment, making it very attractive
to potential buyers (Trabish, H. 2012). In addition to this, being able to grow
strawberries in the centre of Birmingham means the produce is reaching
consumers extremely fresh as well as reduced transportation CO2 emissions and
costs associated with that (Dring, 2016).
The glass house will have a control system installed which
will enable temperature, lighting, CO2 and humidity levels to be monitored. The
monitoring system will make it possible for energy savings to be made as of the
reduced water consumption and electricity usage (Franklin, 2017). The glass
house will utilise the natural sunlight available, however strawberries can be
exposed to a maximum of 14 hours a day. This means the natural sunlight will topped up by
artificial LED lights when the quantities aren’t sufficient but turned off when
they aren’t needed (Man, 2014).