A food desert is an urban area in which it is difficult to buy affordable or high-quality fresh food.  Rather than supermarkets or market stalls these areas are often served by smaller, higher priced corner shops where shelf space is often reserved for processed convenience foods.  Unfortunately, due to the rise of urban populations it is becoming more and more difficult to provide food for this growing demand resulting in and increased number of these food deserts.  In fact, it is estimated that 1.2m people in the UK live in a food desert with 8 out of 10 of Scotland’s worst food deserts located in Glasgow.

The huge number of people living in food deserts as well as the damage that traditional agriculture can pose on rural environments such as the disruption of wildlife ecosystems suggests that the farming of fresh foods should be brought into our cities.  Urban agriculture ranges from small community gardens to indoor vertical farms and these often have huge benefits.

Indoor farming allows farmers to control environmental conditions to maximise growth enabling them to grow more in a smaller space.  One of the main barriers to larger indoor farms is the high cost of real estate in urban areas however large farms can be built in disused or abandoned buildings and smaller personal farms can be integrated into our homes.  The use of space in the city itself means that the food can be produced in the middle of food deserts and then sold incredibly locally to retailers and restaurants.  This not only reduces food miles but also means that the food is as fresh as possible.   Farms in the inner city will also create jobs which is especially useful in food deserts which tend to be in areas which are most economically deprived.

One of the most successful methods of urban agriculture is aquaponics which combines aquaculture (growing fish) with hydroponics (growing plants without soil).  An ecosystem cycle is created in which the fish produce waste which is then converted into fertiliser for the plants by microbes.  These nitrifying bacteria convert the ammonia in the fish waste into nitrites and then nitrates which are the form of nitrogen that plants can uptake and then use to grow.  The plants act as a filter for the water which is reused to house the fish.

 

Aquaponics solves a lot of problems compared to hydroponics on its own such as the fact that there is now no build up of salts or chemicals in the water so the water can be constantly recycled rather than having to be disposed of which poses an environmental risk.  Aside from the lack of toxic run-off, other benefits of this indoor farming method include the fact that it uses 1/10^th of the water compared to traditional soil farming and also eliminates the risks of soil borne diseases.  There are also no harmful chemicals used in this method of farming, so the food produced is organic, fitting well with today’s drive towards natural foods.  Aquaponics systems are also very scalable; from a countertop herb garden to a full-scale farm. This means that local areas can implement this method in a way to best suit themselves.

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A selection of images from Urban Organic showing their aquaponics systems.

The most space-saving technique is vertical aquaponics in which plants are stacked on top of each other.  Water flows through the top of the tower which then travels through a wicking material under gravity.  The plants use this material to get their water and nutrients and any excess water falls into the fish tanks.

Another technique is called the nutrient film technique which involves nutrient rich water flowing through a narrow through or pipe. Plants are placed in staggered holes in this material with their roots dangling into the water. This method is handy because it can be hung from ceilings utilising otherwise dead space.

Currently, the at-home technology allows us to grow leafy greens such as lettuce and spinach as well as low-nutrient vegetables like spring onions and radishes.  More advanced and commercial systems allow us to grow cabbages, tomatoes, cucumbers, beans and broccolis.  Other systems that are still in the R&D stage have been able to grow sweet potatoes and some are even trying to grow fruit trees.  In terms of fish, fresh water species like tilapia and trout work really well and you can even cultivate snails and prawns.

Climate control technologies are being developed and improved in order to make the farms as efficient as possible.  LED grow lights are becoming increasingly efficient and can provide the correct wavelengths of light for the growth of plants.  The different that this can make is shown by Professor and Dr Qichang Yang who works at the Research Centre for Protected Agriculture & Environmental Engineering (CPAE) who said “Compared to conventional farming, a plant factory with natural solar light can increase productivity per unit area by between two and ten times. With artificial light this rises to 40 times and by adding vertical farming this goes to 1000 times.”  The lights can be moved back and forth over many plant arrays to reduce energy costs and the distance of plants from the light and also be adjusted for the same reason as the plants grow.   The plants are bathed in light continuously in the days before they are harvested to reduce the nitrate content in their leaves.  Temperature can also easily be controlled and managed for growth that is efficient as possible. Other control systems such as nutrient solution management are also being developed and implemented to supply nutrients.

Tuber vegetables can be grown in the air with their roots dangling from racks in a process invented by CPAE.  This allows vegetables to be harvested individually and repeatedly from the plant without having to lift and disturb the entire plant.  CPAE have succeeded in doing this with a plant that is now 10 years old and has produced a huge 500 potatoes.

The application of this type of farming has the potential to completely change our eating culture. For example, a customer could select their plants directly from the living wall in a restaurant before they eat it.  This industry is going through a huge boom of interest and development and I’m sure that as the technology is refined, we will be able to grow more and more higher nutrient foods in this way.