The Vertical Farm - Book Review.

Shaun mentioned that he had recently read an interesting book called “The Vertical Farm” which has radical ideas for growing food in the future. Here is Shaun’s overview of the book.

Dickson Despommier is an American professor in microbiology and public health. His book, The Vertical Farm, explores the history of agriculture from its origins to the modern day. The chapters continue by looking at the current and future problems of feeding a growing population with more people living in cities.

Dickson explains that the vast majority of the world’s clean water (70%) is used for growing food. The water running off the fields returns to the rivers and oceans together with some of the chemicals the farmers have sprayed on to the land. Not only do the pesticides and herbicides cause ecological damage to the aquatic environment, they also consume limited fossil fuel resources and cause emissions of greenhouse gasses. Carbon emissions and air pollution are produced by transporting food ever greater distances from the countryside to the cities.

The solution advocated by Dickson is to build vertical farms in cities. Although none have actually been constructed at the time of writing, the idea is to erect specially designed sky scrapers where each floor grows crops using hydroponics or aeroponics. He claims that the first method uses around 70% less water than conventional agriculture and the aeroponic system uses 70% less than hydroponics. Dickson proposes ways of collecting and recycling water to ensure crops can be produced using as little water as possible. He doesn’t mention anything about the production or carbon impact of the nutrients that would be required to make a hydroponic system work so I would suggest more research is required. He focuses on using renewable energy and waste to energy to power the farms. Food miles could be slimmed down to a fraction of today’s figures as the farms would be located in cities where the demand for food is the greatest.  The salad in your lunch might have been grown above your head or just down the road!

Besides producing food, Dickson suggests that vertical farms could be used to turn used grey water into clean water. This would be achieved by collecting the clean water in the form of transpiration from plants by using dehumidifiers. There are no figures given to support how much water could be produced and how much electricity it would consume. I know from the floods of 2007 that industrial dehumidifiers consume lots of energy but don’t collect much water.

Another goal of the vertical farm is to return agricultural land back to forests. I’m not sure if this would happen especially if the world’s population keeps growing, and the vertical farm can’t replace livestock farming. Nevertheless, Dickson does provide some evidence of where this has happened – A strawberry farmer in America used a stacking system to grow the same amount of fruit using much less land.

At the end of the book, Dickson mentions that several trial vertical farms have been set up in Tokyo, Korea, Holland and Manchester which they are learning lessons from.

Whilst the book went into some detail about the design of vertical farms, it glossed over a significant number of construction and design issues as well as operational requirements. For me, this was a disappointment - I was expecting the book to focus on these issues and not to focus so heavily on the history of agriculture. However, I was impressed by the idea of the vertical farm, but I was left wanting more answers to many obvious questions. I appreciate this is early days for the vertical farm and it’s difficult to give answers when there are no full scale farms in operation. His website features interesting blogs and more information to complement the book. Hopefully, in a few years’ time the on-going research will allow an updated book to be produced with a better technical assessment of whether vertical farms are feasible financially and environmentally.