Previously this blog has looked at the role of automation in farming: at how the use of robots, drones and data analytics can achieve a kind of precision agriculture far beyond the scope of traditional practice. It remains the case, however, that farms spread out over fields in the open air lie victim to forces of nature and circumstance (climate, weather, pests) that put even automation on the back foot.

What if there were a way of removing adverse agricultural variables altogether? What if farms could be relocated to weatherproof, pest-free indoor spaces so that light, temperature, water, and nutrients could all be exactly administered to achieve maximum productivity and minimum waste? Such is the thinking behind the vertical farm.

Is the idea as good as it sounds? Could the things it wants to do differently change the way we think about farming? And what does it take, in terms of technology and design, to make the vertical farm a reality? Is it, in the end, a legitimate industrial concept or just another futurist fantasy?

What is vertical farming?

There is certainly creative forward-thinking in the idea. As the world’s population steadily grows, becoming ever more urbanised, and as land available for arable use becomes scarcer, it would seem sensible, if not necessary, to import a measure of food production into our cities. Indeed visionary architects have been making space for plant cultivation in their high-rise schemes from Le Corbusier onwards.

Socially utopian as this strand of thinking tends to be, vertical farms are also inspired and made possible by the hard sciences of Controlled Environment Agriculture. Hydroponics (whereby crops are fed only by water-based nutrient solutions), aeroponics (in which the exposed roots are simply sprayed) and aquaponics (plants are grown in water fertilised by fish) have all now been proven viable methods of indoor farming.

Freed from the field, vertically farmed plants are reared in an environment where watering, lighting, humidity and fertigation (fertilisation through the irrigation system) are regulated precisely and automatically. The high quality of the produce may be further enhanced by AI-assisted breeding programs. And in their new home, to make the most of available square metres, crops are stacked on top of each other in shelves: hence the vertical. 

Impact of vertical farming on the environment

Part social planning, part science; to these motivating currents has more recently been added a third: environmentalism. Columbia Professor Dickson Despommier, today’s leading enthusiast for vertical farms, points out the catalogue of ways – deforestation, topsoil erosion, water pollution through agricultural runoff – in which conventional farming has done harm to the world’s ecosystems.

Transferring crop production to urban structures, Despommier says, will not only be good for people and for cities; it will above all be good for the planet, which, relieved of the burden of agriculture, will recover its natural biodiversity and balance. And, of course, with food now grown on site at the point of consumption, the environmental problem of food miles is dramatically downscaled.

Clear, coherent and confident as they are in theory, in practice vertical farms are struggling to find their feet. There have been some early commercial failures. Atlanta-based PodPonics went under after only six years. And FarmedHere, a warehouse outside Chicago at one time advertising itself as the largest example of its kind in America, lasted about the same time.

Hoping for better success are the flagship AeroFarms project, up and running since 2016 in an old New Jersey steel mill, and the UK’s largest venture, operational since last year, a converted cold store near Scunthorpe run by the Jones Food Company.

Can vertical farming be really sustainable?

Vertical farms are expensive to set up (AeroFarms spent $30m renovating and equipping their site). The huge amounts of start-up capital required reflect not just the necessary heavy tech but the typically ambitious scale of operations, which are more likely to clear profit the more product they grow.

They are also expensive to run. Employment costs are markedly higher than those associated with fieldwork (no seasonal migrant labour here). And the energy bills, of course, once round-the-clock lighting, climate control, pumps, fans, HVAC and computing equipment have been accounted for, are considerable.

For many environmentalists, of course, the energy footprint of vertical farms (one square metre of crop using over ten times the number of kilowatt hours per year than in a conventional greenhouse), threatens to make a nonsense of their claim to be part of a greener, more planet-friendly future.

Solving the power problem is, in fact, the principal challenge facing today’s vertical farm engineers. Much of Despommier’s work, certainly, is concerned with ways in which these buildings might create their own sustainable energy. In particular, methane generated from human, agricultural and even neighbouring restaurant food waste could, he thinks, enable the vertical farm of the future to be entirely self-sufficient.

In the meantime, many are considering the gains to be derived from cogeneration projects and renewable energy sources such as solar panels. And work is always being done to drive down the cost of energy by improving aspects of system efficiency, especially, in this context, that of the all-important LEDs.

It may not be enough. It may be that vertical farms in the guise of such commercial monoliths as are currently being attempted will prove a dead end. This would not be to say that the hydroponic cultivation of plants in dense population centres could not find alternative mainstream expression – vertical allotments and market gardens incorporated into residential buildings, for example.

The urban vertical garden farming

Incorporation is possibly the key. Farm.One, a 1,200 square foot vertical farm under a restaurant in Manhattan’s Tribeca neighbourhood, has prospered because it supplies the kind of leafy, exotic greens that the nearby restaurants queue up to buy. It is proof that even as contested a concept as the vertical farm can function well, provided it assumes more or less the scale and role the surrounding network demands of it.

It is, after all, the principle of system integration – and likely as important to the viability of next year’s startup as it is to any radically reconceived metropolis of the future.