Will our vegetables in the future no longer be cultivated in fields, but in skyscrapers? In any case, the principle of vertical farming promises progressive agriculture that can save space and conserve resources. However, the idea that lettuce, tomatoes and the like will grow on a large scale in urban centers, making traditional farming obsolete, is still a pipe dream.
The principle of vertical farming
There are different approaches to vertical farming. However, the basic concept is always to grow food crops not exclusively horizontally, but distributed over several floors or stories. Visions paint the picture of “farm scrapers,” entire skyscrapers that could supply metropolises of the future with fresh food. Vertical cultivation is often accompanied by other innovative technologies. These include, for example, autonomous irrigation systems that use sensors to supply plants as needed, or robotic arms that assist with harvesting. In many cases, hydroponics or aeroculture are used.
Hydroponics and aeroculture
Plants grown in hydroponics no longer grow in substrate, but instead root in containers filled with a nutrient solution. The plants can thus be optimally supplied in a closed-loop system, and fertilizers and water are saved.
Aeroculture also enables resources to be used sparingly. With this method, water and nutrients only reach the root system via a spray generated by fine nozzles.
Problems of conventional agriculture
Agriculture is facing ever-increasing challenges. According to the UN’s World Population Prospects, the world’s population will grow from just under eight billion today to around ten billion by 2050. However, the difficulties lie not only in the growing overall population, but also in the expansion of urban areas. The UN predicts that by 2050, some 66 percent of the world’s population will live in cities.
At the same time, calls are growing louder for agriculture that is more climate and environmentally friendly, as many practices in conventional agriculture have fatal consequences for the climate and the environment. In order to continue to provide food for the world’s population, incredibly large areas of land would have to be redeveloped for agriculture – at the expense of virgin forests, moors and wild meadows. Can vertical farming be the solution here?
Less land, less fertilizer, shorter transport routes
The major advantage of vertical farming is obvious: if the height is utilized, the amount of land required is reduced. If vertical farming becomes established, it would even be possible to renaturalize previously used fields and thus also restore the natural habitats of diverse animal and plant species. Dispensing with agricultural machinery would also result in a reduction in the consumption of fossil fuels. And because the slim “farmscraper” could easily be located in or near cities, short transport distances would be possible.
Because vertical farms are often equipped with efficient supply systems, water consumption is also reduced – in contrast to conventional agriculture, this can be significantly reduced in some cases. Many vertical farming concepts provide for closed cycles in which water is purified and fed back into the system. This also means that less fertilizer is needed and excess nutrients are recycled instead of being washed into the groundwater.
Another big plus is that high hygienic standards prevail in closed systems. This also means that pests and diseases cannot get in. Pesticides become superfluous.
Vertical Indoor Farming: Farming under artificial sunlight
There are vertical farms that not only do without conventional substrate, but even do without sunlight – this is called “indoor farming”. Such facilities use modern sensor technology to control all parameters that determine plant growth, from ventilation and irrigation to temperature. Yields thus become independent of weather and climate, and plants can in principle grow all year round, 24 hours a day, which means they are also ready for harvesting more quickly. Crop failures caused by weather extremes such as drought or floods could thus be circumvented. Indoor farms therefore also offer great opportunities for inhospitable locations such as desert areas.
The problem with energy consumption
When replacing sunlight with artificial LED lamps, however, one also encounters the decisive weak point of vertical or indoor farming. With lighting around the clock, the energy demand shoots through the roof. In addition, there is often a need for cooling when temperatures rise due to the lamps.
The energy requirements of each plant also play a role. Tomatoes, lettuce or herbs consist largely of water and require comparatively little energy, so they are already well suited for vertical farming. Crucial for future food security, however, are more calorie-dense crops such as corn, rice and wheat. Because of the high biomass involved in cultivation, vertical farming is more difficult here – or at least even more energy-intensive.
For vertical farms to be truly resource-efficient, they would of course have to be powered by renewable energy. However, that in turn could negate their land advantage, since wind turbines or photovoltaic systems also take up land.
Vertical farming: Naive utopia or ready for mass production tomorrow?
They are still the exception, but vertical farms already exist. Some of the largest are located in Dubai, the USA, Japan and Great Britain, for example. There, we can see how efficient and profitable these systems can be. But whether it makes sense to switch to vertical farming always depends on cultivation methods and the region in question.
It is undisputed that new and sustainable solutions are needed to meet the upcoming challenges in times of climate crisis and the impending collapse of the ecosystem. And many vertical farming approaches could make a major contribution here. But for the benefits to actually materialize, further improvements are needed in terms of energy efficiency.