Vertical farms look hi-tech and advanced, but the premise is simple: plants are grown without soil, with their roots in a solution containing nutrients. This innovative approach to agriculture is growing in global market value and is expected to reach $23.23 billion (£18.55 billion) by 2029.
Typically, this soil-less cultivation takes place in enormous greenhouses or warehouses, with plants stacked high on rows and rows of shelves. Parameters such as lighting, temperature and humidity can be controlled by computer systems, which is why vertical farming is also called controlled environment farming.
There are three types of vertical farming. Hydroponics involves keeping plant roots in a liquid nutrient solution. In aeroponics, roots are exposed to the air and a nutrient-rich mist or spray is applied to the roots. In aquaponics, nutrients from fish farm waste replace some or all of the chemical fertilizers delivered to plants through hydroponics.
There are huge opportunities to produce a lot of food using these growing methods, but there are four key myths about vertical farming that need to be debunked:
1. Vertical farms will dominate
Some people may worry that vertical farming is endangering traditional field farming, but this couldn’t be further from the truth. Currently it is only profitable to grow a limited number of small, fast-growing and high-quality plants such as lettuce and leafy vegetables in this way.
Costs for vertical farming are expected to drop due to economies of scale and standardization of processes, allowing a wider range of crops to be grown. But there is an ethical issue to consider: just because something can be grown this way doesn’t mean it should be. Vertical farming of grain crops, such as wheat, is technically possible, but requires so much energy that it is not profitable.
While vertical farming uses land efficiently – stacking allows more crops to fit per unit area – it cannot compete with the enormous scale of food production needed worldwide. It is a complementary way of producing food, which can increase food production and resilience within UK supply chains. Growing more lettuce on vertical farms reduces the need to import salads from abroad, reduces food miles and reduces reliance on overseas field production, which can be vulnerable to drought.
Vertical farms can support traditional agriculture by providing space for the development of new crop varieties or for the growing phase of young trees and crops that are later planted in the fields. By freeing up substantial areas of land, vertical farming provides space for other food production, bioenergy plans or reforestation and ecosystem restoration. It can improve conventional agriculture, but will never completely replace it.
2. Vertical farming will feed everyone
While this is a nice idea, it is not currently a reality. Most vertically grown crops are sold at a premium. Simple economics means that because the product is more expensive to make, it should be sold for a higher price. Vertical farms have high capital expenditures due to the infrastructure required: climate-controlled growing spaces, soilless systems, lighting, heating, cooling and ventilation. They are energy intensive, even if they run on renewable energy sources such as solar energy. Their operating expenses are also high due to the energy costs of running the systems and the need for more highly qualified workers.
Some researchers suggest that urban vertical farms could help address nutritional food deserts. That could be true, because they produce food close to the consumer, but to scale this up, costs have to come down. Robin Hood’s innovative business model – charging richer people more and giving less fortunate people discounts for the same product – could provide fair access to everyone in urban areas.
3. Vertical farming is not sustainable
This argument usually stems from the fact that vertical farms require electricity to function. That’s true, but a carbon-free grid running on 100% renewable energy sources makes this point moot. Many commercial vertical farms already source their electricity from renewable energy suppliers. Conventional field production of crops also involves emissions, due to the use of diesel tractors and so on.
In some ways, vertical farming can be more sustainable than field production. It is a closed recirculation system, which means that water and fertilizer are reused many times. No waste water flows into the environment, as is the case in agriculture. When it rains, excess agricultural chemicals run off the crops and enter the soil, groundwater or rivers.
Many of Britain’s leafy greens are currently grown abroad in water-scarce areas and require irrigation that exacerbates any water shortages. Field agriculture uses large amounts of herbicides (weedkillers) and pesticides (chemicals that kill insects). The controlled environment of vertical farms reduces or eliminates the need for these synthetic chemicals. If pests become a problem in vertical farms, natural enemies such as ladybugs can be introduced to kill aphids.
4. Vertical farming is not natural
Naturalness is subjective. Vertical farming essentially uses technology to mimic processes and environments found in nature. It does not manipulate or defy natural processes.
In field cultivation, crops grow in the soil and use the sun for photosynthesis. They have access to nutrients from both the soil and fertilizers. In vertical farming, LED lights mimic sunlight and can even be programmed to improve lighting conditions and help plants grow faster with higher nutrient levels. The fertilizers used are composed of exactly the same elements as those used in the field.
Vertical farming will not save the world or feed the poor. But it is a complementary method of producing food closer to end users, with greater control and higher land use efficiency. It can build systemic resilience within our food system, because yields from vertical farms will not be vulnerable to extreme weather events caused by climate change. It can increase local food security, which could otherwise be at risk due to increased political unrest abroad.
Vertical farming is currently limited in the crops it can produce economically, but by integrating these technologies into the transition to more regenerative and nature-based agricultural practices it could have broader environmental benefits.
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This article is republished from The Conversation under a Creative Commons license. Read the original article.
Zoe Harris receives funding from the Department for Energy Security and Net Zero as part of the Biomass Feedstock Innovation Programme, and has received funding from the Natural Environment Research Council as part of an Industrial Innovation Fellowship.