Vertical farming is increasingly popular, and agritech businesses specialising in it are attracting investors. Ocado, the UK food delivery company, has invested £17m in vertical farming since it announced that it would be looking to deliver its own produce to urban customers.
UK businesses such as Grow-Up and V-Farm are continuing to expand and the vertical farming sector in the US alone is expected to reach £2.3bn by 20241.
Still, questions remain over the long-term viability of vertical farming as focus shifts to environmentally friendly practice. What role can vertical farming play in feeding future generations and can it be a truly sustainable solution?
The global food challenge
Land covering the area of South America is needed to feed the seven billion people currently on the planet. And the world population is expected to grow by 25% in the next 30 years, reaching almost 10bn by 2050, with 70% of people living in cities2.
The problem is that there isn’t a lot of spare room available: 80% of the land that could be used to grow crops is already in use3. The challenge is to feed more people with less land and keep production close to the urban areas where the population will be concentrated.
Space saving agricultural solutions
Vertical farming is well adapted to supplying cities with fresh produce. It uses layers of growing surfaces, stacked vertically. The environment is minutely controlled and many systems are totally soil free, using hydroponics to grow a wide range of crops.
Hydroponic growth systems – growing plants in nutrient-dense water – are significantly more efficient way of using water than traditional agriculture. One study found that in Arizona 1kg of lettuce grown in open fields would use 250l of water. Grown in a greenhouse, it would require 20l. In a vertical farm, one kilo of lettuce would use just one litre of water4. The process is at its most efficient in closed-loop system, where water can be recovered and re-used in a controlled environment.
Vertical farming makes the most economical use of space which is crucial in densely built areas or those with high land value. Whether building upward, or tunnelling down like London-based vertical farm company Growing Underground, technology is used to control every element of the growing process with robotics and AI increasing yields and reducing costs.
Vertical farming has two interrelated benefits. Space that might otherwise be wasted is put to use – and with food able to be produced in the heart of cities, the cost and emissions involved in transport and storage is massively reduced.
Is vertical farming sustainable?
Predictably, the issue isn’t black and white. In environmental terms there are benefits and drawbacks to vertical farming, with a significant downside being the high energy consumption necessary for indoor farming. That is one problem that agritech companies will always need to mitigate for: sunshine may be inconstant, but it’s free.
Even high-efficiency LEDs consume a large amount of energy, though ways to improve climate efficiency in vertical farms are being explored. These include heat recovery from vented air and recycling of water and nutrients.
Andrew Jenkins, a research fellow at Queen’s University Belfast, sounds a note of caution about the impact of vertical farms stating that “we should be exploring the potential of naturally lit environments before we delve into dimly lit buildings where special technologies, artificial lighting and air handling units are needed to produce food.”5
Jenkins is exploring how flat inner-city rooftops cold be converted to use for naturally lit greenhouses. His approach would be less productive than a multi-layered vertical farm, but would use 70% less energy.
The trade-off for businesses to weigh up is between vertical farming’s yield of up to 200% more than a traditional greenhouse and a significant reduction in energy consumption (and cost) in naturally lit environments.
Some companies, like Scotland’s Intelligent Growth Solutions, argue that artificial intelligence in their farms improves efficiency, reduces labour costs by 80%, and produces a hugely higher yield per m2 than a traditional greenhouse or polytunnel6.
A sustainable investment
Growing crops in vertical farms is may appear to a less green option than growing them under glass in a warm climate. But once air miles and the emissions cost of transporting produce to markets is factored in, vertical farming can still play a strong role in a less carbon-intensive supply chain.
Improving technology and AI systems will continue to drive better efficiency and reduced environmental impacts. Vertical farming is not the only answer to feeding the population of tomorrow, but it will undoubtedly form part of the solution, and the UK’s agritech start-ups are helping hasten the process throughout the value chain.