December 4, 2020 Jess Moseley

Is Vertical Farming Really Better For The Planet?

by Jess Moseley

A food system can be described as the journey that food takes from field to fork. Over the last century, food systems have developed from simple, local structures into global, commercialised industries, which has been great (so far) for feeding an exponentially growing population, but devastating in terms of habitat destruction, soil degradation and ecosystem pollution. The hugely expanded scale of food production and distribution has been achieved through significant advances in technology and the intensification of agriculture. We can now refrigerate and freeze food to extend its shelf life, transport food internationally via aircraft, HGVs and ships and use the Haber process to produce synthetic ammonia to artificially fertilize our soils.

However, conventional farming practices rely upon finite resources such as the availability of arable land, fossil fuels and clean water. As such, conventional farming practices cannot support our growing population indefinitely. We are also facing additional pressures caused by climate change, including more frequent extreme weather events (such as droughts, forest fires and flooding) and invasive pest species surviving further afield due to warming climates; both issues will have a significant impact on crop yields and decrease our capacity to feed people and livestock in the future. Some studies predict that climate change could reduce global crop yields by as much as 2% per decade over the next century.

Without sustainable solutions, we will struggle to protect the integrity of our environment and feed an estimated 9.7 billion people by 2050.

So the bottom line is that we need to find smarter, forward-thinking farming methods, and quickly! Without sustainable solutions, we will struggle to protect the integrity of our environment and feed an estimated 9.7 billion people by 2050 (crikey!). Controlled Environment Agriculture (CEA) is an innovative concept that could help to increase the efficiency of food production, shorten supply chains and reduce food waste. Our first commercial site in Clapham, London, is a leading Controlled Environment Farm (CEF) which produces delicious, local food using sustainable methods and principles. We will now examine what controlled environment agriculture is, and crucially if it is really better for the planet.

What is Controlled Environment Agriculture?

Controlled Environment Agriculture (CEA) is a new technology-led approach to crop production with a whole lot of potential. Controlled Environment Farms (CEFs) use closed-loop principles by cleverly incorporating feedback (data from a vast array of sensors) to monitor and adjust variables such as water temperature, air velocity and humidity. This control gives the CE farmer the ability to maintain optimal growing conditions for a given plant species and produce reliably high yields independent of seasonality, allowing them to meet the demands of consumers whilst using finite resources such as land and water more sparingly.

CEFs can be set up in a wide range of indoor settings – in our case a deep level tunnel system used during WW2 as a bomb shelter! The key is to provide crops with a stable growing environment that is completely enclosed and thus protected from extreme weather patterns and pest species. Crops can be grown hydroponically (without soil), using LEDs instead of sunlight for photosynthesis. At ZCF we use an ‘ebb and flood’ irrigation system, in which water floods and drains through our growing trays at precise intervals throughout the day. This allows our microgreens and salad leaves to uptake all the water and nutrients they require, without relying on adequate rainfall levels or depleting minerals such as nitrates and phosphates from the soil.

How Controlled Environment Farms use finite resources more efficiently

Controlled Environment Farms use growing trays which can be stacked vertically, meaning that they are not limited to just one horizontal surface for growing. This gives CEFs the potential to produce many times more food per square metre than conventional in-field farming (as you can’t stack fields one on top of another!). So, CEFs are clearly more efficient in terms of land use. Their productivity has proven especially valuable in cities, producing food locally where space is very limited and there is a high population density. Potentially, many more CEFs could be set up in redundant urban spaces such as disused factories, multi storey car parks and subterranean tunnels in the future, creating new jobs and reducing a city’s reliance on food imports. If expanded upon, a model of local food production and distribution within cities could help to keep carbon emissions associated with food transportation and refrigeration down to a minimum, helping to prevent further climate change and giving city folks access to food with a longer shelf life.

But it’s not just land requirements where CEFs have the edge over conventional farming techniques. Hydroponic systems use in the region of 70% less water than in-field farming. Aeroponic systems (which atomise water into a fine mist) have shown to be even more efficient, with a 90% reduction in water use compared to in-field farming and great crop yields. With a growing global population, fresh water is likely to become a more precious commodity over time and we will have to use it more sparingly. If we can optimise the recycling of water within CEFs even further, then this bodes well for the future of food production.

CEA does not contribute to soil degradation

By switching the production of salad leaves and microgreens from growing in fields to in CEFs, we can help to retain arable land for grazing livestock or growing larger crops that cannot (yet) be grown hydroponically. This alternative way of producing food will help to alleviate the concerning issue of soil degradation, whereby conventional, in-field farming is rapidly depleting the soil of its nutrients. By over-exploiting our soil by intensively growing crops and aggressively applying artificial fertilisers, we are draining the soil of its fertility. Some estimates suggest that the UK only has in the region of 100 harvests left before its soil becomes completely exhausted, so it really is in our interest to protect the integrity of our soil sooner rather than later!

Even more alarmingly, soil formation is a process that takes thousands of years for minerals to accumulate, so once our soil’s health is gone, it’s gone. Therefore, the more crops we can produce in CEFs using non-soil growing substrates, the better, and the more chance we have of avoiding an agricultural crisis in the future. At ZCF we use a capillary matting made from a recycled material; it is porous enough for a seedling to push its roots through and provides anchorage to support the weight of the plant. The material is great at retaining moisture and nutrients, effectively tricking the plant into believing it is growing in soil.

CEA does not contribute to habitat destruction

When trees are cut down or fires are started to make way for new in-field agricultural sites, biodiversity is severely disrupted. Within the fragments of forest left behind, animal species experience increased competition for shelter, food and water. Habitat loss threatens many species with extinction in the wild, and has already caused plenty of species to die out. For example, the Formosan Clouded Leopard, native to Taiwan, was declared extinct in 2013; this was very likely due to starvation caused by the removal of lowland forests cleared for agricultural purposes, forcing the leopards into smaller, overlapping hunting ranges. As CEFs can be set up in a wide variety of indoor settings, crops can be produced without any additional deforestation, thus producing food without subjecting endangered species to further harm. CEFs can also help to reduce eutrophication of aquatic ecosystems, caused by fertiliser run-off from in-field farming. CEFs contain their post-irrigation water in drainage systems, whereby water is filtered and then recycled without polluting rivers with excess nutrients or endangering wild fish species.

Some estimates suggest that the UK only has in the region of 100 harvests left before its soil becomes completely exhausted.

If we increased the number of CEFs operating around the world and adapted them for growing larger plants and trees, pressure could be alleviated on ecosystems. Let’s take the Borneo Rainforest as an example: this rainforest has already lost over half of its tree cover due to the clearing of land for oil palm plantations. Palm oil is a lucrative commodity for local farmers to sell on to global markets as a food additive. Imagine if oil palm trees could instead be produced in Bornean towns, using Controlled Environment infrastructure (perhaps with aeroponics to emulate the high humidity seen in tropical habitats) – what a lifeline this would be for animal species living in the rainforest!

Hypothetically, a diversity of tree species could then be replanted where the oil palm plantation sites used to be, reconnecting rainforest fragments and reintroducing the few isolated populations of critically endangered animals such as orangutans and Borneo pygmy elephants left in the wild. This would help to increase their numbers and support their long-term survival, whilst providing the local farmers with a sustainable, alternative farming method.

CEA is great, but it isn’t perfect yet

However, despite all of the advantages discussed above, there are still a few limitations to CEA that need to be addressed. First of all, CEA is a relatively new technology and as such, setting up a new CEF requires a large capital expenditure to become operational and commercially viable. A prospective CE farmer will need to finance a suitable site, acquire LED lights, sensor equipment and data monitoring software, a powerful ventilation system, as well as all of the growing infrastructure, substrates, seeds, and of course labour needed to run the site, none of which is inexpensive. However, there is a lot of traction in the AgTech industry, as investors are realising the potential of controlled environment farming technology and its reliability of yields, so don’t feel disheartened – setting up a CEF will likely become a much more affordable option in the future!

Another concern that people have about CEFs, is that they require a lot of energy to power the LEDs needed for plants to photosynthesise. Whilst this is true, LEDs are increasing in energy efficiency with each new generation, and any ‘wasted’ heat energy produced by LEDs can be utilised to keep plants warm, reducing energy requirements for heating. Additionally, there is the option of using renewable energy to power a CEF. At ZCF, we are very committed to achieving carbon neutrality and so we use a UK energy provider that only supplies 100% renewable energy (a mixture of wind, biogeneration, solar and hydro). A CE farmer could also get involved with carbon offsetting projects, which aim to reduce carbon emissions to combat climate change; such projects may include planting trees, installing solar panels in schools, or providing communities in developing countries with clean and energy efficient cooking stoves.

So there we have it. We have examined how Controlled Environment Agriculture triumphs over conventional farming practices in terms of using finite resources such as land and water more efficiently and how CEFs do not contribute to soil degradation or habitat destruction. We can conclude that CEA is better for the planet in these ways, and whilst it may not be perfect, it is improving all the time in terms of affordability and energy efficiency. What is clear, is that there is no one-size-fits-all solution for continuing to produce enough food for coming generations, so the more sustainable, forward-thinking and high-yielding farming practices that we can use in conjunction with Controlled Environment Agriculture, the brighter the future of food will look.

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