By Professor Katherine Denby, N8 AgriFood Academic Lead at the University of York, and Fix Our Food Lead for Grow It York
In this blog I will focus on indoor vertical farming under controlled environmental conditions.
Vertical farming is a sector on the rise. It involves growing fresh produce on walls or in stacked beds – these can be outdoors where the climate permits, or indoors under natural or controlled lighting conditions. Plants are typically grown without soil on matting and irrigated using hydroponics or aeroponics. In hydroponic systems plant roots are submerged in nutrient solution (often with cycles of submergence) whereas aeroponics uses technology to spray the plant roots with a fine mist. Aquaponics combines hydroponics with aquaculture to provide fertiliser to the plants from the fish waste.
Indoor vertical farming will not replace existing agricultural methods for food production but has much to contribute to developing a food system that delivers healthy, affordable, accessible diets from a healthy planet and supports a thriving and equitable food economy. Vertical farming systems significantly reduce the water use for production; water is recycled in the system and directly applied to plant roots. The indoor farm is protected from the weather and can deliver produce the year round. Often farms are located close to food businesses that will use the produce or consumers who directly buy, greatly reducing the distance food needs to travel and helping support localised supply chains which can be more resilient in the face of global shocks, such as Covid 19, or significant changes to international trade as we have seen with the UK’s EU exit. Localised production and supply chains also promote the local economy; money is spent locally and the vertical farm can stimulate local enterprises such as food processors and retail. Shorter supply chains impact on greenhouse gas (GHG) emissions too – a recent analysis (EDGAR-FOOD*) demonstrated that the GHG emissions associated with food transport, cold chain and packaging were considerable (~5% total emissions each) and what’s more, have increased since 1990. Reducing food waste at all parts of the supply chain is a vital component of sustainable agriculture with the level of control in vertical farming meaning minimal loss during production, and the short growing cycles from controlled lighting giving farms the flexibility to adapt to changing produce demands.
A major component of agriculture’s GHG emissions results from the use of synthetic nitrogen fertiliser (the manufacturing process causes significant CO2 and NO2 release). Vertical farming technology greatly reduces the use of synthetic fertiliser along with little or no use of agri chemicals such as herbicides and pesticides. However, the often cited drawback of vertical farming in controlled environments is the high energy use (per kg of produce) for lighting and climate control. The GHG emissions associated with an indoor vertical farm depend on the LED lighting efficiency but most significantly on the source of energy being used (renewable versus non renewable). With renewable energy sources, GHG emissions from vertical farming can be significantly lower than traditional greenhouse horticulture production in many countries.
One of the most significant contributions that vertical farming has the potential to address is land use efficiency and public health outcomes from our food system. Over 70% of the UK’s land is already used for agriculture and whilst traditionally agriculture has been a rural affair, vertical farming offers the potential for production of fresh produce in urban areas. Vertical farms have high yield per area meaning viable farms can be sited in areas with limited space and/or high land value. Rapid urbanisation is a global phenomenon and with a common neglect of food in urban planning has led to the development of urban food insecurity. Food deserts abound – neighbourhoods with limited access to affordable healthy food, where available food outlets are typically convenience stores and fast food shops with imperishable and often highly processed food – contributing to obesity and micronutrient deficiencies. Locating vertical farms within food deserts can improve access to nutritious food and can increase citizen’s agency within the food system. Closer connection between producers and consumers provides greater transparency about production and promotes enhanced consumption of fresh produce. This will require community engagement around sustainable diets and food systems, as well as affordability of the produce
Vertical farms are popping up around the world and York is no exception – we have recently started Grow It York, a vertical farm located within a shipping container in Spark York, a CIC in the centre of York. We want Grow It York to empower the local community around fresh produce – reducing transport, waste and packaging of fresh produce for local food businesses, increasing access to quality nutritious food, providing educational opportunities and engaging the community in building a sustainable food system. We are using Grow It York for more than just food production; to explore how we best integrate vertical farming into urban communities for social, economic and environmental benefits.
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