More yield, less field: how vertical farming is saving space, water and emissions

The Guardian

13-02-2025

If the UK is to hit its target of net zero carbon emissions by 2050, our food supply chains will have to become much more sustainable, given global food systems now account for one-third of all greenhouse gases. Supermarkets have a key role to play in how those systems change, but it's a daunting task, especially when it comes to ensuring the fresh produce we expect stays on our shelves all year round.
As consumers, we've all become used to having fruit and veg out of season. But those shopping habits have come with a price that goes beyond the checkout – produce that's not in season or native to the UK has to be imported, and that increases the carbon footprint of our weekly shop. So, how is Tesco stepping up to the challenge?
One way involves supporting innovation among its suppliers, such as Wicks Farm, one of a handful of growers using vertical farms to supply Tesco with some of the British strawberries it sells year-round. This high-density approach – which, sees the crop being grown in stacked layers, in a controlled, indoor environment, instead of being grown on tabletops in polytunnels – reduces carbon emissions and requires 50% less water than conventional growing methods, while also delivering three and a half times more fruit per square metre.
It's just one of the strategies Tesco is employing in partnership with British suppliers to farm more sustainably and reduce the carbon footprint of our food.
Low-carbon fertiliserProducing conventional fertilisers is a very energy intensive process, accounting for almost 1.5% of total global CO2 emissions, with the UK currently importing about 60% of the fertiliser it needs. As such, this is an area Tesco is particularly keen to target across its supply chain.
To get the ball rolling, in 2023 Tesco partnered with five of its largest suppliers of field vegetables to launch the UK's biggest commercial trial of low-carbon fertiliser. Low-carbon fertilisers are made using renewable energy sources, instead of fossil fuels, but maintain the same chemical and physical composition as fossil-fuel derived fertilisers.
The initial results were hugely promising, showing that low-carbon fertilisers are just as effective as conventional fertilisers, while slashing emissions by up to 50%.
This ambitious trial could pave the way for the large-scale production of low-carbon fertiliser here in the UK. The hope is that this, in turn, can boost home-grown food security and reduce carbon emissions in the supply chain.
Responsible sourcingDeforestation is a major issue globally and many commodities linked to deforestation have complex supply chains, making it difficult for supermarkets to accurately trace the origins of these products. However, Tesco is committed to help mitigate the impact of food production on the environment.
According to Tesco's group sustainability director, Gemma Brierley, one of the main challenges facing the industry as a whole is soy. 'Soy is a key ingredient in animal feed, which contributes to deforestation,' she says. 'That's why we are working together with our industry partners to work towards a groundbreaking target of sourcing 100% of soy from verified deforestation and conversion-free areas.' In addition, the retailer is also looking at ways to support farmers directly, including offering low-interest loans to farms that commit to growing soy without causing deforestation or land conversion.
Another key tool in tackling deforestation will be regulation. Across its entire group, including in the UK, Tesco will comply with new EU deforestation regulations, which mandate that only deforestation-free products can be placed on the EU market or exported. To help create a coherent regulatory landscape, the retailer is pushing for similar regulations to be introduced in the UK. This will help businesses eliminate raw materials that have been sourced from newly deforested areas from their supply chains.
Leaf MarqueBut sustainable change also needs consumer backing, and to this end all 500 of Tesco's UK fruit and veg growers are Leaf Marque certified. The certification, which can be seen on fresh produce packaging in Tesco stores, is an assurance to shoppers that growers are committed to protecting biodiversity and farming more sustainably. Such labelling makes it easier for shoppers to make more sustainable choices.
Having hit the significant milestone of rolling out Leaf Marque certification to all its UK growers, Tesco is now looking towards its next target: bringing its entire global fresh-produce supply chain that supplies the UK on board by the end of 2025, making everyone's groceries that bit greener.
Want to know more? Watch the video Journey to Greener Groceries: Innovative Supply Chains, to see vertical farming in action