The green growth hiding in Nicola Harrison's tomato leaf

A tomato leaf is usually a problem to be cleared away. At best, it becomes compost. At worst, it is simply a cost of doing business. Nicola Harrison sees something else in it: a potential raw material for the packaging that protects the tomatoes themselves.

That idea sits at the heart of her new Nuffield Farming Scholarships report, Mapping a Green Growth Strategy for UK Horticulture: From Sustainable Production to the Circular Bioeconomy. It is a report about British horticulture, but its central question reaches far beyond the UK: can a sector under pressure from labour shortages, rising energy costs, climate change and fragile supply chains become a driver of green industrial growth?

For Harrison, now Managing Director of Wageningen-based agrifood accelerator StartLife, the answer is yes. But only if horticulture stops viewing sustainability as a compliance burden, and starts building the systems needed to turn biological resources into new businesses, materials and supply chains. “Green growth is not an endpoint but a transition pathway,” she writes. It positions horticulture not only as a producer of food, but as a contributor to “climate solutions, materials innovation, and regional economic development.”

A study tour interrupted, not stopped

The report has a distinctly personal beginning. Harrison set out in February 2020 with a clear plan: travel through leading horticultural regions, learn how growers, researchers and policymakers were responding to sustainability pressures, and bring those lessons back to the UK.

Her first stop was Australia. Within weeks, COVID-19 closed borders, cancelled flights and sent her home far earlier than planned. “At the time, this disruption felt like a significant setback,” Harrison writes. Instead, it became the defining feature of the study. Unable to travel, she spent the next two years speaking online with growers, scientists, entrepreneurs, innovators and policymakers around the world. The timing turned out to be unexpectedly useful. Her conversations did not take place in a theoretical debate about resilience; they took place while food systems, labour markets and supply chains were being tested in real time.

The result is a report that combines international observations with a clear personal conviction: horticulture lacks no ideas. It lacks the long-term systems that allow those ideas to become a commercial reality.

“As a senior female scientist working in a traditionally male-dominated sector,” Harrison also saw the scholarship as an opportunity to build confidence, broaden her network and strengthen her own voice in debates about leadership, sustainability and the future of food. That personal strand matters. The report is not written by someone observing the sector from a distance, but by someone trying to shift it from within.

From eucalyptus oil to billion-dollar apples

One of Harrison’s first lessons came from Kangaroo Island in South Australia, where she met Larry Turner, an entrepreneur who had moved away from sheep farming to build a eucalyptus and essential-oil business.

What impressed her was not diversification alone. Turner had built a system around it. He worked with the University of Adelaide on eucalyptus genetics, invested in extraction technology and maintained on-site laboratory capacity for product development. The residues from oil extraction were examined for secondary uses, while wood left over from distillation was earmarked for a community-scale biomass heating system.

Waste, in other words, was not an unavoidable cost. It was part of the business model.

The same logic appeared in New Zealand, where Harrison saw a horticultural system with a much clearer alignment between industry ambition, research funding and public policy. The country’s apple sector is worth around NZ$800 million, exports roughly 95 per cent of its production, and aims to reach NZ$1 billion in export value.

But the lesson was not that the UK should copy New Zealand. It was about continuity. Harrison points to a long-running trial involving elite rootstocks and optimised growing systems that achieved yields of up to 220 tonnes per hectare. The point was not a single breakthrough, but the fact that the work had been sustained for more than a decade.

“The lesson here was not about replication,” Harrison writes, “but about the value of long-term, coordinated investment in foundational science.” That observation runs through the whole report. Countries and regions that make progress do not rely on a single promising technology, a single grant scheme, or a single pioneering grower. They connect research, infrastructure, finance, processing and market demand.

The false divide between nature and technology

Harrison’s vision of green growth is not a return to low-tech farming. Nor is it a future of fully automated greenhouses managed by algorithms. “The perceived divide between technology and nature is a false one,” she writes.

The strongest horticultural systems combine biological understanding with technological precision: crop genetics and biological control with sensors, data platforms, AI-supported decision tools and carefully controlled growing environments. Technology should not replace growers’ expertise, she argues. It should make that expertise more effective.

That combination is increasingly visible in protected horticulture. Precision irrigation can reduce water use. Environmental monitoring can improve crop quality and timing. New varieties can be bred for disease resistance, climate tolerance, flavour and nutritional value. Biological crop protection can reduce dependence on synthetic inputs.

But none of these developments, Harrison warns, should be treated as isolated fixes. The real gains come when they are embedded in systems that make commercial sense for growers.

Horticulture as a supplier of industrial raw materials

The report’s most ambitious argument is that horticulture should look beyond the food aisle.

Crop residues, trimmings, rejected produce and processing by-products can become feed ingredients, functional compounds, renewable energy, fibres, packaging materials and even construction products. Horticulture, Harrison argues, can become a supplier of renewable biological feedstocks for industries currently dependent on fossil resources.

There are already early examples. A UK collaboration between APS Produce and Biotech Services Ltd showed that tomato leaves can be converted into packaging for tomatoes. Elsewhere, citrus peel is being used to extract essential oils and flavour compounds. Crop residues can be processed into fibres for textile applications. Mycelium-based materials point towards alternatives to leather and carbon-intensive construction products.

The technical possibilities are no longer the main problem. “The recurring challenge is therefore not innovation capability, but system design,” Harrison writes. Individual growers cannot create collection systems, regional processing hubs, standards, customer demand and manufacturing partnerships on their own. Circularity only works when the full chain works.

That means growers need to be linked to food processors, materials companies, packaging specialists, construction firms, investors and customers. It means biomass needs to be aggregated at a sufficient scale. And it means policymakers must provide businesses with sufficient certainty to invest.

Turning research into a programme

Harrison did not wait for the report to be finished before testing its ideas. In 2021, she led the Growing Green pilot in Kent and Medway, a sustainability programme for horticultural and plant-based food and drink businesses. Over three months, 33 companies received sustainability training, environmental assessments, tailored decarbonisation plans and opportunities for peer learning. Twenty-four businesses received grants, together worth £180,000, to implement low-carbon innovations.

An independent assessment found that all participating businesses were on track to reduce their carbon footprint, while also improving recycling, reducing waste and saving water. The programme was expected to support more than 20 jobs and generate £3 million in gross value added in Kent and Medway by 2028.

For Harrison, that experience matters because it proves that the gap between strategy and action can be closed. “Translating research into action is not only possible, it is urgently needed,” she writes.

The model was simple but powerful: give smaller companies trusted advice, practical tools, financial support and a network of peers. It reduced the risk of trying something new. More importantly, it gave businesses a reason to see sustainability as an investment in resilience, rather than another cost.

Examples of modern horticultural environments where improved genetics, crop management, and precision technologies are converging to strengthen productivity, quality, and resilience. Source: © Nicola Harrison

The missing infrastructure

Harrison’s final call is blunt. The UK (the world?) should create long-term, ten-year-plus innovation programmes for horticulture, rather than expecting businesses to transform through short funding cycles and fragmented projects.

She argues for regional processing hubs, stronger links between horticulture and manufacturing, better market intelligence, stable standards and policy alignment between food, agriculture, climate and industrial strategy. She also argues that the UK should revisit the idea of a Green Bioeconomy Centre: a national or regional facility that could bring together research, demonstration, commercialisation support and supply-chain development.

A previous funding application for such a centre was unsuccessful. Harrison does not hide the disappointment. But she treats it as evidence of the very problem her report identifies: promising cross-sector ideas often struggle because they do not fit neatly into existing funding and policy silos. The need, she argues, has only become more urgent.

Horticulture is often discussed in terms of farms, harvests and supermarket shelves. Harrison’s report asks us to picture something larger: a sector that produces food, captures carbon, reduces waste, supplies new materials, strengthens regional economies and builds businesses around biology.

The tomato leaf is a small example. But it carries a big message. The value is already there. What is missing is the ecosystem able to keep it in play.