The Green Garden Audit is already reducing the carbon emission of this year’s Chelsea gardens and has the potential to have an even wider impact if adopted across the industry.

This year’s RHS Chelsea Flower Show is already being touted as the greenest yet – and it’s hardly surprising, considering all designers for Main Avenue and the Sanctuary Gardens were asked to calculate the sustainability of their gardens at pre-selection stage. They were all required to complete a new Green Garden Audit, put together by design and build company Nicholsons.

The audit has been an ongoing project for managing director Liz Nicholson, who is passionate about reducing the carbon footprint not just of her company but of the entire landscaping industry. “There are two themes that we need to be concerned about: climate and nature. And climate is very well established. There’s an awareness of the Task Force for Climate-related Financial Disclosures (TCFD) and people talk about scope 1 and 2 and carbon offsetting. That’s all language that many businesses are familiar with. But increasingly, people are understanding nature. The Task Force for Nature-related Financial Disclosures (TNFD) is a new policy that’s coming down the tracks and businesses are now being called to account for their broader impacts on nature, which can include societal impacts such as impacts on poverty, people and education, but also true nature like water, air and biodiversity would be a big one.”

Liz Nicholson, who spearheaded the Green Garden Audit

It’s easier said than done, though. “It’s a big subject and it’s very science based; it’s difficult to find pathways because for every question you ask, there might be people who naysay it and ask how we really know that and whether we have measurements for it. It’s difficult to get 100% accurate. So, it’s a draft audit – a work in progress – that’s dynamic. We want feedback from people to help us learn.”

The Green Garden Audit for RHS shows takes into account everything from how many skips are being used and the litres of fuel used for plant on site through to the impact on biodiversity when the garden is relocated and whether Plant Healthy nurseries are being used. It goes into the carbon impact of the products, the deliveries and getting labour to and from the showground, though it does not account for the carbon when the garden is relocated elsewhere after the show.

It’s a condensed version of the wider audit that Nicholson has created for her own company and others to use on real world projects, something that she has been working on for a while after seeing no associations or trade bodies were making much progress in producing their own for the industry. During lockdown, with socialising off the cards, Nicholson became a charted environmentalist with the Institute of Environmental Management and Assessment (IEMA), something which she says gave her confidence to take it on herself.

“We’re really lucky at Nicholsons. We have a garden design company and a contracting company, but also an ecology department, a landscape architecture department, a soils department and an arboriculture department. So, we didn’t just have the immediate skillset, but we also could reach out to colleagues for help.”

One of those colleagues is Jake Conway, an estimator and qualified surveyor who has been integral with the carbon accounting for the audit, says Nicholson. They worked together to choose the most common building materials and what would most typically cause emissions, working out the “carbon maths” of these items.

But the audit has also been peer reviewed too, by Paul Cowell of PC Landscapes – a landscaping company renowned for its sustainable approach – and construction giant Morgan Sindall Group, which looked at the methodology and linked Nicholson to carbon reduction tool CarboniCa.

After a soft launch with the designers at Chelsea this year, Nicholson is now hoping to bring the RHS, the British Association of Landscape Industries, the Society of Garden Designers, the Association of Professional Landscapers and the Landscape Institute together in one room to agree a framework for all their members to work towards. “That would be my dream, and if that could happen, our whole industry would lift.”

As a tool, it challenges a designer or landscaper to consider the environmental impact of their choices at an early stage and allows them to see where reductions in their carbon footprint could be made. It made a significant impact ahead of this year’s Chelsea, with changes as a result of going through the audit leading to a 28% reduction in carbon emissions across the two show garden categories.

There are six silos to it: waste, carbon, biodiversity and ecology, water and air, sustainability and on-site materials, and communities and access. Scores are provided for each of these silos and a traffic light system shows where these scores sit in terms of their environmental impact – a low score would be red, meaning it’s not very environmentally friendly, for instance.

Nicholsons uses a less condensed Green Design Audit across its own projects

It takes Nicholson team members around an hour to complete the audit per garden, as they have designed it on Vectorworks and can measure the necessary elements. The first one can take around a day, though, as you need to think about all the materials, admits Nicholson.

She says she has tried to make it as simple as possible for users to fill in the dashboard. “I don’t think it’s particularly clever, but it provides one place to capture what we all should be doing. I’ve got a sort of strapline for this project: ‘Don’t let detail be the enemy of progress.’ If I’d let detail own this, we wouldn’t be where we are now.”

The first Chelsea designers to go through the audit were “really positive,” says Nicholson. It’s not part of the judging process but it was mandatory at the pre-selection phase and all the designers “welcomed it” and saw its value. More designers have got in touch with Nicholson since to ask to use the Green Garden Audit in their own work, something which she not only welcomes but is actively encouraging. “We don’t charge people to use it and we don’t see it as intellectual property; we want to share it with the industry and for the whole industry to rise together.”

As Nicholson alludes to, the impact of the Green Garden Audit extends beyond Chelsea and could be adopted across the landscaping industry to start measuring but also considering the environmental impact of projects. If it can reduce the carbon footprint of this year’s Chelsea gardens by more than a quarter, the possibilities outside of RHS shows are possibly far greater.