Dr Marc Redmile-Gordon

Dr Marc Redmile-Gordon leads the research in soil biology and ecosystem nutrient cycling to highlight sustainable ways gardeners can improve their soil and deliver climate mitigations

What do you do?

As an environmental scientist, I help deliver RHS sustainability targets through research and review.
My research aims are:

  • 1) To develop more efficient and rewarding ‘gardening practices’, which dovetail into local ecosystems and processes.
  • 2) To further research into soil microbial exudates, ‘Extracellular Polymeric Substances’ (EPS), which maintain soil structure bringing benefits to both climate and soil health.

I am investigating the role of microbial EPS in maintaining soil health and climate with international collaborators. The laboratories at RHS Hilltop are now equipped to extract and investigate these sticky microbial substances. This lab-work helps us to understand i) how soil microbes underpin good soil health and plant productivity; and ii) how soil microbes affect soil carbon storage.

EPS functions like a glue or ‘mortar’, it is vital for holding small soil particles together (silts and clays). A combination of fungal hyphae and EPS maintains soil structural stability, keeping the tiny channels and pores of a healthy soil ‘open for business’ – enabling transport of water, air and nutrients. We have found that improvements in soil structure follow increases in EPS.

Why is your team’s research important?

Soil health: This forms the basis for good-looking plants, wholesome fruit and veg, and biodiversity. At the heart of good soil health is biodiverse food web, releasing nutrients to plants, which in return, provide carbon to the soil. Healthy plants and soil support one another.

Most soil biology is invisible to the naked eye. Microscopic organisms form an intimate relationship with plant roots. The plants invest carbon (taken from the atmosphere) as sugars into the soil. In return, microbes make useful substances (EPS) from these sugars. EPS maintain a soil’s structural stability, which brings benefits to climate, soil biology, and plant-health.

Climate-positive gardening: We can only be confident we are working to combat climate change if we progressively reduce our dependency on fossil fuels. Home-grown carbon has immense value over imported carbon. Once ‘fossil-free’ methods of gardening are established, a well-structured soil can help to mitigate climate change by reducing emissions of greenhouse gasses. Improving soil health also improves a soil’s resilience against drought and flood – bringing additional plant-health benefits. Improved plant growth enables the temporary removal of more CO2 from the atmosphere. This carbon can then be stored in the local soil for decades.
Climate-positive soil management requires attention to the seasons. Soils rich in organic matter tend to lose nitrogen in wet conditions, with some of this becoming N2O (a potent greenhouse gas). We are investigating treatments and approaches to prevent this.

Projects I’m working on now

  • Climate-positive lawns Supported by Innovative Farmers, this work on the South Downs is trialling the use of a ‘climate-positive’ soil treatment, which slows grass growth.
  • Peat-free carnivores Carnivorous plants are among those often thought to require a peat-based growing medium. We aim to demonstrate if this is ‘fact or fiction’ by comparing a range of alternative growing media with peat.
  • EPS research The RHS is contributing world-class understanding on how microbial exudates (EPS) can improve soil-health, plant-health and climate.
  • Biochar research As a practical carbon sequestration technique, biochar deserves consideration as a garden soil amendment. In addition to participating in soil biochar research, I contribute as a member of the Expert Advisory Group on Nottingham’s Greenhouse Gas Removal (GGR) project.

Completed projects

  • A method for reducing nitrate leaching from soil.
  • Understanding the role of extracellular polymeric substances (EPS) in agricultural soils.


  • Successfully defended patents as the inventor of soil nitrogen innovation on 6 continents.
  • Co-supervised 4 PhD students.


  • Shen Q, Redmile-Gordon M, Song J, Li J, Zhang K, Voroney P, Xu J, Brookes PC. (2021) Amendment with biodiesel co-product modifies genes for N cycling (nirK, nirS, nosZ) and greenhouse gas emissions (N2O, CH4, CO2) from an acid soil. Biology and Fertility of Soils, 57(5), pp629–642
  • Fu Y, Kumar A, Chen L, Jiang Y, Ling N, Wang R, Pan Q, Singh BP, Redmile-Gordon M, Luan L, Li Q, Shi Q, Reid BJ, Fang Y, Kuzyakov Y, Luo Y, Xu J. (2021) Rhizosphere microbiome modulated effects of biochar on ryegrass 15N uptake and rhizodeposited 13C allocation in soil. Plant and Soil, 463(1–2), pp359–377
  • Andrade VHGZ de. Redmile-Gordon M, Barbosa BHG, Andreote FD, Roesch LFW, Pylro VS. (2021) Artificially intelligent soil quality and health indices for ‘next generation’ food production systems. Trends in Food Science & Technology, 107, pp195–200
  • Han C, Zhang Y, Redmile-Gordon M, Deng H, Gu Z, Zhao Q, Wang F. (2021) Organic and inorganic model soil fractions instigate the formation of distinct microbial biofilms for enhanced biodegradation of benzo[a]pyrene. Journal of Hazardous Materials, 404 (Pt A), 124071
  • Redmile-Gordon M, Gregory A, White R, Watts. (2020) Soil organic carbon, extracellular polymeric substances (EPS), and soil structural stability as affected by previous and current land-use.
  • Cai P, Sun X, Wu Y, Gao C, Mortimer M, Holden, PA, Redmile-Gordon M, Huang Q. (2019) Soil biofilms: microbial interactions, challenges, and advanced techniques for ex-situ characterization. Soil Ecology Letters, 1(3), pp85–93.
  • Redmile-Gordon M, Evershed R, Hirsch P, White R, Goulding K. (2015) Soil organic matter and the extracellular microbial matrix show contrasting responses to C and N availability. Soil Biology and Biochemistry. 88, pp 257–267
  • Richter G, Agostini F, Redmile-Gordon M, White R, Goulding K. (2015) Sequestration of C in soils under Miscanthus can be marginal and is affected by genotype-specific root distribution. Agriculture, Ecosystems & Environment. 200, pp 169–177
  • Redmile-Gordon M, Brookes P, Evershed R, Goulding K, Hirsch P. (2014) Measuring the soil-microbial interface: Extraction of extracellular polymeric substances (EPS) from soil biofilms. Soil Biology and Biochemistry. 72, pp 163–171
  • Armenise E, Redmile-Gordon M, Stellacci A, Ciccarese A, Rubino P. (2013) Developing a soil quality index to compare soil fitness for agricultural use under different managements in the Mediterranean environment. Soil & Tillage Research. 130, pp 91–98
  • Redmile-Gordon M, Armenise E, White R, Hirsch P, Goulding K. (2013) A comparison of two colorimetric assays, based upon Lowry and Bradford techniques, to estimate total protein in soil extracts. Soil Biology and Biochemistry. 67, pp 166–173

Get involved

The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.