Workshop summary: practical management of peat-free growing media II

Key messages and presentations from the RHS peat-free workshop on 7 February 2024 at RHS Garden Bridgewater

About the workshop

The second in a series of RHS peat-free workshops for growers took place on 7 February 2024 at RHS Garden Bridgewater, Greater Manchester.

The workshop focus was practical management of peat-free growing media, with speakers including Neil Gray and Dr Victoria Wright of Melcourt; Andrea Marshall and Stuart Staples of Westland Sinclair; and Prof Alistair Griffiths, RHS Peat-free Transition Fellow Dr Raghavendra Prasad and Nikki Barker from the RHS peat-free team. 

Introduction by Prof Alistair Griffiths (2.0MB pdf)

Key messages and presentation slides from each of the speakers can be found below.

Prof Alistair Griffiths, RHS

Melcourt growing media samples

Melcourt

Neil Gray – Associate Director
Dr Victoria Wright – Technical Manager

Download Melcourt’s presentation (5.3MB pdf)

Key messages
  • Melcourt have always been peat-free and so have a long history of research and development into peat-free ingredients and mixes. Nothing goes into our bags without extensive testing and research on its properties
  • No one size fits all – we can tailor mixes to ensure the ingredients work for you

 
  • Our mixes work across all types of plants, but irrigation will depend on the mix – the team can work with you to find the best irrigation for your mix
  • Sylvamix is comparable to peat in its properties as it was developed over 20 years ago with peat as the main competitor

Neil Gray, Melcourt

Dr Victoria Wright, Melcourt

Westland Sinclair

Andrea Marshall – Head of Professional Growing Media
Stuart Staples – Head of Technical

Download Westland Sinclair’s presentation (5.5MB pdf)

Key messages
  • Westland/Sinclair produce more than 50% of all bagged growing media sold in the UK, and are also the biggest peat-free producer
  • Growers are understanding more and more about the properties of various peat-free mixes as manufacturers research and learn more about their ingredients and pass this knowledge on

  • Always talk to the technical team from the growing media manufacturer as every nursery has different conditions, environments, irrigation and crops
  • The technical team can help with advice on nutrition and irrigation for you and help if you encounter problems
  • Peat-free growing media is on an upward curve and research and trials show that all kinds of plants can be grown peat-free

Andrea Marshall, Westland Sinclair

Stuart Staples, Westland Sinclair

Nikki Barker – RHS

RHS peat-free policy for RHS suppliers and shows exhibitors

Download Nikki’s presentation (0.9MB pdf)

Key messages
  • The RHS is aiming to be 100% peat-free in all operations by 01/01/2026
  • The RHS peat-free policy for suppliers and exhibitors only applies to the plants that are used or sold at RHS shows or outlets; the supplier or exhibitor does not have to be 100% peat-free

 
  • Any potting action after 31/12/25 must use peat-free growing media. The products may still contain legacy peat (peat that was already in the production system up to 31/12/25)
  • We are here to help!

Nikki Barker, RHS

Dr Raghavendra Prasad, RHS

Dr Raghavendra Prasad – RHS

Monitoring crop performance

Download Raghavendra’s presentation (2.9MB pdf)
The RHS Transition to Peat-Free Fellowship is looking into key challenges across the industry by working with a range of industrial partners.

It is important to standardise peat-free trials against your regular growing media mixes as a control. Replicates help to ensure that human error or environmental factors are not giving a false result.

Trials are randomised and replicated. We do not give peat-free mixes any special treatment – we need to see how they perform commercially, and ensure any changes in inputs that could affect costs can be planned for.

Peat-free growing media needs to be treated differently – for example, with regards to irrigation and nutrition – as physical and chemical properties of the growing media varies depending on the bulk ingredients (woodfibre, composted bark, coir etc). 

Key messages
  • Trials in a commercial setting are being carried out across many plant groups at eight fellowship nursery partners as part of the RHS Transition to Peat-Free fellowship
  • Set out what you want to achieve before you start your trials
  • Ensure there is a control using your regular mix, and trials are repeated and randomised within your setting

  • Test the growing media at the beginning and the end of the trial, and also during trials if possible, to understand the trend/progression of physical and chemical attributes
  • Assess various parameters including selected morphological traits, economics of cultivation (inputs/cost implications) and most importantly plant saleability/marketability

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