Growing Media

AHDB has funded a range of projects to help the horticulture industry become less reliant on peat-based growing media by assisting in the development, adoption and management of a range of new media blends made from various responsibly sourced raw materials.  Other projects and output have focused on the development of best practice methodologies when dealing with growing media.


Growing Media Review magazine

The Growing Media Review magazine provides the latest industry progress and research in the work towards helping the horticulture industry reduce its reliance on peat. The government paper, 'A Green Future: Our 25 Year Plan to Improve the Environment' published in January 2018 has reconfirmed the target to 'restoring our vulnerable peatlands and ending peat use in horticultural products by 2030.' AHDB has funded several research programmes including ' CP 138Transition to responsibly sourced growing media use within UK Horticulture' to help the industry achieve this ambitious target, and the magazine offers a useful update on the progress the project has made. 




Developing new blends of responsibly sourced growing media


AHDB/Defra/industry funded project CP 138: Transition to responsibly sourced growing media use within UK Horticulture aims to increase the uptake of a range of responsibly sourced growing media, based on  materials such as bark, wood fibre, coir and green compost. 

AHDB are supporting this project in order to ease the transition from a dependence on peat-based growing media in horticulture and to encourage the use of a broader range of responsibly sourced growing media to reduce the reliance on any one type of material.

At the core of the five-year project is the creation of a model that can be used to predict the performance of combinations of raw materials.

The research will also take into consideration the effect of different growing media blends on plant quality and shelf life and any required modification of irrigation and nutrition regimes to accommodate the new blends.

Trials are being undertaken on a selection of crops grown in a range of production systems including potted herbs, strawberries, field-grown lettuce, fruit trees, bedding plants and hardy nursery stock.

Events have been held across the UK to share the latest trial results, and will continue throughout the course of the project. Future dates will be announced on our events page













Technical Monograph: Growing Media Laboratory Methods 


Further information about the project and latest results can be found here:


Gallery: Developing new blends of growing media events

Developing New Blends of Growing Media


Sampling methodologies


Regular analysis of growing media can help better refine mixes and nutritional programmes to improve plant growth and quality.


Using the correct methodology to take growing media samples from crops for analysis is critical to ensure results are both accurate and consistent. Understanding and correctly interpreting the analysis results is vital to ensure correct decision making in terms of any remedial action. 


Growers can consult our factsheet: ‘Sampling methodologies and analysis interpretation for growers of hardy nursery stock’ for helpful guidance, the factsheet also covers sampling leaf tissue and irrigation water. 
















A guidance video has also been created to show the recommended method for taking a substrate sample:




Growers interested in optimising the nutrition of container-grown ornamental plants can consult our factsheet, which provides an update on the use of controlled release fertilisers, as well as recommendations on base fertilisers and supplementary feeding techniques.  This factsheet will be updated during 2018.


It also covers the importance of pH, monitoring and water quality in relation to plant nutrition. – This is also covered in ‘Water quality for the irrigation of ornamental crops’.


Strawberry growers can also consult our factsheet that is designed to provide a basic understanding of the nutritional requirements of strawberries grown in soil-less substrates (predominantly peat and coir). It should be used in conjunction with the strawberry feed calculator which helps growers to calculate the quantities of fertilisers they need to use to achieve the recipes included in this factsheet. 


Disease control


AHDB are currently researching how different growing media and production techniques for substrate grown crops might reduce plants susceptibility to disease.


  • Tomato root mat disease

As part of project PE 029, looking at control options for tomato root mat disease, researchers are examining how the use of different growing media might reduce the plants’ susceptibility to disease. Results have been positive using Carbon Gold, an enriched bio-char. The most effective products to reduce symptoms of root mat disease in rockwool production so far have been Carbon Gold Biology Blend and a mixture of the biopesticides Serenade ASO and Trianum P.


  • Hydroponics

As part of trials at The National Cut Flower Centre, research is underway to develop experimental deep-pool hydroponic systems. This is in response to the challenges of controlling fusarium wilt in soil-grown cut flowers, particularly stocks.




For further information on recent AHDB research on growing media for horticulture, please consult the research project pages: 

CP 138: Transition to responsibly sourced growing media use within UK Horticulture

CP 095: Fellowship - Sustainable resource use in horticulture: a systems approach to delivering high quality plants grown in sustainable substrates, with efficient water use, and novel nutrient sources

HNS 182: Developing optimum irrigation guidelines for reduced peat, peat-free and industry-standard substrates