The growing media industry is essential to sustainable horticulture, with peat substitutes offering significant potential to reduce greenhouse gas (GHG) emissions relative to peat-based substrates. HORTICERT, an international certification system for sustainable peat substitutes and substrates, supports the ecological, social, and economic sustainability of peat substitutes used in growing media. By certifying materials like compost, wood fibers, bark humus, and coconut-based products, HORTICERT promotes sustainable horticulture through peat-free and peat-reduced growing media. HORTICERT has developed a uniform methodology for calculating and verifying GHG emissions across the supply chain, from raw material production to the distribution of the final growing media mix, including cultivation or extraction, all processing steps, and the transport and distribution of intermediate and final products, enabling transparent GHG savings statements. The transparent forwarding of sustainability characteristics of products is ensured through a developed digital traceability tool covering all supply chain actors. The project is funded by the BMEL and is carried out under the direction of the Agency for Renewable Resources (Fachagentur für Nachwachsende Rohstoffe e.V. – FNR). Meo Carbon Solutions GmbH has been commissioned with the development and implementation of HORTICERT. This article outlines the sustainability standard of HORTICERT with its sustainability requirements, as well as the methodology for GHG emission calculation and reporting under HORTICERT.

The environmental footprints of growing media and components thereof, particularly those of horticultural peat, are receiving increasing attention. Despite this, a comprehensive overview of the impact of growing media is not well understood. Here we outline a framework for mapping the environmental impacts of growing media, highlight current knowledge, and suggest future avenues for research. The environmental impacts of growing media can be measured at three levels: those of components, those of mixes, and those based on the application context. Most footprint reduction efforts have focussed on the mix level (i.e. substituting components), but reductions can also be made through improving practices in components’ production, using lower volumes through more efficient growing techniques, and by using growing media most fit for purpose for an application setting. The recent, industry led development of standardised guidelines for performing Life Cycle Assessment(LCA) on growing media (the Growing Media Environmental Footprints Guideline - GMEFG) has aimed to facilitating the consistent and comparable measurement of footprints of components and mixes. However, major challenges persist in practice, where current comparisons often overlook the properties and application contexts of growing media, typically evaluating equal volumes rather than equal use cases (e.g. the amount of growing media needed to produce 1 kg of tomatoes). A holistic life cycle perspective on plant production is essential, incorporating the influence of growing media on the utilisation of fertilisers, water, and plant protection products. To aid in this goal, the GMEFG has been integrated into larger horticultural LCA frameworks, such as the FloriPEFCR (cut flowers and potted plants) and FreshProducePEFCR (fruits and vegetables). Researching the impacts of growing media across the entire plant production chain is vital to paving the way for more sustainable practices in horticulture.

The aim of this study is to explore the environmental and social benefits of healthy food and green living in comparison to the lifecycle impact of growing media. In recent years discussions about the sustainability of growing media have focused on the impact of raw materials themselves, like the ecological impact of compost, coir, mineral wool, peat or perlite. At the same time, the growing media industry is at the foundation of horticulture, enabling the growth of fresh fruits and vegetables as well as the production of ornamentals for gardening and urban greening.  While many studies have explained the multitude of benefits from gardening, residing in green (urban) surroundings, and eating healthy food, the role that growing media plays in enabling these benefits has not yet been explored.

In the past years many approaches to quantify impact have included ‘monetization’ to enable a better understanding for a broader range of stakeholders. By quantifying and monetizing the social and environmental externalities of the lifecycle of substrates and what they enable, we are able to put the use of growing media into perspective. We perform a lifecycle assessment of growing media recipes that are commonly used in soft fruits, tree nurseries, landscaping projects and consumer potting soils. As well as provide the key externalities of gardening, healthy food and green surroundings. By quantifying and monetizing the growing media impacts and the externalities a comparison is made.

The impact of growing media is assessed for four different scenarios; (1) soft fruits, (2) tree nurseries, (3) landscaping projects and (4) consumer potting soils. In each scenario common recipes and more sustainable alternatives are assessed. We hypothesize that the social and environmental benefits of healthy food and green living enabled by growing media are significantly higher than the lifecycle impact of their production and use.

In 2023, 7.9 million m³ of growing media were sold in Germany, of which 5.8 million m³ were sold to the German market. On average, growing media produced in Germany still consists of 57% horticultural peat. Current peat extraction areas, remaining available peat quantities, and total CO₂e emissions caused by peat are currently estimated significantly too high by politicians and interested stakeholders, as is the availability of peat substitutes.

The Industrieverband Garten (IVG) e.V. represents, among other interests, the concerns of substrate producers on the German market. The current production quantities and raw materials used are always recorded among the members. This also includes the quantities of peat used as well as data on the extraction area and on imports and exports. The International Peatland Society (IPS) as technical and scientific expert organization is also getting involved in the topic, collecting and interpreting data and giving Peatlands another voice.

Here we discuss the new data for the year 2024 and also provide an overview of the situation in select other European countries.  We also explore the possibilities to adopt the Dutch Covenant on renewable substrates in Germany under current or future political situations. The main question will be how the availability of peat substitutes can be increased without compromising quality, and how horticulture and trade can deal with this situation. Under what criteria could peat continue to be used in gardens and horticulture without negative effects and what would be necessary for this? The answer to this question should also give horticulture planning security and ensure a future in production for all cultures.

In Canada, the areas where the horticultural peat industry operates or has ever operated totals 36,032 hectares. This represents 0.03% of Canada’s total peatland area, and about 1% of the country's impacted peatland area, far behind other disturbances such as agriculture, mining, hydroelectric reservoirs and forestry. To date, one-third of the area impacted by the peat industry has been restored or reclaimed. 

Through close collaboration with academic research teams, including the Peatland Ecology Research Groupe (PERG; Université Laval, Québec), the horticultural peat industry has contributed to the development of a successful and now widely applied peatland restoration method. Both operationally feasible and ecologically successful, this method allows the ecological functions of sites, particularly carbon sequestration and biodiversity, to return rapidly after restoration.  

This presentation will provide an overview of our industry’s approach to restoration, explain our long-standing relationship with academia, and how we translate this science into actions and best practices. We will also summarize the latest results from our research collaborators, such as the greenhouse gas (GHG) emissions at different stages of the peat life cycle, and the development of tools to support industry best practices, such as a GHG calculator to support certification requirements. The latest statistics on peatland used by the industry will be presented, including a follow-up on the implementation of the National Peatland Restoration Initiative aimed at reducing the industry's historical footprint. Finally, new areas of improvement and commitment for the horticultural peat industry in Canada for its sustainable future will be discussed.