The growth of growing media market by 2050: demand and availability of raw materials

1 Introduction

Soilless culture refers to the cultivation of plants in systems without soil in situ (Gruda, 2008), in which the plant roots mainly develop in porous growing media (commonly known as potting soils or soilless substrates). Several materials that have been extensively used as growing media constituents include peat, coir, bark, wood fiber, compost, mineral wool, and perlite (Barrett et al., 2016; Schmilewski, 2017). These raw materials, often produced according to quality standards, carry a lower risk of soilborne pathogen contamination and are easier to sanitize than field soil. This is due to the inherent properties of the materials themselves (e.g., peat) and/or the application of appropriate processing methods, such as external heat treatment (e.g., wood fiber, mineral wool) or internal heat generated through composting. This helps reduce disease pressure from soilborne pathogens and decreases the need for soil fumigants (Postma, 2010; Raviv and Lieth, 2008). Moreover, compared to soil-based cultivation, plants grown in soilless cultivation have a relatively small rooting volume. This limited rooting volume requires more frequent water and nutrient supply, which facilitates plant uptake of water and nutrients and thereby crop yield (Assouline et al., 2012; Maboko et al., 2009; Roosta et al., 2025). The use of growing media also makes it possible to collect and re-use the drainage water, which greatly enhances resource use efficiency (i.e., water and fertilizers) (Zhou et al., 2021). As a result, the global adoption of soilless cultivation is expanding, with increasing production areas and yields (Aitken, 2012; Blok et al., 2021; Walters et al., 2020). This expansion is driving greater demand for growing media. The advantages mentioned, however, need to be weighed against possible disadvantages such as a higher use of energy, growing media material, plastics, and higher demands for economic and cultivation management (Raviv and Lieth, 2008; Van Tuyll et al., 2022). Even more complex questions are the common but avoidable reduction in microbial life of the underlying soil and the use of non-circular fertilizers. Such discussions benefit from numerical data and life cycle assessment (LCA)-like tools.

The growing media industry in Europe and North America has historically relied on peat as its dominant raw material (Schmilewski, 2017). Since the late 1980s, peat extraction from peatlands has raised environmental concerns due to its negative impact on peatland ecosystem services such as carbon sequestration, biodiversity, and water regulation (Bragg and Alexander, 2019). This has brought peat extraction for horticultural use and the use of peat in horticultural products into policy discussions in several countries, including Germany (Bundesregierung, 2019), UK (UK Parliament, 2025), Netherlands (VPN, 2022), and Chile (Chile Law, 2024), among others (Gruda et al., 2024). Raw materials other than peat, whether already commercialized or still under research, also face certain challenges that the industry must address before they can be adopted (Litterick et al., 2025). These challenges can generally be grouped into three main drivers influencing the selection of raw materials: performance, economic, and environmental (Barrett et al., 2016). An effective growing medium must provide reliable and predictable performance to support plant growth and, for professional applications, to facilitate automation as well as irrigation and fertilization practices for growers. Except peat and coir, other organic raw materials pose certain limitations in their properties, which control their maximal possible volume used in growing media (Barrett et al., 2016; Blok et al., 2016b; Vandecasteele et al., 2018). As a result, mixtures are still relying heavily on peat or coir. Significant economic considerations include the cost of material acquisition (including raw material availability and competition from other users), associated treatments or processing (e.g., washing or sanitation to improve material performance), transportation cost, and legislation-related costs. Regarding environmental drivers, there is a growing need to quantify and assess the environmental impacts of raw materials other than peat. Relevant studies have examined the LCA of growing media constituents (GME, 2024; Hashemi et al., 2024; Quantis, 2012; Schmilewski, 2014; Stucki et al., 2019). While environmental considerations are gaining momentum in Europe (partly through voluntary commitments of stakeholders), this movement appears to be less pronounced in other regions. Although it remains unclear how quickly or to what extent environmental restrictions on raw material selection will be implemented regionally, the environmental impacts of raw materials remain a point of interest. Taking these factors into account in raw material sourcing, the key question remains whether the growing demand can be met given the uncertain availability of raw materials.

The growing media industry and governments have attempted to map the demand and availability of raw materials for growing media via surveys and forecasting studies. Trends in the use of raw materials over time have been monitored through periodic surveys, mainly in Europe. These surveys have been organized at the national level by trade associations and governments such as Industrieverband Garten (IVG) in Germany (IVG & GGS, 2024), Vereniging Potgrond-en Substraatfabrikanten Nederland (VPN) in the Netherlands (VPN, 2024), and the Horticultural Trades Association (HTA), the Department for Environment, Food and Rural Affairs (Defra), and the Agriculture and Horticulture Development Board (AHDB) in the United Kingdom (DEFRA, 2023). At the EU level, similar efforts have been undertaken by the International Peatland Society (Schmilewski, 2009, 2017). In addition, potential supplies of growing media constituents have been quantified, including global coir availability (Van Doren et al., 2019) and the potential supply of renewable raw materials for Europe (Blok et al., 2024; Hirschler et al., 2022). These studies indicate that the potential supply capacity of raw materials is sufficient, but the actual available quantity for growing media is unclear due to competition with other sectors and the growth rate of raw material production.

Blok et al. (2021) was the first study to predict growing media demand for 2050 and to quantify the potential supply capacity of raw materials at the global level. The authors predicted a fourfold increase in growing media volume by 2050 compared to that in 2017, considering trends such as population growth, income increase, healthier lifestyles, and urbanization. The authors also projected that approximately 65 Mm³ of new raw materials not yet accounted for would be required to meet this demand, taking into account the realistically available volumes of already commonly used raw materials. One important conclusion was that developments could occur more rapidly than expected when trends and technological advancements align and when societal support for material recirculation grows. However, these developments could also be slowed by less favorable economics.

The study by Blok et al. (2021) used solid data for the two main drivers of demand for growing media in 2050: population growth and income increase per population segment (Aitken, 2012; OECD and FAO, 2014; Rosling et al., 2018). The subsequent quantifications for what the authors called trends (lifestyle, urbanization) were subjected to greater uncertainty due to limited data availability. Regional developments were reported at the continental level. Estimates of growing media use by producers were based on conversions from reliable data on the cultivated areas per application segment to the volumes required. However, the way in which these conversion factors led to the final estimates was not described in detail in the text and required study of unpublished supplements.

Based on the details above, this study set out to improve the estimates by Blok et al. (2021) by (1) using more recent data, (2) incorporating new trends, (3) applying a different segmentation for population and income that better reflects emerging markets, (4) using a more detailed division of global regions, (5) employing an improved segmentation of application categories, and (6) providing a clearer description and use of conversion factors from area to volume and from raw materials to volume. These combined methodological improvements (1-6) aim to better predict the expected increase in demand and to provide more detailed insight into which regions and application segments are likely to drive the most significant changes.

This study addresses two research questions, namely: (1) What is the expected geographical consumption of growing media in 2050? (2) What is the potential availability of raw materials for growing media by 2050, and what is their projected use in growing media production?

2 Methodology

2.1 Part 1: demand for growing media in 2050

Growing media demand in 2050 was estimated based on current figures for growing media use in 2022 and on projected evolution in horticultural product demand between 2022 and 2050. The year 2022 was selected as the reference year because data collection was conducted in 2024, and most input data (e.g., cultivation area) were available for the majority of the market segments and regions in 2022. In addition, 2022 represents a period of market stabilization after the peak of COVID-19 (DEFRA, 2023). Where data for 2022 were unavailable, the closest available data or an average of existing data were used. Volume of growing media and raw materials is expressed as EN 12580 equivalents.

The model comprises five modules representing different market segments that employ growing media: food crops, ornamentals, tree nurseries, mushroom casings, and hobby market (Table 1). Mushroom casings for button mushrooms (Agaricus bisporus) are included because black peat is the primary component used in this application (Noble et al., 2023). Other types of mushroom cultivation fall outside the scope of this study. Due to the difficulty in obtaining reliable data, this model does not account for the use of growing media in medicinal plant cultivation, such as medicinal cannabis, or its use as bulk material for landscaping.

Table 1. Market segments utilizing growing media in soilless cultivation.

The outcome is presented by geographical regions, including North America, South America, Europe, Africa, Middle East, China, and Asia excluding China (Table 2). Each region is further divided into country groupings based on World Bank classifications (The World Bank, 2023), which the FAO used in a model to apply the relevant factors (i.e., population growth, food consumption) to evaluate the future production of food crops (FAO, 2018). In the FAO model, high-income countries form a separate group independent of region, while other countries, classified as low- and middle-income countries (LMIC), are grouped by geographical regions, including Europe and Central Asia (ECA), East Asia and the Pacific (EAP), South Asia (SA), Latin America and the Caribbean (LAC), Near East and North Africa (NENA), and Sub-Saharan Africa (SSA). Details of the country groupings are provided in Supplementary Table 1.

Table 2. Geographical regions with country groupings.

China refers to mainland China.

2.1.1 Demand for growing media used in food crops

The current growing media volume for food crops (GM_F) is calculated based on the cultivation area using soilless cultures (A_{SC_F}, ha) and a conversion factor that translates cultivation area into growing media volume (f_{V_F}, m³ ha^-1). The cultivation area under soilless culture (A_{SC_F}) is derived from the total cultivation area for food crops grown under protection (A_SG), in containers for berries (A_SB), and cultivation area for field vegetable transplants (A_ST).

GMF=ASC_F∗fV_FASC_F=ASG+ASB+AST ASG=AG+AP∗fSG(for greenhouse fruit vegetables, herbs, and soft fruits)ASB=AB∗fSB(for blueberries)AST=(AOF∗pOF)/pN(for field vegetable transplants)

For greenhouse fruit vegetables, herbs, and soft fruits (A_SG, ha), this area is further divided into cultivation area under glass greenhouses (A_G, ha) and under plastic greenhouses (A_P, ha). Data on cultivation area was derived from national and association sources (DEFRA, 2024; Eurostat, 2024; Statistics Canada, 2024b; Statistics Israel, 2024; Statistics Netherlands, 2024b; USDA, 2024) as well as reports (HollandDoor, 2022; Hoogerwerf and Amrouni, 2023; LAN Seoul, 2021; Suzuki, 2020; Wattanapreechanon and Sukprasert, 2012). Data on the proportion of glass and plastic greenhouses were elaborated from World Vegetable Map (Rabobank, 2018, 2024), where data were not available (Supplementary Table 2). While 100% of glass greenhouses use soilless culture, a percentage of plastic greenhouses (f_SG) that use soilless culture is specified for each region or country (Supplementary Table 3). For blueberries (A_SB, ha), the cultivation area using soilless culture is calculated based on the total cultivation area, including outdoor cultivation (A_B, ha) (FAO, 2024; IBO, 2024). A percentage of cultivation area using soilless substrate (f_SB) is applied for each country (Supplementary Table 4). For vegetable field transplants, the soilless cultivation area is determined by estimating the number of transplants required for a given field area. This is based on the open-field cultivation area (A_OF, ha) (FAO, 2024) and the average planting density (p_OF, plants ha^-1). The number of transplants is then converted into the cultivation area in nurseries by dividing it by the planting density in nurseries (p_N, plants ha^-¹) (Supplementary Table 5). Data on vegetable field transplants were only calculated for Canada and European countries where cultivation data were reported separately by crop applications. For other regions, cultivation area for transplants might also be included in the cultivation area data for greenhouse vegetables and fruits.

For the growing media volume required per cultivation area (f_{V_F}), an average factor of 20 L m^-² was used. This value was chosen based on practices, and a normalized average value was applied across crops with different planting densities. Data on cultivation area for vegetables, herbs, and soft fruits were not always reported separately and might overlap among subcategories (vegetables, herbs, and soft fruits; blueberries; and vegetable transplants). Although not ideal, the use of a single average value represents a pragmatic approach under these conditions.

To predict the growing media demand in 2050, the model uses a parameter production demand evolution for food crops (D_F) which depends on population (P), diet (d; kcal of fruits and vegetables per capita per day), and food waste (w, %) per country groupings (FAO, 2018). Cultivation area using soilless culture in 2050 is a function of current soilless culture area with evolution in production demand (D_F) and a land reduction factor (f_E), which reduces the required cultivation area to produce the same amount of food. Additionally, a proportion of soil-based cultivation area (A_{SO_F}, ha) will be transitioned to soilless culture (f_SC). The same volume factor f_{V_F} of 20 L m^-2 was applied.

DF=[∑P2050∗d2050/(100%−W2050)]/[∑P2022∗d2022/(100%−W2022)]ASC2050=DF∗(1−fE)∗(ASC_F+ASO_F∗fSC)GMF2050=ASC2050∗fV_F

The production demand evolution factor (D_F) represents the global average ratio between the total world production of food crops in 2050 and that in 2022. A single D_F was applied to all geographical regions, even though some countries are net exporters while others are net importers of food crops. Within the scope of this study, accounting for country-specific import–export flows would add substantial complexity. Therefore, a global average value was applied to simplify the modeling approach. Food crop consumption in each region is calculated as a function of population (P), dietary patterns (d), and food loss after harvesting (w), with parameters d and w determined based on country groupings. A single land reduction factor (f_E) and a single soilless shift factor (f_SC) were applied across all regions (Supplementary Table 6).

The factors d and w were derived from the FAO model that reflects fruit and vegetable consumption as a function of income levels, prices, and consumer awareness (FAO, 2018). These drivers are represented through three scenarios to predict food demand in 2050: business as usual (BAU), toward sustainability (TSS), and stratified societies (SSS). In this framework, income growth stimulates substitution away from carbohydrates (staple foods) toward higher-value products such as vegetables and animal-based proteins. Scenario BAU assumes a continuation of current trends and policy directions. In high-income countries, consumers maintain a high consumption of animal products. Scenario TSS represents proactive changes toward sustainable food systems, with increased fruit and vegetable consumption and reduced food waste. In high-income countries, diets shift toward higher fruit and vegetable intake and lower consumption of animal products due to rising consumer awareness of sustainability issues. Scenario SSS reflects growing income inequalities and disparities in resource accessibility. This scenario projects increased food waste and greater consumption of animal products worldwide, with a particularly high rise in high-income countries.

2.1.2 Demand for growing media used in ornamentals

The current growing media volume in ornamentals (GM_O) is calculated based on the cultivation area using soilless cultures (A_{SC_O}) and a conversion factor from cultivation area to growing media volume (f_{V_O}, m³ ha^-1). The soilless cultivation area was derived from the total production area for ornamentals grown under protection and in open fields (AIPH, 2023; LAN Seoul, 2021; OPF Mexico, 2022; Statistics Canada, 2024b; Statistics Italy, 2020; Statistics Netherlands, 2024a; USDA, 2024). A specific proportion of soilless culture was applied to certain countries; where data is unavailable, particularly for Asia, Africa, and South America, the model applies the assumptions outlined in Supplementary Table 7. The volume ratio (f_V) was used as 30 L m^-2.

GMO=ASC_O∗fV_O

To predict the demand in 2050, the model uses the product demand evolution (D_O) as a function of the middle-class population (MC) (AIPH, 2019b; Kharas, 2017) and per capita expenditure on ornamentals (x, € per capita per year) between 2022 and 2050, driven by urbanization and purchasing power (AIPH, 2019a, 2023).

DO=(MC∗x)2050/(MC∗x)2022GMO2050=DO∗[ASC_O+ASO_O∗fSC]∗fV_O

The cultivation area for ornamental crops using soilless culture in 2050 is a function of current soilless culture area (A_{SC_O}) with production demand evolution (D_O) and a proportion of soil-based cultivation area (A_{SO_O}) expected to transition to soilless culture (f_SC). For the three FAO scenarios, the model applies the same soilless shift factor (f_SC) as in the food crops. For ornamentals, it accounts for a geographical shift in production. By 2050, additional production from mature domestic producers—Canada, the USA, Europe, Japan, and China—will be taken over by South America, Africa, and Asia (AIPH, 2019a).

2.1.3 Demand for growing media used in tree nurseries

The current growing media volume in tree nurseries (GM_T) is calculated based on the cultivation area using soilless cultures (A_{SC_T}) and a conversion factor from cultivation area to growing media volume (f_{V_T}, m³ ha^-1). The soilless cultivation area was derived from the total production area for tree nurseries grown under protection and in open fields (AIPH, 2023; Statistics Canada, 2024b; Statistics Italy, 2020; Statistics Netherlands, 2024a; Statistics Switzerland, 2022; USDA, 2024). A specific proportion of soilless culture was applied to certain countries; where data is unavailable, particularly for Asia, Africa, and South America, the model applies the assumptions outlined in Supplementary Table 8. The volume ratio (f_V) was used as 40 L m^-2.

GMT=ASC_T∗fV_T

To predict the demand in 2050, we use the product category demand evolution (D_T). Based on a rough estimate of the cultivation area ratio of 1:9 between fruit trees and other tree crops (ornamentals and forest trees) (AIPH, 2023), product demand was calculated as the proportional contribution of demand for food crops and ornamentals.

DT=0.1∗DF+0.9∗DOGMT2050=DT∗[ASC_T+ASO_T∗fSC]∗fV_T

The cultivation area for nursery crops using soilless culture in 2050 is a function of current soilless culture area (A_{SC_T}) with evolution of production demand (D_T) and a proportion of soil-based cultivation area (A_{SO_T}) expected to transition to soilless culture (f_SC). For the three FAO scenarios, the model applies the same soilless shift factor (f_SC) as for food crops and ornamentals. However, for tree nurseries, no production shifts between geographical areas are considered due to the heavy nature of this crop category.

2.1.4 Demand for casing substrate in button mushrooms

The volume of mushroom casings is calculated based on button mushroom production (PD_M) rather than cultivation area. This approach was taken because cultivation area data may not accurately reflect the mushroom growing cycle. It was assumed that producing 1,000 kg of button mushrooms requires 1.7 m³ of casing in Europe and 1.4 m³ in other regions (Noble et al., 2023). These represent the conversion factor f_{V_M} used in the model.

GMM=(PDM∗fV_M)/1000

To predict the demand in 2050, the production demand increase is based on the population (P_M) of countries that consume button mushrooms and the per capita consumption (c, kg per capita) in 2022 and 2050 (Eurostat, 2024; GFH, 2023; Mayett and Martínez-Carrera, 2010; Rabobank, 2024; Singh et al., 2021; Statista, 2025; UMDIS, 2024) (Supplementary Table 9). For this category, the model does not consider the three FAO scenarios.

DM=(PM∗c)2050/(PM∗c)2022GMM2050=PDM2022∗DM∗fV_M

2.1.5 Demand for growing media in hobby market

Data on growing media use in the hobby market was limited. For Europe, we used data on growing media traded in 2013 (Schmilewski, 2017) and calculate the market growth rate between 2013 and 2022 based on recent available data for the hobby market in Germany (IVG & GGS, 2024), the Netherlands (VPN, 2024), and the UK (DEFRA, 2023). Based on this, a growth rate of 30% between 2013 and 2022 was applied for Europe (Supplementary Table 10). For North America, we assumed that the volume of growing media for the hobby market is approximately 70% of the volume used in Europe. This proportion was based on the lifestyle and the population proportion of North America and Europe. For other regions (South America, Africa, and Asia), no data were available for this market. To predict the demand in 2050, we applied the same growth factor as for growing media in ornamentals.

Figure 1 summarizes the calculation steps in the model to project growing media demand in 2050 for food crops, ornamentals, tree nurseries, mushroom casings, and hobby market.

2.2 Part 2: availability of raw materials for growing media

Raw materials for growing media are categorized into eight main groups of constituents: peat, coir, wood fiber, bark, compost, mineral wool, perlite, and other organic materials/tuffs. Peat refers to the type of peat used in horticulture. Coir is a by-product of coir fiber processing, including mainly coir pith, with a smaller share of coir husk and coir fiber. Wood fiber and bark are limited to coniferous softwood, and composted bark is classified under bark. Compost includes various qualities of green wastes but virtually no household waste. This quality compost is serving both professional and hobby markets. Mineral wool is derived from volcanic rock (stone wool) or sand (glass wool). The last group includes a variety of organic materials (parboiled rice husks, cork, etc.) and mineral components such as vermiculite, pumice, sand, gravel, and volcanic porous gravel.

2.2.1 Recent volume of raw materials

Recent volume for peat was derived from peat harvesting for horticultural use, supplied by the producers in Europe and Canada. Since peat harvesting depends on weather conditions, a 3-year average around 2022 was used to estimate the recent volume. Peat data were obtained from national sources (Statistics Canada, 2024a; Statistics Denmark, 2024; Statistics Finland, 2024; Statistics Hungary, 2024; Statistics Latvia, 2024; Statistics Sweden, 2024) and input from the Scientific Board Advisory of the International Peatland Society (IPS) and Canadian Sphagnum Peat Moss Association (CSPMA). Where data were not available in volume units, a conversion factor (coefficient) was applied to convert the fresh weight of peat (tons) into volume, if applicable (Supplementary Table 11).

Coir data were based on export figures for coir dust (pith, husk) from India, Sri Lanka, and the Philippines (International Coconut Community, 2024; Philippine Coconut Authority, 2022), with the assumption that exports from these countries account for 70% of global production based on the authors’ own estimate. A dry bulk density of 100 kg m^-³ was used to convert dry weight into volume (Joseph-Armstrong and Andekerk, 2000).

Data for wood fiber, bark, compost, and perlite are not readily available, as production depends on individual manufacturers and is not consistently reported. We estimated supply based on growing media demand from part one, identifying key applications of wood fiber and bark—for example, outdoor tree nurseries in the USA primarily use bark, with an estimated ratio of 60% by volume (Fields et al., 2021; Lu et al., 2006). For Europe, we used the survey of Schmilewski (2017) and recent data for Germany (IVG & GGS, 2024), the Netherlands (VPN, 2024), and the UK (DEFRA, 2023) to compare usage rates and estimate recent supply levels. Perlite volumes for USA and Canada were based on USGS data (USGS, 2023). Mineral wool estimates were derived from the area of glasshouse cultivation for greenhouse food crops.

After estimating the volume of the abovementioned raw materials, the remaining category (other organic materials/tuffs) was calculated by difference from the total growing media volume in 2022, based on cultivation area in part one. The remaining category, other organic materials/tuffs, includes various organic and inorganic materials that individually contribute small volumes but collectively form a significant total volume. Volume loss due to interstitial filling during mixing of constituents was not accounted for.

2.2.2 Potential availability of raw materials and their projected use in growing media in 2050

Regarding the raw materials of interest for growing media, we discerned potential availability and projected use. Potential availability of raw materials was defined as the quantity of raw materials suitable for use as feedstock for growing media, regardless of competition with other industries and logistical constraints. One of the basic requirements for such feedstock include a suitable particle size for further defibration; pH, EC, and nutrient levels that are not at extreme values and can be readily adjusted through processing; and the absence of (phyto)toxins and heavy metals. These quality criteria were applied to the intrinsic properties of the feedstock and to processing conditions where the feedstock constitutes the final product. Risks of contamination due to management and transportation were excluded.

Projected use of raw materials in growing media was then calculated as the quantity that can most feasibly be used, taking into account competition for feedstock with other industrial applications and the maximal percentage which can be added to mixtures for various applications. The potential scale-up of the supply industry and growing media industry was assumed to be sufficient to process the available raw materials. For each raw material, the calculation follows a two-step approach (Figure 2). First, the amount of raw material available after accounting for competing uses (net availability) was determined. Second, the demand for the raw material in soilless culture was estimated based on its maximal proportion in growing media mixtures and the growing media volume in 2050. The projected use was defined as the limiting value between these two estimates. If the available amount of raw material after competing uses (step 1) was lower than the estimated demand from soilless culture (step 2), the available amount was taken as the projected use. Conversely, if the available amount exceeded the estimated demand, the latter was taken as the projected use. Projected use of each raw material was evaluated under two scenarios, low availability and high availability, reflecting different assumptions regarding competing usages. The maximal proportion of each raw material in growing media mixtures remained the same across both scenarios. Growing media volume in 2050 was calculated as a mean across three FAO scenarios.

Peat: All the potential availability of horticultural peat was assumed to be used in growing media. The projected volume of peat in 2050 was not constrained by competing uses or by demand for peat in growing media, as peat is a primary component that can be used up to 100% v/v in mixtures. The projected peat volume was instead determined by the harvested peatland area. In the low-availability scenario, peat harvesting was assumed to remain similar to recent conditions for Canada and most European countries. In some European countries, the projected peat volume in 2050 was expected to slightly decrease (based on input from IPS national committee members), while a 20% increase was assumed for Russia, Belarus, and Ukraine. In the high-availability scenario, it was assumed that there will be a 10% increase in European countries and Canada (personal communication, CSPMA) and a 20% expansion in peat yield for Russia, Belarus, and Ukraine.

Coir: Potential availability of coir was based on maximizing coir husk production without expanding recent cultivation areas. The estimate used the 2022 data for countries with copra production exceeding 50,000 ton annually and coconut cultivation areas larger than 30,000 ha (International Coconut Community, 2024). Coir pith production was calculated assuming 1.0 ton coir pith per 10,000 coconuts, a conservative value relative to 1.6 ton coir pith per 10,000 nuts reported by the Coir Board (2016), and converted to volume using dry bulk density of 100 kg m^-3 (Joseph-Armstrong and Andekerk, 2000). Coir can be used up to 100% v/v in growing media mixtures due to its physiochemical properties. Coir as growing medium in soilless cultivation is recently considered the most economically viable and widely applicable use compared to alternatives with lower value or smaller markets, such as soil amendments, binderless fiberboards, and biorefinery applications (Coir Board, 2016). In the low-availability scenario, 80% of the coir volume was assumed to be used in soilless culture, whereas in the high-availability scenario this share increased to 95%.

Wood fiber: The potential availability of wood fiber was estimated based on coniferous wood sources produced in 2022, particularly saw logs and veneer logs (FAO, 2024), which provide higher-quality material. It was assumed that 30% (v/v) of these logs generate sawmill by-products, 8% (v/v) of which were used for energy at sawmills (elaborated from data on sawmill residues in Germany (Kuersten and Mility, 2004)). Of the remaining by-products, 50% (v/v) were considered available as wood chips, with the remainder consisting of sawings, sawdust, slabs, and edgings (elaborated from data on sawmill by-products of softwood in Germany (Kuersten and Mility, 2004)). This wood chips volume was used to calculate the potential availability of wood fiber. Wood chip mass was calculated using a density of 300 kg m^-3 at 40% moisture content (elaborated from Gendek et al. (2016)) and was converted to wood fiber volume using a density of 100 kg m^-3 (Joseph-Armstrong and Andekerk, 2000). To calculate the projected use of wood fiber, in the low-availability scenario, we assumed that 10% of available wood chips (potential availability) could be allocated for growing media production. This assumption was based on competition with other industrial applications such as panel industry, pulp and paper, energy, and others. In the high-availability scenario, 20% of available wood chips was considered to be allocated to growing media production. In both scenarios, the maximal proportion of wood fiber in growing media mixtures was estimated at 40% v/v (own estimate).

Bark: The potential supply of bark was estimated from saw logs, veneer logs, pulpwood, and other industrial round woods from coniferous woods produced in 2022 (FAO, 2024). Bark was assumed to account for 12% of softwood volume. This bark volume was used to calculate the potential availability of bark. A bark density of 350 kg m^-3 was used to convert bark volume to mass. A density 200 kg m^-3 was applied to convert bark mass to growing media volume (Joseph-Armstrong and Andekerk, 2000). To calculate the projected use of bark in growing media, we assumed that 30% of potential bark volume could be allocated for growing media production in the low-availability scenario, reflecting competition with other uses, such as combustion and mulching. In the high-availability scenario, this share was increased to 40% of potential bark volume. The maximal proportion of bark was 30% v/v in ornamentals (own estimate), 60% v/v in tree nurseries in North America (elaborated from Fields et al., 2021; Lu et al., 2006), and 30% v/v in tree nurseries in the remaining regions (own estimate).

Compost: The potential availability of compost was calculated from the potential volume of green wastes from landscaping, parks, and gardens. A global-average amount of annual green waste generation was estimated to be approximately 47 kg per person (Liu et al., 2023). The weight of the final compost was reduced by half compared to the original feedstock. A bulk density of 600 kg m^-3 was used to convert compost mass into compost volume (Joseph-Armstrong and Andekerk, 2000). Compost from green wastes was considered to be exclusively used in horticultural soilless culture due to the price competition with other applications to open soil (Gilbert and Siebert, 2022). The maximum proportion of compost was assumed to be 20% v/v in ornamentals and 40% v/v in the hobby market (own estimate).

Perlite and mineral wool: Since the reserves of perlite ores and volcanic rocks are essentially inexhaustible, natural sources were not used to estimate the potential availability of perlite and mineral wool. Recent industrial production was instead used as an approximate indicator to define their upper availability limit. For perlite, total world production in 2022 was used as total perlite supply (USGS, 2024b). A bulk density of 140 kg m^-3 was used to convert perlite mass into volume (Joseph-Armstrong and Andekerk, 2000). For mineral wool, total world production was estimated from input materials to produce stone wool reported by a major stone wool producer (ROCKWOOL Group, 2025), with the assumption that total world production is double that figure. A bulk density of 50 kg m^-3 was used to calculate the final mineral wool volume (Joseph-Armstrong and Andekerk, 2000). Competing uses were not considered a limiting factor for perlite and mineral wool, given the inexhaustible feedstock and the capacity of the industry to scale up to meet demands. Perlite use was estimated at 20% v/v in food crops and ornamentals (own estimate). Mineral wool was estimated at 30% v/v of growing media used in food crops in Europe and China and 10% v/v of growing media used in ornamentals in Europe and China (own estimate).

Other organic materials/tuffs: The potential availability of this group was estimated based on its dominant raw materials, including rice husk, vermiculite, pumice, sand, clay, and volcanic porous gravel. Recent global production of these raw materials was used to calculate their potential availability. Competing uses were not considered limiting for these raw materials. Their maximum proportion of use in 2050 was assumed to remain the same as their share of total growing media volume in 2022.

New materials: When the total projected use of all of the abovementioned raw materials was lower than the total demand for growing media volume in 2050 (part 1), the resulting gap was quantified as the required amount of new raw materials.

3 Results

3.1 Growing media volume used in 2022

Approximately 116 Mm³ of growing media was used worldwide in 2022, with large shares coming from North America, Europe, and China (Figure 3, Supplementary Table 12).

In terms of volume distribution across market segments, tree nurseries, and the hobby market, each accounted for roughly 30% of the total, followed by food crops at 24%, ornamentals at 14%, and mushroom casing at 4% (Table 3). Due to the limitation in data availability, growing media volume for the hobby market counted only for North America and Europe. When excluding the hobby market from the calculation, tree nurseries emerged as the leading segment consuming the most growing media (40% of the total), followed by food crops (33%). Although food crops had a significantly larger soilless cultivation area compared to tree nurseries (136 vs. 86 Kha) (Supplementary Table 13), the higher growing media volume per square meter in tree nurseries (40 vs. 20 L m^-2) resulted in a substantial overall volume for this segment.

Table 3. Volume of growing media consumption in 2022 by market segment.

Due to data availability, growing media volume counts for the hobby market are only available for North America and Europe.

Within food crops, growing media for blueberries represented 22% of the total growing media used in this category (5.7 Mm³), while growing media for open-field vegetable transplants accounted for 9% (2.4 Mm³) (Supplementary Table 14). Notably, the volume for open-field vegetable transplants excluded China due to potential overlap with data on greenhouse vegetables reported in the Rabobank World Vegetable Map (Rabobank, 2024). The remaining volume was used for greenhouse vegetables and fruits. In tree nurseries, the largest share came from nursery stock crops, particularly open-field production in the USA, which alone accounted for 19 Mm³ (data not shown).

Regarding geographical regions in 2022, North America and Europe accounted for the largest shares of growing media volume when including the hobby market, each at approximately 37%, followed by China at 15% (Supplementary Table 12). However, when excluding the hobby market (due to limited data for Asia and Africa), North America led in growing media consumption (36%), followed by Europe (28%) and China (21%).

In North America in 2022, tree nurseries contributed the largest share of growing media use (Figure 3, Supplementary Table 12). In Europe, the distribution was relatively balanced among food crops, the combined total of ornamentals and tree nurseries, and the hobby market. In China, growing media use was relatively evenly distributed among food crops, ornamentals, and tree nurseries, each using approximately 5 to 6 Mm³. For food crops, an estimated 1.6 Mm³ was used for blueberry cultivation, while 3.9 Mm³ was used for greenhouse vegetables (Supplementary Table 14).

3.2 Growing media demand by 2050

Across all three scenarios, growing media volume in 2050 was projected to increase by 249% to 289% compared to the 2022 usage (Table 4). The toward sustainability (TSS) scenario showed the highest growth at 289%, while the business as usual (BAU) and stratified societies (SSS) scenarios shared a similar projected increase of 249%–251%. It is important to note that all three scenarios used the same population projections and middle-class population estimates. However, variations in consumer preferences (diet, expenditure on ornamentals), food waste levels, land reduction factor, and soilless shift factor influenced the projected demand for growing media.

Table 4. Predicted growing media volume in 2050.

Growth projections for hobby market were not included for these regions. Growth rate (%) between 2022 and 2050 for each market segment in each region were presented in brackets.

For food crops, the model did not account for a shift in production, with China leading at 37%–42% of total growing media volume, followed by Europe at 27%–29%, North America at 11%, Asia (excluding China) at 9%, South America at 6%, and Africa and the Middle East at 4% and 3%, respectively.

For ornamentals, the model accounted for a shift in extra production from mature domestic producers to emerging export producers (AIPH, 2019a). The shares of growing media volume from mature domestic producers, i.e., Canada, the USA, Europe, Japan, and China, in the total growing media for ornamentals were projected to decline slightly in 2050 compared to 2022: China—a 1% decline (34% to 33%), North America—a 4% to 5% decline (29% to 24%–25%), and Europe—a 4%–6% decline (21% to 15%–17%). In Asia (excluding China), the share increased from 13% in 2022 to 17%–19% (a 4% to 5% rise), driven by growth in the Chinese market, as Asia excluding China is exporting to China. Africa and the Middle East had a slight increase of less than 0.3%–1%, primarily driven by a shift in production from Europe. Latin America experienced a 3% to 4% increase, mainly due to a shift of extra production from North America to Latin America.

For tree nurseries, although the absolute values increased across all regions, the projections indicated a sharp rise in China’s share from 15% in 2022 to 40%–46% in 2050. The Middle East also saw a slight increase from 0.05% to 0.06%. In contrast, the share decreased in other regions, with North America dropping from 60% to 36%–41%, Europe from 19% to 13%–14%, and Asia (excluding China) from 4% to 3%.

For the hobby market, limited data availability did not allow for the development of growth projections for several regions: South America, Africa, Middle East, China, and Asia. As a result, the hobby market demand in these regions was not included in the projections. Consequently, total growing media demand in 2050 could be underestimated and could exceed the values presented in Table 4.

3.3 Availability of raw materials for growing media

3.3.1 Peat

Data on peat extraction for horticultural use indicated a recent global volume of approximately 59 Mm³, with approximately 48 Mm³ extracted from Europe (Table 5). Expansion of peat extraction in Europe appears unlikely due to environmental concerns. In the Baltic States and Scandinavian regions, peat harvesting was assumed to continue. In Germany, peat extraction is now primarily limited to black peat. The low-availability scenario assumed no further expansion of peatland extraction in Europe—meaning that no peat extraction in Germany by 2050—alongside strict regulations in some countries. However, it allowed for potential expansion of up to 20% in Ukraine, Russia, and Belarus. The total peat volume in 2050 is expected to slightly decrease compared to the current levels, with a projected reduction of 5.8 Mm³ due to declines in Germany, Latvia, Estonia, Finland, Lithuania, and Sweden. However, in the high-availability scenario, if Canada and the European countries could achieve a 10% yield increase and Russia, Ukraine, and Belarus expanded production by 20%, peat availability in 2050 could reach approximately 63 Mm³.

Table 5. Current volume and projected volume availability in 2050 of horticultural peat.

Peat extraction volume data were calculated as a 3-year average (2021–2023); for Norway, Türkiye, Spain, Ukraine, Russia, and Belarus, data from 2020 to 2022 were used instead. Low-availability scenario (conservative): 20% expansion in Ukraine, Russia, and Belarus, but the same yield in other countries. High-availability scenario (less conservative): 10% peat expansion in Canada, 20% expansion in Ukraine, Russia, and Belarus, and 10% expansion in other European countries.

The potential availability of peat was limited by the volume of peat extraction in 2050, ranging from 53 to 63 Mm³ (Table 6). While the demand for peat in soilless culture, based on its properties as a growing medium, was estimated to be high (305 Mm³, average growing media demand in 2050 across three FAO scenarios), supply remained the limiting factor. Thus, the use of peat in growing media in 2050 is projected at 53–63 Mm³.

Table 6. Potential availability and projected use of horticultural peat in 2050.

Potential availability of horticultural peat was the peat extraction volume.

Peat extraction for horticultural use was assumed to be used exclusively in soilless culture.

Demand for peat in soilless culture was assumed to be equal to the demand for growing media in 2050 (305 Mm³), based on the assumption that peat can be used at up to 100% (v/v) in all applications.

Projected use of peat in 2050 was the net availability of peat, as net availability was the limiting factor compared to peat demand.

3.3.2 Coir

Based on the export quantity of coir from the main producers, the recent supply of coir was estimated at approximately 11.3 Mm³ (Table 7). Considering the maximum utilization of existing coconut husks from countries with large coconut plantations, the potential coir production in 20250 was estimated to be approximately 64 Mm³ (Table 8).

Table 7. Recent supply of coir as raw material for growing media.

Three-year averages (2020–2022) were used, except for the Philippines (2019).

A dry bulk density of 100 kg m^-3 was used to convert coir weight into volume.

India, Sri Lanka, and Philippines were assumed to account for 70% of global production (own estimate).

Table 8. Estimated coir supply for horticultural use in 2050.

Constrained by the maximal coir production from existing coconut plantations, the potential availability of coir in 2050 was estimated at approximately 64 Mm³ (Table 9). After accounting for competing uses such as soil amendments, binderless fiberboards, and biorefinery applications, the net availability of coir was estimated at 51 and 61 Mm³ in low- and high-availability scenarios, respectively. Similar to peat, the demand for coir as a growing medium was assumed to correspond to the total demand for growing media in 2050. As net availability was the limiting factor, it was taken as the projected use of coir in 2050 (51–61 Mm³).

Table 9. Potential availability and projected use of coir in 2050.

Potential availability of coir was the potential coir supply from the maximal utilization of coir husk in countries with large coconut plantations.

After accounting for competing uses (soil amendments, binderless fiberboards, and biorefinery applications), the coir volume available for soilless culture was assumed to be 80% (in low-availability scenarios) and 95% (in high-availability scenario) of the potential availability.

Demand for coir in soilless culture was assumed to be equal to the demand for growing media in 2050 (295 Mm³), based on the assumption that coir can be used at up to 100% (v/v) in all applications.

Projected use of coir in 2050 was the net availability of coir, as net availability was the limiting factor compared to coir demand.

3.3.3 Wood fiber

Based on assumptions regarding the production capacity of wood fiber manufacturers in the USA and the proportion of wood fiber used in growing media mixtures, we estimated that US production was approximately 1.5 Mm³, with Canada producing half of that volume. In Europe, production was estimated at approximately 4 Mm³, bringing the total recent use of wood fiber in growing media to approximately 6 Mm³ (Table 10).

Table 10. Recent supply of wood fiber as raw material for growing media.

IVG & GGS, 2024.

VPN, 2024.

DEFRA, 2023.

Volume of wood fiber in the rest of Europe was calculated from the 2013 wood fiber volume in 13 EU countries (excluding Germany, Netherlands, and UK) in 2013 (0.3 Mm³), scaled using the growth rate of wood fiber in Germany between 2013 and 2022 (2.6 times) and including Norway (0.2 Mm³, estimated).

Volume of wood fiber used in the USA was estimated as the sum of its use in food crops (5% of 1.4 Mm³), in ornamentals (10% of 4.0 Mm³), and in tree nurseries (5% of 19.7 Mm³) (own estimate).

Volume of wood fiber used in Canada was estimated to be half of the US volume (own estimate).

Based on the potential supply of wood chips from the recent world production of coniferous saw logs and veneer logs, nearly 30 million tons of wood chips were projected to be available as raw material for wood fiber production, potentially yielding approximately 295 Mm³ of wood fiber (Table 11). Only 10%–20% of this large volume were assumed to be available for growing media due to competition with other industries, such as panel industry, pulp industry, energy sector, and others. This resulted in a net availability of wood fiber at 30–59 Mm³ (Table 12). Demand for wood fiber as a growing medium was calculated as 40% of the total growing media demand in 2050, resulting in 122 Mm³. As net availability was the limiting factor, the projected use of wood fiber in growing media in 2050 was estimated at 30–59 Mm³ in low- and high-availability scenarios, respectively.

Table 11. Potential supply of wood fiber for growing media in 2050.

Volume of saw logs and veneer logs from coniferous wood sources (FAO, 2024).

The volume of sawmill by-products was assumed to be 30% of the volume of logs.

Of the sawmill by-products, 8% were used for energy at sawmills; 50% of the remaining by-products were considered available as wood chips.

Wood chip mass was calculated from volume using a density of 300 kg m^-3 at 40% moisture content.

Potential volume of wood fiber for growing media was calculated from the available wood chip mass using wood fiber density of 100 kg m^-3.

Table 12. Potential availability and projected use of wood fiber in 2050.

Potential availability of wood fiber was the potential supply of wood chips from sawmills processing saw logs and veneer logs from coniferous wood sources.

After accounting for competing uses (panel industry, pulp and paper, energy, and others), the wood fiber volume available for soilless culture was assumed to be 10% (in low-availability scenarios) and 20% (in high-availability scenario) of the potential availability.

Demand for wood fiber in soilless culture was assumed to be 40% of the demand for growing media in 2050 (305 Mm³), based on the assumption that wood fiber can be used at up to 40% (v/v) in all applications.

Projected use of wood fiber in 2050 was the net availability of wood fiber, as net availability is the limiting factor compared to wood fiber demand.

3.3.4 Bark

Given the large share of substrate volume used in outdoor tree nurseries in USA (19 Mm³), bark production was assumed to be approximately 11.4 Mm³ in USA and 1 Mm³ in Canada (due to the small area of soilless culture in Canada) (Table 13). Including the 3 Mm³ of bark used in Europe, the current total volume of bark was approximated at 17.5 Mm³.

Table 13. Recent supply of bark as raw material for growing media.

IVG & GGS, 2024.

VPN, 2024.

DEFRA, 2023.

The volume of bark in the rest of Europe was calculated from the 2013 wood fiber volume in 13 EU countries (excluding Germany, Netherlands, and UK) in 2013 (1.3 Mm³), scaled using the growth rate of bark in Germany between 2013 and 2022 (1.7 times).

The volume of bark used in the USA was estimated as its use in outdoor tree nurseries (60% of 19 Mm³).

Own estimate.

The potential supply of bark was calculated from the recent world production of coniferous saw logs, veneer logs, pulpwood, and other industrial roundwood. The results indicated that up to 45,500 Mt of bark could be potentially available for growing media, translating to nearly 228 Mm³ (Table 14). After accounting for competing uses such as combustion and mulching, 30%–40% of this volume was assumed to be available for growing media use, resulting in 68–91 Mm³ (Table 15). Given that bark constitutes approximately 60% of growing media mixtures in tree nurseries in North America, 30% in tree nurseries in the remaining regions, and 30% in potted plants, approximately 57 Mm³ of bark was estimated to be needed for growing media. This demand was the limiting factor relative to net availability after competing uses. Therefore, 57 Mm³ was estimated as the projected use of bark in growing media in 2050.

Table 14. Potential supply of bark for growing media in 2050.

Volume of saw logs, veneer logs, pulpwood, and other industrial roundwood from coniferous wood sources (FAO, 2024).

Bark was assumed to account for 12% of wood volume.

Bark mass was calculated from volume using a density of 350 kg m^-3.

Potential volume of bark for growing media was calculated from available bark mass using density of 200 kg m^-3.

Table 15. Potential availability and projected use of bark in 2050.

Potential availability of bark was the potential supply of bark from sawmills processing saw logs, veneer logs, pulpwood, and other industrial roundwood from coniferous wood sources.

After accounting for competing uses (combustion and mulching), the bark volume available for soilless culture was assumed to be 30% (in low-availability scenarios) and 40% (in high-availability scenario) of the potential availability.

Demand for bark in soilless culture was calculated as the sum of its use in ornamentals (30% of 43 Mm³), in tree nurseries in North America (60% of 42 Mm³), and in tree nurseries in the remaining regions (30% of 65 Mm³).

Projected use of bark in 2050 was the demand for bark in soilless culture, as this value is the limiting factor compared to the net availability of bark after competing uses.

3.3.5 Compost

The recent supply of compost was estimated at 3.5 Mm³ in Europe and 5 Mm³ in North America (Table 16). The potential and net availability of compost was feasible (381 Mm³) due to the large availability of green waste feedstock (47 kg per person annually) and the stronger competitive position of growing media relative to other uses of compost (Table 17). For 2050, assuming compost constitutes 40% of the hobby market and 10% of ornamental growing media, the potential global demand was estimated at 43 Mm³. This value represented the projected use of compost in soilless culture in 2050.

Table 16. Recent supply of green compost as raw material for growing media.

IVG & GGS, 2024.

VPN, 2024.

DEFRA, 2023.

Volume of compost in the rest of Europe was calculated from the 2013 composted green waste volume in 13 EU countries (excluding Germany, Netherlands, and UK) in 2013 (0.7 Mm³), scaled using the growth rate of green compost in Germany between 2013 and 2022 (2.1 times).

Volume of compost used in the USA was estimated as 70% of the compost produced for commercial horticulture (landscapers, nurseries, and topsoil blenders) (2.2 Mt (US Composting Council, 2025)), with a bulk density of 600 kg m^-3.

Own estimate.

Table 17. Potential availability and projected use of compost in 2050.

Potential availability of compost was calculated from total green waste generation worldwide (9.7 world population and average green waste generation of 47 kg per person (Liu et al., 2023)), with 50% weight loss during composting and final compost bulk density of 600 kg m^-3.

Green compost was assumed to be used exclusively for soilless culture.

Demand for compost in soilless culture was calculated as the sum of its use in ornamentals (20% of 43 Mm³) and in the hobby market (40% of 86 Mm³).

Projected use of compost in 2050 was the demand for compost in soilless culture, as this value is the limiting factor compared to the net availability of compost.

3.3.6 Perlite, mineral wool, and other organic materials/tuffs

The recent volume of perlite used in horticulture was estimated at approximately 1.7 Mm³ worldwide (Table 18). Assuming that perlite can be used up to 20% v/v in mixtures for food crops and ornamentals, in 2050 we would need approximately 21 Mm³ (Table 19). There is no current limit on the supply for such a quantity of perlite as the natural reserves are ample (USGS, 2024b). The calculated potential availability of perlite based on recent world production was 35 Mm³ (Table 19). For mineral wool, the recent volume was estimated based on the cultivation area of glass greenhouses that use mineral wool (approximately 34,000 ha, excluding cannabis), with approximately 6.8 Mm³. With an estimate of 30% share of growing media for food crops in China and Europe and 10% share of growing media for ornamentals in China and Europe, the potential use of mineral wool by 2050 was approximated at 14 Mm³ (Table 19). The potential availability of stone wool was estimated to be 112 Mm³. Other organic materials/tuffs could maintain their 6% share of total growing media as in 2022, resulting in an estimated volume of 18 Mm³ by 2050.

Table 18. Recent supply of perlite as raw material for growing media.

IVG & GGS, 2024.

VPN, 2024.

DEFRA, 2023.

Volume of perlite in the rest of Europe was calculated from the 2013 perlite volume in 13 EU countries (excluding Germany, Netherlands, and UK) in 2013 (0.25 Mm³), scaled using the growth rate of perlite in Germany between 2013 and 2022 (1.6 times).

Volume of perlite used in the USA was calculated from US perlite production for horticulture (0.08 Mt (USGS, 2023)), with a bulk density of 140 kg m^-3.

Own estimate.

Table 19. Potential availability and projected use of perlite, mineral wool and other organic materials/tuffs in 2050.

Potential availability of perlite was calculated from total perlite production worldwide (4.9 Mt in 2022 (USGS, 2024b)) and bulk density of expanded perlite of 140 kg m^-3. Potential availability of mineral wool was calculated from estimated feedstock material (112 Mt, estimated (ROCKWOOL Group, 2025)) and mineral wool bulk density of 50 kg m^-3. Potential availability of other organic materials/tuffs was estimated as the sum of availability of rice husk production worldwide (1.5 Mm³, calculated from 0.15 Mt rice husk (Kordi et al., 2024) and a bulk density of 100 kg m^-3), vermiculite (3.7 Mm³, calculated from 0.5 Mt vermiculite (USGS, 2024e) and a bulk density of 140 kg m^-3), pumice (45.5 Mm³, calculated from 18 Mt pumice (USGS, 2024c) and a bulk density of 400 kg m^-3), sand and gravel (0.2 Mm³, calculated from 0.3 Mt (USGS, 2024d) and a bulk density of 1,600 kg m^-3), volcanic porous gravel (1.3 Mm³, calculated from 1 Mt (NPA, 2022) and a bulk density of 800 kg m^-3), and clay (60 Mm³, calculated from 72 Mt (USGS, 2024a) and a bulk density of 1,200 kg m^-3).

Competing uses were not considered limiting for these raw materials.

Demand in soilless culture was assumed to be 20% v/v perlite in food crops and ornamentals, 30% v/v mineral wool in food crops in Europe and China, and 10% v/v mineral wool in ornamentals in Europe and China. Other organic materials/tuffs were assumed to retain their 2022 share at 6% of total growing media volume.

Projected use of these raw materials in 2050 was their demand in soilless culture, as these values were the limiting factor compared to their net availability.

3.3.7 New materials

With an estimated growing media demand of approximately 305 Mm³ in 2050 (based on the average across three FAO scenarios) and the projected use of above-mentioned raw materials, there remained a gap of approximately 17 Mm³ for new materials in the low-availability scenario (Table 20). In the high-availability scenario, no additional new raw materials were projected to be required, as the projected supply of commonly used raw materials could meet the demand in soilless culture. It is very important to note that this projection relies on the assumption that the supply industry and growing media infrastructure can scale up sufficiently to process all available raw materials. This assumption requires further validation, as such rapid expansion is unlikely to occur seamlessly in real-world conditions. A more detailed discussion is provided in Section 4.6.

Table 20. Volume of raw materials used in soilless culture in 2022, and their potential availability and projected use in 2050.

Potential availability of raw materials was defined as the quantity of raw materials suitable for use as feedstock for growing media, regardless of competition with other industries and logistical constraints.

Projected use of raw materials was defined as the quantity that can most feasibly be used in soilless culture, taking the limiting factor between net availability after competing uses of feedstock with other applications and the demand for raw material in growing media determined by the maximal proportion of that raw material in growing media mixtures. Low- and high-availability scenarios reflect less and more competition for feedstock with other industrial applications, respectively. Demand for raw material in growing media remained the same between the two scenarios.

4 Discussions

4.1 Recent growing media volume

Our model uses a bottom-up approach to estimate the global growing media volume used in 2022 for food crops, ornamentals, tree nurseries, and mushroom casings based on cultivation area or mushroom production data and conversion factors for the growing media volume required per area or production. For the hobby market, growing media volume was projected by applying an estimated growth rate to the 2013 volume. The results showed that approximately 116 Mm³ growing media was used in 2022 worldwide (Figure 3). While exhaustive national census or primary survey data are currently insufficient for a direct global comparison, existing industry reports from several key regions are available to validate our findings.

For Germany, our model calculated a total growing media volume of 1.9 Mm³ for 2022 as the sum of food crops (0.6 Mm³), ornamentals (0.4 Mm³), tree nurseries (0.8 Mm³), and mushroom casings (0.13 Mm³). This total aligns with the 2.0 Mm³ professional market usage reported by IVG & GGS (2024) for 2023.

For the Netherlands, our results showed a total growing media of 3.7 Mm³ for 2022, comprising food crops (1.2 Mm³), ornamentals (0.9 Mm³), tree nurseries (1.2 Mm³), and mushroom casings (0.4 Mm³). This value is highly comparable to the volume reported by VPN members for 2023. VPN reported that 5.3 Mm³ of growing media was sold domestically for both professional and hobby market (VPN, 2024). After subtracting the 1.3 Mm³ for consumer market (which we assumed to be sold primarily domestically), the resulting 4.0 Mm³ for professional market is consistent with our findings.

For UK, the total volume for 2022 was estimated at 0.64 Mm³, consisting of food crops (0.1 Mm³), ornamentals (0.1 Mm³), tree nurseries (0.3 Mm³), and mushroom casings (0.14 Mm³). This value is of the same order of magnitude as the 1.1. Mm³ reported for 2022 (DEFRA, 2023).

For China, our estimate of 17.5 Mm³ of growing media used in China in 2022 is broadly consistent with, though higher than, the industry report (Wakefield, 2025), which stated that the total volume used in China exceeded 10 Mm³ annually in 2024. Data on cultivation area for China varies significantly. This variation, combined with the country’s vast scale, leads to substantial differences in estimations. According to the Rabobank World Vegetable Map, China’s greenhouse area has expanded significantly, if not surprisingly, between 2016 and 2022 from 82,000 to 990,000 ha (Rabobank, 2018, 2024). Compared with other studies, the greenhouse area reported by Rabobank for 2016 is substantially lower than the estimate reported by Sun et al. (2025). The estimate derived from satellite imagery, which reported total protected cultivation without distinguishing between vegetables, ornamentals, and tree nurseries, indicated areas of 554,460, 835,920, and 1,295,480 ha in 2010, 2016, and 2022, respectively. The 2022 estimate from Rabobank aligns with the 2019 figure of 796,100 ha for total greenhouse area derived from satellite images by Tong et al. (2024). Our estimate suggests that the soilless cultivation area in China is approximately 59,300 ha: approximately 27,500 ha for food crops, 19,000 ha for ornamentals, and 13,000 ha for tree nurseries. This estimate is generally consistent with the reported 50,000 ha of soilless cultivation in 2020 by Sun et al. (2022).

4.2 Projected growing media demand in 2050

The growth projections under the business as usual (BAU) and stratified societies (SSS) scenarios (289–291 Mm³) align with the 2050 estimate of 283 Mm³ of growing media reported in a previous study by Blok et al. (2021). In the more optimistic scenario toward sustainability (TSS), a higher volume of 335 Mm³ was projected. Across the three scenarios, growing media use in 2050 was expected to be 2 to 2.5 times the volume in 2022.

As the same conversion factors from area to growing media volume are used to calculate the volumes in 2022 and 2050, the increase in growing media between 2022 and 2050 depends on the increase in the area of soilless culture for food crops, ornamentals, and tree nurseries. This increase in cultivation area is driven by several factors (or trends) such as population growth, diet consumption, food waste, conversion of soil-based to soilless culture, etc. Given the complexity of these variables and the varying quality of the data used to quantify them, it is difficult to judge whether our projection is an underestimate or an overestimate. However, we can at least identify the leading drivers (though not the single power to control the demand) for each market segment, allowing us to monitor market developments and adjust model parameters to improve future projections. By averaging these factors across all regions, we can quickly identify the contribution of each driver to the increase in growing media within each market segment.

For food crops, growing media demand in 2050 was driven by a 22% increase in population, an 18-31% increase in fruit and vegetable consumption, a 0%-5% production increase due to food waste, a 5%-10% reduction due to less land being required to produce the same yield and a 57% increase in the fractional area of protected soil-based cultivation shifted to soilless culture.

For ornamentals, the demand in 2050 was driven by 61% increase in middle-class population, 15% increase in consumer expenditure, and 18% increase in the fractional area of soil-based cultivation shifted to soilless culture. In this segment, middle-class population growth was the leading driver of the overall increase.

For tree nurseries, the demand in 2050 depended on 81% increase in product demand (driven mainly by ornamental demand) and 61% increase in the ratio of soil-based area converted to soilless culture. Demand for mushroom casings was driven by 2% increase in the consuming population and 43% upward trend in mushroom consumption.

Population growth, middle-class growth was based on the prognosis of the FAO (FAO, 2018), AIPH (AIPH, 2019b), and the Brookings Institution (Kharas, 2017). As authors, we have relied on these established institutional projections rather than adjusting them ourselves. Cultivation area in 2022 and the share of soilless culture in 2022 seem justified based on comparable findings in several countries as mentioned in Section 4.1. The conversion factor (f_SC), which represents the shift from soil-based to soilless culture by 2050, plays a major role in the projections for food crops and tree nurseries. A small change in this factor can result in a large change in the result, particularly for the regions with large cultivation area. For mushroom casings, the upward trend in mushroom consumption was the leading driver. However, this assumption was based on the industry’s own aspirations and must be monitored.

Overall, the prediction for ornamentals seems robust, as the main driver (the middle-class population) was based on established projections. For food crops and tree nurseries, the soilless shift factor appears as the primary driver. This factor was based on the authors’ assumption using a single value for all regions. Therefore, it needs to be monitored and adjusted for updated regional data. For all four segments, the scale of demand could be lower if smaller growing media volumes are needed per cultivation area in the future.

4.3 Considerations on parameter sensitivity

This study was not intended to provide a full sensitivity analysis. Selected calculations were instead used to illustrate the relative sensitivity of key parameters and assumptions. Supplementary Table 15 presents the calculations for growing media use in China for food crops in 2022 and 2050 under the BAU scenario as an example to discuss the sensitivity of the results to data fluctuations and deviations.

The 2022 calculations were based on cultivation area data from the Rabobank World Vegetable Map and FAOSTAT for blueberries. The cultivation area data for greenhouse vegetables in 2022 are comparable to those reported in other studies and are therefore not subject to large fluctuations. However, allocation of cultivation area to specific crop groups is less certain, as this information cannot be usually verified using aerial or satellite imagery. Consequently, percentage allocations and conversion factors are the most sensitive components, as small changes in these values can substantially affect the results.

For the 2022 data, the most sensitive parameters are as follows: (1) The percentage of cultivation under glass greenhouses in China was assumed to be 1%. This value was derived from the Rabobank World Vegetable Map classification, which indicates that more than 95% of Chinese greenhouses are plastic. Although the plausible range of 1%–5% is small, China’s large cultivation area means that this assumption can result in large absolute changes. The selected value of 1% is uncertain but was chosen to avoid excessive deviation. (2) The percentage of blueberries cultivated outdoors using growing media (10%) is considered close to the upper bound for 2022 and is expected to fluctuate between 1% and 10% over time (3). The conversion factor from cultivation area to growing media volume (200 m³ ha^-1, equivalent to 20 L m^-2) is less sensitive overall despite representing an average across crops with large differences in substrate requirements, such as berries (50 L m^-2) and tomatoes (7–10 L m^-2). Overall, the estimated volume of growing media used in China in 2022 is considered conservative.

The 2050 calculations multiply the 2022 volume by an estimated increase in demand based on assumptions regarding population growth, diet, and food waste. The population growth assumptions are relatively robust. Dietary changes are more uncertain, as they depend on public trends that are difficult to quantify; however, given the health-driven need for dietary change, the assumed increase is considered plausible. The food waste factor (6%–17%) has a limited effect, as waste is not expected to exceed approximately 10% of total production. Overall, the estimated demand increase is not highly sensitive to changes in these factors.

The cultivation areas in 2022 were converted to expected areas in 2050 by multiplying demand growth and correcting for improvements in area efficiency (land reduction factor, f_E) and a transition from soil-based to soilless cultivation (f_SC). (1) The land reduction factor of 5% has a limited effect in China, as the area converted from soil to soilless cultivation is eventually about three times larger than the current soilless area (i.e., 108,679 ha compared to 27,465 ha). (2) The transition factor from soil-based to growing-media-based cultivation (5%) results in an area approximately three times larger than the area currently under greenhouse soilless cultivation and has the greatest influence on the final outcome. (3) The factor converting cultivation area in 2050 to growing media volume is much less sensitive, consistent with the 2022 analysis.

Thus, the predicted growing media volume in China for 2050 is far more sensitive to the assumed transition factor from soil-based to soilless cultivation (5%) than to other parameters. A more-in-depth analysis of the calculation frame and sensitivity of parameters remains open for future studies.

4.4 Methodological considerations

The outcome of this study is briefly compared to previous results (Blok et al., 2021), using the numbering of the adapted factors of this study given in the “Introduction”: (1) We conclude that the use of more recent data did not in itself change the overall outcome of the previous study on the demand for growing media; (2) The change from the population segmentation according to WHO to the one suggested by FAO did not significantly alter the predictions; (3) The more detailed division into global regions provides significantly improved information on China, as data are generally more often based on individual country statistics; (4) The improved classification of applications illustrates, for the first time, the important and previously overlooked role of tree production in the use of growing media. Moreover, the production of berries and vegetable crops has become much more prominent. (5) The clearer description and use of the conversion factors will greatly facilitate both the replication of this study and scientific critique on the chosen values.

Our project was undoubtedly ambitious, and numerous elements deserve a critical review. We identify the following areas where we suggest improvements for future research: (1) A general observation to start with is the common optimistic bias in industry forecast data. This is partly because new adverse developments are much more common than unknown stimulating developments. We choose not to downplay our predictions to maintain methodological integrity. Some estimates are supported by relatively weak data, such as branch organization outlooks, for example, the mushroom consumption data; (2) We use one single factor of growing media volume per area for each cultivation category for all regions. It is possible to further specify these factors per region, crop, and cultivation system. For the present study, we choose to use the more general approach as we expect the answer to lie close to the middle of the extremes (5–50 L m^-2), and any additional accuracy would be lost by the most sensitive conversion factor used, the conversion factor for soil to soilless; (3) Another possible improvement on our methods is to differentiate the production demand evolution (D_F) in food crops, showing a difference between countries producing for their internal market only versus more export-oriented producers. Not many countries, however, are exporting a consequential part of their horticultural production; (4) The soilless shift factor requires further revision to better account for regional variability.

4.5 Recent volume of raw materials for growing media

We employed different estimation approaches for the volume of raw materials, dictated by the availability of primary data. For peat and coir, we utilized a top-down approach based on peat extraction data and coir pith export data from major producers. For wood fiber, bark, compost, and perlite, a hybrid approach was used: where reliable data on reported volume were available, we applied a top-down approach; where data were unavailable, usage was estimated based on the key application markets for these materials.

Peat is currently used at approximately 60 Mm³ as soilless substrate, representing approximately 50% of the recent growing media volume. This figure is 20 Mm³ higher than 40 Mm³ reported by Blok et al. (2021). The difference arises because Blok et al. (2021) relied on peat data from 2005 (Verhagen et al., 2009). Our figure was based on updated peat extraction data provided directly by peat producers and is therefore considered more current.

Coir volume of approximately 11 Mm³ is consistent with the figures reported by Van Doren et al. (2019) (9.6 Mm³ in 2016) and Blok et al. (2021) (11 Mm³ in 2017). This suggests that annual coir production has remained relatively stable at approximately 10 to 11 Mm³. Our assumption that 70% of coir is produced in India, Sri Lanka, and the Philippines is lower than the 90% assumed by Van Doren et al. (2019). This adjustment accounts for the growing contribution of smaller producing countries (e.g., Vietnam, Indonesia, Mexico, Costa Rica, etc.) for both export and domestic use.

Wood fiber, bark, and mineral wool showed a larger volume in this study compared to the 2017 data reported by Blok et al. (2021). The difference is due to our methodology, which categorizes cultivation areas by crop segment, allowing for a more precise assignment of raw material proportions within their respective markets.

4.6 Potential availability of raw materials and their projected use in growing media in 2050

The potential availability of most raw materials was projected to be sufficient to meet the demand for soilless culture. The primary exceptions were peat and coir, which were constrained by the limited capacity for expanding their production (i.e., extraction sites for peat and cultivation areas for coir). For wood fiber and bark, the projected supply potential from existing coniferous log production remained sufficient. Compost from green wastes was also projected to be substantial. Similarly, the projected potential for perlite, mineral wool, and the remaining aggregates group, based on current production across all sectors, was sufficient to cover demand. However, the actual usage of these materials is ultimately limited by at least two factors: their net availability after accounting for competing uses and the demand from soilless culture, which is restricted by the maximal allowable mixing rate for each raw material.

The potential availability of peat in this study (53–63 Mm³) is lower than the quantity estimated by Blok et al. (2021) primarily because we limited potential availability based on recent peat extraction capacity, whereas the previous study estimated it based on total peatland area. Similarly, the projected use estimated in this study is lower than the previous one because of a more conservative assumption regarding peat harvest expansion. The share of peat in total growing media volume is projected to drop by more than half, from 50% in 2022 to approximately 20% by 2050. While it is difficult to project the extent of the impact of future legislative restrictions on peat extraction, particularly within Europe, the growing media industry has been actively investing in and developing peat alternatives. While peat will likely continue to constitute a major component in specific applications where it is technically essential (e.g., for acid-loving plants or propagation), its use in other applications can be gradually substituted with alternative raw materials. The extent of this replacement will ultimately depend on the functional properties of these alternative materials.

Coir is the most promising raw material that can be used as a predominant (or sole) source in growing media much like peat. Our potential availability (64 Mm³) is broadly comparable to, though slightly higher than, the values of approximately 50–60 Mm³ projected for 2050 in other studies (Blok et al., 2021; Van Doren et al., 2019). Compared to the potential availability reported by Hirschler et al. (2022), our estimated weight of coir (6.4 Mt) is substantially lower than their reported 21 Mt. The projected use of coir in our study (51–61 Mm³) is substantially higher than the previous projection by Blok et al. (2021) (46 Mm³). The difference arises because the previous study applied a growth factor, assuming a fourfold increase in production capacity between 2017 and 2050, whereas our projection did not assess the growth rate as a factor, focusing instead on competing uses and demand from soilless culture. Van Doren et al. (2019) also highlighted the logistical and economic challenges of scaling coir production in tropical developing countries, including limitations in infrastructure, skilled labor, political stability, and proximity to major seaports. Furthermore, nascent social sustainability standards, such as those promoted by certification schemes like Horticert, are becoming increasingly relevant for coir products targeting the European market. In this projection, coir’s share of the total growing media market nearly doubles, increasing from approximately 10% in 2022 to 20% in 2050. In our opinion, coir will become a highly competitive raw material, with different regions vying for supply. Specially, the high demand for growing media from China (75–100 Mm³) and the rest of Asia (16–18 Mm³) could attract a significant share of the global coir supply, which is primarily produced in Asia (potentially approximately 58 Mm³).

The potential availability of wood fiber in this study is approximately four times lower than the value projected by Blok et al. (2021). This variation arises from our use of a more stringent feedstock filter, which specially selects log types capable of producing high-quality wood chips for fiber production. Although the methodologies for estimating projected use differ, our projection of 30 Mm³ aligns with the previous study’s estimate (Blok et al., 2021). We applied a conservative assumption that only 10%–20% of wood chip by-products are available for the growing media sector. This fraction was based on established feedstock allocation patterns reported for Germany (Kuersten and Mility, 2004), where market shares of wood chips were allocated as follows: 30% for pulp and paper, 22% for composite panels, 37% for trade (which is also supplying for wood-based panels), 10% export, and 0.3% for energy. We assume that competition with the energy sector might be less problematic as it is already familiar for peat producers (Blok et al., 2024). Competition with the panels, pulp, and paper sectors may present significant challenges. In our current projection, the market share of wood fiber in growing media was expected to double, increasing from 5% in 2022 to 10% in 2050.

The potential availability and projected use of bark in this study are higher than the value reported by Blok et al. (2021), as the separation of crop-specific inputs was not feasible in the earlier analysis. We assigned a large proportion of the bark feedstock to growing media use (30%–40% of potential availability) compared to wood fiber (10%–20%) mainly because the bark faces fewer competing uses. The market share of bark remained relatively stable at 15%–18% between 2022 and 2050.

The projected uses of the remaining raw materials (compost, perlite, mineral wool, and other organic materials/tuffs) are also higher than the projections in the previous study. In our projection, compost production was expected to increase fivefold. Scaling supply to this level presents a significant challenge regarding the expansion of production facilities and the systematic separation of green waste feedstock. Furthermore, attention must be paid to compost quality issues, including composition variability affecting batch-to-batch consistency, high bulk density, relatively high pH value, and high electrical conductivity (Gruda, 2021).

The competition for feedstock between the growing media sector and other industries leads not only to price competition but also to the necessity of establishing long-term relationships with primary producers. The challenge of competing uses is, however, not insurmountable. First, price competition with energy applications and building boards in the cheaper price segment is already to the advantage of growing media (Blok et al., 2024). Second, competitors outbidding the growing media industry commonly still have substantial residual flows of the contested material. Therefore, cooperative strategies serving multiple purposes would, at least economically, be a logical approach.

Finally, the requirement for new raw materials was identified in the low-availability scenario, whereas it was not deemed necessary in the high-availability scenario (Table 20). The introduction of these new raw materials is addressed in the following section. Before proceeding, we must emphasize that our projections rely on the assumption that the growing media industry can successfully scale its production. This assumption is not robust and subject to change. Moreover, it also significantly influences the final outcomes of this study. The challenges associated with scaling up production for raw materials were discussed previously. Future research should develop a systematic approach to project the production growth rates of these raw materials.

Furthermore, risk factors that disrupt the supply chain, such as climate change, directly impact the availability of raw materials—for example, peat shortage occurred in Europe in 2025 due to wet summer (Hortidaily, 2025). Cyclone Ditwah disrupted coir production in the “Coconut Triangle” of Sri Lanka in late 2025 (Wijewardane, 2025). International conflicts, such as the invasion of Ukraine, have affected energy costs and resource transportation. Therefore, the feasibility of scaling up production should be considered carefully when interpreting the results of this study.

4.7 New raw materials

Several raw materials have been tested as renewable alternatives for growing media (Barrett et al., 2016) Considering criteria such as potential availability (>100,000 m³ per year) to ensure economic feasibility for producers, a few materials stand out: acrotelm, Sphagnum moss, plant fibers from grass species, new wood fibers, and biochars (Blok et al., 2024).

Acrotelm is the uppermost, actively growing layer of a peat bog, composed of peat moss and other peat-forming plants. Since it can regenerate into a harvestable layer within 25 years, it is considered a renewable raw material for substrate production (Karvonen and Myllyviita, 2026). After harvesting, acrotelm undergoes drying, maturation, and sieving before use. Sphagnum moss, cultivated in restored peatlands for harvesting, is another promising material (Gaudig et al., 2018). Compared to acrotelm, it is assumed to have lower contamination of weeds, but both materials exhibit a similar performance. The estimated potential supply of these materials is approximately 2 Mm³ per year (Blok et al., 2024), not counting a possible future increase in Sphagnum moss production. Both materials may still have to face a legal discussion on how to discern them from non-renewable peat.

Plant fibers from miscanthus and other grass species have potential (Altland, 2010; Kraska et al., 2018; Kuisma et al., 2014; Nguyen, 2022), though their supply is constrained by land availability and other industrials such as combustion, animal bedding, and biogas production (Lewandowski et al., 2016; Winkler et al., 2020). Other plant fibers, such as hemp, flax shives, and jute, as well as new wood fibers or bark, have also been tested (Chemetova et al., 2019; Nguyen et al., 2025; Vandecasteele et al., 2018). The main challenge with these fibers is their low biological stability. They contain high amounts of easily degradable organic matter, which leads to nitrogen immobilization and reduced nitrogen availability for plants. This limits their practical use in growing media, where a maximum share of 30%–40% is generally recommended. Research efforts have explored ways to optimize these materials for use as standalone substrates, showing promising results (Kraska et al., 2018; Woznicki et al., 2023). However, due to differences in conditions and practices between research settings and commercial growers, translating these findings into practical applications requires further communication and research efforts.

Various types of biochars are under evaluation, but their availability remains limited (Blok et al., 2017; Blok et al., 2016a). Given the ongoing efforts within the industry and research sectors to enhance the performance and scalability of these materials, the potential for new raw materials to meet the future demand for growing media appears promising.

Besides the strategy of using of new materials in growing media, other strategies like reuse of growing media are gaining importance as well. The practice of directly reusing growing media has been tested, demonstrating its feasibility (Vandecasteele et al., 2020, 2024; Woznicki et al., 2024). Knowledge of sanitation and fertilization management is required to safely advance this practice (Blok et al., 2023). Logistic challenges also need to be addressed, particularly in terms of efficiently collecting spent growing media and reusing it on-site. In the Netherlands, approximately 45,400 m³ of spent growing media has been recovered, primarily for the hobby market (VPN, 2024). The potential for reuse of growing media is expected to be much higher than the volume that is currently reused. There are several variants of reuse of growing media, including direct reuse as a stand-alone material by the same grower, reuse for other crops by another grower after sanitation, and reuse as a growing medium constituent after sanitation or composting at a centralized processing plant.

New raw materials, acrotelm, Sphagnum moss, softwoods and deciduous species, fiberized bark, plant fibrous mass (including bagasse and bamboo), biochar, spent casing, and spent growing media, all still require significant development (Gruda, 2021). This begins with establishing long-term relationships with primary producers. Since there are often many of these producers, complex logistics and corresponding safety controls are also necessary. In addition to safety controls, which address both biological and non-biological contaminants, these raw materials must be processed to achieve reliable and homogeneous technical properties (Blok et al., 2024). Non-limiting examples of such processing include sanitation, rinsing, sieving, fractioning, stabilizing, and pH reduction. Therefore, quality control systems, sanitation, and technical pre-treatment for these materials demand substantial research and development efforts.

The additional efforts needed to improve raw material performance, combined with rising demand for growing media, are likely to increase costs. This underscores the need for innovative cultivation strategies. Growers may respond by using smaller volumes of substrate or reusing spent growing media to reduce expenses. These practices can help maintain productivity while reducing pressure on raw material supplies.

5 Conclusions

The results of this study indicate a significant increase in the demand for growing media by 2050, with an estimated growth of 250%–290% relative to the 2022 levels. The ornamental and tree nursery markets are projected to experience a higher growth rate than the food crop market, driven by economic expansion. The increase in demand will be particularly pronounced in China and emerging markets in Asia, South America, and Africa.

Regarding feedstock, we identified significant potential availability for wood fiber, bark, compost, perlite, mineral wool, and aggregates group to meet the demands of soilless culture. Conversely, the availability of peat and coir remains limited by constraints at the production sites. In the high-availability scenario, the projected supply of these raw materials is sufficient to meet the total growing media demand without requiring novel alternatives. However, in low-availability scenarios, approximately 17 Mm³ of new materials will be required.

These projections rely on the assumption of maximal potential production scaling; however, this assumption is subject to change given existing industrial challenges. Consequently, securing raw material supplies and developing new materials are critical strategies. Therefore, it is necessary to investigate new raw materials, along with new and improved techniques to process lower-quality raw materials into suitable growing media.

This study is intended not merely as a static forecast but as an evolving tool. It serves as a foundation for future improvements, specifically regarding the refinement of the soilless-shift factor, the analysis of competitive feedstock use in other industries, regional application-specific constraints, and the processing growth rates for all raw materials. Regardless of future refinements to model parameters and assumptions, this study underscores the necessity of growing media as a pillar for the ongoing expansion of soilless culture.

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Supplementary material

The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fhort.2026.1800056/full#supplementary-material

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Footnotes

Edited by: Xiao Yang, Chinese Academy of Agricultural Sciences, China

Reviewed by: Rhuanito Soranz Ferrarezi, University of Georgia, United States

Olivier Hirschler, Leipzig University, Germany