Products

Growing medium (substrate). A product other than soil in situ, the function of which is for plants or mushrooms to grow in. Source: based on Regulation (EU) 2019/1009 (Fertilising Products Regulation). 

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Soil in situ. Natural soil in its original place that has not been moved. Source: Growing Media Europe.

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Soil improver. A product the function of which is to maintain, improve or protect the physical or chemical properties, the structure or the biological activity of the soil to which it is added. Source: based on Regulation (EU) 2019/1009.

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Potting soil. A collective term for different kinds of soil, each with its own composition and specific structure, especially for plants in pots and flower containers. Potting soil is lightweight, in contrast to heavier garden soil. Source: RHP. In UK English, "compost" is often used to mean potting soil.

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Mulches (soil covers). Mineral or organic granulated products used to cover the soil, protecting bare soil from environmental influences such as desiccation, heavy precipitation, extreme temperatures or weed growth. Synonyms are soil covers or ground covers. Source: based on Foucard J-C, Filière pépinière : de la production à la plantation.

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Casing soil. A layer of about 5 cm covering the mushroom growing medium (mushroom compost). The casing soil protects the mushroom mycelium and serves as a moisture buffer from which the mushroom draws the moisture it needs. Source: based on information from Inagro, Belgium.

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Growing systems

Soilless culture (soilless growing). Soilless culture of plants in containers involves a restricted root system and a reduced root zone volume compared with soil-based (in situ) production. The physical and chemical properties of the growing medium must provide adequate storage of water and nutrients for the plant while maintaining good aeration. Source: Carlile, Raviv and Prasad (2019), Soilless Culture: Theory and Practice, 2nd ed., Chapter 8. See also: hydroponics.

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Hydroponics. A method of growing plants in a water-based, nutrient-rich solution. The root system may be supported by growing media such as perlite, stone wool, clay pellets, peat moss, vermiculite or coir slabs. Source: Growing Media Europe.

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Controlled environment agriculture (CEA). A technology for plant production in environmentally controlled structures such as high tunnels, greenhouses, growth chambers or indoor vertical farming. Source: based on Horticulturae (2018) 4, 28, and maximumyield.com. Partially controlled and uncontrolled environments are gradations of the level of control.

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Protected cropping (protected growing). The most general expression for crop production under cover, including greenhouse growing, other under-cover growing and mushroom culture. Source: European Commission, final report on greenhouse production. Not to be confused with crop protection (protection of crops against pests, diseases and weeds).

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Plant biostimulant. A product the function of which is to stimulate plant nutrition processes independently of the product's nutrient content, with the sole aim of improving one or more of the following characteristics of the plant or the plant rhizosphere: nutrient use efficiency, tolerance to abiotic stress, quality traits, or availability of confined nutrients in the soil or rhizosphere. A plant biostimulant can be microbial or non-microbial. Source: based on Regulation (EU) 2019/1009.

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Growing media constituents

Constituent. Any raw material that can be used, after processing, to manufacture growing media. This includes peat, coir, wood fibre, green compost and other organic materials; mineral materials such as perlite, pumice and lava stone; and additives such as fertilisers, liming materials and wetting agents. All growing media constituents, including peat, have their own characteristic properties and cannot simply be replaced by one another. Source: Growing Media Europe.

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Bark. Bark from coniferous (softwood) trees, either fresh, aged or composted, for use in growing media, soil improvers and mulches. Source: based on Spanish Royal Decree 865/2010, Annex 1; CEN CR 13456:1999.

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Coir. The fibrous husk (mesocarp) of the coconut (Cocos nucifera), underlying the smooth outermost layer (exocarp) and surrounding the hard woody layer (endocarp). Coir consists of fibres and pith. Source: Schmilewski G.K., Kultursubstrate und Blumenerden: Eigenschaften, Ausgangsstoffe, Verwendung, Industrieverband Garten (IVG). The terms "coco peat" and "coir peat" are not used: coir is not peat. "Coco fibre" and "coco chips" are acceptable.

• Coir fibres. Fibres that, together with the coir pith, form the mesocarp of the coconut. Used for mats and drainage pipe coverings as well as a growing media constituent.

• Coir pith. The spongy fruit tissue between the coir fibres of the mesocarp. A side product of fibre extraction (combing), containing 2 to 20% (v/v) short fibres (< 20 mm) depending on the intensity of combing and sieving.

• Coir chips. Cut dry pieces of the coconut mesocarp in which the naturally occurring fibres and pith have not been separated.

Source: Schmilewski G.K., IVG.

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Compost. The product of a biological decomposition process under aerobic conditions, in which organic residues are turned over several weeks into a substrate constituent rich in humus and nutrients. Source: Schmilewski G.K., IVG. Because "compost" often means potting soil in English, the constituent is referred to as green compost.

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Green compost. Compost used in horticulture, made from green residues, ideally from gardens and parks, plus forestry residues. Source: Schmilewski G.K., IVG.

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Sphagnum moss (peat moss). Sphagnum is the plant genus of the peat mosses. The family Sphagnaceae (division Bryophyta) contains one genus, Sphagnum, to which 292 known species are assigned worldwide. Source: Michaelis D. (2019), The Sphagnum species of the world, Bibliotheca Botanica 162. Peat and Sphagnum moss are not the same. When referring to Sphagnum (living, or dead and dried) as a raw material or constituent, use the botanical name Sphagnum or "peat moss".

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Wood fibre. Mechanically and thermally frayed wood for horticultural purposes. If necessary, conditioning agents are added during production to stabilise the nitrogen imbalance. Source: Schmilewski G.K., IVG.

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Peat and peatlands

Peat. A heterogeneous mixture of more or less decomposed plant (humus) material that has accumulated in a water-saturated environment and in the absence of oxygen. Source: Priede A. and Gancone A. (eds) (2019), Sustainable and responsible after-use of peat extraction areas, Baltijas Krasti, Riga.

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Peatland. An area, with or without vegetation, where organic matter accumulation has exceeded decomposition. Source: Clarke D. and Rieley J. (2019), Strategy for Responsible Peatland Management, glossary, referring to Joosten H. and Clarke D. (2002), Wise Use of Mires and Peatlands.

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Mire. A peatland where peat is currently being formed and accumulating. The prevailing topographical and hydrological conditions determine the type of mire that develops. Mires fall into two main types: bogs and fens. Source: Growing Media Europe. Note: a drained peatland, such as one under extraction or agriculture, is still a peatland but is no longer a mire, because peat is no longer accumulating.

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Raised bog. A rain-fed (ombrotrophic) peatland dominated by Sphagnum peat mosses and Eriophorum spp. as the main peat-forming plants. Raised bogs usually develop from fens and transitional mires and are considered the climax stage of succession. They are usually dome-shaped, with one or more cupolas. Source: Priede A. (ed.) (2017), Protected Habitat Management Guidelines for Latvia; Silamiķele et al.

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Fen. A minerotrophic peatland: in addition to rainwater, it receives water that has been in contact with mineral soil or bedrock. The vegetation is dominated by reeds (Phragmites spp.) and sedges (Carex spp.), with woody shrubs (carr) on drier margins and water-tolerant trees such as alder (Alnus spp.) and willow (Salix spp.). Source: Joosten H. and Clarke D. (2002), Wise Use of Mires and Peatlands; Rydin H. and Jeglum J. (2006), The Biology of Peatlands. The difference from a raised bog is the water supply: a raised bog is fed by rain only, a fen also by groundwater.

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Transitional mire. A mire fed both by groundwater (minerotrophic) and by precipitation (ombrotrophic), in which the influence of groundwater recedes and that of precipitation increases. Species of both fens and bogs may be found. Source: Priede A. (2017); Silamiķele et al. (2010).

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Peat decomposition. The percentage of decomposed plant cells in the total amount of peat-forming plant residues. It is expressed either as a percentage (5 to 80%) or on the von Post scale, which runs from H1 (undecomposed) to H10 (completely decomposed, colloidal). The von Post scale was devised by Lennart von Post for the 1926 Soil Survey of Sweden. Source: Priede and Gancone (2019).

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Weakly (low) decomposed peat (H1–H4) "White peat" (raised bog peat only)

Moderately (medium) decomposed peat (H5–H6) "Brown peat"

Strongly (well) decomposed peat (above H6) "Black peat" 

Source: Priede and Gancone (2019); Growing Media Europe.

 

Weakly decomposed raised bog peat consists mainly of Sphagnum, Eriophorum, Scheuchzeria palustris and wood residues, and is valued for its high water absorption and air capacity. Strongly decomposed peat usually forms the lower, denser peat layer. The colour terms are informal and not used in formal documents.

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Frozen peat. Well-decomposed peat (H6–H10 on the von Post scale) that has been through at least one freezing cycle after harvesting. Freezing draws water out of the peat and opens its structure, which improves its physical properties. Source: Growing Media Europe.

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Milled peat. Peat harvested by milling the surface to a depth of usually 2 to 7 cm with a rotary tine implement, then harrowed to speed air drying before being collected into windrows for storage. In some areas the surface is loosened by harrows alone, to a depth of 1 to 3 cm. Source: Growing Media Europe.

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Block peat (sod peat). Peat extracted in block form by machine cutting. The blocks are cut vertically from the bog and stacked to dry over a longer period, during which the water content falls to about 50 to 60% by weight. For use in growing media the blocks are crushed into particle size ranges. Source: RAL Gütezeichen.

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Peat harvesting (peat extraction). The process of removing peat raw material from a peatland and collecting it. Source: Puustjärvi V. (1977), Peat and its use in horticulture.

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Responsible peatland management. The implementation of the Wise Use of peatlands principles, safeguarding the environmental, social and economic functions of peatlands and respecting local, regional and global rights and values. Management should be appropriate to the peatland type and use and to socio-economic, cultural and environmental conditions. Source: Clarke and Rieley (2019); International Peatland Society (IPS).

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Source: Growing Media Europe (2020), Terminology for the growing media and horticultural sector