FprEN 17731
(Main)Growing media - Methods for the determination of the electrical conductivity, pH, dry matter content, quantity, total copper and zinc content, water soluble chloride content, and CaCl2/DTPA extractable nitrogen, P2O5 and K2O content
- Abstract
This document specifies references to methods to be used for the determination of specific parameters in growing media, but does not contain the methods themselves. The specific parameters in this document are:
— electrical conductivity;
— pH;
— dry matter content;
— quantity;
— total copper and zinc content;
— water soluble chloride content;
— nitrogen, P2O5 and K2O content extractable by CaCl2/DTPA
This document is applicable to the fertilizing product blends where a blend is a mix of two or more fertilising products belonging to the categories of fertilizers, liming material, soil improvers, growing media, inhibitors and plant biostimulants, and where growing media are the components with the highest percentage in the blend by mass or volume, or in the case of products in liquid form by dry mass. If the growing media are not the components with the highest percentage in the blend, the European Standard relevant to the component with the highest percentage in the blend applies. In case a blend is composed of fertilising products mixed in equal quantities, the user of the standard decides which standard to apply.
NOTE A growing medium consists of a single bulky (volume-building) component or a mix of bulky (volume-building) components (for example peat, wood fibres, coconut coir, compost, expanded perlite).
- Status
- Not Published
- Publication Date
- 31-Jan-2027
- Technical Committee
- CEN/TC 223 - Soil improvers and growing media
- Drafting Committee
- CEN/TC 223/WG 6 - Harmonization
- Current Stage
- 4599 - Dispatch of FV draft to CMC - Finalization for Vote
- Start Date
- 19-Aug-2026
- Due Date
- 26-Aug-2026
- Completion Date
- 19-Aug-2026
- Mandate
- M/XXX - M/XXX
FprEN 17731 is a draft CEN European Standard for growing media. It specifies which European test methods to use for electrical conductivity, pH, dry matter, quantity, total copper and zinc, water soluble chloride, and CaCl2/DTPA extractable nitrogen, P2O5 and K2O. It is written for users working with growing media and with certain fertilising product blends in the scope of EU fertilising products.
What does FprEN 17731 specify?
FprEN 17731 points users to the methods that shall be used to determine the listed parameters in growing media. It does not restate the laboratory methods themselves; instead, it links each parameter to a separate standard and clause.
The document applies to fertilising product blends where growing media are the highest-percentage components by mass or volume, or by dry mass for liquid products. If another component is present in the highest amount, the standard for that component applies instead. When products are mixed in equal quantities, the user chooses which standard to apply.
| Annex | What it covers |
|---|---|
| Annex ZA | Relationship with Regulation (EU) 2019/1009 and the correspondence between this standard and the relevant essential requirements |
The body of the document is organized into scope, normative references, terms and definitions, sampling and sample preparation, and determination. Clause 5 then separates the different parameters so users can go directly to the relevant reference method.
What are the key requirements of FprEN 17731?
FprEN 17731 works as a route map for compliance testing. The practical point is that laboratories and quality teams must use the cited sample-preparation and measurement standards, rather than choosing their own procedure.
Sampling and sample preparation
Sampling for quality and quantity control is carried out according to EN 12579:2024. Sample preparation for chemical and physical tests follows prEN 13040-1:2025, Clauses 6 to 10. This matters because the result depends on taking a representative sample and preparing it in the same way each time.
Chemical and physical determinations
Electrical conductivity is determined according to prEN 13038:2025, Clause 9, and pH according to prEN 13037:2025, Clause 9. Dry matter is determined according to prEN 13040-1:2025, Clause 11, and chloride content according to prEN 18252:2025, Clause 8. In practice, these are the core quality indicators for salinity, acidity and moisture-related checks.
Nutrients and elements
The nitrogen, P2O5 and K2O content extractable by CaCl2/DTPA is determined according to prEN 13651:2025, Clauses 9 to 11. For copper and zinc, the standard first points to aqua regia digestion in prEN 13650:2025, Clause 9, and then to prEN 18259:2025, Clause 9 for the element determination. This split tells the laboratory when to digest the sample and when to measure the elements.
Quantity rules by product form
Quantity is determined differently depending on the form of the growing media. Pre-shaped growing media in the form of plugs use prEN 18250:2025, Clause 8; other pre-shaped growing media use FprEN 15761:2025, Clause 7. Growing media with particle size not greater than 60 mm use EN 12580:2022, Clauses 8 to 13, while material with particle size greater than 60 mm uses EN 15238:2022, Clauses 8 to 11. This matters because the measuring approach changes with product geometry.
What terms does FprEN 17731 define?
FprEN 17731 uses the terms and definitions of prEN 17732:2025. The following abbreviations and terms are central to reading the document:
- Growing media - a single bulky component or a mix of bulky components, such as peat, wood fibres, coconut coir, compost or expanded perlite.
- PFC - product function categories under Regulation (EU) 2019/1009; growing media are PFC 4.
- CaCl2/DTPA - the extraction route used here for nutrient determination before measuring nitrogen, P2O5 and K2O.
- P2O5 - phosphorus pentoxide, the reporting form used for extractable phosphorus in this standard.
- K2O - potassium oxide, the reporting form used for extractable potassium in this standard.
- OJEU - the Official Journal of the European Union, where citation of the standard supports presumption of conformity.
Who uses FprEN 17731?
FprEN 17731 is used by laboratories, manufacturers, importers, and quality control teams working with growing media and growing-media blends. It is also relevant to conformity assessment and regulatory staff dealing with EU fertilising products, especially where the product is classified as PFC 4. Buyers and technical evaluators use it to check that declared test results come from the correct method for the product form.
What changed in FprEN 17731 from the previous edition?
FprEN 17731 will supersede CEN/TS 17731:2022. The stated changes are:
- the title was revised;
- quantity requirements were added in the Introduction;
- an applicability statement was added in the Scope;
- Clause 2, Normative references, was updated;
- Annex ZA was added.
Which standards are used with FprEN 17731?
FprEN 17731 relies on these normative references and companion parts:
- EN 12579:2024 - sampling
- EN 12580:2022 - quantity for growing media with particle size not greater than 60 mm
- prEN 13037:2025 - pH
- prEN 13038:2025 - electrical conductivity
- prEN 13040-1:2025 - sample preparation and dry matter
- prEN 13650:2025 - aqua regia digestion
- prEN 13651:2025 - CaCl2/DTPA extraction of nutrients
- EN 15238:2022 - quantity for materials with particle size greater than 60 mm
- FprEN 15761:2025 - dimensions and bulk density of pre-shaped growing media
- prEN 17732:2025 - terminology
- prEN 18250:2025 - plugs
- prEN 18252:2025 - chloride content
- prEN 18259:2025 - aqua regia soluble elements
What does the FprEN 17731 document contain?
The document mainly contains a clause-by-clause map from each parameter to the applicable test standard and clause. It also contains the sampling and sample-preparation route that must be followed before testing. Annex ZA gives the link to Regulation (EU) 2019/1009 and a correspondence table showing which clauses support which essential requirements.
Relations
- Effective Date
- 20-Nov-2024
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Frequently Asked Questions
FprEN 17731 is a draft published by the European Committee for Standardization (CEN). Its full title is "Growing media - Methods for the determination of the electrical conductivity, pH, dry matter content, quantity, total copper and zinc content, water soluble chloride content, and CaCl2/DTPA extractable nitrogen, P2O5 and K2O content". This standard covers: This document specifies references to methods to be used for the determination of specific parameters in growing media, but does not contain the methods themselves. The specific parameters in this document are: — electrical conductivity; — pH; — dry matter content; — quantity; — total copper and zinc content; — water soluble chloride content; — nitrogen, P2O5 and K2O content extractable by CaCl2/DTPA This document is applicable to the fertilizing product blends where a blend is a mix of two or more fertilising products belonging to the categories of fertilizers, liming material, soil improvers, growing media, inhibitors and plant biostimulants, and where growing media are the components with the highest percentage in the blend by mass or volume, or in the case of products in liquid form by dry mass. If the growing media are not the components with the highest percentage in the blend, the European Standard relevant to the component with the highest percentage in the blend applies. In case a blend is composed of fertilising products mixed in equal quantities, the user of the standard decides which standard to apply. NOTE A growing medium consists of a single bulky (volume-building) component or a mix of bulky (volume-building) components (for example peat, wood fibres, coconut coir, compost, expanded perlite).
This document specifies references to methods to be used for the determination of specific parameters in growing media, but does not contain the methods themselves. The specific parameters in this document are: — electrical conductivity; — pH; — dry matter content; — quantity; — total copper and zinc content; — water soluble chloride content; — nitrogen, P2O5 and K2O content extractable by CaCl2/DTPA This document is applicable to the fertilizing product blends where a blend is a mix of two or more fertilising products belonging to the categories of fertilizers, liming material, soil improvers, growing media, inhibitors and plant biostimulants, and where growing media are the components with the highest percentage in the blend by mass or volume, or in the case of products in liquid form by dry mass. If the growing media are not the components with the highest percentage in the blend, the European Standard relevant to the component with the highest percentage in the blend applies. In case a blend is composed of fertilising products mixed in equal quantities, the user of the standard decides which standard to apply. NOTE A growing medium consists of a single bulky (volume-building) component or a mix of bulky (volume-building) components (for example peat, wood fibres, coconut coir, compost, expanded perlite).
FprEN 17731 is classified under the following ICS (International Classification for Standards) categories: 65.080 - Fertilizers. The ICS classification helps identify the subject area and facilitates finding related standards.
FprEN 17731 has the following relationships with other standards: It is inter standard links to CEN/TS 17731:2022. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
FprEN 17731 is associated with the following European legislation: EU Directives/Regulations: 2003/2003, 2019/1009; Standardization Mandates: M/564, M/564 AMD 1, M/564 AMD 2, M/XXX. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
FprEN 17731 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-april-2026
Rastni substrati - Metode za določanje električne prevodnosti, pH, suhe snovi,
količine, celotnega bakra in cinka, klorida, topnega v vodi, ter dušika, P2O5 in
K2O, dobljenih z ekstrakcijo s CaCl2/DTPA
Growing media - Methods for the determination of the electrical conductivity, pH, dry
matter, quantity, total copper and zinc content, water soluble chloride content, and
CaCl2/DTPA extractable nitrogen, P2O5 and K2O content
Bodenverbesserungsmittel - Bestimmung spezifischer Parameter
Supports de culture - Vue d'ensemble des méthodes pour la détermination de la
conductivité électrique, du pH, de la matière sèche, de la quantité, de la teneur total en
cuivre et en zinc, de la teneur en chlorures solubles dans l'eau, de l'azote
extractable/CaCl2/DTAPA, et de la teneur en P2O5 et K2O
Ta slovenski standard je istoveten z: prEN 17731
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
DRAFT
EUROPEAN STANDARD
prEN 17731
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2026
ICS 65.080 Will supersede CEN/TS 17731:2022
English Version
Growing media - Methods for the determination of the
electrical conductivity, pH, dry matter, quantity, total
copper and zinc content, water soluble chloride content,
and CaCl2/DTPA extractable nitrogen, P2O5 and K2O
content
Supports de culture - Méthodes pour la détermination Kultursubstrate - Verfahren zur Bestimmung der
de la conductivité électrique, du pH, de la matière elektrischen Leitfähigkeit, des pH-Werts, der
sèche, de la quantité, de la teneur totale en cuivre et en Trockensubstanz, der Menge, des Gesamtkupfer- und -
zinc, de la teneur en chlorure soluble dans l'eau et de la zinkgehalts, des Gehalts an wasserlöslichem Chlorid
teneur en azote, en P2O5 et en K2O extractibles par und des Gehalts an mit CaCl2/DTPA extrahierbarem
CaCl2/DTPA Stickstoff, P2O5 und K2O
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 223.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17731:2026 E
worldwide for CEN national Members.
prEN 17731:2026 (E)
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Sampling and sample preparation . 6
4.1 Sampling . 6
4.2 Sample preparation . 6
5 Determination . 6
5.1 Determination of the electrical conductivity . 6
5.2 Determination of the chloride content . 6
5.3 Determination of pH . 6
5.4 Determination of dry matter . 6
5.5 Determination of the nitrogen, P O and K O content extractable by CaCl /DTPA . 6
2 5 2 2
5.6 Determination of the aqua regia soluble copper and zinc content . 7
5.7 Determination of quantity . 7
Bibliography . 10
prEN 17731:2026 (E)
European foreword
This document (prEN 17731:2026) has been prepared by Technical Committee CEN/TC 223 “Soil
improvers and growing media”, the secretariat of which is held by NEN.
This document is currently submitted to the CEN Enquiry.
This document will supersede CEN/TS 17731:2022.
prEN 17731:2026 includes the following significant technical changes with respect to
CEN/TS 17731:2022:
— The title has been revised;
— The quantity requirements have been added in the Introduction;
— An applicability statement has been included in the Scope;
— Clause 2, Normative references, has been updated;
— Annex ZA has been added.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
For the relationship with EU Legislation, see informative Annex ZA, which is an integral part of this
document.
prEN 17731:2026 (E)
Introduction
Different product functions warrant different product safety, quality and quantity requirements adapted
to their different intended uses. EU fertilizing products have therefore been divided into different product
function categories (PFCs), which are subject to specific safety, quality and quantity requirements, as
specified in the Regulation (EU) 2019/1009 [1].
Growing media have been classified as PFC 4. The specific safety, quality and quantity requirements in
relation to specific parameters are specified in this document, as well as normative references of the test
methods to be used to assess the compliance with the related requirement.
prEN 17731:2026 (E)
1 Scope
This document refers to methods to be used for the determination of specific parameters in growing
media, but does not contain the methods themselves. The specific parameters in this document include:
— electrical conductivity;
— chloride;
— pH;
— dry matter;
— nitrogen, P O (phosphorus pentoxide) and K O (potassium oxide) content extractable by
2 5 2
CaCl /DTPA;
— copper and zinc content;
— quantity.
This document is applicable to the fertilizing product blends where a blend is a mix of two or more
fertilising products belonging to the categories of fertilizers, liming material, soil improvers, growing
media, inhibitors and plant biostimulants, and where soil improvers and/or growing media are the
components with the highest percentage in the blend by mass or volume, or in the case of products in
liquid form by dry mass. If the soil im
...