oSIST prEN 17731:2026

• 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
• Public Enquiry End Date: 19-Apr-2026
• ICS: 65.080 - Fertilizers
• Technical Committee: KAT - Soil quality
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 11-Feb-2026
• Due Date: 01-Jul-2026
• Completion Date: 29-Apr-2026
• Directive: Not Harmonized2003/2003 - Regulation (EC) N° 2003/2003 of the European Parlament and of the council of 13 October 2003 relating to fertilisers
• Directive:

  ---

  Harmonized Standard2019/1009 - Regulation (EU) 2019/1009 of the European Parliament and of the Council of 5 June 2019 laying down rules on the making available on the market of EU fertilising products and amending Regulations (EC) No 1069/2009 and (EC) No 1107/2009 and repealing Regulation (EC) No 2003/2003 (Text with EEA relevance)
• Mandate: M/564 - Fertilising products in support of Regulation (EU) 2019/1009
• Mandate: M/564 Amd 1 - amending Implementing Decision C(2020) 612 as regards certain harmonised standards and standardisation deliverables, deadlines for their adoption and the duration of the validity of the standardisation request
• Mandate: M/564 Amd 2 - Commission Implementing decision amending Implementing Decision C(2020)612 as regards harmonised standards, the deadlines for the adoption of those standards and the duration of the validity of the standardisation request to the European Committee for Standardisation as regards the EU fertilising products in support of Regulation (EU) 2019/1009 of the European Parliament and of the Council
• Mandate: M/xxx - COMMISSION IMPLEMENTING DECISION of XXX on a standardisation request to the European Committee for Standardisation, the European Committee for Electrotechnical Standardisation and the European Telecommunications Standards Institute in support of the implementation of Commission Regulation (EU) 2025/2052 laying down ecodesign requirements for external power supplies, wireless chargers, wireless charging pads, battery chargers for portable batteries of general use and USB Type-C cables, pursuant to Directive 2009/125/EC of the European Parliament and of the Council and repealing Commission Regulation (EU) 2019/1782
• Ref Project: FprEN 17731 - 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

• Revises: SIST-TS CEN/TS 17731:2022 - Growing media - Determination of specific parameters
• Effective Date: 20-Nov-2024

Overview

oSIST prEN 17731:2026 is a CEN standard focusing on growing media analysis for fertilizing products. The document provides references to standardized methods for determining key physical and chemical parameters in growing media, including electrical conductivity, pH, dry matter content, quantity, total copper and zinc content, water soluble chloride content, and nutrients (nitrogen, phosphorus pentoxide (P₂O₅), potassium oxide (K₂O)) extractable by CaCl₂/DTPA.

The standard applies to blends of fertilizing products where growing media or soil improvers make up the largest proportion by mass or volume, or by dry mass in liquids. This ensures the proper assessment of growing media’s suitability and compliance with EU regulations, notably supporting Regulation (EU) 2019/1009 regarding the marketing of EU fertilizing products.

Key Topics

• Scope and Applicability

  • References internationally recognized testing methods for determination of specified parameters.
  • Applies to fertilizing product blends where growing media are the predominant component.

• Parameters Assessed

  • Electrical conductivity: Indicator of soluble salt content affecting plant growth.
  • pH: Measures acidity or alkalinity, critical for nutrient availability.
  • Dry matter content: Determines moisture and organic content.
  • Quantity: Standardized methods for measuring batch volume or mass.
  • Total copper and zinc content: Evaluation for trace element content to prevent toxicity and ensure plant nutrition.
  • Water soluble chloride content: Important for plant health and regulatory compliance.
  • CaCl₂/DTPA-extractable nitrogen, P₂O₅, and K₂O: Assessment of readily available nutrients for plant uptake.

• Sampling and Preparation

  • Details required sampling and sample preparation procedures to ensure reliability and reproducibility of test results.

• Standardization References

  • Does not include the test methods themselves, but provides up-to-date references to corresponding European standards for each parameter.

Applications

The referenced methods enable consistent and reliable analysis of growing media in the following contexts:

• Manufacturing and Quality Control

  • Fertilizer and growing media producers use these guidelines to ensure compliance with statutory quality and safety requirements.
  • Supports accurate labeling and nutrient content verification for blended products.

• Regulatory Compliance

  • Aligns with EU regulations, particularly Regulation (EU) 2019/1009, ensuring products placed on the market meet key safety and quality criteria.
  • Establishes a presumption of conformity with EU requirements when referenced methods are applied.

• Agronomy and Research

  • Essential for research institutions and agronomists assessing the quality and suitability of growing media for diverse crop requirements.
  • Facilitates comparative studies and international trade by harmonizing measurement practices.

• Blended Fertilizing Products

  • Used for mixtures comprising multiple fertilizing categories-fertilizers, liming materials, soil improvers, inhibitors, plant biostimulants-where growing media are predominant.

Related Standards

This standard operates alongside a suite of referenced and related European standards for growing media and soil improvers, including:

• EN 12579: Sampling procedures for soil improvers and growing media.
• EN 12580 / EN 15238: Determination of quantity, tailored for different particle sizes and product forms.
• prEN 13037 / prEN 13038: Determination of pH and electrical conductivity.
• prEN 13040-1: Sample preparation, dry matter, and physical tests.
• prEN 13650 / prEN 13651: Element digestion methods and nutrient extraction procedures.
• prEN 17732: Terminology for consistency in communication.
• prEN 18250 / prEN 18252 / prEN 18259: Specialized protocols for plugs, chloride, and trace elements, respectively.

By referencing these harmonized standards, oSIST prEN 17731:2026 promotes a unified approach to growing media assessment, supporting fair competition, product safety, and agricultural productivity across Europe.

Keywords: oSIST prEN 17731:2026, growing media standard, fertilizer blends, electrical conductivity, pH determination, dry matter content, copper and zinc analysis, chloride in growing media, CaCl2/DTPA extractable nutrients, European fertilizer regulations, CEN standards for growing media

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
...