FprEN 13037

• Abstract:

  This document specifies an instrumental method for the routine determination of pH in a suspension of soil improvers or growing media with water.; NOTE This method has been validated in an interlaboratory study with specific products that were present on the market during the study (as included in Annex A, being bark (Pinus pinaster, 20 mm to 40 mm fraction), coir pith (0 mm to 12 mm, washed and buffered), biowaste compost (Rottegrad 3), green compost (Rottegrad 5, 0 mm to 15 mm), liquid digestate, expanded clay (whole granules, 8 mm to 16 mm), growing media blend 1 (white peat, green compost, wood fibre, lime, inorganic fertilizer (NPK + micro elements)), growing media blend 2 (white peat, black peat, expanded perlite, lime, organic fertilizer) and growing media blend 3 (white peat, black peat, clay, inorganic fertilizer (NPK + micro elements))).

• Status: Not Published
• Publication Date: 06-Jan-2027
• ICS: 65.080 - Fertilizers
• Technical Committee: CEN/TC 223 - Soil improvers and growing media
• Drafting Committee: CEN/TC 223/WG 4 - Analytical methods
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Start Date: 27-Jul-2026
• Due Date: 10-Jul-2023
• Completion Date: 27-Jul-2026
• 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 - M/XXX
• Ref Project: oSIST prEN 13037:2025 - Soil improvers and growing media - Determination of pH

• Revises: EN 13037:2011 - Soil improvers and growing media - Determination of pH
• Effective Date: 19-Jan-2023

Overview

FprEN 13037 is a European draft standard developed by CEN for the determination of pH in soil improvers and growing media. This document defines an instrumental, routine method to accurately measure the pH value in a suspension of soil improvers or growing media with water. The standard is relevant for products such as compost, bark, coir pith, digestate, expanded clay, and various peat-based blends. Accurate pH determination is essential for assessing the suitability and safety of soil amendments and growing media, especially for regulatory compliance and quality control.

The method described in FprEN 13037 supports producers, laboratories, and regulators in obtaining reliable, repeatable, and comparable pH measurements across different material types, thereby supporting compatibility with the EU Fertilising Product Regulation (EU 2019/1009) and ensuring high product quality in horticultural and agricultural applications.

Key Topics

• Scope: Specifies the procedure for routine pH determination in a wide variety of soil improvers and growing media.
• Instrumental Method: Describes the preparation of a suspension using a defined sample-to-water ratio, followed by pH measurement using calibrated laboratory equipment.
• Product Types: Covers materials such as composts, coir, bark, peat blends, digestates, and expanded clay.
• Sample Representation: Emphasizes proper and representative sampling as outlined in related standards to ensure valid results.
• Validation: Method performance was validated across several laboratories and product matrices to guarantee repeatability and reproducibility in accordance with ISO 5725-2.
• Test Reporting: Outlines the essential information required in test reports, including the identification of the sample, measurement details, and any deviations from the method.

Applications

Implementing FprEN 13037 offers several practical benefits for the horticulture and agriculture sectors:

• Quality Control: Producers of compost, growing media, or other soil improvers use this standard to monitor product consistency and compliance with relevant regulations.
• Regulatory Compliance: Laboratories and manufacturers can demonstrate conformity to the EU Fertilising Product Regulation by applying standardized pH measurement procedures.
• Product Development: R&D teams use reliable pH data to formulate growing media blends or soil improvers tailored for specific crops or uses.
• Market Confidence: Buyers and users of soil amendments can rely on test results obtained via this standard, knowing they meet harmonized European quality benchmarks.
• Environmental Monitoring: Helps assess potential effects of soil amendments on soil chemistry and plant health.

Related Standards

To ensure comprehensive and accurate pH testing, FprEN 13037 should be used in conjunction with related European standards, including:

• EN 12579:2024 - Defines proper methods for sampling soil improvers and growing media, ensuring representative and unbiased samples for pH analysis.
• CEN/TS 17732:2022 - Provides standardized terminology for soil improvers and growing media, aligning technical language.
• prEN 13040-1:2025 - Outlines procedures for sample preparation, such as determining dry matter content, moisture content, and bulk density, which are essential for correct and consistent pH measurement.
• ISO 5725-2 - Describes methods for validating accuracy, repeatability, and reproducibility of measurement methods.

Applying these standards collectively enables consistent product evaluation and supports both commercial and regulatory needs related to soil improvers and growing media.

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Keywords: soil improvers, growing media, pH determination, FprEN 13037, compost, peat blend, EU Fertilising Product Regulation, CEN standards, horticulture, agriculture, laboratory testing, quality control.

SLOVENSKI STANDARD
01-november-2025
Izboljševalci tal in rastni substrati - Določanje pH
Soil improvers and growing media - Determination of pH
Bodenverbesserungsmittel und Kultursubstrate - Bestimmung des pH-Wertes
Amendements du sol et supports de culture - Détermination du pH
Ta slovenski standard je istoveten z: prEN 13037
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
prEN 13037
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2025
ICS 65.080 Will supersede EN 13037:2011
English Version
Soil improvers and growing media - Determination of pH
Amendements du sol et supports de culture - Bodenverbesserungsmittel und Kultursubstrate -
Détermination du pH Bestimmung des pH-Wertes
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
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 13037:2025 E
worldwide for CEN national Members.

prEN 13037:2025 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Reagents . 4
6 Apparatus . 5
7 Sampling . 5
8 Preparation . 5
9 Procedure . 5
9.1 Safety . 5
9.2 Suspension of material in solid form . 6
9.3 Suspension of material in pre-shaped form . 6
9.4 Suspension of liquid or pasty materials . 6
9.5 Measurement . 6
9.5.1 Calibration of the pH meter . 6
9.5.2 Measurement of the pH of solid samples . 6
9.5.3 Measurement of the pH of liquid and aqueous pasty samples . 6
10 Test report . 7
11 Validation of the method . 7
11.1 Validation in accordance with ISO 5725-2. 7
11.2 Performance characteristics. 7
Annex A (informative) Performance characteristics of the method . 8
Bibliography . 10

prEN 13037:2025 (E)
European foreword
This document (prEN 13037:2025) 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 EN 13037:2011.
prEN 13037:2025 includes the following significant technical changes with respect to EN 13037:2011:
— adaptation of scope and applicability with respect to the EU – Fertilizer Product Regulation [2].
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.
prEN 13037:2025 (E)
1 Scope
This document specifies an instrumental method for the routine determination of pH in a suspension of
soil improvers or growing media.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
CEN/TS 17732:2022, Soil improvers and growing media – Terminology
EN 12579:2024, Soil improvers and growing media - Sampling
prEN 13040-1:2025, Soil improvers and growing media — Sample preparation — Part 1: Sample
preparation for chemical and physical tests, determination of dry matter content, moisture content and
laboratory bulk density
3 Terms and definitions
For the purposes of this document, the terms and definitions given in CEN/TS 17732:2022 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
4 Principle
A sample is extracted with water at 22 °C ± 3,0 °C in an extraction ratio of 1 to 5 (1 V sample + 5 V water).
The pH of the suspension is measured using a pH meter.
5 Reagents
Use only reagents of recognized analytical grade.
5.1 Water with a specific conductivity not higher than 0,2 mS/m at 25 °C.
5.2 Buffer solution, pH = 4,00 at 20 °C.
Dissolve 10,21 g of potassium hydrogen phthalate (C H KO ) in water (5.1) and dilute to 1 000 ml in a
8 5 4
volumetric flask.
Commercially available buffers (e.g. in the form of tablets) covering the required pH may also be used.
5.3 Buffer solution, pH = 7,00 at 20 °C.
Dissolve 3,800 g of potassium dihydrogen phosphate (KH PO ) and 3,415 g disodium hydrogen
2 4
phosphate (Na HPO ) in water (see 5.1) and dilute to 1 000 ml in a volumetric flask.
2 4
The potassium dihydrogen phosphate shall be dried before use for 2 h at 115 °C ± 5 °C.
Commercially available buffers (e.g. in the form of tablets) covering the required pH may also be used.
5.4 Buffer solu
...