FprEN 13037
(Main)Soil improvers and growing media - Determination of pH
- 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
- 13-Jan-2027
- Technical Committee
- CEN/TC 223 - Soil improvers and growing media
- Drafting Committee
- CEN/TC 223/WG 4 - Analytical methods
- Current Stage
- 5020 - Submission to Vote - Formal Approval
- Start Date
- 24-Sep-2026
- Due Date
- 28-Aug-2023
- Completion Date
- 24-Sep-2026
- Mandate
- M/XXX - M/XXX
prEN 13037 is a CEN draft European Standard for the routine instrumental determination of pH in a suspension of soil improvers or growing media with water. It is intended for laboratories and product users who need a repeatable way to prepare the sample, measure pH, and report the result for these materials. The document also includes method validation data and will supersede EN 13037:2011.
What does prEN 13037 specify?
prEN 13037 specifies how to determine pH in soil improvers and growing media by measuring a water suspension. The scope is focused on routine laboratory testing, while sampling and sample preparation are handled by other documents.
The document is organized into clauses on scope, references, terms, principle, reagents, apparatus, sampling, preparation, procedure, test report, and validation. Annex A gives the method’s performance characteristics.
| Annex | What it covers |
|---|---|
| A | Informative performance characteristics from the interlaboratory study |
What are the key requirements of prEN 13037?
Clause 4 sets the basic measurement principle: the sample is extracted with water at controlled temperature and in a fixed sample-to-water ratio, then the pH of the suspension is measured with a pH meter. In practice, this means laboratories must keep extraction conditions consistent so results can be compared between samples and sites.
Clause 5 requires analytical-grade reagents, low-conductivity water, and buffer solutions around pH 4, 7, and 9 to 9.5. This matters because the meter must be calibrated against known references before a sample is measured.
Clause 6 defines the apparatus needed: a pH meter with slope adjustment and temperature control, a balance, suitable electrodes, a thermometer, containers, and a shaker or mixer. The document also notes that electrodes for extreme pH values should be chosen when needed, so the instrument matches the sample range.
Clauses 7 and 8 link the method to upstream handling. Sampling follows EN 12579, and sample preparation follows prEN 13040-1, including laboratory bulk density. For users, this means the pH result depends not only on the meter but also on receiving a representative sample and preparing it in a standard way.
Clause 9 gives separate procedures for solid, pre-shaped, liquid, and pasty materials. Solid materials are shaken in suspension, liquid materials can be measured directly, and pre-shaped materials are pressed after extraction before measurement. This is important because the method adapts to the physical form of the product instead of forcing one preparation route for all samples.
Clause 9 also sets the measurement practice: calibrate with at least two suitable buffers, measure after the suspension has stabilized, and read the result to one decimal place. That makes the reported value usable for specification checks, product comparison, and routine quality control.
Clause 10 defines the test report items: the standard reference, sample identification, result to 0.1 pH unit, any deviations or optional steps, factors that may have influenced the result, and laboratory bulk density. Clause 11 and Annex A show that the method was validated by interlaboratory study and provide repeatability and reproducibility information for several material types.
What terms does prEN 13037 define?
- Soil improvers - Materials tested by this method when they are intended to improve soil properties.
- Growing media - Materials used as a root zone or substrate for plant growth.
- pH meter - The instrument used to measure the acidity or alkalinity of the suspension.
- Suspension - The mixture of sample and water prepared for the pH measurement.
- Pre-shaped form - A material form that is handled differently in the preparation and measurement steps.
- Laboratory bulk density - A characteristic of the sample that is determined during preparation and reported with the result.
Who uses prEN 13037?
prEN 13037 is used by testing laboratories, manufacturers of soil improvers and growing media, quality control teams, and technical buyers who need consistent pH data. It also supports regulators and certification bodies that assess product information, product consistency, and conformity claims.
In practice, users apply it for routine release testing, incoming inspection, product comparison, and documentation of batch quality.
What changed in prEN 13037 from the previous edition?
prEN 13037 will supersede EN 13037:2011. The foreword states that the significant technical change is an adaptation of the scope and applicability in relation to the EU Fertilizer Product Regulation.
Which standards are used with prEN 13037?
- CEN/TS 17732:2022 - Provides the terminology and definitions used in the document.
- EN 12579:2024 - Covers sampling of soil improvers and growing media.
- prEN 13040-1:2025 - Covers sample preparation for chemical and physical tests and the determination of laboratory bulk density.
- ISO 5725-2 - Provides the statistical basis used for validation, repeatability, and reproducibility assessment.
What does the prEN 13037 document contain?
prEN 13037 contains the full test method for pH determination in water suspensions of soil improvers and growing media. It includes the principle of the method, reagent requirements, apparatus, sample handling routes for different material forms, calibration and measurement steps, and the required test report items.
The document also includes a validation section and an informative annex with interlaboratory study results. Annex A summarizes the materials used in validation and the performance characteristics needed to judge how the method behaves across different product types.
Relations
- Effective Date
- 19-Jan-2023
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Frequently Asked Questions
FprEN 13037 is a draft published by the European Committee for Standardization (CEN). Its full title is "Soil improvers and growing media - Determination of pH". This standard covers: 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))).
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))).
FprEN 13037 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 13037 has the following relationships with other standards: It is inter standard links to EN 13037:2011. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
FprEN 13037 is associated with the following European legislation: EU Directives/Regulations: 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 13037 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-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
...