kSIST FprEN 13037:2026
(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
- Public Enquiry End Date
- 01-Dec-2025
- Technical Committee
- KAT - Soil quality
- Current Stage
- 5020 - Formal vote (FV) (Adopted Project)
- Start Date
- 13-Oct-2026
- Due Date
- 01-Dec-2026
- Mandate
- M/XXX - M/XXX
kSIST FprEN 13037:2026 is a SIST draft European standard for the routine determination of pH in soil improvers and growing media. It specifies an instrumental method for measuring pH in a water suspension, so laboratories can obtain comparable results for products such as composts, peat blends, bark, coir pith, digestate, and expanded clay.
What does kSIST FprEN 13037:2026 specify?
kSIST FprEN 13037:2026 specifies how to determine pH in soil improvers and growing media using a measured suspension with water. The document covers the test principle, reagents, apparatus, sampling linkages, sample preparation, procedure, reporting, and method validation.
The method is organized into clauses 1 to 11, plus Annex A and a bibliography. Clause 2 points users to the sampling and terminology documents used with this method, Clause 9 gives the detailed measurement procedure, and Annex A summarizes performance characteristics from the validation study.
| Annex | What it covers |
|---|---|
| Annex A | Performance characteristics of the method, based on the interlaboratory study |
What are the key requirements of kSIST FprEN 13037:2026?
kSIST FprEN 13037:2026 requires a water extraction followed by pH measurement with a pH meter. In practice, the result depends on preparing the suspension consistently, controlling temperature, and calibrating the instrument correctly.
Sample and suspension preparation
The document requires extraction with water at 22 °C ± 3 °C using a 1 to 5 ratio of sample to water. For solid materials, the sample quantity depends on particle size or form, including separate procedures for material passing 20 mm, passing 40 mm, and material larger than 40 mm. Pre-shaped materials are squeezed after shaking, and liquid materials may be measured directly.
For pasty materials, the document uses a water suspension similar to the solid procedure. This matters because the same product family can be supplied in different forms, and the method tells the laboratory how to prepare each one for a comparable reading.
Reagents and apparatus
The document requires analytical-grade reagents and water with very low conductivity. It also uses buffer solutions around pH 4, pH 7, and about pH 9 to 9.5 for calibration and instrument checking.
The apparatus includes a pH meter with slope adjustment and temperature control, an analytical balance, suitable electrodes, a thermometer, containers, and a shaking or mixing machine operating at 150 rpm ± 25 rpm. In practice, the equipment list matters because stable electrodes, correct mixing, and temperature control influence the final reading.
Measurement and calibration
The pH meter must be calibrated with at least two buffer solutions suitable for the sample range. The suspension is measured after thorough agitation, and the reading is taken when it stabilizes to within 0.1 pH unit over 15 s. Results are reported to one decimal place.
For liquid samples, direct measurement is allowed. For aqueous pasty samples, the same suspension approach is used as for the prepared paste procedure.
Sampling, preparation, and reporting
Sampling is not part of the method itself, and the document points users to EN 12579:2024. Sample preparation follows prEN 13040-1:2025, and the laboratory bulk density is determined as part of preparation.
The test report must identify the document, identify the sample, give the pH result to the nearest 0.1 pH unit, record any non-standard or optional operations, and include the laboratory bulk density. That makes the result easier to trace and compare across laboratories.
Validation
The method was validated in accordance with ISO 5725-2, and Annex A gives the repeatability and reproducibility data. For users, this shows the method has been checked across multiple laboratories and product types.
What terms does kSIST FprEN 13037:2026 define?
kSIST FprEN 13037:2026 uses the terms and definitions from CEN/TS 17732:2022. The method also relies on several practical terms that matter in use.
- Soil improvers - materials intended to improve soil properties and are one of the product groups covered by the method.
- Growing media - materials used as plant substrates, including blends and organic or mineral components.
- pH meter - the instrument used to measure the pH of the prepared suspension or liquid sample.
- Laboratory bulk density - a sample property recorded in the test report and determined during preparation.
- Repeatability - how closely results agree when the same method is used under the same conditions.
- Reproducibility - how closely results agree between different laboratories.
- pH - the acidity or alkalinity reading obtained from the suspension.
Who uses kSIST FprEN 13037:2026?
kSIST FprEN 13037:2026 is used by laboratories testing soil improvers and growing media, especially where routine pH control is needed. It is also relevant to manufacturers, quality managers, and buyers who need a comparable test method for product release, specification checking, or regulatory documentation.
The validation set includes bark, coir pith, biowaste compost, green compost, liquid digestate, expanded clay, and three growing media blends. That shows the method is meant for a wide range of real products, not just one material type.
What changed in kSIST FprEN 13037:2026 from the previous edition?
kSIST FprEN 13037:2026 supersedes EN 13037:2011. The foreword states that the significant technical change is an adaptation of the scope and applicability with respect to the EU Fertilizer Product Regulation.
Which standards are used with kSIST FprEN 13037:2026?
kSIST FprEN 13037:2026 refers to these companion standards:
- 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 and the determination of laboratory bulk density.
- ISO 5725-2 - is used for method validation and for calculating repeatability and reproducibility.
What does the kSIST FprEN 13037:2026 document contain?
kSIST FprEN 13037:2026 contains the full method structure for pH determination, from principle through test report and validation. It gives the reagent requirements, apparatus list, preparation steps for solid, pre-shaped, liquid, and pasty materials, and the calibration and measurement steps for the pH meter.
It also includes an informative annex with performance characteristics from an interlaboratory study. Annex A identifies the tested materials and summarizes statistical results for repeatability and reproducibility, which is useful when assessing the method for routine laboratory use or comparison work.
Relations
- Effective Date
- 01-Nov-2025
Get Certified
Connect with accredited certification bodies for this standard
Control Union Certifications
Global certification for agriculture and sustainability.
ECOCERT
Organic and sustainability certification.
FSC International
Forest Stewardship Council certification.
Sponsored listings
Frequently Asked Questions
kSIST FprEN 13037:2026 is a draft published by the Slovenian Institute for Standardization (SIST). 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))).
kSIST FprEN 13037:2026 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.
kSIST FprEN 13037:2026 has the following relationships with other standards: It is inter standard links to SIST EN 13037:2012. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
kSIST FprEN 13037:2026 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.
kSIST FprEN 13037:2026 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
oSIST prEN 13037:2025
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
oSIST prEN 13037:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN 13037:2025
oSIST prEN 13037:2025
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.
oSIST prEN 13037:2025
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
oSIST prEN 13037:2025
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.
oSIST prEN 13037:2025
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
...