oSIST prEN 18250:2025
(Main)Soil improvers and growing media - Plugs - Determination of the dimensions, volume and bulk density
Soil improvers and growing media - Plugs - Determination of the dimensions, volume and bulk density
This document specifies a method for the determination of the dimensions, volume and the bulk density of pre-shaped and non pre-shaped plugs.
Bodenverbesserungsmittel und Kultursubstrate - Plugs - Bestimmung der gemessenen Abmessungen und der Schüttdichte
Dieses Dokument legt ein Verfahren für die Bestimmung der Abmessungen, des Volumens und der Schüttdichte von vorgeformten und nicht vorgeformten Plugs fest.
Amendements du sol et supports de culture - Plugs - Détermination des dimensions, du volume et de la masse volumique apparente
Le présent document spécifie une méthode pour la détermination des dimensions, du volume et de la masse volumique apparente des plugs préformés et non préformés.
Izboljševalci tal in rastni substrati - Substrati (plugs) - Določanje mer, prostornine in prostorninske gostote
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2025
Izboljševalci tal in rastni substrati - Substrati (plugs) - Določanje mer, prostornine
in prostorninske gostote
Soil improvers and growing media - Plugs - Determination of the dimensions, volume
and bulk density
Bodenverbesserungsmittel und Kultursubstrate - Plugs - Bestimmung der gemessenen
Abmessungen und der Schüttdichte
Amendements du sol et supports de culture - Plugs - Détermination des dimensions, du
volume et de la masse volumique apparente
Ta slovenski standard je istoveten z: prEN 18250
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2025
ICS 65.080
English Version
Soil improvers and growing media - Plugs - Determination
of the dimensions, volume and bulk density
Amendements du sol et supports de culture - Plugs - Bodenverbesserungsmittel und Kultursubstrate - Plugs
Détermination des dimensions, du volume et de la - Bestimmung der gemessenen Abmessungen und der
masse volumique apparente Schüttdichte
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 18250:2025 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 6
5 Apparatus . 6
6 Calibration of the measuring cylinder . 9
7 Sampling . 11
8 Procedure . 11
8.1 Accuracy . 11
8.2 Determining the mass . 11
8.3 Number of measurements . 11
8.3.1 Measurement dimensional measurements . 11
8.3.2 Measurement of volume . 12
8.4 Test procedure . 12
8.4.1 Dimensions . 12
8.4.2 Volume . 12
8.5 Optional procedure for reusing the glass beads . 13
9 Calculations and expression of results. 13
9.1 Length, width, height and diameter . 13
9.2 Volume . 13
9.2.1 Accuracy . 13
9.2.2 The bulk density of the glass beads . 13
9.2.3 Volume of the plug . 13
9.3 Bulk density . 14
10 Validation of the method . 14
10.1 Validation in accordance with ISO 5725-2 . 14
10.2 Performance characteristics . 14
11 Test report . 14
Annex A (informative) Performance characteristics of the method (informative annex) . 16
Bibliography. 23
European foreword
This document (prEN 18250:2025) 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 for CEN Enquiry.
This document has been prepared under a standardization request given to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
Introduction
This document has been developed to provide a standardized method to measure and weigh plugs and
to calculate their volume and bulk density.
It is important for consumers, manufacturers, and traders to know the volume of a plug product when
placed on the market. For the cultivation of plants, it is critical that the volume of the plug corresponds to
the chosen cultivation technique, e.g. when propagating seedlings in trays having specific-sized rooting
units.
The bulk density is crucial as the reporting of all chemical analytical results is expressed in units of mass
per volume, and the volume is determined from the mass of the sample used for the chemical analyses.
Pre-shaped growing media can be made from mineral wool, synthetic materials and others from
stabilized organic materials. Plugs can be pre-shaped and non-preshaped.
1 Scope
This document specifies a method for the determination of the dimensions, volume and the bulk density
of pre-shaped and non pre-shaped plugs.
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
3 Terms and definitions
For the purposes of this document, the terms and definitions given in CEN/TS 17732:2022 and the
following apply.
3.1
length
l
longest linear dimension of the major surface of the regular rectangular plug, expressed in millimetres
(mm)
3.2
width
w
shortest linear dimension of the major surface of the regular rectangular plug measured at right angles
to the length, expressed in millimetres (mm)
3.3
height
h
linear dimension measured from top to bottom of the plug, expressed in millimetres (mm)
3.4
diameter
D
average distance between two points taken transversally of the conical or cylindrical plug at its widest
and thinnest part of the truncated conical form, expressed in millimetres (mm)
3.5
bulk density
p
b
ratio of the plug’s mass to its total volume
Note 1 to entry: The bulk density is expressed in grams per litre (g/l) or in kilograms per cubic metre (kg/m ).
3.6
plug
small, self-contained unit of growing medium, used for plant propagation
Note 1 to entry: Typically, plugs have a size from 1 ml up to 100 ml.
3.7
pre-shaped plug
small, solid, uniform shaped, stable growing medium, which does not require reconstitution by wetting
(other than blocks) and is ready to use for propagation, including rooting of seedlings or plant material
Note 1 to entry: The bulk density is expressed in grams per litre (g/l) or in kilograms per cubic metre (kg/m ).
3.8
non pre-shaped plug
small unit of growing medium, other than pre-shaped plugs, used for propagation, including rooting of
seedlings or plant material
Note 1 to entry: Non pre-shaped plugs can require reconstitution.
3.9
block
pre-shaped growing medium, possibly containing holes to take plugs
Note 1 to entry: Blocks are generally used for propagation purposes.
Note 2 to entry: Blocks can vary in size.
3.10
pressed tablet
compressed non pre-shaped plug, composed of organic components (such as peat, coir or wood fibre)
and which requires reconstitution with water
3.11
plug holder
small container of the size of a plug, with openings for roots
4 Principle
The plug is placed on a flat surface.
For regular rectangular material, measurements of the dimensions length, width and height are taken.
For (truncated) conical plugs and cylindrical plugs, measurements of the dimensions height and diameter
are taken.
NOTE These measurements are made to determine the dimensions, but are not to be used for the volume
calculation.
The volume is determined using the pycnometer’s method (see 8.3.2) [1].
The bulk density is calculated based on the weight and volume of the plug.
5 Apparatus
The following laboratory apparatus shall be used.
5.1 Flat surface, horizontal, flat stable surface, e.g. table top, which is large enough for the plug and the
measuring devices.
5.2 Metal rule or metal tape, graduated in millimetres and permitting reading to 0,5 mm or less.
NOTE Measures conforming to the requirements of OIML R35-1:2007, Material measures of length for general
use. Part 1: Metrological and technical requirements [2], Class II are appropriate. This can be obtained from
https://www.oiml.org/publications/.
5.3 (Height) gauge, having a maximum scale interval of 0,5 mm.
5.4 Measuring cylinder, the measuring cylinder shall be rigid, transparent, regularly cylindrical and
with a volume of approximately three times the estimated volume of the plug.
NOTE A logic range for measuring cylinder sizes is 10, 25, 50, 100 and 250 ml.
5.5 Balance, having a maximum scale interval of 0,001 g.
NOTE Any balance conforming to the requirements of OIML R76-1:2006, Non-automatic weighing instruments.
Part 1: Metrological and technical requirements – Tests [3], Class II is appropriate. This can be obtained from
https://www.oiml.org/publications/.
5.6 Balance, having a maximum scale interval of 0,1 g.
NOTE Any balance conforming to the requirements of OIML R76-1:2006, Non-automatic weighing instruments.
Part 1: Metrological and technical requirements – Tests [3], Class II is appropriate. This can be obtained from
https://www.oiml.org/publicat
...
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