Methods for testing plant response
to composted material and its contamination
by weed seeds and propagules
Method code: OFW004-006
Version: 3.1
Published: October 2015
© REAL CCS October 2015
1
Publishing and copyright information
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Publication history
First published in PAS 100:2002, Annex D, British Standards Institution, London.
Revised version published in PAS 100:2005, Annex D, British Standards Institution, London.
Then specified in PAS 100:2011 with reference OFW004-006:
 OFW004-006, Method for testing plant response to composted material and its
contamination by weed seeds and propagules, WRAP, Banbury, September 2010, version
1.0, ISBN 1-84405-425-X.
 OFW004-006, Method for testing plant response to composted material and its
contamination by weed seeds and propagules, WRAP, Banbury, March 2014, version 2.0,
ISBN 1-84405-425-X.
 OFW004-006, Methods for testing plant response to composted material and its
contamination by weed seeds and propagules, Renewable Energy Assurance Limited,
London, August 2015, version 3.0.
 OFW004-006, Methods for testing plant response to composted material and its
contamination by weed seeds and propagules, Renewable Energy Assurance Limited,
London, October 2015, version 3.1.
© REAL CCS October 2015
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1
ACKNOWLEDGEMENTS .................................................................................................... 5
2
INTRODUCTION ................................................................................................................ 5
2.1
2.2
Tomato plant response .................................................................................................... 5
Field bean plant response ................................................................................................ 6
3
LEGAL CONSIDERATIONS .................................................................................................. 7
4
PRINCIPLE ........................................................................................................................ 7
5
PERSONNEL ...................................................................................................................... 8
6
APPARATUS ..................................................................................................................... 8
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
6.10
6.11
6.12
6.13
6.14
6.15
6.16
7
Balances............................................................................................................................ 8
Capillary matting (optional) ............................................................................................. 8
Controlled environment for plant growth ....................................................................... 8
Fertiliser............................................................................................................................ 8
Firming board ................................................................................................................... 9
Ground dolomitic limestone ............................................................................................ 9
Seed template .................................................................................................................. 9
Seed trays ......................................................................................................................... 9
Sieve ................................................................................................................................. 9
Shallow trays (optional) ................................................................................................... 9
Sphagnum moss peat ..................................................................................................... 10
Supplementary lighting and light meter ........................................................................ 10
Tomato seeds ................................................................................................................. 10
Transparent plastic covers (optional) ............................................................................ 10
Water .............................................................................................................................. 10
Watering can with fine rose ........................................................................................... 11
PREPARATION OF THE GROWING MEDIA ....................................................................... 11
7.1
7.2
7.3
7.4
Peat................................................................................................................................. 11
Compost ......................................................................................................................... 11
PBGM control ................................................................................................................. 12
Test Sample .................................................................................................................... 12
8
CONTROLLED GROWTH ENVIRONMENT ......................................................................... 13
9
QUALITY CONTROL ......................................................................................................... 14
10 TEST SET-UP AND MAINTENANCE................................................................................... 14
10.1
10.2
10.3
10.4
10.5
Replication in each set ................................................................................................... 14
Sets of Test Sample per set of PBGM control ................................................................ 14
Setting up PBGM control and Test Sample using a seed template with holes .............. 14
Setting up PBGM control and Test Sample using a seed template with protrusions .... 15
Using transparent plastic covers (optional) ................................................................... 16
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10.6
10.7
10.8
10.9
10.10
Capillary matting and shallow trays (both optional) ...................................................... 16
Placing out trays ............................................................................................................. 17
Light ................................................................................................................................ 17
Temperature................................................................................................................... 18
Inspecting and maintaining growing media and plants ............................................. 18
11 RECORDING PLANT OBSERVATIONS ............................................................................... 21
11.1
11.2
11.3
11.4
Tomato plant germination ............................................................................................. 21
Tomato plant growth and abnormalities ....................................................................... 21
Tomato plant mass ......................................................................................................... 22
Weed plants ................................................................................................................... 22
12 CALCULATION AND EXPRESSION OF RESULTS ................................................................. 22
12.1
12.2
12.3
12.4
Tomato plant germination ............................................................................................. 22
Tomato plant abnormalities after germination ............................................................. 23
Tomato plant mass ......................................................................................................... 23
Weed plants per litre of compost ‘as received’ ............................................................. 25
13 VALIDITY OF THE TEST .................................................................................................... 25
13.1
13.2
13.3
Tomato plant germination ............................................................................................. 25
Abnormalities after germination.................................................................................... 25
Tomato plant mass ......................................................................................................... 26
14 LABORATORY RECORDS ................................................................................................. 26
15 REPORT OF TEST RESULTS .............................................................................................. 28
16 REFERENCES ................................................................................................................... 29
ANNEX A: GUIDANCE ON LIGHT, TEMPERATURE AND TRAY LAYOUT IN CONTROLLED GROWTH
ENVIRONMENTS ................................................................................................................... 30
A.1
A.2
A.3
A.4
Light ................................................................................................................................ 30
Temperature................................................................................................................... 33
Other considerations: replication and layout of the trays ............................................. 34
Sources of information ................................................................................................... 37
ANNEX B: TOMATO SEED STORAGE ...................................................................................... 39
ANNEX C: GUIDANCE ON ABNORMALITIES ............................................................................ 40
ANNEX D: METHOD FOR TESTING FIELD BEAN GERMINATION AND GROWTH RESPONSE ...... 43
© REAL CCS October 2015
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1
Acknowledgements
This version of the tomato plant response and weeds test specified in BSI PAS 100 1 was written
by Emily Nichols (Renewable Energy Association) with contributions from Paul Waller (Paul
Waller Consulting Limited), the author of Annex A. Contributions from Jim Frederickson and
Graham Howell (Open University) during the drafting of this document are also gratefully
acknowledged. Photographs and feedback from Julian Davies (Stockbridge Technology Centre)
about experience implementing earlier versions of the method has been valuable during this
latest revision.
Annex D sets out a method for testing field bean germination and growth response to compost
destined for use as growing media. This method is unchanged since publication in version 2.0
of the methodology document (see publication history section above).
Front cover photography: Tomato plants at 28 days after sowing (mid-June 2015), grown by
Stockbridge Technology Centre.
Photography in section 10: Tomato plant response and weeds test in progress at Stockbridge
Technology Centre.
Photography in Annex C: Symptoms of herbicide damage in tomato plants, tests carried out by
Stockbridge Technology Centre during a research project.
Photography in Annex D: Symptoms of herbicide damage in field bean plants, tests carried out
by Stockbridge Technology Centre during a research project.
2
Introduction
2.1
Tomato plant response
This document sets out a method for assessing tomato plant performance and assessing
contamination by weed seeds and other propagules in compost samples. Its basis is Annex D in
the British Standards Institution’s Publicly Available Specification for Composted Materials,
2005 edition (PAS 100:2005). The Annex D methodology was designed as a single multipurpose
test assessing weed content, tomato seed germination, seedling growth and abnormalities in a
sphagnum peat medium containing 20 to 33 % by volume of the compost sample under
evaluation.
1
At the time of publication, BSI PAS 100:2011 is the current version of the specification for composted
materials.
© REAL CCS October 2015
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Version 3.0 of the methodology incorporated many of the recommendations made as part of a
WRAP supported review of the plant response test2. The review recommended retention of the
multipurpose Annex D test provided it was made clearer and more robust. The information and
instructions in version 3.0 of the methodology addressed those recommendations, where
possible without further experimental research. It clarified the scope of the test and materials
to use and standardised the quantities of peat and compost to use. It required checking of
spatial and environmental variations in the controlled growth environment and that these are
taken into account. It also provided guidance on light and temperature for germinating and
growing tomato plants and on replication and layout of trays. Version 3.0 of the methodology
provided updated and clearer instructions on what must be recorded and included improved
instructions for assessing, calculating and reporting results of the test and its validity. The
minimum required mean mass per plant in each tray of peat control, a key measure of test
validity, was increased (see sections 8 and 13.3) in version 3.0.
The latest version of the methodology, 3.1, provides a corrected formula for calculating the
weeds result (see section 12.4), makes the weeds unit of reporting (item 16 in section 15)
consistent with the unit described in section 12.4, and makes the unit of electrical conductivity
recording and reporting consistent (in mS m -1).
2.2
Field bean plant response
Since the introduction of the original plant response and weeds test, incidences of herbicide
contamination in compost have been reported outside the UK (for example, in the USA and
New Zealand). In this context, WRAP has carried out a number of investigations and concluded
that the risk of harm from contaminated composts in the UK is low and that the tomato plant
response test is suitable for screening composts intended for use in agriculture and field
horticulture. However, the evidence suggests that the tomato plant response test is not
sufficiently sensitive to detect herbicide concentrations of interest to the growing media sector,
specifically when composts are to be included in growing media used for cultivating sensitive
plant species.
On this basis, a more sensitive plant response test has been developed, using field bean (Vicia
faba cv Fuego), which is recommended for testing composts destined for use as a growing
media. Since growing media containing compost could be used to cultivate both sensitive and
insensitive plant species, it is recommended that all batches of compost intended for supply to
the growing media sector be subjected to testing using the field bean. The methodology for
carrying out the field bean plant response test is provided in Annex D.
2
BSI PAS 100 Update: Review of the PAS 100:2005 Plant Growth test – Part 2 – Laboratory and Method
Appraisal, OFW006-002, March 2009, WRAP, Banbury. ISBN: 1-84405-408-X
© REAL CCS October 2015
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3
Legal considerations
REAL CCS, Paul Waller Consulting and Open University believe the content of this document to
be correct on the date of publication. The methodology published herein provides clear
instruction and guidance where necessary. REAL CCS, Paul Waller Consulting and Open
University cannot accept responsibility or be held liable to any person for any loss or damage
arising out of or in connection with this document being inaccurate, incomplete or misleading.
It is the responsibility of any laboratory that implements the methodology to do so correctly.
When sourcing products to use when setting up and carrying out the test the laboratory
should consult with the supplier or manufacturer and ascertain whether a particular product
will satisfy their specific requirements as well as those defined in this methodology.
The naming of particular products in this document provides examples of some of the products
that were suitable and available at the time of publication. This does not constitute an
endorsement by any organisation referred to in this disclaimer and none of these organisations
guarantee the performance of individual products or materials. This document does not claim
to cover all relevant products available on the market. This document must not be used to
endorse or used to suggest endorsement of a commercial product or service by REAL, Paul
Waller Consulting or Open University.
4
Principle
This method of test investigates how a compost-amended peat growing medium (the Test
Sample) affects tomato seed germination, top-growth and health, when compared with a
standard peat growing medium (the control) under controlled conditions over a 28 day test
period. The effect of variable soluble salt contents in the composts under test (as judged by
their electrical conductivity) is substantially limited by controlled dilution of the compost with
sphagnum peat that has low conductivity. This means that any significant negative response in
the Test Sample that is not seen in the control can be taken to indicate phytotoxic factors in the
compost, which might then require further testing before the compost can be used.
This method includes simultaneous assessment of weed seeds and other propagules that may
be present in the Test Sample, taking account of any that appear in the control.
This test is designed to assess many of the compost grades used in growing media and most soil
improvers, such as those with particle size ranges 0 - 6 mm, 0 - 10 mm, 0 - 12 mm, 0 - 15 mm,
0 - 20 mm, 0 - 25 mm, and 0 - 40 mm. However, is not suitable for composts that retain no soillike particles, such as mulch grades that consist only of coarse woody particles, e.g. 10 – 40 mm.
PAS 100 does not require such mulch grades to undergo this test for tomato plant performance
and weed seeds.
© REAL CCS October 2015
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Please note that the Test Sample (comprising a mix of compost and peat, with inorganic
fertiliser and dolomitic limestone) is not intended to represent an optimized commercial
growing media formulation.
5
Personnel
The person who carries out each test shall be trained and experienced in carrying out plant
growth tests and/or supervised by such a person.
6
Apparatus
6.1
Balances
Balance one; capacity 200 g, accurate to 0.01 g or better. Balance two; capacity 3 kg, accurate
to 1 g.
6.2
Capillary matting (optional)
Material which is designed to absorb and hold water, placed underneath trays of growing
media.
NOTE Inadequate moisture will adversely affect tomato seedling germination and growth.
Capillary matting helps maintain adequate moisture in the growing medium and humidity in the
aerial environment (during this 28 day test). However, the matting should not be kept saturated
and over-watering of the growing medium, with its attendant leaching and potential for
cross-contamination between the different materials, should be avoided.
6.3
Controlled environment for plant growth
Greenhouse, plant growth chamber or other controlled environment suitable for plant growth,
with supplementary lighting (see section 10.8) and heating (see section 10.9), capable of being
maintained in the day and night time temperature ranges recommended in Annex A.
6.4
Fertiliser
A complete powdered, inorganic N - P2O5 - K2O fertiliser containing trace elements that is
recommended for the formulation of growing media. The K 2O to N ratio of the selected
fertiliser should be ≤ 1.33:13.
3
Suitable mixes, for example, include Hortifeeds Hortibase Peat Mix A (14-16-18, see
http://www.hortifeeds.co.uk/index.php/hortibase/) and Yara PG Mixes 14-16-18 and 15-10-20 (see
http://yara.co.uk/crop-nutrition/products/other/01d0-pg-mix-14-16-18/ and http://yara.co.uk/cropnutrition/products/other/01d1-pg-mix-15-10-20/). Small quantities of Hortibase (25 kg bag) are
available direct from Hortifeeds (tel: 01522 704404) on which carriage would be paid. For PG mixes
contact Yara Ltd (tel: 01472 889300). Product examples are provided for the convenience of users of
© REAL CCS October 2015
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6.5
Firming board
Board for firming PBGM and Test Sample material down after placing tomato seeds in partially
filled trays. Prepare the board from a rigid material (e.g. plywood) to fit the seed tray exactly
when filled, and affix a sturdy handle.
6.6
Ground dolomitic limestone
Ground dolomitic (magnesian) limestone, fine horticulture grade.
6.7
Seed template
Seed template, prepared from a rigid material (e.g. plywood) to fit the seed tray exactly when
filled, providing a guide that allows ten tomato seeds to be evenly distributed in each seed tray.
Drill 2 rows of holes (5 holes per row, each approximately 5 mm diameter) in the template at
approximately 35 mm intervals. The rows should be approximately 75 mm apart if there is no
spacing between the trays and up to approximately 90 mm apart when there is spacing
between the trays.
NOTE A sturdy handle can be affixed to the template to enable its use also as a firming board.
An acceptable alternative is a rigid board with a sturdy handle, that fits the seed tray exactly
when filled and has ten protrusions (e.g. wooden pegs or screws) firmly attached and evenly
distributed as instructed above. The length of each peg shall be approximately 6 mm and be
approximately 5 - 10 mm in diameter.
NOTE A seed template with protrusions should not be used as a firming board (see 6.5) after
placing tomato seeds in the growing media (see section 10.4).
6.8
Seed trays
Seed trays, nominal size 210 mm long, 150 mm wide and 45 mm deep.
NOTE The quantity of material required to fill each tray (allowing for it to be pressed down in
accordance with the requirements of sections 10.3 and 10.4 below) is 1.5 litres.
6.9
Sieve
Sieve, with 10 mm apertures formed by square mesh.
6.10 Shallow trays (optional)
Shallow trays of suitable dimension for use underneath seed trays (see 6.8).
this methodology and do not constitute an endorsement by any organisation referred to in this
document. Equivalent products may be used if they lead to the same results.
© REAL CCS October 2015
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6.11 Sphagnum moss peat
Irish sphagnum moss peat within the range of H3 to H6 on the von Post scale, with electrical
conductivity in the range of 4 to 12 mS m -1 (equivalent to 40 to 120 µS cm-1) determined using
BS EN 13038.
NOTE Peat products with specified particle size range of 0 to 15 mm are typical medium grade
products4 and create less wastage during sieving (see section 7.1) than coarser grade products.
Peat should be lightly damp and friable. Extra time may be necessary to re-wet the peat before
the start of the test, using water that meets the specification in 6.15.
6.12 Supplementary lighting and light meter
Professional horticultural specification lamps, for supporting plant growth and a light meter to
ensure the provision of light levels as set out in Annex A in the controlled growth environment.
6.13 Tomato seeds
Viable tomato seeds, cultivar Shirley F1 hybrid.
NOTE See Annex B for guidance on tomato seed storage which affects the viability of seeds.
6.14 Transparent plastic covers (optional)
Transparent plastic covers, shaped and sized to cover individual seed trays.
6.15 Water
Mains water of quality specified in supply regulations provided that its electrical conductivity
does not exceed 100 mS m-1, equivalent to 1000 µS cm-1 (see section 16 for references).
Alternatively, water that conforms to BS EN ISO 3696 grade 3 for analytical laboratory use.
Examples for production of the latter are single distillation, deionization or reverse osmosis.
Table 1. Specified characteristics of grade 3 water for analytical laboratory use
Parameter
pH at 25 oC
Electrical conductivity at 25 oC
Oxidisable matter (oxygen content)
Residue after evaporation on heating at 110 oC
Grade 3
5.0 to 7.5
≤ 0.5 mS m-1
(equivalent to 5 µS cm-1)
≤ 0.4 mg l-1
≤ 2 mg kg-1
See BS EN ISO 3696 for specified methods of test.
4
Bord na Móna’s medium substrate peat for professional use is an example of a suitable product. See
http://www.bordnamonahorticulture.ie/professional/our-products/substrate-range/ for more
information. This product example is provided for the convenience of users of this methodology and
does not constitute an endorsement by any organisation referred to in this document. Equivalent
products may be used if they lead to the same results.
© REAL CCS October 2015
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NOTE Water supply regulations allow electrical conductivity of up to 250 mS m-1 (equivalent to
2500 μS cm-1) at 20°C, to accommodate very hard water.
6.16 Watering can with fine rose
Portable water container with a long spout and a detachable cap perforated with fine holes
(rose), used for watering plants.
7
Preparation of the growing media
7.1
Peat
Pass sufficient peat (see 6.11) through the sieve (see 6.9) to obtain at least 8.5 litres of sieved
peat (≤ 10 mm particles). Moisten the sieved peat if necessary.
NOTE This quantity is sufficient for the PBGM and the peat portion of the Test Sample mixture
(see section 7.4).
Determine the laboratory compacted bulk density (LCBD) of the sieved peat in accordance with
BS EN 13040 and record it (record 1 in section 14). Then determine and record its electrical
conductivity (EC) in accordance with BS EN 13038 (record 2 in section 14).
Store the prepared peat in a sealed bag, or other sealable container (to prevent any loss of
moisture and alteration of the LCBD), until needed for preparation of the PBGM and Test
Sample.
7.2
Compost
Prepare the compost sample, ‘as received’ by the laboratory, in accordance with BS EN 13040,
with particular reference to its clause 8.1.
NOTE The compost sample tested at the laboratory should be representative of the batch or
portion of compost sampled at the production site (or elsewhere in the supply chain). To
achieve this, the sample taker should have followed the instructions in BS EN 12579.
Pass sufficient compost through the sieve to obtain at least 2 litres of sieved compost (≤ 10 mm
particles). Separately retain the ≤ 10 mm and > 10 mm fractions and record the mass of each
(records 3 and 4 in section 14). Calculate and record the percentage of compost particles ≤ 10
mm in the compost ‘as received’ (report item 3 in section 15).
Determine the laboratory compacted bulk density (LCBD) of the sieved compost (≤ 10 mm
particles) in accordance with BS EN 13040 and record it (record 5 in section 14). Then
© REAL CCS October 2015
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determine its electrical conductivity (EC) in accordance with BS EN 13038 and record it (report
item 4 in section 15).
NOTE Composts with an EC exceeding 200 mS m-1 (equivalent to 2000 µS cm-1) are less likely to
pass this tomato plant response test than those with an EC below this value.
Store the prepared compost in a sealed bag, or other sealable container (to prevent any loss of
moisture and alteration of the LCBD) until needed for preparation of the PBGM and Test
Sample.
7.3
PBGM control
Calculate the mass of sieved peat (≤ 10 mm fraction, see 7.1) required to provide 4.5 litres of
PBGM. Do this by multiplying the required volume (in litres) of sieved peat by its LCBD (in
grams/litre). Record the grams of prepared peat used in the PBGM (record 6 in section 14).
Example calculation for peat with LCBD of 350 g/l: 4.5 x 350 = 1575 g.
Mix into approximately one third of the weighed out quantity of sieved peat 18 (± 0.05) g of
dolomitic limestone (see 6.6) and sufficient fertiliser (see 6.4) to provide 150 mg N / l5 (for the
whole 4.5 litres). Once mixed, blend the mixture thoroughly with the remaining two thirds of
the weighed out portion of sieved peat.
NOTE Thorough incorporation can be achieved by spreading two thirds of the prepared peat
thinly on a flat surface and evenly distributing the mixture that contains the lime and fertiliser
over it. Techniques such as coning and quartering will help to achieve even distribution of lime
and fertiliser throughout. Avoid excessive handling of the prepared peat to minimise
degradation of its structure.
Record the mass (g) of dolomitic limestone and fertiliser used (record numbers 7 and 8 in
section 14).
Store the PBGM in a sealed bag or other sealable container (to prevent any loss of moisture and
alteration of the LCBD) if it is not immediately used in test set up (see section 10).
7.4
Test Sample
Four and a half (4.5) litres of Test Sample is required which consist of three parts (3.375 litres)
of sieved peat (see 7.1) thoroughly mixed with one part (1.125 litres) of sieved compost (see
7.2) plus lime and fertiliser.
5
For example, if 14:16:18 NPK fertilizer is used, this would require 1.071 g fertiliser per litre of sieved
peat; if 15:10:20 NPK fertiliser is used, this would require addition of 1.0 g fertiliser per litre of sieved
peat.
© REAL CCS October 2015
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Calculate the mass of sieved peat and compost required by multiplying the required volume of
each material (in litres) by its LCBD (in grams/litre). Weigh out the required quantities and
record the mass of screened peat and compost used in the Test Sample (records 9 and 10 in
section 14).
Example calculations of mass of peat and compost required for a test mix of 3.375 litres of
sieved peat and 1.125 litres of sieved compost:
If the peat’s LCBD is 350 g/l, weigh out 3.375 x 350 = 1181 g.
If the compost’s LCBD is 750 g/l, weigh out 1.125 x 750 = 844 g.
Also weigh out 13.5 (± 0.05) g of dolomitic limestone (i.e. 4 g per litre of peat) and sufficient
fertiliser to provide 150 mg water-soluble N / l of the whole Test Sample (i.e. for 4.5 litres)
according to the concentration of nitrogen in the fertiliser. Record the masses of dolomitic
limestone and fertiliser used (records 11 and 12 of section 14).
Thoroughly mix the dolomitic limestone and fertiliser into approximately half of the sieved
peat. Once this is completed, thoroughly blend this mixture with the remaining quantity of
sieved peat and compost and ensure that the final mixture is homogeneous (see the note in
section 7.3).
NOTE Addition of fertiliser should provide a moderate amount of water-soluble nutrients in the
Test Sample, irrespective of water-soluble nutrients released from the compost. The latter are
not determined in this test.
Store the Test Sample in a sealed bag, or other sealable container to prevent loss of moisture, if
it is not immediately used in test set up (see section 10).
8
Controlled growth environment
The tests shall be carried out in a controlled environment suitable for germinating and growing
tomato plants (see 6.3). The test environment shall be a temperature-controlled glasshouse,
growth room or growth cabinet. Light and temperature shall be sufficient to ensure normal,
healthy growth of tomato plants throughout the year (see Annex C for guidance on
abnormalities). This requires the use of supplementary lighting in glasshouses to supplement
the low levels of natural light available in the UK from mid-October to mid-March. In all other
controlled growth environments (CGEs) where natural light is absent or minimal,
supplementary lighting is needed throughout the year and shall provide sufficient light in the
Photosynthetically Active Radiation range to produce a mean top growth fresh mass per
tomato plant of at least 2.0 g, for each of the 3 PBGM control trays at 28 days after sowing.
NOTE See section 13.3 which specifies this test validity criterion. It applies to PBGM control
plants grown in glasshouses as well as those grown in other types of CGE. The previous version
© REAL CCS October 2015
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of this method required a mean top growth fresh mass per tomato plant of at least 1.5 g, for
each of the 3 PBGM control trays at 28 days after sowing.
Guidance on light and temperature is provided respectively in sections A.1 and A.2 of Annex A.
9
Quality control
Quality Control procedures shall include initial and on-going checks on spatial and
environmental variations in the CGE. Such variations affect the rate and characteristics of plant
germination and growth and can bias the results. Influential factors include proximity to the
edges of each area used and to lights, doorways, ventilation points and any heat sources.
Replication of PBGM control and Test Sample trays is designed to ensure that natural plant
variation within a set of trays is taken into account as well as variation between a set of PBGM
control and the associated set(s) of Test Sample. Replication also enables variation in growing
conditions due to their position on the bench to be taken into account. Guidance on replication
and layout of trays is provided in section A.3 of Annex A.
10
Test set-up and maintenance
10.1 Replication in each set
The PBGM control (see section 7.3) shall be set up in 3 trays, as one set of PBGM control. The
compost plus peat Test Sample (see section 7.4) shall be set up in 3 trays, as one set of Test
Sample.
10.2 Sets of Test Sample per set of PBGM control
One set of PBGM control (3 trays) is allowed for up to 6 sets of Test Sample (18 Test Sample
trays, for 6 different compost samples), provided that all are set up on the same day.
10.3 Setting up PBGM control and Test Sample using a seed template with
holes
Put 1.3 litres of PBGM into each of 3 trays (see 6.8) to act as one set of PBGM control. Put 1.3
litres of TS into each of 3 trays to act as one set of Test Sample. Lightly firm the material in each
tray by pressing into corners and around the edges with finger tips. Apply light pressure using
the firming board (see 6.5) to tamp and level the surface of the growing medium. Separately
retain sufficient of the PBGM and Test Sample materials for later covering of the positioned
tomato seeds.
© REAL CCS October 2015
14
Use a watering can with a fine rose (see 6.16) to water (see 6.15) the growing medium in all six
trays until thoroughly moistened. Avoid over-watering as this leaches nutrients from the
growing media and can cross-contaminate growing media in other trays if phytotoxins are
present. If the growing medium in any tray is over-watered, do not allow leachate from that
tray to cross-contaminate the growing media in any other trays. Over-watering may lead to the
growth of algae on the growing medium’s surface and this may inhibit plant growth.
For each of the trays in turn, place the seed template (see 6.7) on the surface of the growing
medium. Place one tomato seed (see 6.13) per hole then remove the seed template. Take
particular care not to drop any extra seed onto the growing medium during sowing. If any extra
seed is dropped, find and remove it.
NOTE See second paragraph in section 11.1 about identification and recording of weeds.
Cover the seeds in the PBGM trays by sieving a layer of PBGM over the surface, such that the
layer is 6 mm deep and each tray then contains a total of 1.5 litres of PBGM. In the same way,
cover the seeds in the Test Sample trays by adding a 6 mm layer of sieved Test Sample medium,
again resulting in each tray containing a total of 1.5 litres of Test Sample. Use the firming board
(see 6.5) to very lightly press down the covering layer of material so that it makes good contact
with the moistened material below.
NOTE A layer of six millimetres of suitable material covering the seeds assists shedding of the
seed coat soon after emergence and facilitates full expansion of the cotyledons (seed leaves).
Watering the growing medium in each tray before sowing and adding the growing medium
cover layer avoids seed displacement when watering from above. However, if the cover layer
does not wet (which is more likely with the PBGM) a very careful watering using a fine rose may
be applied to bond the layers of growing medium together after pressing the cover layer down.
10.4 Setting up PBGM control and Test Sample using a seed template with
protrusions
Instructions in this section provide an alternative to those in section 10.3.
Put 1.5 litres of PBGM into each of 3 trays (see 6.8) to act as the control. Put 1.5 litres of Test
Sample into each of 3 trays to act as the Test Sample. Lightly firm the material in each tray by
pressing into corners and around the edges with finger tips. Apply light pressure using the
firming board (see 6.5) to tamp and level the surface of the growing medium.
For each of the trays in turn, place the seed template on the surface of the growing medium
such that its pegs make holes in the growing medium, then carefully remove the template. Put
one tomato seed into each hole then lightly press the growing medium together so it surrounds
the seed. Take particular care not to drop any extra seed onto the growing medium during
sowing. If any extra seed is dropped, find and remove it.
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NOTE See second paragraph in section 11.1 about identification and recording of weeds.
Use a watering can with a fine rose (see 6.16) to water (see 6.15) the medium in all six trays
until thoroughly moistened. Take care that water flow during watering does not displace the
seeds. Avoid over-watering as this leaches nutrients from the growing media and can crosscontaminate growing media in other trays if phytotoxins are present. If the growing medium in
any tray is over-watered, do not allow leachate from that tray to cross-contaminate the
growing media in any other trays. Over-watering may lead to the growth of algae on the
growing medium’s surface and this may inhibit plant growth.
10.5 Using transparent plastic covers (optional)
After setting up the growing media and tomato seeds in the control and Test Sample trays and
watering, place the trays in the controlled growth environment (see 6.3). They can then be
covered with individual transparent plastic covers (see 6.14). These covers can help to maintain
good levels of moisture in the growing media during germination but there is risk of
over-heating and drying-out if the trays are exposed to hot sun in glasshouses during the
warmer months of the year or to excess radiant heat from lights in some growth rooms.
NOTE Provided the trays are subject to the growing conditions as specified in this methodology,
and moisture levels in the growing medium are regularly monitored and can be readily
maintained, there will be no significant effect on germination or emergence if the covers are
omitted. This is usually easier in a specialist glasshouse facility.
If used, remove the covers as soon as stems of approximately half of the sown seeds emerge
from the growing medium.
Record the dates when transparent plastic covers are put on and removed, if used (record 13 in
section 14).
10.6 Capillary matting and shallow trays (both optional)
If capillary matting (see 6.2) is used it shall be replaced after a maximum of two test periods6 or
at the end of the test if any abnormalities attributable to man-made chemical contaminants are
seen in any of the plants grown in PBGM control or Test Sample trays. Record the dates when
capillary matting is first used and later replaced (record 14 in section 14).
If capillary matting is not used, each tray filled with PBGM or Test Sample should be placed on
an individual shallow tray such that any leachate that seeps into the shallow tray is retained by
6
This means after two periods of 28 days plus the test set-up time and any interval between the two
test periods when the specific area capillary matting is not in use.
© REAL CCS October 2015
16
it. This will reduce risk of cross-contamination if any phytotoxins (including man-made chemical
contaminants) are present in any tray of Test Sample.
NOTE A Test-Sample-filled-tray might contain one or more man-made chemical contaminants
or other phytotoxic substance(s) that could, if overwatered, translocate to other filled trays and
impair tomato seed germination and growth.
10.7 Placing out trays
In an ideal situation there would be no spatial or environmental variations in the controlled
growth environment, so the positioning of trays on the test benches would be irrelevant.
However, some spatial and environmental variation is present in all horticultural test
environments and consequently it is important to understand how the growing conditions vary
due to position.
To take account of known or likely variations, particularly those associated with edges, a three
block layout is recommended. In this arrangement one tray of each treatment is allocated to
each of three rows (or blocks) across the axis of the greatest change in conditions – usually
across the bench. In addition the position of each treatment tray within a row is chosen to
minimise the grouping of each set of trays relating to each treatment in a single column or
corner of the test area. By this means, and the use of guards at the ends of rows, the bias due
to variations of temperature, light intensity, drafts or desiccation on plant growth is evened
out. Guidance on placing out trays, including diagrammatic examples, is provided in Annex A.
Taking account of the guidance and spatial and environmental variations in the controlled
growth environment, set out the 3 trays of Test Sample and 3 trays of PBGM. Record test set
up such that each set of PBGM control trays can be readily associated with the set(s) of Test
Sample allocated to it (record 15 in section 14).
10.8 Light
After each PBGM and Test Sample tray has been placed in its test location use a light meter (see
6.12) to check light intensity 5 cm above the surface of the growing media. If natural light
makes any contribution during the required 16 hour light period per day, light intensity should
be checked when natural light is absent or at its lowest during this period. Adjust
supplementary lighting (see 6.12) if necessary then recheck light intensity.
NOTE The mean light level for each bench/shelf area used should be at least the minimum
recommended according to the light source as set out in section A.1 of Annex A.
The laboratory carrying out the test shall decide and record the details of initial and on-going
checks on lighting and light intensity, as part of its quality control procedures. Checks shall be
carried out at an appropriate number of sampling points for determining the mean light level,
at the appropriate height, that is representative of each bench or shelf area used.
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At intervals during the test check that supplementary light is adequate during the 16 hour light
period per day (see section A.1 of Annex A). Initially measure at 5 cm above the surface of the
growing media then as tomato plants germinate and grow, measure at plant canopy height.
For Controlled Growth Environments in which natural light provides all or some of the light,
each check should be done when natural light is absent or at its weakest during the 16 hour day
(light) period.
NOTE For example, in a glasshouse in winter lux should be checked during day lightening and
darkening within the 16 hour day (light) period. These meter readings will provide indication of
when supplementary lighting should be switched on and off during the 16 hour day (light)
period.
Control supplementary lighting automatically or manually. It shall be visually checked for faults
on a frequent basis unless the lighting system has a fault identification and alert function.
If light intensity becomes insufficient make changes to the supplementary lighting then recheck
light intensity. Record the results of each light meter check and any corrective action and
recheck (record 16 in section 14). Record also the number of hours during each day of the test
when the supplementary lighting was on or the times at which they were switched on and off
(record 17 in section 14).
10.9 Temperature
After each PBGM control and Test Sample tray has been placed in its test location check that air
temperatures within the CGE are maintained in suitable ranges for the 16 naturally and/or
artificially light hours and for the 8 unlit/night hours per day. Maintain air temperatures in the
CGE within suitable ranges. See section A.2 in Annex A for guidance.
Monitor and record minimum and maximum air temperature in the CGE on each working day
when the test is in progress, within the 16 hour light period and the 8 hour unlit/night period
(records 18.a and 18.b in section 14). Record any action taken to maintain suitable
temperatures (record 19 in section 14).
10.10 Inspecting and maintaining growing media and plants
Inspect all trays on each working day. Tailor the watering regime to plant needs and take
particular care not to over-water trays in which plants are growing slowly.
Where transparent plastic covers have been used (optional), remove a cover from its tray when
5 of the 10 seeds sown have emerged through the surface of the growing medium.
Practitioners should note the differences between seedlings that have emerged above the
surface of the growing medium (see figure 1) and seedlings that have germinated (see figure 2
and definition in the paragraph following figure 1).
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Figure 1. Emerged tomato plant seedlings
For the purposes of this test germination is defined as the stage when both cotyledons (leaves)
have expanded and the seed coat has been shed. Provided there are no distortions or
discolouring such seedlings would be described as normal and usable for horticultural purposes
(see figure 2). Each seedling should reach this stage approximately 10 days after sowing. In this
test, plants that have not reached this stage by 14 days after sowing are deemed have not have
germinated and are not worthy of growing on. Where the cotyledons have grown to full size
but are still held together by the seed coat, it is acceptable to carefully pinch or snip off the
seed coat from the tip of the cotyledons to free them and allow such plants to grow on.
At 14 days after sowing, remove any seedlings that have failed to germinate or develop
normally, i.e. those which break through the PBGM control or Test Sample material’s surface
but do not otherwise thrive (e.g. have a damaged or non-functioning growing point), and any
seedlings whose cotyledons are very small or shrivelled.
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Figure 2. Germinated tomato plant seedlings
At 14 days after sowing (or sooner if all seeds sown in the PBGM control and Test Sample trays
have germinated), the frequency of inspection can be reduced. However, continued
inspections each working day are encouraged and shall be frequent enough to ensure that
adequate moisture is maintained in the growing media.
Water whenever necessary using water as specified in 6.15. Use a can with a fine rose (see
6.16) for watering at the surface of the growing media and do this only until water just begins
to drain though the base of the tray. Take care not to over-water and do not water via the base
of each tray.
NOTE Over-watering leads to leaching of nutrients and increases the potential for translocation
of nutrients and/or phytotoxic components from one tray to another, thereby reducing the
reliability of the results. Over-watering may lead to the growth of algae on the growing
medium’s surface and this may inhibit plant growth.
© REAL CCS October 2015
20
11
Recording plant observations
11.1 Tomato plant germination
At 10 days after sowing, for each tray of PBGM control record the total number of germinated
tomato seedlings (see the definition of ‘germinated’ and figure 2 in section 10.10 and record
20.a in section 14). Do the same for each tray of Test Sample (record 20.b in section 14). Do
not record seedlings that have only emerged (see figure 1 in section 10.10) from the PBGM
control or Test Sample growing medium as germinated.
The instructions above in this section apply only to the tomato plants that germinated and grew
from the ten sown tomato seeds. Any other tomato seed that emerged or germinated is a
weed so shall be recorded as a weed, removed and excluded from the tomato plant
germination results.
Do not include any seedlings that have failed to develop normally in the recording, calculation
and reporting of the number of germinated tomato seeds per tray of PBGM control and per
tray of Test Sample at 14 days after sowing. Failure to develop normally means those which
break through the PBGM control or Test Sample material’s surface but do not otherwise thrive,
and any seedlings whose cotyledons are very small or shrivelled. Where the cotyledons have
grown to full size but are still held together by the seed coat, it is acceptable to carefully pinch
or snip off the seed coat from the tip of the cotyledons to free them and record these seedlings
as ‘germinated’.
At 14 days after sowing, for each tray of PBGM control record the total number of germinated
tomato seedlings (record 21.a in section 14) and for each tray of TS record the total number of
germinated tomato seedlings (record 21.b in section 14).
NOTE The 10-day recording indicates speed of germination and the 14-day recording indicates
the number of seedlings with fully emerged cotyledons, i.e. that have germinated and look
normal.
11.2 Tomato plant growth and abnormalities
At 14 and 28 days after sowing, compare and record any visible differences in tomato plant
growth characteristics between those in the 3 TS trays and in the 3 PBGM control trays. Note
any abnormal symptoms (see Annex C for guidance) in germinated Test Sample and PBGM
plants and take photographs. See record 22 in section 14.
NOTE See section 12.2 for assessing and reporting abnormalities in the Test Sample plants and
section 13.2 for assessing validity of the test in terms of absence or presence of abnormalities in
the PBGM plants.
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11.3 Tomato plant mass
At 28 days after sowing, cut the tomato plants off at the surface of the growing medium in each
PBGM control tray then weigh and record the total fresh mass (± 0.01 g) of tomato plant ‘top
growth’ (TGfMass) from each tray (record 23.a in section 14). Do the same with the tomato
plants that have grown in each of the Test Sample trays (record 23.b in section 14).
NOTE This applies only to the tomato plants that germinated and grew from the deliberately
sown tomato seeds. Any other tomato seed that emerged or germinated is a weed, so shall be
recorded as a weed, removed and excluded from the TGfMass results.
11.4 Weed plants
At 28 days after sowing, record the number of weed plants (germinated from seed or grown
from a propagule) in each of the 3 PBGM control trays (record 24.a in section 14) and in each of
the 3 Test Sample trays (record 24.b in section 14). Any tomato plant that has germinated from
a tomato seed that was not sown shall be recorded as a weed and included in the weed results.
12
Calculation and expression of results
12.1 Tomato plant germination
Calculate report item 6 in section 15:
At 10 days after sowing, total number of germinated tomato plants in Test Sample trays as
a percentage of total number of germinated tomato plants in PBGM controls trays =
((mean number germinated in T1 + mean number germinated in T2
+ mean number germinated tomato in T3)
÷
(mean number germinated in P1 + mean number germinated in P2
+ mean number germinated tomato in P3))
x 100
Where: T1 is tray 1 of Test Sample, T2 is tray 2 of Test Sample, T3 is tray 3 of Test Sample,
P1 is tray 1 of PBGM control, P2 is tray 2 of PBGM control and P3 is tray 3 of PBGM control
at 10 days after sowing.
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Calculate report item 7 in section 15:
At 14 days after sowing, total number of germinated tomato plants in Test Sample trays as
a percentage of total number of germinated tomato plants in PBGM controls trays =
((mean number germinated in T1 + mean number germinated in T2
+ mean number germinated tomato in T3)
÷
(mean number germinated in P1 + mean number germinated in P2
+ mean number germinated tomato in P3))
x 100
Where: T1 is tray 1 of Test Sample, T2 is tray 2 of Test Sample, T3 is tray 3 of Test Sample,
P1 is tray 1 of PBGM control, P2 is tray 2 of PBGM control and P3 is tray 3 of PBGM control
at 14 days after sowing.
12.2 Tomato plant abnormalities after germination
Check observation records and any photographs taken for abnormalities in any of the
germinated tomato plants in the 3 Test Sample trays. Report the absence or presence of such
abnormalities and, if possible, their known or likely causes (report item 9 in section 15).
Photograph(s) of any abnormal, germinated tomato plant shall be included in, or provided with,
the report of test results (report item 10 in section 15).
NOTE Abnormalities are not expected in germinated tomato plants in the 3 PBGM control trays;
if present they invalidate the test (see section 13.2).
12.3 Tomato plant mass
Using the recorded germination and top growth (TGfMass) results (see records 21.a and 23.a in
section 14) calculate the mean TGfMass per tomato plant that grew in each the 3 trays of
PBGM control at 28 days after sowing, reporting the result for each tray (report item 13.a in
section 15).
Calculation:
Mean TGfMass per tomato plant in PBGM control tray 1 (in grams) at 28 days after sowing =
(total TGfMass of tomato plants in P1 at 28 days after sowing)
÷
(number of germinated tomato plants in P1 at 14 days after sowing)
Where: P1 is tray 1 of PBGM control.
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23
NOTE Germination is counted for the second and last time at 14 days after sowing. Germination of
further seedlings after this time is not expected, so mean TGfMass per tomato plant at 28 days after
sowing is calculated, in part, by using the germination results at 14 days after sowing.
Repeat the calculation for trays 2 and 3 of PBGM control. (P2 is tray 2 of PBGM control and P3
is tray 3 of PBGM control.)
Using the recorded germination and top growth (TGfMass) results (see records 21.b and 23.b in
section 14) calculate the mean TGfMass per tomato plant that grew in each the 3 trays of Test
Sample at 28 days after sowing, reporting the result for each tray (report item 13.b in section
15).
Calculation:
Mean TFfMass per tomato plant in Test Sample tray 1 (in grams) at 28 days after sowing =
(total TGfMass of tomato plants in T1 at 28 days after sowing)
÷
(number of germinated tomato plants in T1 at 14 days after sowing)
Where: T1 is tray 1 of Test Sample.
NOTE See note above in this section.
Repeat the calculation for trays 2 and 3 of Test Sample. (T2 is tray 2 of Test Sample and T3 is
tray 3 of Test Sample.)
Using results for report items 13.a and 13.b in section 15, calculate the mean TGfMass per
tomato plant for all 3 Test Sample trays as a percentage of the mean TGfMass per tomato plant
for all 3 PBGM control trays, at 28 days after sowing (report item 14 in section 15).
Calculation:
((Mean TGfMass per tomato plant in T1 + Mean TGfMass per tomato plant in T2
+ Mean TGfMass per tomato plant in T3)
÷
(Mean TGfMass per tomato plant in P1 + Mean TGfMass per tomato plant in P2
+ Mean TGfMass per tomato plant in P3))
x 100
Where: T1 is tray 1 of Test Sample, T2 is tray 2 of Test Sample, T3 is tray 3 of Test Sample;
and P1 is tray 1 of PBGM control, P2 is tray 2 of PBGM control and P3 is tray 3 of PBGM
control.
© REAL CCS October 2015
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12.4 Weed plants per litre of compost ‘as received’
Calculate and report the number of weed plants per litre of sieved compost (the ≤ 10 mm
fraction) that emerged during the 28 day test (report item 16 in section 15).
Calculation:
((WT1+WT2+WT3) – ((WP1+WP2+WP3) x (3.375/4.5))) / 3.375
Where:
WT1 = Number of weed plants in Test Sample tray 1
WT2 = Number of weed plants in Test Sample tray 2
WT3 = Number of weed plants in Test Sample tray 3
WP1 = Number of weed plants in PBGM control tray 1
WP2 = Number of weed plants in PBGM control tray 2
WP3 = Number of weed plants in PBGM control tray 3
N.B.: The correctness of the formula above is conditional upon the 3 trays of PBGM and Test
Sample containing each containing a total of 4.5 litres of growing medium and the ratio of
compost to peat being 1:3 in the Test Sample, on a volumetric basis.
13
Validity of the test
Results of the test are influenced by the suitability and control of the test environment to suit
the germination and growth of tomato plants and the viability of tomato seeds used. The
criteria in this section specify the minimum tomato plant PBGM control performance required
for the test to be valid.
13.1 Tomato plant germination
Report the total number of tomato seeds that germinated in all 3 PBGM control trays at 14 days
after sowing (report item 8 in section 15).
If fewer than 27 tomato seedlings have germinated in all 3 PBGM control trays by 14 days after
sowing (i.e. < 90 % germination), the test is invalid. Declare the test invalid if the result is less
than 27 or valid if it is equal to or greater than 27 (report item 8 in section 15).
13.2 Abnormalities after germination
Check observation records and any photographs of abnormal, germinated tomato plants in any
of the 3 PBGM control trays, report absence or presence of abnormality (report item 11 in
section 15). Describe each type of abnormality and, if possible, its known or likely cause.
© REAL CCS October 2015
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Abnormality in any germinated plant in any of the 3 trays of PBGM control shall make the test
invalid. Declare the test valid if all of these plants were normal or invalid if any were abnormal
(report item 12 in section 15).
13.3 Tomato plant mass
The mean top growth fresh mass (TGfMass) per tomato plant for each of the 3 PBGM control
trays at 28 days after sowing was calculated in section 12.3 and results recorded (report item
15 in section 15) and rounded up or down to the nearest decimal place.
Declare the test is invalid if the result is less than 2.0 g per tomato plant in any of the 3 PBGM
controls trays or valid if more than or equal to 2.0 g per tomato plant in all of these trays
(report item 15 in section 15).
NOTE The minimum mean mass per tomato plant corresponds with the least that may be
achieved when the test is carried out during November, December, January, February or March
under glasshouse conditions. Examples of rounding are: a) a calculated mean result of 1.95 g
per tomato plant which should be rounded up to 2.0 g in the report of test results with
declaration that the test is valid (on this measure); and b) a calculated mean result of 1.94 g
which should be rounded down to 1.9 g in the report of test results with declaration that the test
is invalid (on this measure).
14
Laboratory records
The information listed in this section shall be kept in records at the laboratory (see also section
15).
Peat preparation
1.
2.
Laboratory compacted bulk density of the sieved peat ≤ 10 mm particles (see section 7.1).
Electrical conductivity (in mS m-1) of the sieved peat ≤ 10 mm particles (see section 7.1).
Compost preparation
3.
Mass (g) of sieved compost particles ≤ 10 mm (see section 7.2).
4.
Mass (g) of sieved compost particles > 10 mm (see section 7.2).
5.
Laboratory compacted bulk density of sieved compost ≤ 10 mm particles (see section 7.2).
Materials used in the PBGM control
6.
Mass (g) of sieved peat used to form the PBGM control (see section 7.3).
7.
Mass (g) of dolomitic limestone mixed in to form the PBGM control (see section 7.3).
8.
Mass (g) of fertiliser mixed in to form the PBGM control (see section 7.3).
© REAL CCS October 2015
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Materials used in the Test Sample
9.
10.
11.
12.
Mass (g) of sieved peat used in the Test Sample (see section 7.4).
Mass (g) of sieved compost used in the Test Sample (see section 7.4).
Mass (g) of dolomitic limestone mixed in to form the Test Sample (see section 7.4).
Mass (g) of fertiliser mixed in to form the Test Sample (see section 7.4).
Other aspects of test set up and management
13.
14.
15.
16.
17.
18.
19.
Dates when transparent plastic covers are put on and removed, if used (see section 10.5).
Dates when capillary matting is first used and later replaced, if used (see section 10.6).
The set(s) of Test Sample trays that are compared with a specific set of PBGM control
trays (see section 10.7).
Results of each light meter check and any corrective action and recheck (see section
10.8).
Number of hours during each day of the test when supplementary lighting was on or the
times at which they were switched on and off (see section 10.8).
Minimum and maximum air temperature of the controlled growth environment on each
day of the test, within the;
a. 16 hour light period, and
b. 8 hour unlit/night period (see section 10.9).
Any action taken to maintain suitable temperatures (see section 10.9).
Tomato plant germination and appearance
20.
21.
22.
At 10 days after sowing, number of germinated tomato plants in each of the 3 trays of;
a. PBGM control, and
b. Test Sample (see section 11.1).
At 14 days after sowing, number of germinated tomato plants in each of the 3 trays of;
a. PBGM control, and
b. Test Sample (see section 11.1).
At 14 and 28 days after sowing, any visible differences in tomato plant growth
characteristics between those in the 3 TS trays and in the 3 PBGM control trays (see
section 11.2), including photograph and note of any abnormalities.
Tomato plant mass
23.
At 28 days after sowing, total top growth fresh mass (± 0.01 g) of tomato plants that grew
in each of the 3 trays of;
a. PBGM control, and
b. Test Sample (see section 11.3).
© REAL CCS October 2015
27
Weed plants
24.
15
Number of weed plants in each of the 3 trays of;
a. PGBM control, and
b. Test Sample (see section 11.4).
Report of test results
The information listed in this section shall be kept in records at the laboratory and included in
the report of test results.
1.
2.
3.
4.
5.
Reference to this method.
Compost sample identification.
Percentage mass/mass of ≤ 10 mm particles in the compost as received, expressed
rounded up or down to the nearest decimal place (see section 7.2).
Electrical conductivity (in mS m-1) of sieved compost (≤ 10 mm particles, see section 7.2).
Any factors known or suspected to have affected the test and its validity.
Germinated tomato plants
6.
7.
8.
Total number of germinated tomato plants in all 3 Test Sample trays, expressed as a
percentage (rounded up or down to the nearest decimal place) of the total number of
germinated tomato plants in all 3 PBGM control trays, at 10 days after sowing (see section
12.1).
Total number of germinated tomato plants in all 3 Test Sample trays, expressed as a
percentage (rounded up or down to the nearest decimal place) of the total number of
germinated tomato plants in all 3 PBGM control trays, at 14 days after sowing (see section
12.1).
Total number of tomato seeds that germinated in all 3 PBGM control trays at 14 days
after sowing, and declaration that the test is invalid if fewer than 27 or is valid if equal to
or more than 27 (see section 13.1).
Abnormal germinated tomato plants
9.
10.
11.
Absence or presence of abnormal, germinated tomato plants in any of the 3 Test Sample
trays, with description of each type of abnormality and, if possible, its known or likely
cause (see section 12.2).
Photograph(s) of any abnormal, germinated tomato plants (see section 12.2). The
photograph(s) shall be incorporated in the report or provided in conjunction with it.
Absence or presence of abnormal, germinated tomato plants in any of the 3 PBGM
control trays (see section 13.2), with description of each type of abnormality and, if
possible, its known or likely cause.
© REAL CCS October 2015
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12.
Declaration that the test is valid if abnormality is absent from all of the 3 PBGM control
trays (report item 11) or invalid if present (see section 13.2).
Tomato plant mass
13.
14.
15.
16.
16
At 28 days after sowing, mean top growth fresh mass (to 2 decimal places) per tomato
plant that grew in each the 3 trays of;
a. PBGM control, and
b. Test Sample (see section 12.3).
Mean top growth fresh mass per tomato plant for all 3 Test Sample trays as a percentage
(rounded up or down to the nearest decimal place) of the mean top growth fresh mass
per tomato plant for all 3 PBGM control trays, at 28 days after sowing (see section 12.3).
Mean top growth fresh mass per tomato plant (rounded up or down to the nearest
decimal place) for each of the 3 PBGM control trays at 28 days after sowing, and
declaration that test is invalid if the result is less than 2.0 g per tomato plant in any of
these trays or valid if more than or equal to 2.0 g per tomato plant in all of these trays
(see section 13.3).
Number of weed plants per litre of sieved compost (the ≤ 10 mm fraction), that emerged
during the 28 day test (see section 12.4, express result to 1 decimal place).
NOTE The result is unlikely to be a whole number because it takes into account the litres
of compost used in 3 Test Sample trays.
References
The most recent editions of each of these standards shall be used:
BS EN ISO 3696, Water for analytical laboratory use - Specification and test methods.
BS EN 12579, Soil improvers and growing media – Sampling.
BS EN 13038, Soil improvers and growing media – Determination of electrical conductivity.
BS EN 13040, Soil improvers and growing media – Sample preparation for chemical and physical
tests, determination of dry matter content, moisture content and laboratory compacted bulk
density.
Statutory Instruments 2000 No. 3184, WATER, ENGLAND AND WALES, The Water Supply (Water
Quality) Regulations 2000 (as amended).
Statutory Rules of Northern Ireland 2002 No. 331, WATER AND SEWERAGE, The Water Supply
(Water Quality) Regulations (Northern Ireland) 2002 (as amended).
Scottish Statutory Instruments 2001 No. 207, WATER SUPPLY, The Water Supply (Water
Quality) (Scotland) Regulations 2001 (as amended).
Welsh Statutory Instruments 2001 No. 3911 (W.323), WATER, ENGLAND AND WALES, The
Water Supply (Water Quality) Regulations 2001 (as amended).
© REAL CCS October 2015
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ANNEX A: Guidance on light, temperature and tray layout in
controlled growth environments
A.1
Light
General
Uniform light is essential for the proper growth of experimental plants in controlled
environments and it must be of sufficient intensity, quality and duration throughout the year.
Natural sunlight is the cheapest source available but even in glasshouses this needs
supplementation during the late autumn and winter months in the UK.
Plants have a different sensitivity to light colours than humans. That part of the solar radiation
spectrum which can be used by green plants for photosynthesis is between the wavelengths of
400nm and 700nm (nanometres). This is called PAR-light or Photosynthetically Active Radiation.
Plants respond to light across this whole spectrum for photosynthesis, with a slightly greater
response at the red end. Blue light is also important for minimising stem elongation (also
known as stretching). Overall, a balance of red and blue light is required.
One way in which the spectral quality of lamps can be compared is by reference to their ‘colour
temperature’ which is measured in degrees Kelvin (˚K). On this scale the higher the
temperature the bluer (or ‘cooler’) the light and the lower the temperature the redder (or
warmer’) the light is. Table 1 illustrates the colour temperature of common light sources.
Table 1. Colour temperature of common light sources
Light Source
High pressure sodium
Soft (or warm) compact florescent
Warm metal halide
Cool white fluorescent
Tubular fluorescent or cool white/daylight compact
fluorescent
Daylight average
Kelvin Temperature (˚K)
2200
3000
3200
4200
5000
5800
The quantity of PAR the plant receives is expressed by reference to the amount of photons
received in ‘mols’ per unit area per day; this is termed the Daily Light Integral (DLI). For the
production of ‘high quality plants’ the minimum amount of PAR required (other than for shade
plants) is often quoted at about 10 mol/m2/day (at plant canopy height). This is equivalent to a
steady Photosynthetic Photon Flux Density of 173 µmol/m 2/s over 16 hours.
DLI is the single most important factor affecting photosynthesis and plant growth (increase in
mass).
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NOTE The use of Light Emitting Diodes (LEDs) is becoming more popular as they are cheaper to
install and run; and they can also be selected to provide the best possible spectrum of
wavelengths for any particular plant growth application. However, whilst the general principles
set out in this guidance apply, LED lighting is not discussed specifically in this annex.
Measuring light intensity
The determination of PAR irradiance is best achieved by the use of a PAR (or Quantum) sensor
linked to a meter (and logger), which provides the information necessary for the DLI to be
calculated or logged. Unfortunately, such equipment is very expensive and is usually only
cost-effective for dedicated research facilities.
Lux (illuminance) meters are more readily available and are used to measure light intensity in
work and display areas, and in photographic applications. These can be much cheaper than
PAR equipment but they must be properly calibrated/corrected and be capable of producing
repeatable results. However, it must be appreciated that these are tuned to the sensitivity of
the human eye which is most responsive to green light and, because of this, they do not
actually measure PAR. Nevertheless, they can provide an approximation of PAR or DLI by the
application of a factor which is appropriate to the light source used. Table 2 illustrates the
conversion of lux to DLI assuming constant illumination for 16 hours for various lux values.
Sixteen hours is chosen as it is the recommended day length for the growth of tomato plants
with supplementary lighting in this test.
Table 2. Conversion of lux to DLI
Light source
Sunlight
Cool white fluorescent
Plant growth fluorescent
(Gro-Lux®)
High-pressure sodium
High-pressure metal halide
Lux to DLI
Factor
(assuming
16 hour
illumination)
0.00109
0.00081
Approximate DLI for 16 hours
illumination at various measured lux
levels (mol/m2/day)
4000 6000 8000 10000 12000
lux
lux
lux
lux
lux
4.4
6.5
8.7
10.9
13.1
3.2
4.9
6.5
8.1
9.7
0.00173
6.9
10.4
13.8
17.3
20.8
0.00069
0.00081
2.8
3.2
4.1
4.9
5.5
6.5
6.9
8.1
8.3
9.7
It must also be noted that actual values for each artificial light source will depend on the
luminaire, lamp, ballast and hours of use - as efficiency declines with age.
Glasshouse supplementary lighting
In the UK the DLI outdoors ranges from about 5 mol/m2/day in winter to < 50 mol/m2/day in
summer. In glasshouses light incidence can be reduced due to shading from the structure and
the glass by 40 % or more; which illustrates why it is vitally important to keep the glass clean for
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winter growing. From the above data it can be calculated that in a UK glasshouse in
mid-December natural sunlight may provide a DLI of less than 3 mol/m 2/day whilst in
mid-summer it may be ten times this.
For this tomato growing test, it is recommended that between mid-October and mid-March
daylight is supplemented with 6000 lux of artificial light continuously for 16 hours per day
(04:00 to 20:00). At other times during spring and autumn up to 16 hours of supplementary
lighting may be given (at 6000 lux) dependent on the intensity of solar radiation, but generally
only used to extend the day length to 16 hours. Under summer conditions (May to August
inclusive) no supplementary lighting is necessary.
Sufficient PAR light must be available to ensure that an average plant fresh mass of at least 2
g is achieved in each of the three replicate trays at all times in the PBGM control 28 days after
sowing.
The most common form of supplementary lighting for enhancing growth in glasshouses (as
opposed to simple day length extension) has been high pressure sodium (HPS) lamps. These
lamps are highly efficient but generate a lot of heat and produce more red and less blue light
than ideal. However, neither of these issues is a problem in glasshouses as the heat is useful in
maintaining set temperatures during the cooler/darker months and there is sufficient
additional blue and ultra violet light coming from the sky to help prevent excessive stem
elongation. For the reasons given above HPS lamps are not recommended for use in growth
rooms and cabinets.
With reference to the table above, the standard 6000 lux regime for 16 hours using HPS lamps
can provide an additional 4 mol/m2/day which, combined with the sunlight contribution of 3
mol/m2/day, means that the minimum DLI under these glasshouse conditions will be about 7
mol/m2/day in mid-December. This compares with a DLI of < 30 mol/m2/day at the height of
summer from sunlight alone.
Growth room or cabinet lighting
The aim is, as far as practicable, to produce similar conditions to those in glasshouses so that
growth, performance and outcomes are comparable and largely independent of the
environment where the test is conducted.
Such environments are usually interior spaces without windows or any natural light.
Accordingly, and in all circumstances, the supplementary lighting must provide all the PAR-light
required, and the minimum DLI must at least match that in a glasshouse under winter
conditions with supplementary lighting over a 16-hour period; i.e. about 7 mol/m2/day. Unless
the PBGM control plant fresh masses fail to meet the 2 g minimum 28 days after sowing, the
maximum DLI should probably not need to exceed 10 mol/m 2/day.
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The choice of light source is critical and, to ensure that it provides sufficient blue light to control
stem elongation, lamps with a colour temperature of at least 4000 ˚K should be used. These
lamps or tubes may be described as ‘cool’, ‘daylight’ or ‘grow-lights’. An example of the latter is
the Gro-Lux® range produced by Havells Sylvania which is designed to provide sufficient red and
blue light to support plant growth.
As has been shown in the earlier table the measured lux required to achieve a particular DLI
depends on the lamps chosen (and their condition and position). The required lux level
(measured at canopy height) to achieve a DLI 7 - 10 mol/m2/day of will vary from about 4000 to
12000 lux according to the light source employed.
Another important consideration is the homogeneity of light in growth rooms and cabinets. The
use of point sources such as HID lamps will result in more variation than densely spaced
fluorescent tubes (or LEDs) covering the entire growing area. There is also a significant fall-off in
light intensity close to the walls of a growth room and it is vital that all possible surfaces are
reflective to minimise this; including the door and floor. A white coating helps but is less
effective than a mirrored surface for this.
Light intensity increases or decreases with the inverse square of the distance from the source;
this means that halving the distance quadruples the intensity and vice versa. Therefore, it is
important that the distance from the light source to the canopy is adjusted to ensure that it
provides the desired minimum light intensity. Furthermore, since light output decreases with
age, light intensity at canopy height should be checked regularly and before each batch of
plants is grown.
Sufficient PAR light must be available to ensure that an average plant fresh mass of at least 2
g in each of the three replicate trays is achieved at all times in the PBGM control 28 days after
sowing.
A.2
Temperature
General
The recommended (air) temperatures at which tomato plants are grown are a compromise as
the interaction between temperature and light is complex, different growth stages respond
differently and the cost of heating and lighting have to be taken into account. Maximum
growth rates in young tomato plants occur when both day and night temperature is high (25 ˚C)
- irrespective of light intensity - although the plants grow taller and thinner if the light is poor.
However, this does not mean that test plants should be grown at uniformly high temperature –
see below.
Seed germination is best achieved at 20 – 21 ˚C, with lower temperatures resulting in slow,
uncertain germination whilst higher temperatures can generate more abnormal, malformed or
‘blind’ seedlings known as ‘rogues’ or ‘jacks’.
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Glasshouse temperature regime
The benchmark for raising tomato plants in this test is a glasshouse where the standard is a
daytime temperature (during the 16 light hours) set at a minimum of 20 ˚C with venting
beginning at 22 ˚C and a maximum daily temperature of 25 ˚C, whilst the night-time minimum
(during the 8 unlit/dark hours) is set at 16 ˚C with a maximum of 18 ˚C. However, during hot
summer conditions it is recognised that both day and night maxima may be exceeded on
occasions.
Growth room or cabinet temperature regime
The aim is, as far as practicable, to produce similar conditions to those in glasshouses so that
growth, performance and outcomes are comparable and largely independent of the
environment where the test is conducted.
It is important that the temperature at night (during the 8-hour dark period) is lower than that
during the day (during the 16-hour illuminated period) as this would be normal under the
glasshouse temperature regime and helps prevent excessive growth and stem elongation.
A day temperature of 20 – 22 ˚C with a night temperature of 16 – 18 ˚C should be maintained at
plant canopy height.
A.3
Other considerations: replication and layout of the trays
General
This test is carried out by comparing the relative growth of tomato plants in three trays of each
Test Sample with that in three control trays of Peat-based Growing Medium (PBGM). The
purpose of using three trays of each (30 plants in total) is to minimise the influence of any
inherent variability between individual plants and to allow for any variability in the
management or environment to which individual trays are exposed.
Glasshouses
On an experimental glasshouse bench where light levels and temperature should be reasonably
uniform there will still be differences in the micro-environment to which the plants are
exposed. There will be some shading due to the structure but the most obvious and dominant
effect is the ‘edge effect’. Plants on the outside of the block of test plants are exposed to more
moving air which will also be less humid than the air in the centre. These plants tend to be
more stressed and to dry out more quickly with the consequence that the plants on the outside
of the block are often visibly smaller. The axis of greatest variability will usually be across
rather than along the bench, although more individual plants will be affected along the edge(s)
of the bench next to an aisle(s) since this is the longest and ‘driest’ edge.
The ‘edge effect’ must be minimised and allowed for in the layout of the trays. One commonly
used experimental design in glasshouses is a ‘randomised block’. Where the number of
replicates for each treatment is three (as in this test), trays are arranged in three rows (or
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blocks) across the bench - with each treatment replicated once in each row and in a different
position (column) in that row; the position in each row being chosen randomly if the data is to
be analysed statistically.
This randomised design can lead to anomalies and by chance one treatment may end up in one
column or one end of the experiment. For this test it recommended that the trays of each
treatment are distributed pseudo-systematically, ensuring that not only do the replicates
appear only once in each row) or block but, as far as possible, no two replicates appear in the
same column. This protects against the possibility that there is a significant difference in heat,
light or humidity along the bench which could bias the results – especially for the trays in the
columns at the ends.
Ideally the area of experimental plants (Test Sample and PBGM control) plants should be
surrounded by ‘guard’ plants so that the test plants are not be exposed to any significant ‘edge
effects’; but this is rarely practical under glasshouse conditions. However, as a minimum, an
extra tray of plants should be placed at the ends of each of the three rows, since the end of row
‘edge effect’ cannot usually be taken into account by the replication. But, irrespective of
whether or not ‘guard’ rows are employed, it is important to ensure that the three replicates of
any treatment (including the PBGM control) are represented in different positions in each row
and not all placed in the same column or predominantly at the ends.
These points are illustrated in the three diagrams below featuring a plant growth test with six
treatments - five Test Samples (A, B, C, D, E) and a PGBM control - using three replicates (trays)
of each on a bench with unknown variability in the distribution of light and temperature along
the length of the bench:
Diagram 1. Good Bench Layout
Row 3
Row 2
Row 1
Guard
Guard
Guard
Col 1
PBGM
D
C
Col 2
A
E
B
Back edge
Col 3
Col 4
D
B
A
C
PBGM
E
Front edge
Col 5
C
PBGM
D
Col 6
E
B
A
Guard
Guard
Guard
Aisle/ Access
Diagram 1 shows the following positive features of good practice:
 Guards at ends of rows (although not along front and back edges)
 Each Test Sample and PBGM control tray is only represented once in each row
 The PBGM control trays are distributed amongst the Test Sample trays
 No two replicates of any treatment are in the same column nor adjacent to one another
 No treatment is represented more than once at a row end (columns 1 and 6)
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Diagram 2 shows a systematic version of the first layout which has several negative features
that should be avoided:
 Treatments are all in columns; no allowance for possible positional effects along the
bench
 PBGM controls not distributed amongst the Test Sample trays
 Two treatments (PBGM and E) are only present at the ends of the rows and are far
apart, making comparison potentially invalid if the environment along the bench is not
uniform
Diagram 2. Poor Bench Layout (a)
Row 3
Row 2
Row 1
Guard
Guard
Guard
Col 1
PBGM
PBGM
PBGM
Col 2
A
A
A
Back edge
Col 3
Col 4
B
C
B
C
B
C
Front edge
Col 5
D
D
D
Col 6
E
E
E
Guard
Guard
Guard
Aisle/ Access
Diagram 3 illustrates the poorest practice:
 No guards; four exposed edges!
 PBGM controls not distributed amongst the Test Sample trays
 Three trays of two treatments (A and C) are each in a single row and the other three
treatments have two replicates in the same row
 Replicates of three treatments (PBGM and E) occupy the corners of the experiment
 Replicates of all treatments grouped together and are adjacent to one another negating
some of the value of replication
Diagram 3. Poor Bench Layout (b)
Row 3
Row 2
Row 1
Lefthand
edge
Col 1
C
PBGM
PBGM
Back edge
Col 2
Col 3
Col 4
C
C
A
B
B
A
PBGM
B
D
Front edge
Col 5
E
A
D
Col 6
E
E
D
Righthand
edge
Aisle/ Access
Growth rooms and cabinets
In growth rooms or cabinets the same principles apply. Indeed, because the test area and the
number of treatments/trays that can be accommodated at any one time are smaller, the
influence of edges and micro-climates will be greater (see also comments about light above).
This will be more so if there is a single light source and exaggerated further when the bench(es)
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on which the trays are placed cannot accommodate them in three rows, making the
distribution of the replicates more problematic.
In these circumstances it is even more important that trays of each treatment are not grouped
together. Where plant trays are contained in larger trays no more than one replicate of each
treatment should be placed in each holding tray. Because of the restricted space in growth
rooms and the fact that the ‘block design’ used on glasshouse benches can rarely be used, it
may be necessary to rotate the trays into different positions during the period of the test to
counter the environmental variability. Tiering of benches within growth rooms adds to the
heterogeneity of the growing environment (both in terms of light and temperature) – unless
each bench has its own individual lighting (using banks of fluorescent tubes) and there is
sufficient air movement to counteract the stratification of heat within the room.
Overall, these issues make it difficult for tests conducted in smaller controlled growth
environments to match the robustness of those conducted in a purpose-built experimental
glasshouse.
A.4
Sources of information
1. Variation in Light Intensity at Different Latitudes and Seasons, Effects of Cloud Cover, and
the Amounts of Direct and Diffuse Light. Paul Burgess, 2009.
http://www.ccfg.org.uk/conferences/downloads/P_Burgess.pdf
2. Environmental Growth Chambers, Lighting Radiation Conversion:
http://www.egc.com/useful_info_lighting.php
3. Light and Lighting Controls in Greenhouses:
http://www.arguscontrols.com/resources/Light-and-Lighting-Control-in-Greenhouses.pdf
4. Li-cor Inc: http://www.licor.com/env/products/light/quantum sensors/
5. Evaluating Supplemental Light for Your Greenhouse:
http://www.greenhouse.cornell.edu/crops/factsheets/SuppLight.pdf
6. Measuring Daily Light Integral in a Greenhouse, Torre A.P. and Lopez R.G., Purdue
University: https://www.extension.purdue.edu/extmedia/HO/HO-238-W.pdf
7. Phytotron Procedural Manual, Technical Bulletin 244 (Revised), November 2009:
http://www.ncsu.edu/phytotron/manual.pdf
8. Philips LED Lighting in Horticulture, 2012:
http://www.lighting.philips.co.uk/pwc_li/main/shared/assets/downloads/pdf/horticulture/l
eaflets/general-booklet-philips-led-lighting-in-horticulture.pdf
9. Growing greenhouse tomatoes in soil and soilless media, Papadopoulus A.P., 1991:
http://www.hydro-gardens.com/PDF%20Files/Growing%20GH%20Tomates.PDF
10. Greenhouse Tomatoes, Lettuce and Cucumbers, Wittwer S.H. and Honma S., Michigan State
Press, 1979.
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11. The UK Tomato Manual, Grower Books, London, 1973.
12. ‘The art of growing plants for experimental purposes: a practical guide for the plant
biologist’, Poorter H. et al, Functional Plant Biology, 2012, 39, 821–838:
http://www.publish.csiro.au/?act=view_file&file_id=FP12028.pdf
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ANNEX B: Tomato seed storage
Temperature, relative humidity and seed moisture are the important factors that determine
how long seed can be stored without loss of viability (potential for germination). In general,
longer seed storage life is obtained when seeds are kept under dry and cool conditions in the
dark.
Seed wholesalers’ practices and guidance varies; one of the suppliers checked stores its tomato
seed packets in a warehouse kept at 13 to 16 °C and 26 % relative humidity. Another supplier
recommends storage of unopened and opened packets at 5 °C, with the latter being kept at
between 25 to 30 % relative humidity. Storage temperatures between 35 and 50 °F (1.7 and 10
°C) are satisfactory when the moisture content of the seed is low. These guidelines apply to
storage of packaged tomato seed at the laboratory as well as at the wholesaler’s location.
Keep the tomato seeds both dry and cool. Storage in a sealed container such as a plastic box in
a refrigerator set at 5 to 10°C is recommended. Do not store the seeds in the tomato growing
environment or under ambient conditions in an office or laboratory.
If carefully packed and stored as recommended above, tomato seed should remain viable for up
to four years. However, to maximize the likelihood that tomato seeds are viable when testing
compost as per the methodology in this document, frequent small orders should be placed with
the supplier rather than infrequent, large, bulk orders. If a bulk order has to be made, limit it to
the minimum quantity.
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ANNEX C: Guidance on abnormalities
Abnormalities can indicate the presence or absence of phytotoxins, such as volatile organic
acids or pesticides (particularly herbicides), which may not be apparent from the germination
and mean fresh mass per tomato plant results.
Examples of abnormalities are: surface rooting, plant distortions (such as twisting of the stems,
blindness or cupping or curling of the leaves) unusual colouring, lesions, chlorosis (yellowing),
nettling (increased serration and a wider leaf which is typically more hairy) or other
abnormalities in shoots or leaves. See figures 1, 2 and 3 for examples.
Any incidence of ‘purpling’ in tomato plant seedlings is most likely to be caused by
temperatures significantly lower than the minimum specified for this test rather than of
nutrient deficiency, contamination or some other problem.
Figure C.1 A severe case of herbicide damage at 4 weeks after tomato seed sowing in a
compost sample diluted with peat. Symptoms are deformation of the leaflets, some
curling/twisting, ‘nettling’ and downward rolling/cupping.
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Figure C.2 Tomato plant in front row second from right shows nettling on the developing leaf
as it is unfolding. The new leaves will open but will probably be stunted and nettled.
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Figure C.3 A close-up of figure C.2, showing cupping of the uncurled leaf in the plant centre and
older leaf more lobed rather than serrated.
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ANNEX D: Method for testing field bean germination and growth
response
N.B.: This test is recommended for samples from compost batches destined for use as
growing media.
The methodology for this field bean bioassay is based on the seed germination and plant
growth response test specified in BSI PAS 100 (the BSI PAS 100 test) 7. The methodology
specified for the BSI PAS 100 test, including the methodology for collecting compost samples,
shall be followed unless otherwise specified below.
Methodology
a.
b.
c.
d.
e.
f.
g.
Thoroughly clean the area before each test is started.
For each test a minimum of 3.5 litres of peat-based growing medium (PBGM) and 1 litre
of test mix sample (TS) are required, and must be prepared as described in the BSI PAS
100 test, with the following exception: once prepared, PBGM and TS shall be mixed in the
ratio 2PBGM : 1TS to provide the test mix.
A control of PBGM is required for this test. A maximum of six Test Samples can be tested
for every one PBGM control.
Fill lightly a 2 litre plastic pot to the top of the pot with the PBGM or test mix as
appropriate, and firm with a spare pot.
Distribute evenly 10 field bean seeds (Vicia faba cv Fuego) on the surface and cover with
spare PBGM or test mix as appropriate.
Place the pot onto a plastic saucer to ensure that any run off is collected and does not
contaminate the area where the test is being conducted.
Watering can be applied overhead but splash must be avoided.
NOTE Since this test relies on scoring of individual plants, the use of replicate pots is not
considered necessary. Users of the test may specify replication if they require it.
Assessments
a.
b.
Record the number of seeds germinated at 14 days. If:
o fewer than 70 % of seeds have germinated in the PBGM control, the test is invalid; and
o if the test is valid, but fewer than 70 % of seeds have germinated in the test mix, the
sample will have failed8.
Record the number of plants at 28 days after sowing.
7
At the time of publication, BSI PAS 100:2011 is the current version of the specification for composted
materials.
8
The germination requirements are different to the standard BSI PAS 100 plant growth response test
because field bean is a slightly less reliable germinator than tomato.
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c.
Record the number of plants with visible symptoms of herbicide damage at 28 days after
sowing. Visible symptoms should be categorised in accordance with the following:
0 (nil) – no visible symptoms, plant growth and leaf development look normal
compared to the PBGM control
1 (Slight) - leaf curling on some newly developing or older leaves
2 (Slight – moderate) – leaf curling and cupping on most leaves
3 (Moderate) – leaf cupping on most leaves and slight twisting/distortion in the plant
head
4 (Moderate - severe) – leaf cupping of most leaves and moderate twisting of the plant
head
5 (Severe) – severe leaf cupping, and clearly abnormal growth of the plant head.
The photographs provided below should be used to decide the damage category.
d.
Report on a per plant basis the number of plants in each applicable category of symptom
severity at 28 days after sowing:
0
(Nil)
1
(Slight)
2
(Slight moderate)
3
(Moderate)
4
(Moderate severe)
5
(Severe)
Number of
plants
Test validity
The test is invalid if symptoms are observed in the PBGM grown plants. As specified above (see
a. in assessments section), the test is invalid if after 14 days fewer than 70 % of seeds germinate
in the PBGM control.
Pass / failure
A sample will have passed the field bean germination and plant growth response test if all
plants grown in the test mix exhibit symptoms of 2 or less.
A sample will have failed the field bean germination and plant growth response test if any
plants grown in the test mix exhibit symptoms of greater than 2.
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Photographs illustrating characteristic symptoms on the 0 - 5 scale
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~ End page ~
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