| TGA
Standards
Introduction:
These standards apply only to cultivated
produced by the members of the Turfgrass Growers Association (TGA)
and supplied with a declaration that it meets set criteria. The
intention is to set a minimum standard for good quality cultivated
turf for use in general landscape situations. Turf intended for
some uses on sports facilities demands a more rigorous standard,
particularly in relation to soil type, which this standard does
not address. Turf consisting predominantly of agricultural or
wild grasses cannot by definition meet the TGA quality standard.
Declaration:
The results of the following assessments, together with a statement
that turf has been grown from good quality turfgrass cultivars
on a suitable soil type are to be recorded on a declaration form
completed by the turf grower on the day of lifting and made available
to customers.
Dimensions:
The dimensions of the turves in the consignment are to be declared.
The most common type of cultivated turf in the UK is the roll,
1 square metre (406mm x 2465mm) or 1 square yard (16" x 81")
in area, and those parts meeting of a standard relating to this
manual. 'Big rolls' in a variety of dimensions (most commonly
25 square yards in area) are increasingly popular for large-scale
landscape projects. Turf may also be supplied in rectangular pieces
of other sizes to be agreed with the customer in advance. Deviation
from the declared size shall be plus or minus 15mm in width and
plus or minus 5% in length.
General Health
of Turf:
The sward must be green and must not be visibly affected by any
pest or disease.
Soil Classification:
Suitable types of soil for turf production for landscape purposes
are peats, sands (including organic sand) and loams containing
less than 40% clay as determined by particle size analysis. Turf
grown on soil designated, as 'clay' is not suitable for general
landscape purposes.
Grasses:
Cultivars of turfgrass used for cultivated turf production should
be shown in the edition of 'Turfgrass Seed' *1 current in the
year of sowing the crop and listed in the declaration. The turf
is to be composed of the sown turfgrasses which should occupy
at least 95% of each turf. Any other species present and their
approximate % cover are also to be listed in the declaration.
The content of plants in the turf (grasses and broad-leaved weeds)
is to be objectively assessed with the appropriate quadrats using
the techniques described in 'Methods'. In the first instance a
rectangular quadrat, such as the standard TGA 75cm square may
be used, but in the event of a dispute or for a more accurate
ground cover assessment the more precise "New optical point
quadrat"2 should be used. This is a more accurate instrument
for the assessment of ground cover in close mown turf and the
results of an assessment conducted as described in the 'Methods'
(section B.1.b) will be final. *1 obtainable from The Sports Turf
Research Institute, Bingley, West Yorkshire BD16 1AU
Cutting Height:
The height of the sward when harvested should not exceed 35mm
as measured using the technique described in the 'Methods' (section
B.2.i)
Thatch or Fibre
Thickness:
The thickness of uncompressed thatch should not exceed 10mm as
measured using the technique described in the 'Methods' (section
B.2.ii, a and b)
Thickness of Soil:
The soil layer beneath the thatch should be between 5 and 15mm
deep as measured using the technique described in 'Methods' (section
B.2.iii) and this thickness should be uniform within a consignment
of turf.
Netting:
A declaration must be made as to whether sod netting is incorporated
in the turf. If it is present at point of sale it should be embedded
in the turf and must not project above the thatch layer. (This
statement does not apply to removable netting wrapped around pallets
or "big rolls" to protect the harvested turf.)
Strength:
To demonstrate strength, it should be possible to lift 1 sq. metre
or 1 sq. yard turves clear of the ground by their shortest side.
At least 15 out of 20 turves tested in this way should remain
intact.
Weight:
Rolls of 1 square yard or 1 square metre in area must weigh less
that 20kg, unless the turf is very wet due to rain on the day
of harvest.

|