TGA Standards

TGA certified turf is only available from members of the TGA (turfgrass growers association).

Introduction:

These standards apply only to cultivated turf 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.

Online Turf is not currently a member of the TGA.