Peat is made of incompletely decomposed plant remains, mainly sedges, grasses, reeds and mosses. It forms when the natural processes of decay are arrested by waterlogging and exclusion of oxygen, with the remains of succeeding wetland plants becoming compacted to form peat. It is a slow process with the layer of peat increasing by an average rate calculated to be no more than 1mm (1/16in) depth per year. It is used in horticulture for its unique characteristics that make it an ideal growing medium.

Where does it come from?

Existing peatlands cover about 10 billion acres of the land and freshwater surface of the planet and are found throughout the world. Currently, though, peat formation is occurring mainly in the northern temperate zone.

In the United Kingdom peatlands cover 1.6 million hectares, 95% of which is upland blanket bog and the remainder is lowland raised bog. Not all peat types are suitable for commercial extraction and it is the lowland raised bog, composed of deep sphagnum moss peat, that gives rise to most of the product destined for horticulture. Of the 70,000ha of lowland raised bog in the UK, estimates suggest that only 3,800-8,000ha remain in pristine or near-natural condition.

Peat extraction
and use

The effects of extraction are irreparable as peatlands take thousands of years to form. Reclamation schemes at previously worked sites have succeeded in creating attractive wetland areas, but they have not re-created peatlands. Peat forms at a rate of only 1mm (1/16in) per year, while peat extractors remove up to 22cm (9in) a year. A 10m (33ft) deep peat reserve, which took around 10,000 years to form, will be cleared in less than 50 years. Bearing these timescales in mind, it is impossible to envisage rehabilitated and restored peatlands. Even if peatlands could be restored, it is important to remember that preservation is cheaper than restoration.

Defra estimates that 2.96 million cubic metres of peat is used in the UK annually, of which 99% is used as growing media and 69% of which is used by gardeners. 68% of all peat used in the United Kingdom is imported from other countries, including the Republic of Ireland and the Baltic states (Defra, 2010).

Legislation

Until recently, horticulture was focused on achieving UK Government targets for reducing peat use by 2010. Major retailers (such as B&Q, Homebase, Focus and Marks & Spencer) sought to match or better these targets. It was hoped that such leadership would encourage commercial nurseries away from using peat.

The Growing Media Initiative (GMI), a scheme involving the Horticultural Trades Association, the Growing Media Association, retailers, Defra, the RSPB and the RHS, aims to encourage the horticultural industry in the UK to reduce peat use in line with Government targets.

The European Union shares concern about peatland preservation. Most peatlands are now so rare that they are being designated as Special Areas of Conservation and member states are required to protect them. The EU also advocates the view that preservation is cheaper than restoration. Outside the EU, the special conservation status of peatlands is increasingly recognised, though with variable legislative effectiveness.

Defra consultation

Previous Defra targets for peat use in 2010 were not achieved so, on 17 December 2010, Defra announced the launch of its revised consultation on horticultural use of peat.

The important points of this consultation are that Defra recognises the different challenges facing the home and professional markets and has therefore proposed that peat is phased out by 2020 for the home gardening market for bagged growing media and by 2030 for professional growers.

A shared interest in protecting peatlands

The following organisations are among those with a shared interest in the protection of peatlands as a wildlife habitat:

The Royal Society for the Protection of Birds, The Lodge, Sandy, Beds SG19 2DL
01767 680551

The National Trust, Conservation Department, Heelis, Kemble Drive, Swindon SN2 2NA
01793 817400

Plantlife, 14 Rollestone Street, Salisbury, Wiltshire SP1 1DX
01722 342730

The Wildlife Trusts, The Kiln, Waterside, Mather Road, Newark, Notts NG24 1WT
01636 677711

Friends of the Earth, 26-28 Underwood Street, London N1 7JQ
020 7490 1555

Natural England, Northminster House, Peterborough PE1 1UA
0845 600 3078

Countryside Council for Wales, Maes-y-Ffynnon, Penrhosgarnedd, Bangor LL57 2DW
0845 1306229

Scottish Natural Heritage, Silvan Hs, 3rd Floor East, 231 Corstorphine Rd, Edinburgh EH12 7AT
0131 316 2300

Joint Nature Conservation Committee, Monkstone House, City Road, Peterborough PE1 1JY
01733 562626

Growing Media Initiative The HTA, 19 High Street, Theale, Reading RG7 5AH
0118 930 3132

References

Naasz, Caron, Legault and Pichette (2009)

Efficiency factors for bark substrates: biostability, aeration or phytotoxicity. Soil Science Society of America Journal, 73(3) 780-791.

Schilstra, A.J. (2001) How sustainable is the use of peat for commercial energy production? Ecological Economics, 39 285-293.

Monitoring of the horticultural use of peat and progress towards the UK biodiversity Action Plan target. Department for Environment, Food and Rural Affairs, London, p.19.

Further reading on peat

Read RHS advice on peat-free media
See the RHS policy on peat

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