Growing media and peat

Transcription

1 Information sheet Growing media and peat This information sheet is designed to support garden centres in their training of staff. It forms part of the wider WRAP garden centre training programme aimed at building awareness of growing media ingredients and the alternatives to peat and on giving the best advice to customers. What s in your compost? Manufacturers are using a range of materials to make composts. Each material has different characteristics that customers need to be aware of to successfully grow their plants: Material What type of product is this material found in? COIR GREEN COMPOST PEAT Composted BARK BARK (Pine) WOOD FIBRE OTHER WOOD BY- PRODUCTS Used as a 100% peat free material to grow many plants such as houseplants and conifers and also mixed with other materials as a peat diluent especially wood fibre and green compost (where it helps balance the nutrient content). Is used as high quality soil conditioners and is increasingly used to reduce the % of peat in many growing mediums. Often blended with other diluents to make peat free composts. Traditionally the main ingredient in most growing media such as Multi Purpose Composts but due to environmental reasons and government reduction targets the % of peat is being reduced in bags through the addition/dilution of other more sustainable ingredients Used in Multi-Purpose Composts to reduce the % of peat in a bag, also the main ingredient in traditional peat free mixes Used in Tree and Shrub mixes (upto 20%) and more specialist products such as Orchid composts Now commonly used as a major peat diluent in Multi-Purpose Composts as it has good shelf life qualities Often found as diluents in peat free mixes and have similar characteristics to composted bark Characteristics Very lightweight and so easily transported; stable and good for seedlings; structure very similar to peat; good natural water holding properties but may need extra feeding High quality material derived from green waste and made under BSI PAS 100, a recognised industry standard. Readily available, with good levels of natural nutrients, such as NPK, and with excellent slow release qualities. High ph, biologically active and can suppress plant diseases. Can be heavy to handle so often diluted with lighter material in growing media. Light, inert, with a low ph making it good for ericaceous plants. It has good storage capability, generally requires feeding after 6 weeks when the base fertiliser has run out It s a by-product from forestry and often sold as FSC certified but may need extra feeding especially if over 6 months old Adds good drainage, structure and air into compost for more mature plants. Very light material, excellent drainage properties, often sold as FSC certified Readily available and often locally sourced, good air holding qualities but may need extra feeding.

2 What is peat? Peat is an organic material that forms in the waterlogged, sterile, acidic conditions of bogs and fens. These conditions favour the growth of mosses. As plants die, they do not decompose. Instead, the organic matter is laid down, and slowly accumulates as peat because of the lack of oxygen in the bog. The peat we see today has taken tens of thousands of years to form. What are the impacts of using peat in horticulture? Peat bogs play a number of important roles, for example: Peat bogs support unique wildlife they are the homes for thousands of species of insects, plants and birds, many of which are rare. Under EU legislation some bogs have been designated as conservation areas e.g. Sites of Special Scientific Interest (SSSI). Peat bogs are a huge store of carbon in the UK they lock carbon in the ground. When we extract peat we release some of this store to the atmosphere. Peat bogs are important for water quality - over 70% of the UK s drinking water comes from upland catchments, most of which contain peat. Peat bogs have high recreational value - they provide vast areas for recreational purposes and also support the income of many local communities. Why is this relevant to UK horticulture? Peat is not renewable - Once extracted it cannot be replaced. Peat is made very slowly and cannot regain its original thickness in our lifetime. Peat bogs are under threat - pristine peat bogs in the UK are some of our last remaining tracts of unfragmented, semi-natural areas. 90% of the UK s peat bogs have been lost so far, mainly as a result of human activity. The UK s use of peat for horticulture the UK currently uses 3 million cubic metres of peat per annum; 69 % is used by amateur gardeners and 30 % by professional growers. The majority of peat for UK horticultural markets is extracted from peat bogs in the Republic of Ireland and the Baltics and these countries are becoming increasingly concerned about the impact of this. Peat reduction targets Defra s ambition is to reduce, and ultimately phase out, the horticultural use of peat in England by The plans for this are outlined in Defra s Natural Environment White Paper, published in June These targets impact all growing media manufacturers, growers, retailers, gardeners and the public sector through the following milestones: A progressive phase-out for government and the public sector on direct procurement of peat in new contracts for plants by 2015; A voluntary phase-out target of 2020 for amateur gardeners; and A final voluntary phase-out target of 2030 for professional growers of fruit, vegetables and plants. The Scottish Government also has an ambition to see a reduction in the use of peat for horticulture and its eventual phase-out.

3 A Task Force with representatives from across the industry has been identifying and addressing the key barriers to peat reduction in the horticultural sector. They have looked, for example, at economics, availability of alternatives to peat, consistency and quality of peat alternative products. The Sustainable Growing Media Task Force (SGMTF) reported its conclusions in June The final report of the SGMTF detailed several key actions to move the industry towards a more sustainable footing, including the use of sustainability criteria to measure the impacts of all raw materials. The HTA s Growing Media Initiative is actively working with leading retailers, garden centres and manufacturers to reduce the peat content in growing media and promote the use of alternatives. Customer frequently asked questions A customer ultimately wants to know that the growing medium they are buying will consistently grow good plants, is safe to use, looks good, doesn t have an offensive smell and provides value for money. Some questions they may ask you include: Why don t you sell a 100% peat product? Most modern growing media products rarely contain 100% peat and are often a blend of several different materials. The aim of blending is to impart more desirable characteristics to growing media such as increasing the natural water holding capacity to prevent the compost from drying out; adding weight; providing structure for good rooting; and providing natural nutrients for plants. Alternatives to peat composts don t work as well as peat do they? There have unfortunately been some poor products on the market in the past. The more recent products have however overcome many of the issues. Peat reduced and peat free products do need to be treated differently to peat - they may need more nutrients or more or less water to achieve similar results to peat-based products. The key is to follow the manufacturers advice. Is it true that some plants prefer peat reduced and peat free growing media? Yes. For example, many over-wintered containerised shrubs, grey leaved species, forest floor plants and bulbs forced over the winter requiring good drainage thrive in peat reduced/free media. Are there any plants that are difficult to grow in peat-free medium? Yes. Carnivorous plants are. It has been suggested that ericaceous plants are difficult to grow too but peat free ericaceous products are now available. Why is is this bag of compost heavier to the one over there? When compared to peat, products containing green compost or composted wood and bark materials will generally be heavier whereas products containing coir and wood fibre will be slightly lighter because they are a less dense material. What does the dragonfly on the label mean?

4 The dragongfly logo is the mark that means the bag of compost has been manufactured by a full member of the Growing Media Initiative. This means that the manufacturer has abided by a strict sourcing code, they have been independently verified and that the product contains less than 50% peat. What does FSC mean on a bag of compost? I thought that it meant good forestry. Many products no longer contain 100% peat but contain bark and wood by-products that have come from responsibly managed forests. The Forest Stewardship Council (FSC) is an internationally recognised forest management system that helps protects the world s forests. The FSC logo and chain of custody number on the bag means there is a system in place to trace the product from the store, through manufacturing back to the forest origin. What s a SSSI Sites of Special Scientific Interest (SSSIs) are the country's very best wildlife and geological sites. They include some of our most spectacular and beautiful habitats - large wetlands teeming with waders and waterfowl, winding chalk rivers, gorse and heather-clad heathlands, flower-rich meadows, windswept shingle beaches and remote uplands moorland and peat bog. The unique and varied habitats of SSSIs have developed over hundreds of years through management practices such as grazing and forestry, and need active management to maintain their conservation interest. They are designated and protected by EU law.

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