Guide to peat-free compost
Joanna Long and Tim Hunt explain which is the best peat-free alternative and who to buy it from.
Despite the well documented environmental consequences of its extraction peat still remains the growing medium of choice among many amateur and professional gardeners.
In 2013, 1.9 million cubic metres of peat were sold in the UK, which accounts for just over half of the overall market for growing media.
Of this huge volume of peat, over 95% was used in growing media, with the majority (two-thirds) being consumed by amateur gardeners, and the remainder by professional growers, local authorities and landscapers. Just under half of the peat sold for growing media came from the Republic of Ireland, with a further 38% coming from the UK, and the rest from Northern Europe.
Reducing peat consumption among amateur gardeners is key to continuing the decline of peat production, not just in Europe but globally, as this group still presents the greatest demand.
In an effort to protect the environment, the UK government produced a Natural Environment White Paper in 2011, setting out targets for the complete phase-out of peat usage by 2030.
As a result, UK peat production declined by just under a third between 2011 and 2013. Production in the Republic of Ireland, a key source of peat to the UK market, has also declined. However, extraction from cheaper sources in Northern Europe have held steady.
The popularity of peat is relatively recent, growing out of a deliberate campaign by producers in the 1950s to replace heavy, loam-based growing media (those made of plant material) which were costly to transport.
Peat is much lighter and, although naturally sterile, holds nutrients and water well, releasing them as required. Peat is also a good soil improver, breaking up heavy, clay soils and binding sandy, silty ones. Its low pH also makes peat good for acid-loving (ericaceous) plants.
Peatlands under threat
Peat extraction in South Lanarkshire.
But this quality and convenience comes at a cost for both biodiversity and the earth’s climate.
According to the International Union for the Conservation of Nature, the biodiversity of UK peatlands is of international significance.5 These peatlands, especially blanket bogs, support multiple bird species which have legal protection under national and EU conservation law, such as golden plover, greenshank and red-throated diver.
Indeed, one of the most important functions of peatlands is to reproduce themselves as a global carbon store. In waterlogged bogs plants do not decompose when they die, rather their organic matter is laid down and slowly accumulates as peat due to the lack of oxygen. In the process, the carbon that would have been released during decomposition remains stored in the peat itself, released only when the bogs are drained and cut or when the peat is burned.
This process of laying down new peat accumulations make peatland ecosystems vital to maintaining the global peat store.
However despite the multiple environmental issues associated with peat extraction it remains widely available on the UK market. This is partly due to the negative attention peat-free alternatives continue to receive.
Community & home composting
There may be local composting projects in your area which sell locally produced products, such as the Fairfield Composting community composting project in East Manchester. You can get advice on starting your own scheme via the Community Composting Network, 0114 258 0483.
You may also want to produce your own compost. See below for wormeries and bokashi bin home composting. Or see the following websites for guides:
Wormeries & bokashi
If you don’t have a garden or enough space for a compost bin, you can still make your own soil conditioner using kitchen waste. One method is to have a wormery, feed your kitchen scraps into it and collect the resulting ‘juice’ to add to your soil. It is very rich, so it’s best to use in small amounts.
Downsides of wormeries are that you can’t just put anything in (dairy, meat and bones are no-nos); some things need to be cooked before adding them (such as onions, garlic and citrus peel); they can give off a very pungent odour; and the worms themselves are not free to roam.
A more versatile, and animal-free, alternative is a bokashi bin, which pickles your kitchen waste (bokashi is Japanese for ‘fermentation’). Simply add all your cooked and uncooked kitchen waste (dairy, meat and bone included), add the special bacterial bran and leave it to work for a couple of weeks (it can be useful to have more than one bokashi bin so that you can alternate).
The smell of fermentation is contained inside the bucket and you can keep the conditions inside just right by draining off excess liquid using the little tap at the base of the bucket. After a couple of weeks, empty the contents onto your soil and dig in, or add it to your existing compost bin.
Three top tips for using peat-free compost
- Know your plants and what they need before buying a compost product. Seeds and cuttings need low nutrient, well draining composts and as plants grow they need more nutrient-rich compost. The nutrients and soil type required by plants should determine the compost type you buy, for example: acidic or alkaline, well draining, etc. So research plants first!
- Try to source a compost made from local materials. For example, soil collected from mole hills is excellent for sowing seeds.
- Try to grow in the ground wherever possible (not just pots) and sheet mulch (an agricultural technique that attempts to copy a forest’s natural processes).
Companies who also sell products containing peat:
- William Sinclair
- Scotts Sierra
Ethical Consumer urges these companies to remove peat-based products from sale before the 2020 deadline as part of their corporate social responsibility programmes.
The Scotts Miracle-Gro Company, which owns both the Miracle-Gro and Levington brands, is the world’s largest marketer of branded consumer lawn and garden products, including Monsanto’s Roundup brand. Although Miracle-Gro and Levington both offer peat-free composts, the company also sells Irish peat alongside a range of toxic herbicides and insecticides. In 2012 the company was fined $4.5m (US) by a US District Court for adding unlicensed pesticides to their wild bird feeds.
The company also scores Ethical Consumer’s worst ratings for likely use of tax avoidance strategies, environmental reporting and supply chain management. In 2014 it paid four of its directors between $2.9m and $4.1m (US) each, which Ethical Consumer deemed to be excessive.
Another big name in the horticultural market is William Sinclair, which owns the J. Arthur Bower brand and the New Horizon peat-free brand. The company formerly extracted peat for its products from Chat Moss, an area of lowland bog, farmland and woodland in Greater Manchester and a source of significant wildlife interest, but its application to renew this extraction contract was refused by Salford City Council in 2011. Apparently ignoring the inherent climate change implications of all peat extraction, the company lamented that it would now have to import peat from Ireland and the continent, “with the carbon footprint that travel imposes on that.”
Viridor and Vital Earth offer peat-free composts based on recycled green and kitchen waste.
Viridor is the larger of the two, composting over 300,000 tonnes of green and organic waste each year. It is owned by the Exeter-based environmental utility infrastructure company, Pennon Group Plc, which also owns South West Water. While Viridor receives a best Ethical Consumer rating for environmental reporting, this sister subsidiary has, over the past five years, incurred fines totalling more than £140,000 for contaminating various waterways and beaches in the south west with sewage.
The smallest fish in the pond are Carbon Gold and Fertile Fibre, both of which exclusively offer environmental alternatives to peat in the form of biochar (a high carbon form of charcoal) and coir-pith based composts respectively. Although neither company performed well on environmental reporting or supply chain management, both are small companies making a difference it the growing-media market by offering exclusively non-peat-based products.
This product guide is part of a Special Report on Gardening. See what's in the rest of the report.