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Peat or peat-free: which side of the compost debate are you on?

Growing seeds in pots with peat compost

Nothing divides gardeners like peat. Some say it’s essential for sowing seeds and growing plants, others have switched to peat-free and haven’t looked back. Which are you – and will you be swayed by our interview?

Pro-peat campaigners point out that peat is burnt as a fuel in Ireland and claim that there’s plenty of it in some parts of the world.

The anti-peat lobby says that peat is a valuable source of carbon and a wildlife habitat, too.

Whether gardeners like it or not, peat is set to disappear from our composts by 2020, thanks to a government target. That means that alternatives must be found. One man who is helping to ensure that they are is Dr Alan Knight. He’s a sustainability specialist and business consultant and chair of Defra’s Sustainable Growing Media Task Force.

I interviewed Alan recently about the task ahead of him and found that the ‘peat debate’ has moved on a bit recently. You can read the full interview in the March issue of Which? Gardening, but here are the edited highlights:

Q: It’s claimed that peat is plentiful in some places, and is even burned as a fuel. So why are British gardeners being asked to use less peat?
A: That’s the very question the Sustainable Growing Media Task Force is trying to find a definitive consensus for. Twenty years ago, the argument was that English peat bogs needed to be saved from destruction and we should not export the problem by buying peat from foreign sources. More recently, it’s become a discussion about carbon. No one denies that we need to protect peatlands and peat bogs, but the train of thought is now: what is the real problem with peat? Is all peat bad?

Q: And what do you think about that – is all peat bad?
A: A lot of peat is harvested badly from the wrong source. But not all peat comes from bogs. In Somerset, for example, peat extraction from agricultural land creates wildlife habitats. Lots of Scandinavian countries have huge areas of peatland that have not been living bogs for ages.

Q: So some peat is OK, then?
A: Like oil, peat is a finite resource: it will eventually run out. And we can’t control what happens in the countries we import peat from. It might be needed for fuel, or conserved as a carbon sink. Being less reliant on peat makes commercial sense, and manufacturers are beginning to understand this.

Q: Is there any point in boycotting peat-based products?
A: The thinking is now similar to the tropical hardwood debate in the 1990s. The argument moved from ‘Don’t buy tropical hardwood’ to ‘If you buy tropical hardwood, buy it from a well-managed forest’. Peat-based composts already contain less peat than they did before. But if you like peat-free products, you’re providing an incentive to companies who are making the move, so stick with it.

Q: Will the 2020 target for phasing out peat in growing media be met?
A: I don’t think we’ll end up with an absolute 0% peat target but it can and should be very close. What we really need is a 0% peat bog destruction target. At the end of the day, consumers want a bag of compost or a growing bag that will perform well. People will lose their attachment to peat when they know the alternatives work.

Here at Which? Gardening we test composts that contain both peat and no peat. This year, two out of three of our Best Buys for growing plants in containers are peat-free, which shows that peat-free alternatives can work. We’ve yet to find a good peat-free compost for seed sowing, though.

Are you prepared to go peat-free, or have you already? What do you think of this new perspective on an old argument?

John Nicholson says:
25 May 2012

There is a degree of hysteria in this debate that is deeply disturbing. We are told by Friends of the Earth that 95% – 66,500 hectares – of England’s lowland peat bog has been destroyed by the extraction of peat. This is simply not true – not even nearly true. More than 90% of all the peat bog degraded in the last hundred years was converted to forestry or agricultural use. The total area currently being exploited for its peat reserves comes to around 1,000 hectares – a small fraction of the area of protected peat bog in England. At its maximum the area zoned for peat extraction over the last 50 years was 5,400 hectares. Including upland blanket bog the area of peatland in the UK (with peat depth of more than 1 metre) is 1,650,000 acres. Including shallow peats (depth less than a metre) the total is closer to 5m hectares.

Carbon dioxide is released by the drainage and extraction of peat; peat itself is formed below the water table, so decomposes anaerobically – without oxygen – and exposure to the air allows the partially decomposed material to complete the process. I cubic metre of peat will release 250kg of CO2; a 60L bag of multi-purpose compost contains about 50L of peat (70%) and represents 12.5kg of CO2 released by the peat extraction process. In the UK the average resident is responsible for the release of 8,500kg CO2 equivalents per annum, so a 60L bag represents 0.147% or 1/680th of an average persons CO2 liability.

In comparison growing 1 square metre of mixed fruit and veg will offset your carbon load by 1.5kg CO2 equivalent. A productive 200 sq m / 240 sq yrd allotment laid out in 30 x 4 sq m beds will offset 180kg of carbon dioxide – more if you grow tomatoes.

There is no moral high ground won by the exclusive use of peat-free composts. On the contrary, the abuse of statistics, the misapplication of environmental concerns and the emotive hectoring of peat using gardeners are counter-productive in every respect.

Readers of Which? Gardening will be delighted to know that the Mar 2011 Which container compost trial established that at last some brands of peat-free composts performed as well as peat-based compost and were awarded Best Buy status for container use. However, given the poor performance of peat-free media in the Feb 2011 W?G trials of seed and potting on composts you will be surprised to know that the peat-free lobby make no distinction in reporting the success of peat-free as a general purpose compost. Overwhelmingly this wishful thinking is at odds with the experience of huge numbers of British gardeners, who have tried peat-free and been utterly disappointed.

By all means we should be composting kitchen and garden, making leafmold, adding animal manures and composted woodchip/bark mulches to our soils – I get through about 6 cubic metres of organic soil conditioners in a year, free except for my transport costs. Peat is far too precious to be used as a soil conditioner, and peat-free is good enough to support container growing. But nothing comes close to the performance of peat for seed sowing and potting on – particularly with regard to tomatoes.

Gardeners should not worry about the (voluntary) end of peat use by amateur horticulturalists in the UK by 2020. They will still be able to import peat composts from Europe. The Dutch and German governments for example have reviewed their nations’ use of peat and have no interest in introducing trade restrictions.

May you all enjoy your gardens, and feed your soil as you feed your soul.


Never mind the carbon dioxide. Extraction of peat causes a lot of environmental damage and that can be avoided by using alternative materials. Some manufacturers are labelling their bags of compost as ‘reduced peat’ with out any indication of what this means.

I wonder how much more damage will be caused by the time we have got round to banning peat extraction.

John Nicholson says:
26 May 2012

There is no viable peat-free alternative to peat based sowing and potting on composts – after £100 million spent on research and development. The best performing peat free brands achieved half the score of the peat-based G?W Best Buy. I make up 6 cubic metres of green compost, manure, mulches and leafmold in a year – 6,000L. I buy 60L of peat based compost for seed sowing and potting on. Peat makes up 1% of my growing media, and I will happily continue to use peat year on year. I have considered the environmental issues, and understand that they do not outweigh the environmental benefits achieved by limited peat use.

Lowland peat bog – the area used for peat extraction – is a limited resource in England and Wales. Less so in Scotland, or Ireland, where most of the peat extracted goes to fire electric power stations, also practised in Sweden, Finland, the Baltic States, Russia and North America. It is entirely appropriate to preserve the limited peat bog habitats we have in this country and they are not threatened by the remaining 1 sq km of active peat extraction sites. Worldwide, however, peatlands cover 2-3% of the world’s surface, 3 – 4 million sq km, of which 93% is untouched by agriculture, forestry or peat extraction. Shallow peat soils (less than 1 metre depth of peat) are twice as common again as true peatlands.

In the UK lowland peat bogs are rare, and as such they are protected. In other parts of the world the same peat bog environment is common, and there is consequently no environmental reason to restrict peat extraction.

There is no likelihood of peat extraction being banned anywhere in the next 20 years. As earlier mentioned, there is considerable opposistion within EU nations, and any trade restrictions imposed in the UK will be illegal under EU law; supply will simply shift to Europe, and gardeners will nip across the channel to fill their boots with the stuff.

There is nevertheless a need for everyone to be re-educated in the issues surrounding peat extraction and use, beginning with the anti-peat lobby itself. Until environmentalists can learn to desribe their concerns rationally and above all honestly they have nothing to teach anyone.

Howard Drury says:
27 May 2012

What a biased opinion! no wonder we have policies like the peat issue it is NOT like oil it is a growing media literally oil is not, peat is made over many years and a sustainable bog can yield a certain amount of peat the can be environmentally friendly harvested as I have seen in south island of New Zealand by helicopter and the sale of the young sphagnum moss funds the conservation project and helps monitor the eco system Peat managed is no different to a managed forest but over a much longer period harvesting on commercial scales leads to bogs being drained and habitats lost this is what must be outlawed. Remember also to get at the older hard peats for power stations the younger peats we use in horticulture are pushed to one side and if we do not use them they are burned! But I DO STRESS we must reuse peat use low peat mixes and never waste it where there are other alternative – from the complaints i get as advise the peat free alternatives are a waste of time with local Trading Standards going to court for poor composts we still need a proper uniform alternative before anyone can consider banning peat! DO NOT WASTE IT please

chris seagon says:
6 July 2012

I have tried a number peat free compost over the years some with coir and some with total bark and with green waste they all have there problems the market leader is very good for all sorts of plants I grow mints to lavenders and thymes in it and compared to peat compost my winter loss are far lower as this potting mix drain very well in the winter but the negative point is in a hot dry summer you might use more water if not managed properly feeding can be a problem have over come with slow release controlled fertilizers for those who say well you only grow in 9 cm pots no I do not we use 9 cm pots to start of are plants then use 1lt to 12 lt pots and find get very little shrinking over time unlike some peat compost get price shop around as they are coming down all the time as for seed sowing this were problems can turn up as the only one that’s worked for me is coir based but as this has to shipped over here then use massive amounts of water to
re hydrate
we have to ask are we willing pay for it is it a price worth paying to save are wet lands and the wild life that lives there ? To the hobbies nursery / person selling by side the road every penny counts and car boot selling plants saying we can charge less of course they can because they do not use same compost most the time MY nursery decide to use peat potting compost because found it grew better plants faster then peat and I’ve not looked back even thou supply’s been a problem in the early days as for see sowing we use small amount peat just for seed sowing but are bulking it out with other things have to say coir was better ever gardener and grower has there favored compost we all I will say is take look at the comments on the website then tell your views I’m not paid to talk about the compost I use just have a passion for using it like some pl who use coir been growing herbs for nearly 28 year

terrym says:
5 June 2014

Many compost producers are using re-cycled green waste which contains selective weed killer mixed with their compost it is impossible to separate and as little as 1 part per billion can affect plant growth even grass treated the eaten by live stock will continue to be contaminated
I purchased several bags of Arthur Bowers compost which was contaminated and all my seed failed even 5 sowings of runner beans failed avoid any compost that uses recycled green waste

John Walker says:
5 June 2014

It makes sense to recycle green waste and tap into its environmental and economic benefits, rather than send perfectly a good/renewable resource to landfill/for incineration.

The problem here isn’t with seed and potting compost, but with pollution of the chain of raw materials that go into compost. If we insist on allowing highly persistent weedkillers (chiefly aminopyralid and clopyralid in lawn treatments) to be used by just about anyone, then problems of contamination will always exist. Unless, that is, we get serious about stopping the pollution at source, and banning these chemicals without further bluster or delay. All the soothing talk of ‘improved stewardship’ is not going to work, because as you say, just a little of these persistent weedkillers goes a long way. Misinformation spread by the gardening media doesn’t help the matter one bit.

You can read here about why the use of clopyralid in lawn weedkillers used by gardeners continues to be a ticking time bomb: http://earthfriendlygardener.net/2012/10/12/aminopyralid-clopyralid-lawn-weedkiller-herbicide-pollution-residue-damage-contamination-chemical-poison-compost/

The main message is that blaming the bag of contaminated compost is like blaming the postman because you don’t like what’s in the parcel…

John Nicholson says:
6 June 2014

It does make perfect sense to recycle green waste as compost. I collect grass cuttings (from pubs etc…,) spent beer grain and sawdust, weeds, kitchen waste from my neighbours etc. to create around 3,000 litres of finished compost a year. I allow weeds to grow to flower where possible to bulk up for composting. I have tried using peat free green composts, and been robbed blind every time. Particles of plastic are common; shards of broken glass are thankfully less common, but I cut myself again this year in a bag of gp reduced peat compost from the leading brand. Three years ago I found half a mummified rat in a bag of peat free, yellow pus dripping from its severed guts. That particular experience cost me £30 of wasted seed; even courgette seeds were damping off in the contaminated filt