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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 filth sold as compost. I would cite the brands but I’m getting used to the practice of the anti-peat mob using the internet mods to censor green waste critics on legal technicalities.

This last point raises a serious issue. If consumers do not feel confident about reporting faulty and dangerous products to the world’s most effective consumer organisation what does that say about the hysteria of the anti-peat fanatics? Where do gardeners turn for an honest discussion of the issues? Not to the environmental lobby, that much is clear. John Walker (above) suggests that the contamination of green waste composts can be controlled. Anyone who visits a green waste composting site and will be rapidly disabused of this notion. Some loose metal objects are screened out by magnets to protect the shredder mechanism, but otherwise the material is unscreened, and contamination is inevitable; glass, plastics, metal inbedded in wood, dead animals etc… all go into the shredder before being sold to the consumer as seed compost. You can find details of your nearest green waste recycling centre online. Phone ahead and bring your wellies.

Given his wide ranging research on this issue, I’m surprised that Mr. Walker was not aware of this when responding to TerryM’s post about clopyralid contamination.

John Walker says:
6 June 2014

Putting the blatant scaremongering here aside (puss-oozing rats, etc), you have conveniently sidestepped the issue of pollution of the raw materials that go into making green waste compost, with persistent weedkillers, including clopyralid which is available to gardeners (it might help if you actually read the article I provide a link for). If we stop using persistent, polluting lawn weedkillers, the lawn mowings won’t carry the weedkiller to the composting plant, so the pollution threat recedes. Yes or no?

A reluctance to name which composts are giving problems seems a defining characteristic of those arguing vociferously against peat-free composts. Have you got any independent, verifiable evidence of “the practice of the anti-peat mob using the internet mods to censor green waste critics on legal technicalities.” I’m sure we would all appreciate a link so we can examine the evidence for this.

I think most of us can agree that in the past some peat-free composts haven’t been satisfactory in terms of quality, and we’ve all experienced some of the contaminants you describe. But today’s good quality and reliable peat-frees are a world away from what you describe. Many have been around for years, and many gardeners are using them. Some don’t even contain green waste compost, rather deflating the ‘it’s all rubbish’ argument.

This spring, in my garden, I have had excellent results, from sowing to potting on, with various peat-free composts of the highest quality. Together they represent real, impressive progress. Among them are (in alphabetical order):

Alan Titchmarsh & Waitrose Peat Free Multi-purpose
Carbon Gold All Purpose
Miracle-Gro Peat Free All Purpose
SylvaGrow (multipurpose)
Vital Earth Multi Purpose
Westland Gro-Sure Peat Free All Purpose
Wool Compost Seed & Cutting

Myself and others have been sharing some of our results on Twitter. If you go there and search for #peatfree, you’ll see them.

John Nicholson says:
6 June 2014

No, Mr. Walker, this will not do at all.

Never mind your nonsense about ‘blatant scaremongering’. This is a consumer magazine – how dare you deny my right to comment on an obviously substandard product? Who appointed you our censor? No-one.

I have not ‘sidestepped’ the issue of clopyralid contamination. That is simply untrue. I pointed out that contamination with a range of materials is a inevitable result of the green waste process – something that you seem not to register – yes or no? There is some confusion because by the middle of your comment you seem to be agreeing with me.

I am very aware of the clopyralid issue and supported the campaign against its use and reintroduction. IF I want to know more about clopyralid I will refer to a source that I can trust, thankyou.

Your antagonistic badgering really does give you away with regard to the censoring of support for peat – I will let your own comments speak for me on that score. I am not reluctant to mention the compost suppliers who provided me with contaminated peat. I am however wary of having my comments removed – again. And precisely because the post was moderated the link does not and can not exist, as you would understand if you had thought about it rather than subjecting me to your sneers. Just who do you think you are?

I did not claim that ‘all’ green waste ‘is rubbish’. You are putting words into my mouth. Why? Why do you not respond to what I did say, rather than the strawmen you have created? As to the reliability of peatfree composts I already recomend Vital Earth and Westland Gro-Sure or New Horizon pfc’s for those who want to go that way. I would also refer anyone who is really interested in the research to refer to results of the peat-free trials you refer in your post from a few years back. I think most gardeners would question if the majority of brands you trialled were giving excellent results. But hey, that was 2012 and apparently everything has changed since then.

The big problem with pfc’s is not that it is ‘all rubbish’ but that the quality is very variable, even between sacks of the same compost produced by the same manufacturer stacked on the same shelf. That is my experience, the experience of most gardeners I have spoken to on the subject and it is the finding of every Which? peatfree trial I have studied. Variability. That is the issue that you refuse to address. I got half a dead rat in one bag. I’m happy to presume that besides the fella who got the other half everyone else did okay from that batch. Nevertheless you’ve invented the myth that we complain that ALL peatfree compost is rubbish. Not true, Mr. Walker. More invention, when what we want are reliable facts and honest debate.

I produce enough high quality home made composts to serve all my container plant needs. I buy peat based seed compost because the objective trials I have seen all graded even the best peatfree composts you refer to above as markedly inferior for seed composts. Its that simple. I can’t afford to waste expensive seed on the basis of your obsessions.

I do know some gardeners who get good results from peat-free. I also know that most gardeners get results like the poor specimens you produced in your earlier trial, or those in the photo at the top of the page. And there are better brands, I’m sure of it. The problem is that there is not enough of the better peat-free composts to go around. As far as I can establish the ratio is 30% good or good enough, 40% less satisfactory than garden soil or home made compost and 30% that will kill or stunt your plants. Your answer to this problem is to harangue anyone who dares speak up for peat, presumably so that the more timid fall in step behind you.

I am used to dealing with bullies. I am not even mildly impressed by your performance here.

John Walker and John Nicholson – consider this a formal warning. Do not antagonise each other. Be polite in your disagreements – if you think another person is being rude, please don’t respond in the same manner. Instead, report the comment for our moderators to look into. Thank you.

John Nicholson says:
6 June 2014

So, with a nod to those following this debate, I responded to a comment about chemical contaminants in peat free composts by mentioning that I had my own similar issues with pfc’s.

On consideration I won’t be using any green waste compost or reduced peat compost in the future. The risk of losing the growing season is too significant, and the benefits to the environment are negligible at best. I remain to be convinced that they outweigh the real and visible environmental benefits of an organic gardening programme. On top of this I simply can’t afford to lose money on seed and even less lose the yields that I depend on to eke out my income. When peat is removed from sale in England in 2020 I will simply import it from Scotland when I make my annual winter trek up there to see my folks at New Year.

In March 2011 I bought a 60L sack of Grandiol Peat Free Multi-Purpose Compost, which advertised itself a general purpose compost for seed and containers. I sowed it with a £30 range of seeds in 20 cell trays and 50 cl pots; tomatoes, cucumbers, gherkins, squash, pumpkins and courgettes, two seeds to a pot, 240 seeds in all. I would normally expect 95% germination with such seeds and although the strike right was below par – about c. 85% – it wasn’t far off. But over the next two weeks almost all the seedlings died of damping off disease. This was despite the use of a light bordeaux mix in the watering spray as ever, and good ventilation in a frost free lean to. My worst sowing experience in 18 years. Just six seedlings survived, to make pitiful runted plants I had to put out of their misery.

In May of that year I used the remains of that particular sack as a container compost for some bought-in replacement tomato plants. When breaking up a large, stubborn ball of compost I found myself staring at a very large, dead and partially mummified rat in my hands. Its fur was so entirely matted in with peat as to make the two almost indistinguishable. Then I noticed that it was in fact only half a rat and it was leaking yellow pus out of its severed belly. I buried the rat and disposed of all the remaining and used compost in my local recycling plant.

This year in March I bought a 60L sack of reduced peat Multi Purpose Compost from the B+Q Verve range. I have previously had very good results with this a seed compost, particularly for the more robust seed types – pumpkins, squash, courgettes and tomatoes. This brand is the Which? Best Buy, and has apparently won some quality awards.

When using it however I noticed that that the material appeared visibly different than before. The compost itself was flecked with white specks, small fragments of a wood fungi, I think. I also found small sections of black and blue lightweight polythene about 2cm square, and chunks of coarse, poorly composted but softened woody material up to about 4cm / 1.5 in length. This material can be put to one side and used as mulch materiel, or buried at the bottom of a container quite safely. I was more disturbed to find a few pieces of entirely uncomposted, solid, undarkened wood, still showing the grain, up to 5cm long. This can be put to one side and used as kindling for a barbecue, carved into a chess piece or crafted into a fetching shamanistic talisman to wear about your neck; it is a little chunk of wood, after all. More alarming than that as I ran my fingers through the compost to sift it through I scratched the lower palm of my hand on a sharp fragment of glass embedded in a ball of woody compost. The scratch was deep enough to be painful but drew virtually no blood and led to a mild red swelling. Not such a big deal. I was less happy with the results of my sowing.

Verve multi-purpose did as well as expected with the most robust seeds; cucumbers, squash and courgettes. Tomatoes fared less well, with a very marked variation in the development of the young plants – both Gardener’s Delight and Tamina. The Fi sweetcorn fared still worse. I sowed 20 seeds each of two Fi varieties that yielded 12 and 13 seedlings. Barely 60% germination for an expensive Fi seed where I would normally expect a 90 – 95% strike rate. Worst of all were the Runner Beans T&M ‘White Lady’, where germination yielded barely 30% seedlings. The compost simply got wet in the rain and never quite dried out as one would expect, even when brought into an outhouse to dry. We’ve had a pretty dry spring here, but the seeds seem to have rotted away. I have previously had very good results with this well regarded brand, and have almost always had very good results with the seed, which cost about £25.

On neither occasion did I report my lack of content to the vendor or manufacturer. To be honest, when folk start taking the mick I tend to lose interest quickly. I still have half the bag of verve multi-purpose and the glass that cut me, and I can show you where the rat is buried. Bring your own spade.

This debate has come by me recently due to the rubbish I found in the peat free recycled rubbish. I have suffered major losses with brassica seedlings, which make up most of my horticultural produce. Us growers know that plants breathe carbon dioxide and produce oxygen (and wholesome food). Im no expert in physics but I’m pretty sure that the carbon released from the peat in say, one tray of seedlings, is used many many times over by the growing plants. As they grow they gulp more and more co2 from the air and release good old oxygen.

One tray of seedlings grown in peat based compost will cover 300m sq allotment with many brassicas. When they are fully growing at full chat they will eat all the co2 they can get.

Remember history lessons about all the trees planted in London to clean the air? Nicknamed the lungs of London? …now imagine all the produce on farmland sucking up co2 in mid summer. A huge proportion of this is raised as seedlings in a relatively tiny amount of compost, peat probably and a the payback is huge both in carbon taken in by the produce and the lush, healthy acres of Cabbage, Cauliflower and Brussels Sprouts. No contest I think, and I will continue to use good quality peat based compost from now on until I can’t.