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Is Coir an Eco-friendly Substitute for Peat Moss?

In the search for a peat moss alternative, coir is the one that is most often discussed. Coir is made from the outer husk of coconuts and is a waste product from the coconut industry. Environmentalists are quick to point out that “since it is a waste product it’s use is more environmentally friendly than using peat moss.” How can such common sense logic be wrong?

Shipping coconut husks to a coir processing plant in Vietnam

Shipping coconut husks to a coir processing plant in Vietnam

What is Coir?

A coconut consists of two main parts, the inner coconut kernel which we eat, and the outer husk. The outer husk consists of fibers and corky material found between the fibers. The fibers are extracted and used for many applications including floor mats, doormats, brushes and mattresses. The remaining dust and short fibers are known as coir pith.

In horticulture, the term coir is used interchangeably with the term coir pith and is sometimes called coir peat, coir dust, coir meal or coco peat. The material is brown, sawdust-like and looks similar to dry peat moss. Most of the coir used in horticulture comes from larger coconut fiber processing mills located in Sri Lanka and India.

Orchid repotting - coconut husk, by Robert Pavlis

Orchid repotting – coconut husk, by Robert Pavlis

In some cases the husk is simply broken into chucks without removing the fiber and sold as potting media for plants like orchids. The exceptional water holding capacity and airiness of the material make it a perfect media for such plants.

Choir has many of the same properties as peat moss including an ability to hold a lot of water. It is sold dry, but after soaking in water it expands 3-4 times in size as it soaks up all the water. Coir tends to have high levels of potassium and low levels of calcium (ref 4). It is not a perfect substitute for peat moss, but for the purpose of this post let’s assume it is good enough to be used as an alternative potting media.

The key question then becomes, is coir more sustainable than peat moss? If it is, we should certainly consider switching to it. If not, we might as well stick with peat moss.

What is Sustainability?

There is so much talk these days about products being green, eco-friendly, or environmentally friendly, but what do these terms really mean? I’ll bet most people can’t explain what they mean except in very vague terms such as “it is a product that is better for the environment” or “it is sustainable” – another term that gets thrown around and is rarely understood by the general public – including me. I had to look up the definition. You probably have a sense about their meaning, but can you really define them?

Wikipedia defines environmentally friendly as having “minimal, or no harm on ecosystems or the environment.” By that definition there is not much we humans do or use that would qualify. Clearly neither coir nor peat moss meets this standard. However, in our quest to harm the environment less, we can use this definition to compare two options to see which does less harm to the environment.

Sustainability is “the study of how natural systems function, remain diverse and produce everything it needs for the ecology to remain in balance” (ref 2). It measures how much damage something does to the environment and to society – note the word society – it is not just about the environment.

Our Perception is Easily Confused

Humans are not good at using logic to compare two options for eco-friendliness and peat moss is a good example.

Coir is a waste product so immediately people assume that using it has very little environmental impact. When I asked people about the environmental impact of shipping the product half way around the world they dismissed this issue and focused solely on the fact that it was a waste product. It is a myth to think that using of a waste product is automatically eco-friendly.

Newspapers and environmental sites flash pictures of the raped peat bogs in Canada as evidence against peat moss. These are strong images and people respond deeply to them. Add to that the fact that many people know that our wetlands are in danger. Without any real facts, people quickly conclude that this is a catastrophe and that any other option must be a better option.

If we really want to make a difference to the environment, we have to start asking for real data. We can’t rely on common sense and gut feelings.

Is Choir Sustainable?

A recent study (ref 1) looked at this question in great detail. They tried to quantify parameters for many aspects including:

  • Key materials in the supply chain
  • Economy
  • Biodiversity
  • Water, air and soil pollution
  • Water consumption
  • Energy consumption
  • Culture and working conditions

It would be nice if such studies resulted in a sustainability number that could then be compared to the sustainability number of other options, but it doesn’t work that way. Instead the study highlights areas of concern, what they call hotspots. The following are some hotspots for the coir manufacturing process (full details can be found in ref 1).

Processing Coir Pith

Creating coir pith requires more than just physically separating the fiber. Once the coir is freed from the fiber it goes through a maturation process to stabilize the product and this can take up to 6 months. During this process salt, tannins, and phenolic compounds are removed. It is buffered, washed and calcium nitrate is added to displace sodium and balance the pH.

This process requires input chemicals and it produces waste products.

Water Consumption

Processing coir requires a significant amount of water and in some areas like India, water is already in short supply. It takes 300 to 600 liters of water to wash one cubic meter of coir pith (80-160 gallons per 1.3 cubic yards). The result is polluted water that impacts the environment.

Comments such as “the horticultural use of coir helps solve a waste disposal problem”, does not hold water.

Worker Health

The whole process is very dusty and creates an unhealthy environment. Workers in coir pith factories often work six-day weeks with multiple shifts. We don’t normally think of this as a factor in sustainability, but it is.

A study on this concluded that “coir work induced nasobronchial allergy and pulmonary function abnormalities” (ref 5). In North America and Europe it would be illegal to work under such conditions.

Nutrient Depletion

As coconuts grow they remove nutrients from the soil. If the resulting coir is now shipped overseas it can’t be used as a local organic source to replenish the missing nutrients. The result is that more fertilizer needs to be brought into the plantations to grow coconuts which has an additional environmental impact.

Small coconut farmers are not sending their coir for processing and instead use it as a fertilizer source. But this will change as the demand for coir increases.

Coconut plants are renewable – new trees bear fruit in 6-10 years. But the soil being used for growing them is not renewable if the majority of organic matter is shipped overseas.

Conclusion: Coir is Not Sustainable

Package of coir pith making false eco-friendly claims

Package of coir pith making false eco-friendly claims

Many websites claim that coir is sustainable since it is a waste product. Packages of coir even have the word on their label, telling customers they are eco-friendly. It is simply not true.

Coir requires significant processing that uses input resources and produces waste products. It also posses health risks. Perhaps the most significant long term problem is the depletion of soil nutrients.

Admittedly, there are degrees of sustainability, but I think it is a stretch to call coir sustainable or environmentally friendly.

Coir vs Peat

Use of either coir or peat has an impact on the environment – so which one is worse?

There is not a lot of good data on this yet but I did find one study that looked at this problem. A study by Quantis looked at the environmental impact of various soil-less mixes to try and determine which had the least impact (ref 6).

The study looked at the complete life cycle of the material; production, delivery, processing, distribution, use and end of life. It considered impacts to climate change, resources, human health, and ecosystem quality. It concluded that “it is not possible to clearly identify any among the growing media as the least or the most impacting across all the indicators” (ref 6).

Peat moss affects climate change and resources the most. The impacts by peat include transportation, land use change, CO2 production, and aquatic eutrophication (loss of bogs).

Coir affects human health and ecosystem quality more than peat. The impacts by coir are due to transportation, electricity consumption, use of calcium nitrate for buffering, land occupation, and production of particulate matter.

 This type of study is based on estimations and limited accurate data, but they do provide a general understanding of the situation. Both peat and choir have significant impacts on the environment and according to the current data, neither one is considered significantly better than the other.

Is Coir a Good Alternative to Peat?

From my previous posts, Peat and Peat Moss The True Story and Peat and peat Moss Alternatives, it is clear that the use of peat in horticulture is not having a significant impact on the loss of peatlands. Year over year, the amount of global peat is increasing faster than it is being used. Some 86% of global peatlands are untouched by humans – there is no environmental catastrophe.

If society wants to reduce peat use, their efforts need to be focused on agriculture and forestry, not horticulture which uses less than 1% of the yearly peat harvest.

However, it does make sense to reduce the use of peat as a soil conditioner. There are better options that have less environmental impact. Finding an alternative to peat moss for the cultivation of plants in pots will have little environmental impact.

Coir may be a suitable alternative to peat for pot culture, but it also has environmental issues. Based on current data, it is not more environmentally friendly than peat. The environmental cry to replace peat with coir is unfounded. This is especially true for societies that live close to peat sources where transportation  of peat can be kept to a minimum.

References:

  1. Coir: A Sustainability Assessment; http://newleafpractice.co.uk/pdf/Coir%20sustainability%20assessment%20sp.pdf
  2. What is Sustainability; http://www.environmentalscience.org/sustainability
  3. Spotlight on Coir Pith; http://www.ethicalconsumer.org/ethicalreports/gardening/coirpith.aspx
  4. A Comparison of Coconut Coir and Sphagnum Peat; http://cpl.usu.edu/files/publications/factsheet/pub__9468201.pdf
  5. Abnormalities Among Coir Workers of Alappuzha; http://www.japi.org/july_2010/Article_03.pdf
  6. Life Cycle Assessment of Horticultural Media; http://www.epagma.eu/sites/default/files/documents/epagma_growing-media-lca_final-report_2012-01-17_quantis.pdf
  7. Photo source; Richard Allaway

 

Robert Pavlis
Editor of GardenMyths.com
I live in southern Ontario, Canada, zone 5 and have been gardening a long time. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

I hope you find Garden Myths an educational site that helps you understand your garden better.

28 Responses to 'Is Coir an Eco-friendly Substitute for Peat Moss?'

  1. Kyle says:

    This is not related to this post, but I couldn’t find a place to send suggestions.

    I’ve heard all my life that pruning plants increases plant growth and/or flowering and fruiting, but this makes absolutely no sense to me. I can see how pruning increases bushiness and makes the plant look more full after a while, but I think it must necessarily lead to LESS plant growth. If you’re taking away surface area that the plant could be using to either make more food or to store it, how in the world would this lead to the plant growing faster? Or why would this lead to increased flowering/fruiting?

    Anyway, I’d love a post about this issue if possible. I think this is one of the most common ideas that are floating around about gardening.

    • Pruning in fall or spring will not normally increase plant growth in trees, nor does it increase flowering. If pruned in summer, it can lead to more growth since more dormant buds are initiated. Don’t know if it also increases flowers. Good idea for a future post.

  2. Inger Knudsen says:

    You have so many good inputs in this article. If we look at the overall production of coir it cannot be called sustainable at all. It might provide financial benefit for some communities but in the longer run it is not really a good product.
    Could you provide the same view on Rockwool which was supposed to displace peat, for a while

    • From Wikipedia: “Stone wool is a furnace product of molten rock at a temperature of about 1600 °C, through which a stream of air or steam is blown”.

      A man-made product that uses large amounts of energy is never sustainable. Is it more environmentally sound than using peat? Those are very difficult questions. I think that in the case of rockwool, it is just too hard to use for containers because watering becomes tricky.

  3. Carolyn Langdon says:

    I would suggest that we use neither as a soil conditioner. If you need to use peat for indoor plants until a better alternative surfaces then it’s a relatively small amount. I use composted wood bark and even well composted wood chips to amend my sandy soil. I live in a forested area (Haliburton Highlands) and the local tree arborists and saw mills have plenty of wood chips to spare and provide them free of charge. I believe gardeners need to look at what “waste” resources exist in their region that can be used to amend our soil. A colleague works in a varnish factory that has excess insect particulate waste that she carts home by the bag full to add to her garden. There is carbon rich agricultural waste that needs no processing and can be used.

    • For commercial culture in pots – the topic of this post – you have to come up with an alternative before companies will stop using peat. Your suggested alternatives are great for your garden, but not for the nursery industry.

  4. annekeire says:

    I believe the only truly sustainable answer is to use locally produced compost, and that can be several sources
    – food waste / wormery compost
    – garden / forestry/ mushroom farm compost
    – any weeds that are invasive and have little other use (but care should be taken not to spread non-native invasive species).

    Bracken is a good example in my country; it’s native here, but it’s invasive at the same time as current farming practices means it’s become a dominant species in areas outside its natural habitat. Cutting it down twice a year will reduce its area and will give a decent compost / potting ground, especially if combined with other material like sheep wool. I agree it’s not sustainable to rely on imported co-co coir (to Europe or America) but many of our bogs are a unique and threatened habitat in their own right, already too heavily exploited for fuel demand.

  5. uilyam says:

    I shared to Facebook with the comment: “A look behind the hoopla. This blog post can also be used as a kind of template for considering such questions. Obviously, the best alternative is to understand your local ecosystem well and use local resources in a way that meets your needs while improving the complexity, productivity, and resilience of the total system.”

  6. Trees-are-us says:

    Love the way you challenge conventional ideas – thought provoking and seems based on facts and science rather than emotional responses or vogue thinking. A distinct absence of pyramids and crystals that lends credibility to your briefings. Thank you.

  7. Chuck Chapman says:

    Thanks. A good read. Most issues involving environmental impact are more complicated then they first seem

  8. Roger Brook says:

    Environmentally coir is an almost unmitigated disaster and as a compost ingredient is next to useless – in my opinion!

  9. Troy says:

    🙂
    I appreciate your research and logic here. I live in Thailand, where I suppose this is indeed a sustainable resource. I had no idea of the processing the stuff goes through. I wonder if the stuff produced in Thailand does go through this process at industrial scales. I suppose though that small processors just chop the husks either by hand or machine, stuff the chunks into sacks, and sell them 😉 Aside from chunks, yes, fiber strands are available, and I suppose I’ve seen the sawdust-like stuff.

    Only part of your article that I’d like to discuss regards nutrient depletion part. C’mon … is there any substantial loss of nutrient to the soil by sending the husks off the land? It seems to me I’ve read of research (haven’t seen an actual paper) that says that the loss of soil nutrients due to harvesting plants is infinitesimally small. In addition … if Elaine Ingham is correct in saying that (the great majority of) all soils on earth have way way more soil nutrients than necessary for plant growth, then the issue of Nutrient Depletion is moot. If I remember correctly, you’ve taken issue with Elaine in the past, so I wonder what you have to say about her claim on this. Maybe you’ll stand by this claim of nutrient depletion.
    🙂

    • Re: “if Elaine Ingham is correct in saying that (the great majority of) all soils on earth have way way more soil nutrients than necessary for plant growth”. I have not researched this claim. Consider this, we know for sure that adding extra fertilizer to farms makes for larger harvests. Given that, how can we conclude that the farms have more nutrients than the plants need? It depends on how you define “plant growth”. Sure the farm soil has enough nutrients to grow some kind of plant – weeds will do just fine. If plant growth is defined as producing suitable yields of specific crops, then I think it is clear that her statement is wrong in reference to farming.

      However, in home gardens, especially landscape gardens, the statement might be true.

      Is the removal of husk important for local soil? Lets ask a different question, do coconut farmers add fertilizer to their fields? If they do, then yes the removal of husk makes the situation worse. If they don’t, and nutrients levels remain the same over long periods of time, then the removal is insignificant. I am fairly sure they fertilize.

  10. Cynthia Olen says:

    I don’t think I was terribly clear in my previous post. I guess what I’m saying is that, given how peat and coir are used—especially as a general soil amendment—wouldn’t any fibrous plant waste do the same job?

  11. Cynthia Olen says:

    Maybe this is stating the obvious, but why not use whatever organic waste is available locally instead of using something that must be shipped thousands of miles? By local, I don’t necessarily mean just down the road, but say, within a few hundred miles.

    Even the residential neighborhood in which I live seems to produce a lot of bio-waste as people go about their garden, tree, and lawn tending activities. We put it in dedicated bins for pickup by the recycling company, who in turn sells it to a composting company. Where it goes from there, I don’t know, but I certainly don’t see bags of amendment and mulch labelled “Sourced from North Central California” sold in the garden stores here.

    And wouldn’t it help if more people kept and composted their own gardening waste? I keep as much of mine as I can. If I had a small wood chipper, I would be able to keep even more. I don’t generate a lot of coarse woody waste, but I do end up having to send rose and shrub prunings off to wherever it goes on pick up day. It almost kills me to see all those nutrients and potential mulch leave my yard! Worse is that, when I need such waste, I have to buy it, and who knows how far the stuff had to travel or under conditions it was produced. But, people around here don’t seem to retain their yard waste for their own use, and that’s a shame. I almost want to cry when I see great piles of wonderful autumn leaves swept off into the street for disposal by the city. I don’t have any trees, so I would kill to have such leaves!
    So, wouldn’t retaining and processing our own yard waste be, in the long term, more generally eco-friendly and sustainable? I know—that would probably be asking too much of the casual gardener who just wants a nice looking front yard.

    • In the previous two posts I make the point that the use made of the material is important. For amending soil, almost any local organic matter should be used. When talking about container grown plants, consistency of material becomes important and most local organic material does not provide either the consistency or the specific features required.

  12. Dan OConnell says:

    Nice article. Again you take a poke at “transportation” issue. I don’t think most gardeners consider this in purchases of conditioners, compost, fertilizers, even soil.

  13. Editor says:

    “If society wants to reduce peat use, their efforts need to be focused on agriculture and forestry, not horticulture which uses less than 1% of the yearly peat harvest.”

    On the face of it, that statement (unlike peat) doesn’t hold much water. So what is the remaining 99% of the peat harvest used for? Agriculture and forestry? Surely not!

    How, by what means and for what purpose is peat ‘harvested’ for agricultural and forestry purposes? If you are referring to land reclamation for agricultural and forestry purposes, then one might suggest that you have misconstrued something. Land reclamation for these purposes generally takes place on cutaway or cutover peatlands – i.e. peatlands where the peat has already been removed: harvested, most likely, for other purposes, such as horticulture or as fuel for heating, electricity generation but not, in the first instance, for purposes such as agriculture/forestry/etc. These kind of activities only come into play after the harvest.

    • Editor says:

      It hardly needs pointing out that horticulture is a branch of agriculture. However, the author seems to exclude it from his ‘finding’ that agriculture, together with forestry, accounts for the greater part of the ‘yearly peat harvest’. But if this harvest is not being used for horticultural purposes, then what? It’s not being fed to livestock or used in tillage. So what other branches of agriculture could account for the use of peat, far in excess of that consumed for horticultural purposes?

    • For the most part peat lands are used for forestry, and yes peat is harvested to modify agricultural soil. Have a look at the references I provided – I did not make up these numbers.

  14. PJWatson says:

    Great post, Robert. This is very good to know — thank you!

  15. Every product imported from a distance should be tagged with the carbon footprint of transporting it from its source.