In the search for a peat moss alternative, coir, also called coco 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, its use is more environmentally friendly than using peat moss.” How can such common-sense logic be wrong?
What is Coco 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.
In some cases, the husk is simply broken into chunks 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 medium for such plants.
Choir has many of the same properties as peat moss, including the 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 this post, let’s assume it is good enough to be used as an alternative potting medium.
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 of their meaning, but can you 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. 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 they need for the ecology to remain in balance” (ref 2). It measures how much damage something does to the environment and 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 halfway 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 Coco 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” do 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 workweeks 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 the organic matter is shipped overseas.
Conclusion: Coco Coir is Not Sustainable
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 poses 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 to 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 considers impacts on climate change, resources, human health, and ecosystem quality. It concluded that “it is not possible to 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 of 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 of coir are due to transportation, electricity consumption, use of calcium nitrate for buffering, land occupation, and production of particulate matter.
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 does not have 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:
- Coir: A Sustainability Assessment; https://randd.defra.gov.uk/ProjectDetails?ProjectId=18114
- What is Sustainability; https://www.environmentalscience.org/sustainability
- Spotlight on Coir Pith; http://www.ethicalconsumer.org/ethicalreports/gardening/coirpith.aspx
- A Comparison of Coconut Coir and Sphagnum Peat; http://cpl.usu.edu/files/publications/factsheet/pub__9468201.pdf
- Abnormalities Among Coir Workers of Alappuzha; https://japi.org/r2a4c4b4/serum-ige-level-among-coir-workers-with-asthma-a-hospital-based-descriptive-study-from-alappuzha-kerala
- Life Cycle Assessment of Horticultural Media;ย https://erden-substrate.info/wp-content/uploads/2023/02/comparative-life-cycle-assessment-of-horticultural-growing-media-based-on-peat-and-other-growing-media-constituents.pdf
- Photo source; Richard Allaway
It is a complex issue that is glossed over by the gardening press and TV experts. You are looking at coir at the current usage but if it is used to replace all the peat the issues with its growth and production will massively increase. Look at how palm oil has expanded
This article is misleading. Coco coir only takes as long to form as the coconuts take to grow. Peat moss takes millions of years to form. It will eventually run out completely. That’s why it’s not sustainable.
I think you missed the point of the article. Firstly, we will not run out of peat since the earth creates more each year than we use. Secondly, for sustainability, you have to look at many factors – the rate of growth for coconuts is not an important one.
The nutriment taken out of the soil by the growing coconuts will not be in the soil for ever, so technically it is absolutely possible for that soil to run out completely(it’s already happening on tones of agricultural lands all over the world). It will eventually be totally depleted, one of the biggest global problem about land desertification (that’s not about desert expending but about lands becoming fully depleted). If you don’t put anything back in the soil it will run out and be impossible to grow more from it. Try growing a plant in a pot of full sand. Even a cactus will require some type of fertilizer at some point.
Nice article Robert. Thank you.
A lot is said about the energy expended to ship coir, well how about the energy used to harvest peat? The heavy machinery used certainly doesn’t run on sunshine..
I think the point here is they are probably close to equal in both their negative impact as they are in the usability. Coir I find to be the better potting medium, when it was all I changed in my soil mix, its ability to hold water reduced the need to water as often.
I disagree with “I think the point here is they are probably close to equal “. Until someone actually studies the energy inputs in harvesting and using peat, we don’t have an answer. Too many assumptions about what is good for the environment lead to poor decisions.
Great read! It’s good to know about both their impacts on the environment.
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.
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 ยฐC, 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.
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.
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.
The items you listed are not suitable for cultivation in pots, nor are they available in large enough amounts.
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.”