Coco Pith vs. Peat Moss: Which Is More Sustainable To Use In Composting Toilets?

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When we got our Air Head composting toilet it came with a coco pith brick (aka coco peat, coco coir, coir pith, or coir). We followed the directions on how to add the coco pith to our toilet and started using it. When the starter block was used up, we bought more coco pith. It wasn’t for about a year that we actually questioned whether using coco pith was the best option. We figured since coco pith is made from the outer husk of coconuts, something that’s otherwise just thrown away, it was the more sustainable than peat moss. At the same time, we heard whispers about how peatlands were being overly harvested. So out of habit and because we thought we already understood the situation, we kept on buying coco pith.

I started this post thinking that coco pith was the better choice when it came to sustainability. But after reading more about it, I’m not so sure. I’m curious to hear your thoughts after reading this.

What Is Coco Pith

Coconuts consist of two parts: the inner kernel, which is used as food, and the outer husk. The fibers from the outer husk are extracted and used to make products like doormats, ropes, brushes, and mattresses. The remaining dust and shorter fibers are collected to make coco pith for horticulture.

Coco Pith Manufacturing Process

The collected dust and fibers are collected and stored over ~6-month period of time to decrease salt, tannin, and phenol content along with various other reasons. Afterward, the pith is screened to remove any contaminants. Then it’s washed to further remove salt contents and sometimes buffered, where calcium nitrate is added to displace sodium and balance the naturally occurring potassium. The pith is finally dried, compressed into bricks, packaged, and transported overseas. The largest producers of the coconut fiber used to make coco pith are in India and Sri Lanka.

Read more about the manufacturing process:

Planet Coco Coir

Thiraviyam Coco Peat

Dutch Plantin

Downsides of Coco Pith

We automatically assume that coco pith is a sustainable product because it’s made from the discarded waste of the coconut industry. But as always, there are more factors to look at. Without going down the rabbit hole and figuring out how sustainable coconut farms are, we’ll just assume that coconuts will continue to be grown for their meaty center and sweet juices, and there will always be husks tossed out. Instead, let’s look at the coco pith process itself.

A lot of water is needed to process coco pith. Between 80 – 160 gallons of freshwater is used per cubic yard.
Coco pith processing plants in India are located in regions that suffer from water scarcity. This isn’t as much of an issue in Sri Lanka.
Runoff water from cleaning the coco pith may contain levels of sodium, potassium, and physical contaminations that can have a harmful effect on surface water, groundwater, and soil.
There are poor working conditions at the coco pith factories – long work hours and dusty conditions from the coir particles.
Coco pith products get transported from India and Sri Lanka to Europe and North America via cargo ships.

While making coco pith uses waste products from the coconut industry, it also creates water pollution, greenhouse gas emissions, air pollution, soil pollution, marine pollution, and not to mention ethical working practice issues.

What Is Peat And Peat Moss

Peat is a soil-like accumulation of partially decayed vegetation found in peatlands, bogs, and mires. Peat moss is a type of peat and is created mainly from decaying, water-saturated sphagnum moss also found under the surface of peatlands. Peat moss and sphagnum moss are two separate things. Sphagnum moss grows on the surface of bogs and peatlands. Historically, peat has been harvested as fuel. Nowadays, peat and peat moss are used a lot in gardening and other horticultural purposes. Peat moss is the other organic material composting toilet companies recommend being added to their toilets. Like coco pith, its high absorption ability is great for keeping composting toilets’ solid tanks dry and in an aerobic state – which keeps the smells away.

Peat and peat moss harvesting is a very controversial topic. In recent years, the discussion has been focused on how the world’s peatlands are being stripped because of high horticultural demands for peat (aka peat moss). But it’s debatable whether or not peat harvesting is as bad as some say.

Why Are Peatlands Important

Peatlands are mainly found in the northern hemisphere. Canada has approximately 25% of the world’s peatland and almost all of the peat sold in the US is from Canada. There are four reasons that peatlands are important to our ecosystem:

They are a unique natural habitat that supports biodiversity and species that are at risk.
Peatlands are carbon sinks and store 1/3 of the world’s soil carbon. Plants don’t decompose completely and because of that they contain large amounts of carbon. But these plants’ carbon gets locked into the peat. As long as the peat isn’t disturbed, the carbon won’t enter into the atmosphere in any significant amount.
They act like “archives” and offer unique historical evidence on an area and its inhabitants.
Peatlands play an important role in the global hydrological cycle by helping maintain water quality and quantity. They contain 10% of the world’s freshwater resources.

This is a tundra in Yukon Territory, Canada, which isn't exactly a peatland. But it's kind of similar, especially during the summer months when the top layer of semi-frozen soil melts leaving tundra covered in marshes and bogs.

Peat Harvesting Process

Many surveys are completed to determine an ideal place to harvest peat and peat moss. Peatlands with a depth of 2 meters are chosen so it can be harvested for many years. Once selected, the peatland’s living surfaces are removed so the lower layers of peat can be accessed. Ditches are dug to drain surface water and roads are built to allow heavy equipment in and out to operate. Milling machines then come through to loosen the top inch or two of peat, which is left to dry in the sun. Vacuum harvesters are used to collect the top ¼ inch of the dried material and trucks carry the harvested piles to nearby processing facilities. Once the collected peat is screened to removed impurities, it’s packaged “as is” or blended with other materials to create soil-less potting mixes, and then shipped out to stores. Over the course of a year, about a 2 – 3-inch layer in peatlands are harvested.

All the layers and material from a peatland are used. The top layer is sphagnum, undecomposed moss that’s typically used for lining orchid mixes and lining hanging baskets. It’s the next layers that are considered peat and used to in garden propagation mixes and other things.

Downsides of Peat and Peat Moss

The biggest argument against peat harvesting is over whether or not peatlands are a renewable resource. Because the extraction rate for peat exceeds the slow regrowth rate of 1 mm per year, only 30 – 40% of peatlands regrow peat.

According to Paul Short, Canadian Sphagnum Peat Moss Association (CSPMA), “…for the past 10 years, producers have been restoring harvest bogs by allowing them to re-flood and seeding them with shredded moss grafts that that grow and knit together. The moss covers the harvest site within five years and the bog is back to near-natural condition within 10 to 15 years.”¹ In another article, Stephanie Boudreau, Science Coordinator Biologist of Quebec Peat Moss Producers Association and CSPMA, and science coordinator of the Canadian Peat Industry said, “Based on the moss transfer technique developed through the research program, a sphagnum dominated plant cover is re-established within 3-5 years following restoration, biodiversity and hydrology is approaching pre-harvest conditions, and carbon sequestration should become a net sink within 15-20 years.”²

Remember that peat is the accumulation of partially decayed vegetation from peatland and that takes centuries to develop. This is why some even refer to peat as a fossil fuel when talking about using peat as a source of heat.

The second argument why peat isn’t an environmentally friendly product is that when it’s harvested it releases its stored carbon dioxide, a major greenhouse gas. I only came across one study with numbers in The National Gardening Association, “The CSPMA (Canadian Sphagnum Peat Moss Association) commissioned a study on the carbon emissions related to sphagnum harvest. The University of Calgary’s Department of Geology determined that CSPMA’s removal of sphagnum peat only contributed 0.006 percent of the world’s total carbon emissions or 0.1 percent of Canada’s emissions.”³

The other side of the argument is that the peatlands harvested for horticultural use are minute compared to peatlands being cleared for agricultural and forestry purposes. In Canada, which supplies the majority of the US peat market, only 0.03% of the peatlands have been or currently are harvested. 86% of global peatlands are untouched and out of the 14% that are disturbed - 51% is for agriculture, 26% is for forestry, and only 1% is for heating and horticulture.

Coco Pith or Peat

After all this information, which is a more sustainable product: coco pith or peat? I honestly can’t decide. The large amount of water usage and the greenhouse emissions from the long journey coco pith has to make from India to the US makes it not environmentally friendly. But even though peatlands can be restored, peat itself takes centuries to develop. But horticultural uses of peat is a drop in the ocean compared to peatlands being destroyed for agricultural and forestry uses.

Then I realize I’m using this to add to a pile of poop and it seems like neither is worth using, especially when my composting toilet isn’t even actually composting!

In “Achieving environmentally sustainable growing media for soilless plant cultivation systems” review published in ScienceDirect, the authors wrote, “…coir is often used as a peat replacement in Europe because it is perceived to be a more sustainable option. In terms of its impact on climate change, this is probably the case; but when impacts of its production are considered in terms of ecosystem quality and human health, it performs less favourably than peat.”⁴

Adding coco pith to our recently emptied out composting toilet.

Alternatives to Coco Pith and Peat for Composting Toilets

What is the purpose of coco pith and peat in a composting toilet? Organic matter like coco pith and peat are necessary to balance out the nitrogen vs. carbon ratio to keep microbes fed so they are able to continue the composting process. Coco pith and peat also absorb the water content in poop (which is actually very high) so that the compost process stays aerobic and not anaerobic. Keeping compost piles in an aerobic state is crucial to decrease unwanted smells and reach high enough temperatures to kill pathogens. And lastly, the coarse texture of the two products allow air flow through the matter to help with decomposition in an aerobic state.

The only other material we’ve tried using in our composting toilet is sawdust. This works fairly well as long as it’s coarse sawdust or wood shavings. Fine sawdust, like from a circular saw or sander, isn’t useful at all. It doesn’t do a good job keeping the poop in the toilet dry and the whole thing turns into this mucky consistency.

This post written by The Toilet Zone recommends dropping by local mills or woodworker shops to ask for wood shavings and coarse sawdust. These are waste products that can be put to use again, and it doesn’t have to travel far to end up in your toilet. Wood shavings used in dog beds could also be a good alternative according to the website Little House. But organic matter like dead leaves and grass are terrible. The downside of wood shavings or sawdust is that they doesn’t come in a compact brick like coco pith or peat, which are great when you’re a full-time traveler limited on space. The upside is you don’t have to spend any time breaking it up before adding it to your toilet!

This is the starter brick of coco pith that came with our Air Head composting toilet.

Chopped up hemp stalks, or hemp core as it’s called, is also a good alternative to use in composting toilets. The best part is that it’s more sustainable than both coco pith and peat because it’s a very renewable crop, grows in a variety of climates, is naturally resistant to a lot of pest, and uses very little water. But aside from a peat/hemp core mixture called Compost Sure by Sun-Mar that’s really expensive, I haven’t been able to find anything else online – neither 100% hemp core nor a blend.

I’m very interested to hear your thoughts about choosing between coco pith and peat after reading this. What do you currently use for your composting toilet? Do you have any suggestions for other composting toilet bulking material?