In the world of horticulture, peat moss possesses many qualities we want in a growing medium.
Peat moss has a lightweight and spongy texture. It has the uncanny ability to hold on to air and moisture while allowing excess water to drain freely. It’s generally pest and disease free. And it’s inexpensive.
Since the 1940s, peat moss has been used as a soil amendment, in soilless mixes, and as a growing medium for starting seeds. Most commercial potting soil and triple mixes contain peat.
Gardeners love it because it fosters the perfect environment for establishing strong root systems.
As much we appreciate peat moss, using it in our gardens has a steep environmental and ecological cost. There’s very good reason it should stay in the peatland, where it belongs.
What is Peat Moss?
Peat moss is composed of partially decomposed organic matter, the remains of Sphagnums, brown mosses, sedges, and semi-aquatic plants.
Peatlands are found all over the world, but are most abundant in temperate, boreal, and subarctic zones in the Northern Hemisphere.
Peat accumulates in wetlands like bogs, fens, mires, and moors.
Submerged beneath the water, vegetation decays in anaerobic – or airless – conditions that slow decomposition to a crawl.
After many thousands of years, what remains is a soil-like substrate, dark brown in color, with a soft and fluffy texture.
Peat is harvested – technically mined – by draining the wetland and scraping the surface of the ground, several feet deep. The extracted peat is then dried, screened, and compacted.
The terms “peat”, “peat moss”, and “sphagnum peat moss” are sometimes used interchangeably. All of them usually refer to the stuff harvested from the bottom layers of the wetland.
Not to be confused with “sphagnum moss”, which is a different thing.
Sphagnum mosses are living plants that grow in clumping mats on the uppermost layer of peatland. They have a fibrous and stringy texture that holds water exceedingly well, and so are popular in container gardening as growing media and mulch.
Both sphagnum moss and peat moss are harvested from fens and bogs.
What many gardeners might not realize is how using these materials impacts the sensitive ecosystem of the peatland and fuels a warming planet.
4 BIG Problem with Peat Moss…
1. It’s not really renewable
Peatlands take a very, very long time to form.
The vast peatlands in Canada, for example, developed 10,000 years ago, after the last glacial period. During this era, megafauna like mammoths and sabre-toothed cats still roamed the Earth. Humans were just starting to get the hang of farming wheat and barley.
On average, peat accumulates at a rate of less than 2 inches per century.
For this reason, we can hardly call peat moss a renewable resource. At least not in a timescale that our short-lived species can truly fathom.
2. Peat moss sustainability is debatable
Most peat moss sold in the US comes from Canadian peatlands, and its extraction is regulated by the government.
Of the 280 million acres of peatlands, only 0.03% may be harvested from virgin bogs. The peat mining industry is also tasked with restoring the peatlands by re-introducing plant species and re-establishing the water table.
Some have argued that harvesting less peat than is generated each year means that peat moss is a sustainable resource. And that restoration efforts will re-create the original ecosystem.
However, others have pointed out that the natural creation of peatlands takes thousands of years and that once they are destroyed, they can never be fully restored.
Like with tree farming, which looks nothing like old growth forests, peatland restoration tends to become a monoculture that lacks the biodiversity of untouched peat bogs and fens.
3. Peat bogs are a unique and fragile ecosystem
Peatlands are a unique ecosystem, considered by scientists to be as important and fragile as the world’s rainforests.
The conditions of a peat bog are harsher than most. It is very wet and acidic, with low levels of oxygen and nutrients in the water column or substrate. Despite this, it is home to many rare plants and animals that are highly specialized to thrive in such an environment.
Sphagnum mosses are the most dominant plant species and best adapted to boggy places. These plants are root-less, absorbing water through their leaves and spreading by spores instead of seeds.
As layers of living and decaying mosses grow on top of the other, other specially adapted plants will grow. Orchids, rhododendrons, lily pads, carnivorous plants, willows and birches, and countless mushrooms, mycorrhizae, lichens, and other fungi.
Peat bogs are a habitat for millions of songbirds, raptors, and waterfowl. There are an estimated 6,000 species of insects, both aquatic and terrestrial.
Small mammals like lemmings, hares, minks, voles, and muskrats are most common, but larger beasts such as moose, bison, and deer are also known to wander through the wetlands. Some species of small fish, frogs, snakes, and salamanders have become bog specialists too.
There’s no way to extract peat without also utterly destroying the habitat:
Peat bogs and fens tend to be isolated from each other, making it especially difficult for these specialist species to migrate to other wetlands when their habitat is disturbed.
Thread-leaved sundew, spotted turtles, eastern ribbon snake, and woodland caribou some of the bog dwelling species that are now threatened or endangered, largely due to habitat loss.
4. Peat moss harvesting massively accelerates climate change
Peatlands are of great ecological importance, both locally and globally.
Since peat and sphagnum mosses are extremely absorbent, they help mitigate flooding during periods of high rainfall. In drought, they release water slowly to maintain the water table.
Like other types of wetland, peat bogs are nature’s water purifiers, filtering out contaminants to provide safe drinking water to nearby communities. It is estimated that peatlands filter 10% of all freshwater resources worldwide.
But perhaps the most vital service peatlands provide is carbon sequestration.
Peat bogs capture and hold carbon dioxide and prevent it from entering the atmosphere. They are the most efficient terrestrial carbon sink on the planet, holding around 30% of the globe’s soil carbon – more than all the world’s forests combined.
When peatlands are drained and dug up, centuries of stored carbon is released.
So far, disturbances to peatlands has contributed 1.3 gigatonnes of carbon dioxide globally – and counting.
To make matters worse, peatlands drained of water are highly flammable. Peat fires can smoulder beneath the ground surface undetected for months, years, and even centuries, and can be difficult to extinguish.
These fires will emit billions of tonnes of carbon too – a smoldering, smoky peat fire will release up to 100 times more carbon than flaming forest fires.
7 Earth-Friendly Peat Moss Alternatives
The thing is, peat moss isn’t even that special.
There are many great alternatives that will hold water and air as well as peat moss does. In fact, some will even do a better job than peat moss by adding nutrients and fostering microbial life.
They don’t call compost a gardener’s best friend for nothing!
Compost really is the secret to the most productive, lush and beautiful gardens.
Add it to your existing soil and it will do amazing things. Compost binds together sand, clay, and silt particles to create good soil structure. This will create a rich and crumbly loam that is filled with tiny air tunnels that allow oxygen, water, and nutrients to flow through it and reach plant roots.
The most beloved quality of peat moss is water retention – and compost does this just as well, holding up to 80% of its weight in moisture.
But compost is a much better overall soil amendment than peat moss.
While peat contains little by way of nutrients and microorganisms, compost is bursting with fertility and microbial activity. These soil dwelling bacteria and fungi are what make compost so great – they buffer the pH, help resist diseases and pests, and make nutrients available for uptake by plants.
And with no need to mine it, process it, or transport it, composting kitchen scraps and yard waste from the comfort of home is about as renewable and sustainable as it gets.
2. Leaf Mold
The leaves that drop from shade trees are plentiful in autumn. Take advantage of this free and abundant resource by making leaf mold.
Collect up your leaves, moisten and wait. It’ll be ready to use in the garden in two years. Run them over with a mower first and you can have leaf mold in a year.
It’s similar in a way to making compost, except that in leaf mold decomposition happens in cooler conditions and is driven primarily by fungal activity.
Leaf mold is a wonderful all-round soil conditioner.
Work it into your soil or layer it on top like mulch and it will increase the water and air holding capacity of your garden. When added as a soil topper, it will also moderate soil temperatures and reduce evaporation.
Though tree leaves are made up mostly of carbon, they do contain smaller amounts of nitrogen, potassium, phosphorus and other trace minerals. It never hurts to add a bit more fertility to your soils.
Well-rotted tree leaves have a light and crumbly consistency that’s rich in organic matter. This is an ideal habit for soil microbes to flourish and provide their most welcome plant-promoting activities.
Leaf mold is a great thing in the container garden too. Since it retains moisture so well it can be used as a substitute for peat moss when making your own potting soil mix.
If you use those little peat pellets to start seeds, try using leaf mold instead.
Biochar is a special type of charcoal for the garden that confers many benefits to native soils.
To make biochar, you must first make charcoal by heating up wood and other plant materials in a low or no oxygen environment. The charcoal lumps are then crushed into smaller pieces (about an inch or less in diameter) in a bucket. Wear a respirator mask to avoid breathing in the dust.
Fill the bucket with water and add a shovel-full of compost and stir it up. Let the mixture sit for around 5 days before working it into your garden beds.
Biocharging – or inoculating your biochar with nutrients – is an important step that increases soil fertility and microbial activity.
Uncharged charcoal will wick up nutrients in the soil and prevent them from being used by plants.
As an alternative to peat moss, biochar is a really good option. It improves soil structure and water retention. When mixed in with your garden soil, it’s long lasting and will take a very long time to degrade.
Apply biochar at a rate of 10 pounds per 100 square feet of garden area. You can till it into your beds or leave it as a ¼-inch layer on top. Then mulch as normal.
To use it in your potting mix, add biochar at rate of a ½ cup for each gallon of soil.
4. Green Manure
To maintain healthy soil in your garden beds, nutrients and organic matter will need to be replenished every year.
One of the easiest ways to do this is to grow cover crops. Producing green manures is like composting in situ.
Sow nitrogen fixers like clover and alfalfa in September or October, after you’ve harvested your last fruit or vegetable. Let them grow throughout autumn and then chop them down in spring. Lay them over the soil surface or incorporate them into the soil.
Green manures keep soil microbiota happy by adding organic matter back into the soil.
The soil-dwelling microbes help break it down and create those tiny air channels that keep the water, oxygen, and nutrients flowing.
Because green manures maintain good soil structure, that means they also increase the water holding capability of the soil. Moisture is better able to penetrate soils amended with green manure, reducing runoff.
5. Composted Manure
Another good option for improving soil structure – and thus water retention – is well rotted livestock manure.
If you keep chickens, cows, horses, sheep, goats, or pigs on the homestead (or know someone that does), don’t let this valuable peat moss alternative pass you by.
Topdressing your garden with composted manure ramps up nutrient levels and spurs more microbial activity. Though different animal manures will have variable amounts of N-P-K, all herbivore dung will only benefit the soil and its structure.
Fresh manure will burn plants but composting it first will allow nitrogen and pH levels to stabilize. Pile it up and let it age for six months or more before using it in your garden beds.
Or, you can add it in raw to the vegetable patch in late autumn. Turn the soil over in the spring and wait at least a month before planting it up.
6. Coconut Coir
Coconut coir is often touted as the perfect substitute for peat moss.
A waste by-product of the coconut industry, coconut coir comes from the fibrous outer shell of coconuts. Coir is used to make doormats, mattresses, and rope.
The shortest fibers and dust particles are called the coir pith – and this is what we refer to as coconut coir in the gardening world.
Coir pith is brown, fluffy, and lightweight, with a texture that is very much like that of peat moss. It is sometimes referred to as coco peat.
And similar to peat, coconut coir pith acts like a sponge that soaks up water and releases it slowly.
Since it’s low in nutrients, it’s frequently used as a soil conditioner and as a soilless growing medium for starting seeds.
Most of the world’s coconut coir supply hails from India, Sri Lanka, and the Philippines. Though it’s always better to source peat alternatives locally, coconut coir is certainly a more sustainable option compared with peat moss.
7. Living Sphagnum Moss
Possibly the closest analog to peat is sphagnum moss. After all, peat moss is formed from layers upon layers of sphagnum mosses.
When you purchase sphagnum moss from the garden store, it comes dried and brown and devoid of life. Add water and it will hold up to 26 times its dry weight in moisture.
This stingy material is useful in soil mixes, as topdressing for containers and hanging baskets, and as a seed starting mix.
Although most of the sphagnum moss on the market today is sourced from peat bogs, sphagnum peat moss farming is slowly catching on as a way to obtain it more sustainably.
Another earth-friendly way to get sphagnum moss is to learn how to grow it yourself.
If you can provide a high humidity location – a greenhouse, terrarium, or even a marshy spot in the yard – sphagnum moss can be cultured:
As the sphagnum moss grows and spreads, it can be harvested and dried for normal sphagnum moss applications.
Keep it alive, though, and it will become a living mulch. Plant it on top of the soil around humidity loving cultivars like orchids, pitcher plants, sundews, and ferns.