Peat moss plays a big role in the horticulture industry and for home gardeners. But when it comes to sustainability, peat moss may not a great choice for our gardening endeavors. To discuss the challenges of its ongoing use in the face of climate change, my guest this week is Dr. Merritt Turetsky, a wetland ecologist and the “Queen of Peat.”
Merritt is the director of the Institute of Arctic and Alpine Research, known as INSTAAR, at the University of Colorado Boulder, where she is also a professor of ecology and evolutionary biology. She’s always had a passion for research and science that has implications on policymaking and real-world environmental problems. Her interests mainly lie in northern ecosystems and peatlands, and she is an expert on carbon cycling and permafrost science.
Merritt is a passionate advocate for peat and peatlands. To that end, her Twitter and Instagram handle is @queenofpeat. “What I try to create on social media is a glimpse of what it is like to visit these ecosystems, to be surrounded by these ecosystems,” she says. “They are beautiful, intricate, complicated, often miniaturized models of biodiversity. And frankly, many people don’t get to experience them. So I love to be a gateway and a portal to what it’s like to be immersed in a landscape surrounded by peat.”
She also tries to connect her followers to the science and policy surrounding peatlands and shows why so many scientists have dedicated their careers to these ecosystems. “The answer, in short, is because they are extremely important to the world stage right now,” she says.
Peat bogs make up just 3% of the Earth’s surface but store 30% of land-based carbon, according to a recent CBS News report. Merritt says even that statistic doesn’t do justice to the carbon-storing power of peat. That’s because — unlike trees and grasslands, which can burn in wildfires relatively readily and release their carbon — peatlands tame wildfires.
Before proceeding with this week’s discussion, I want to stop and remind you that my 2021 Holiday Gift Guide is out now. You can find 20 great gift ideas for the gardeners in your life (and maybe something for yourself) at joegardener.com/giftguide.
How Peatlands Form
Sloughs, marshes, bogs, fens, mires, moors. These are just a few of the many synonyms for different kinds of peatlands. A peatland is a type of wetland, and it’s just one of the types of environments where peat is found. Peat is also in boreal biomes, aquatic systems and forests.
Peat itself is organic, rich soil created by the accumulation of organic matter from microbial biomass, plant biomass, bugs and even animal remains. That organic matter gets locked away over time in soil layers. “Peat can be very ubiquitous across the landscape, and it’s so important for soil development in a lot of different kinds of ecosystems,” Merritt says.
When peat reaches a depth of 40 centimeters or more, the area is classified as peatland. In a dry boreal forest with lots of black spruce, there can be 25 centimeters of peat, which is a healthy peat layer but not enough by North American definitions to be considered peatland.
By and large, peat accumulation happens more in cold climates because the rate of decomposition is slower in low temperatures. However, peatland is not limited to arctic and subarctic regions. Every state in the United States and every providence in Canada has peatland. In fact, every biome globally has peatlands.
In the tropics, new areas of peatland are being discovered every year, including in Borneo. There, peat is largely formed of vascular plant remains. Peat development there differs from temperate, boreal and subarctic regions, where moss makes up most of the peat.
The Difference Between Peat and Sphagnum Peat Moss
While peat is an encompassing term for all kinds of peat, “Sphagnum peat moss” refers specifically to mosses in the Sphagnum genus. “Sphagnum is excellent for its abilities to form peat,” Merritt says. Both bogs and acidic, nutrient-poor fens in boreal regions are Sphagnum dominated.
Sphagnum is a really diverse genus and a fascinating group of plants. “I call them ‘ecological ninjas,’” Merritt says. “They’re tiny, but they’re cunning. They’re resourceful. They fight like crazy to keep their nutrients locked away inside their own tissue, and that’s how they are so competitive in these ecosystems.”
Sphagnum mosses release acid into their environment, which makes it very difficult for other species to grow. “They’re adorable, beautiful plants, but they’re nasty,” she says.
The peat that we purchase at garden centers is largely harvested from natural peat bogs. Huge commercial vacuums suck up peat from Sphagnum-dominant bogs.
“The reason it’s such a commercially successful product is because of the water holding capacity of that moss tissue,” Merritt says. “It is truly a super sponge.”
Once water is stored in Sphagnum tissue, it is not easily released. When your garden soil becomes dry, the water will slowly come out to benefit our plants.
In peatlands other than bogs, it can be much harder to harvest peat. In fens, for instance, the water tables routinely rise and lower by several meters.
Is Peat Sustainable?
There was a lot more peatland in the past, but these lands are sensitive to land use and development. In the United Kingdom, for instance, at least 90% of the peatlands have been destroyed or highly degraded. Part of the reason for that is that peat has historically been used as a fuel source. Though peat’s not a great fuel, its abundance has made it popular for cooking and heating. In Scotland, peat combustion adds flavor to Scotch.
In North America, peatlands have been destroyed when wetlands are drained. Those drained wetlands will no longer accumulate peat, but they leave so much peat behind that they become very productive when put into agriculture use.
“We’re fending off new drainage projects in peatlands all the time, trying to make the argument that these ecosystems are just too precious to fuel yet another agricultural development,” Merritt says. “We need to be thinking about their role in the world’s climate.”
North America has an enormous expanse of peatlands, especially in Canada and Alaska. Though the peatlands are vast, Merritt says you would be shocked to learn how much they have been disturbed already by roads, oil and gas pipelines and drilling pads. “Every time there is a linear disturbance put through a remote tract of boreal land, it intercepts hydrology of peatlands,” she says.
Merritt warns that North America is on the same path as Europe: the path of damaging, degrading and sometimes completely destroying peatlands. “We have a choice to take a different path and to make sure that the peatlands that are remaining on our landscape are cherished and treasured and protected and conserved,” she says.
Peatlands are more than just carbon sinks. They are hot spots of biodiversity, berry-producing ecosystems and places where indigenous communities and local communities can gather food.
“Let’s learn from what the U.K. has learned over their historical period of peat use, and let’s choose to do something different,” Merritt implores us.
The United Kingdom has become vocal in the past few years about avoiding peat. There’s even a peat-free pledge, and British gardening influencers like Monty Don make videos specifically about not using peat.
We can all speak with our wallets by choosing not to buy peat.
What The Industry Says About Peat Moss Sustainability
To play devil’s advocate, I researched what the Sphagnum peat moss industry has to say about the sustainability of peat harvesting. To begin with, representatives point out that Canada has more than 270 million acres of peat bogs while each year the industry harvests just over 40,000 acres for agricultural use. That’s about 1 acre harvested annually for every 60,000 acres that exist.
Merritt points out that peatland surface area is not an accurate measure of the impacts that peat moss harvesting has on carbon stocks. Harvesting is three-dimensional, digging down through time, releasing carbon that was stored over the course of decades, centuries or even thousands of years. “That is all carbon that we cannot afford right now to have back in the atmosphere,” she says.
Another consideration is which peatlands are being harvested from. It’s not the remote, hard-to-reach peatlands that are being disturbed, but peatlands close to where people live — lands that should be used to educate people.
Harvesting peat and transporting it also has a carbon footprint. And then when gardeners buy that peat and put it in their garden beds, that carbon is no longer sequestered. It’s been taken from its slow-decomposition environment and put into an environment where it will decompose quickly, releasing its carbon.
Merritt gives credit to the peat moss industry for investing its own funds into researching how to rehabilitate and restore these damaged ecosystems. However, she says that the time scale of peatland restoration is measured in decades or even centuries, while we don’t have the luxury of waiting that long to meet our climate and carbon policy objectives.
Alternatives to Peat Moss
To add nutrients, water and moisture retention to your soil, peat is not a great product, Merritt says. There are other products that are less impactful on the environment, unlike peat, which comes from some of the world’s most unique, biodiverse, carbon-sucking ecosystems.
Coir is a fibrous coconut byproduct that excels at holding water. It’s used to make everything from doormats and rope to brushes and mattresses, and it is a peat alternative in horticulture. Merritt points out it is also high in potassium, which is a nutrient that plants need.
I am investigating finely ground pine bark, wood fiber and other products. I see many opportunities ahead for really sound alternatives to peat.
Merritt says to know what exactly it is you are buying and to encourage local business owners to carry alternatives. “You might be the tipping point to convince someone to bring in a new product and to give it a try,” she says.
Your own homemade compost is another alternative to peat that is a superior product to commercial peat, Merritt says. Encouraging your township to begin a municipal composting program can be beneficial and economically viable for an entire town.
Merritt says we’re not aiming to be purists, we’re just trying to do better. So that could mean using less peat rather than going peat-less immediately.
I hope you have a greater understanding of peat and the value of peatlands after listening to my conversation with Dr. Merritt Turetsky. If you haven’t listened yet, you can do so now by clicking the Play button on the green bar near the top of this post.
How have you changed your gardening practices to benefit the environment? Let us know in the comments below.
Links & Resources
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