The Dirty Secret Behind Sphagnum and Peat Moss
If you garden or keep houseplants, you’ve likely used sphagnum/peat moss. Long-fiber sphagnum moss is a popular medium used for rooting plant cuttings, and peat moss (derived from the decomposition of sphagnum & similar mosses) is commonly used in potting mixes due to its aerative and moisture-retaining properties.
What most people haven’t considered is the origin of these belovedly versatile mosses—bog/wetlands—and how their mass harvest negatively impacts the environment. Due to their multitude of uses and popularity in gardening, peat & sphagnum moss are being harvested from boglands faster than they can regrow.
This post does NOT have affiliate links. Sources cited at the end of the article.
QUESTIONABLE IMPACTS ON THE ENVIRONMENT
According to Sustainable Gardening Australia, peat is formed when sphagnum moss and various organisms decompose over thousands of years in cool, moist climates that eventually form bogs.
These bogs are primarily located in Canada, Michigan, Ireland, Scotland, New Zealand, and Peru. When it’s harvest time, ditches are dug to drain the bogs, and the top layers of peat are left to dry in the sun before getting harvested by hand or machinery. Afterward, it’s bound into bales, shipped off, and processed into other forms.
A vacuum harvester. Source: Pro-Mix Horticulture.
Because it takes such a long time for peat to form, mining it means depleting an almost non-renewable resource. - SGA
Besides the loss of the peat itself from harvesting, the regeneration of it is quite slow since it’s formed through such a time-limited decomposition process. In addition, digging ditches impacts existing water currents, leaving more of the wetlands to dry and potentially catch fire when lightning strikes these expansive areas, not to mention disturbing fauna & flora that currently call the wetlands their home.
Fresh sphagnum moss is just as in demand as its decomposed form. For example, exports of sphagnum from Chile, quadrupled from 1998 to 2008. Sphagnum is often the dominant moss species in wetlands, so their excessive harvest can lead to the reduction of biodiversity in wetlands and negatively impact their function as “hydrological and carbon reservoirs” (Diaz et. al, 2012).
ALTERNATIVES TO PEAT & SPHAGNUM MOSS
For an environmentally friendly alternative, opt for coco coir (aka “coco peat”) instead of peat moss if you’re making your own potting mix. Coco coir, the ground form of the outer husk of coconuts, is an interchangeable, readily renewable soil amendment that similarly aerates and add moisture-retaining properties. Since the husks are a byproduct of coconuts typically grown for the food industry, repurposing the husks keeps them out of landfills (source: Washington State University). For an in-depth comparison on using on using peat vs coco coir, check out Planet Natural. Coco chips, another form of coconut husks, are a popular ingredient in chunky mixes for aroids, because the large air pockets allow water to drain quickly and provide ample room for roots to grow.
Feb 2021 update: I recently learned about rice hulls as an alternative to perlite if you’re making a chunky mix—might be worth giving ‘em a shot. I linked to an anectodal forum thread; I recommend doing some research and buying a batch smaller than 50lb of hulls to test out whether it suits your needs.
Coco husk is ground into coco coir (aka coco peat) or shredded to use as fiber. Source: SV Coir Exports
A chunky aroid mix consisting of fir bark, horticultural charcoal, perlite, and coco chips made from coconut husks. Source: Garden.org
Sphagnum moss is commonly used in moss totems because it rewets easily and allows plants to dig in their aerial roots and climb upwards. To reduce your use of sphagnum, you can make coco fiber mat-wrapped totems, jute-wrapped wire trellises, or fill a cylinder of mesh with coco chips instead of sphagnum moss. The simplest, low-mainteance option? Plain wood totems! Tyler of Rousseau Plant Care shows how his philodendron micans’ aerial roots have readily attached to his extendable mapele mahogany totems. He initially guides the plants to stick with a bit of plant velcro, but soon after, the roots attach themselves. Not affiliated with Rousseau, but I have two of his totems and wholeheartedly believe in his thoughtfully designed product.
Totem made out of coco fiber mats secured with fishing line. Source: Palm Nursery
Wire trellis wrapped with jute twine. Source: Etsy
Tyler guides his micans with plant velcro but the roots soon find their way and attach readily to this wood. Source: Rousseau Plant Care
For rooting plants, perlite and LECA (lightweight expanded clay aggregate pellets) are great substitutes for moss. LECA works well because the pellets absorb just enough water to remain damp but provide plenty of air pockets for roots to breathe. The same benefits apply with perlite. Personally, I prefer rooting in perlite over LECA; I like that it’s a bit finer of a substrate. I’ve tossed a snapped Burle Marxe Fantasy cutting into a reused Ziploc bag of perlite and it rooted!
Sarah Villasenor of @favoritefoliage on IG uses a tray of LECA for propagating various hoya cuttings. Source: Instagram
@rootedinplants shares a successful method for propagating monsteras, philodendrons and hoyas in perlite
SUSTAINABLE SOURCES
If you absolutely must use sphagnum or peat moss, here are some sustainably harvested sources:
Sungro Horticulture (peat) - “identifies and harvests only from bogs that can be restored to functioning wetlands, wildlife habitat or farmland” and supports peatland restoration research
Better Gro (sphagnum) - “harvested by hand, using sustainable means to ensure that the Chilean swamps from which the moss is collected remain healthy”
Besgrow (sphagnum) - “Besgrow Spagmoss products are harvested from carefully managed, sustainable swamps” in New Zealand
Phosphor Bio (sphagnum) - sourced from an artificial bog in New Zealand
15% off your order with my code ‘LR9ZB3H’
Special note that Phosphor Bio ships pre-hydrated sphagnum that’s infused with endocytes meant to boost rooting/growth. The other brands listed tend to ship dry compressed bales. Always check the product description to see which medium is best for your needs.
For an in-depth comparison on using on using peat vs coco coir, check out Planet Natural.
SOURCES
Higgins, A. “Is this popular gardening material bad for the planet?”. The Washington Post. 2017.
“Should I Use Sphagnum or Peat Moss?”. Sustainable Gardening Australia.
Diaz, et al. “COS 21-3: Sphagnum moss harvesting in southern Chile: Capacity building for peatland management and conservation” 2008.
Diaz et. al. “Improving harvesting techniques to ensure sphagnum regeneration in Chilean peatlands”. 2012.
“Coco Coir vs Peat Moss”. Washington State University. 2018.
Vinje, E. “Coco Coir or Sphagnum Peat Moss?”. Planet Natural.
“Philodendrons, Elephant Ears, and Other Aroids forum: What is Chunky Aroid Mix and why do I need it?”. Garden.org.
As always, I’m @_plantedparenthood if you want to DM me with any questions. Happy planting!