Peat moss has been the staple soil amendment for home gardeners, commercial nurseries and growers since the mid-20th century. However, in recent years, it has come to light how detrimental widespread reliance on peat moss can be for our ecosystems. This article explores the urgent need to continue to support efforts to regenerate peatlands and presents six renewable alternatives that can help farmers and gardeners maintain healthy soils while preserving precious peatland ecosystems.
But first, what exactly is peat moss?
Peat is composed of decomposing organic matter, primarily from sphagnum moss species. It forms in wet, marshy areas known as peatlands or peat bogs.
Peat moss is highly valued in gardening and farming for its exceptional water-holding capacity and light, airy texture, making it an ideal medium for starting and sustaining plants. Its low cost and widespread availability have made it a popular choice for potting soils, seed-starting mediums, and as a carrier for inoculums and fertilizers.
Peatlands provide critical ecosystem services such as water filtration and groundwater recharge, and are home to many endangered species of flora and fauna. The economic value of these ecosystem services is significant.
Peatlands are also critically important in global carbon cycling. Despite covering less than 5% of the world’s land area, peatlands store nearly one-third of the world’s soil carbon, twice as much as global forest biomass. It is also one of the most stable forms of soil carbon. One-quarter of global peatlands are located in Canada, highlighting a significant opportunity for Canada to mitigate carbon emissions by both reducing peat reliance and increasing efforts to regenerate peatlands.
The Problems with Peat Harvesting
To harvest peat moss, peat bogs must be drained, releasing vast amounts of accumulated carbon dioxide (CO2) and methane (CH4) into the atmosphere, contributing to climate change, and turning peatlands from a carbon sink to a carbon source.
Peatland disturbance also disrupts the fragile ecosystems that reside there. It can take one thousand years or more for a disturbed peat bog to replenish itself naturally, making peat moss a non-renewable resource. However, over the last several decades, there have been significant advances in terms of efforts to regenerate peatlands. Researchers have learned to replant the mosses with agricultural machinery to restore peatlands on a landscape scale. Regeneration Canada hosted a Living Soils Symposium session on the topic of wetland regeneration in 2021.
While the regeneration of peatlands is encouraging, the intensive use of peat in agriculture and horticulture is unsustainable.
“Most of our crop production starts with planting a seed and no food system can be truly regenerative if it relies on non-renewable resources.”
– Rosina Rodighiero, Sustainable Agriculture and Food Systems graduate from Kwantlen Polytechnic University
Encouraging a Shift: Peat Alternatives
Recognizing the detrimental effects of peat moss harvesting, some countries are taking action. The United Kingdom, for instance, plans to ban certain peat-containing products by 2027, with a complete prohibition set for 2030. While the conversation on peat moss has yet to progress towards bans or regulations in Canada, encouraging a consumer shift away from peat now may ignite those discussions in the near future.
Finding ready-made peat-free potting soil mixes locally can be challenging. Gail Winters, a member of Regeneration Canada, recommends this one which is local to Ontario. Another option is to mix your own potting soil.
With this in mind, here are six renewable substitutes for peat moss shared by members of Regeneration Canada that can help you create a more regenerative garden or farm:
1. Coconut coir
Coconut coir, also known as coco peat, is made from the outer husks of coconuts, a by-product of the coconut industry. It is currently arguably the best and most common alternative to peat moss on the market.
Some studies have shown that vegetable crops grow similarly or even better in coconut coir-based mixes than peat-based ones. Coconut coir can be processed in varying sizes, from dust to bark. It is also priced affordably and widely available for home gardeners and horticulturists. As such, coco peat is an easy swap for peat moss.
Advantages:
● Water Retention and Aeration: Coconut coir retains moisture well and provides superior aeration.
● pH Neutral: Unlike peat moss, coconut coir is pH neutral, making it suitable for a wider range of plants.
● Renewable: It utilizes a waste product from coconut harvesting.
Considerations:
● Environmental Impact: The processing and transportation of coconut coir can be environmentally taxing, as it must be transported from tropical regions. Even so, coconut coir is a renewable by-product of coconut harvest that already occurs for food and fiber products, and thus makes use of an otherwise wasted material.
2. Compost
Compost, a.k.a. “black gold” is a nutrient and microbe-rich material that is a great addition to potting soil mixes.
Advantages:
● Nutrient-rich: Provides nutrients and supports beneficial microbial activity, which helps break down organic matter and release nutrients slowly over time.
● Adds Organic Matter
● Affordable and Accessible: Can be purchased from garden centers or farmers or made at home. Some city landfills also offer compost at low or no cost to city residents.
Considerations:
● Homemade Options:
○ Backyard compost bins are widely available and easy to manage. Some cities even offer compost bin rebates or discounted compost bins, so check your city’s website before purchasing.
○ Vermicompost
Paige purchased this backyard compost bin recently and loves it.
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Paige’s indoor vermicomposter. Photo: Paige Fehr
Vermicompost can also be used in potting mix recipes and is a great way to turn kitchen scraps into plant food. In fact, I added some worms from my homemade vermicomposter (lovingly referred to as my ‘closet worms,’ pictured on the left) to my backyard composter for the warmer months.
For our adventurous compost guru readers: you might also be interested in building your own backyard Johnson-Su bioreactor to produce plenty of fungally-dominant compost of your own.
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Application Mixes containing compost and coconut coir are often good for seed-starting. Try mixing a ratio of 3:1 coconut coir to compost and adjust accordingly. |
3. Sand
Good quality potting soil should retain moisture, while still being well-draining. These traits allow seedlings access to oxygen and moisture, both of which are necessary for germination and successful growth. Adding coarse sand to potting mixes provides good drainage and aeration, and can be a suitable peat substitute for these purposes.
Advantages:
● Good Drainage: Enhances soil drainage, preventing waterlogging.
● Aeration: Improves soil aeration, which is vital for healthy root development.
Considerations:
● Weight: Sand is much heavier than peat, which can be a drawback for large pots or containers that need to be moved.
● Sterility:
○ Horticultural sand is typically sterile, but more expensive and difficult to source.
○ Builder’s sand is a cheaper option but is typically non-sterile so may harbour bacteria.
○ Play sand is an affordable option that is often sieved for impurities and sometimes cleaned or sterilized. Both play sand and builders sand are available to purchase from most hardware stores.
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Application For veggies, try a 2:2:1 coir-to-compost-to-sand ratio. |
4. Biochar
Biochar is a carbon-rich, renewable resource made from burning organic materials in the absence of oxygen. Biochar can be made from hardwood, softwood, rice hulls, green waste, tree bark, sugarcane, etc.
In potting mixes, biochar is an effective alternative to peat moss and does not necessarily require pH adjustment. It has also been shown to improve the nutrient content of potting mixes compared to using peat moss.
Advantages:
● Nutrient Retention: Enhances nutrient retention in soil, improving fertility.
● Sustainable: Made from waste organic materials like wood chips, crop residues, and other biomass.
● Soil Health: Promotes beneficial microbial activity and soil structure.
Considerations:
● Requires Pre-Charging: Before using biochar, it should be charged by mixing it with compost and allowed to sit for about 10 days. This step prevents the biochar from prematurely depleting the soil’s nutrients during plant growth. Properly conditioned biochar will optimize nutrient retention and the overall health of the growing medium.
Biochar also appears to be a promising substitute as a carrier agent for inoculum or fertilizers. In these cases, the fertilizer or inoculant product is mixed with biochar and then seeds are coated in the mixture.
While biochar is on the pricier side when it comes to peat moss alternatives, it is widely available and can be purchased at many hardware stores.
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Application Biochar can be incorporated at a rate of 2-10% in the top 6” of your homemade potting soil mix. |
5. Leaf Mold
When raking up leaves next fall, perhaps consider saving some for your compost pile. Leaf mold, made from partially composted leaves, can reach a similar consistency to peat moss over six months to a year.
Leaf mold differs from compost in that it is made up of only leaves and is fungal-dominant, whereas the green matter involved in typical compost systems encourages greater bacterial growth. Leaf mold improves the water-holding capacity of a potting mix as well as adds valuable organic matter, supporting beneficial microbial activity.
Leaf mold has been shown to perform similarly to peat moss when used in combination with compost in seed starting media. This makes it an excellent, budget-friendly alternative to peat moss. This option is particularly beneficial for small-scale farmers and backyard gardeners. The key requirement for this substitute is patience.
Advantages:
● Improves Soil Structure: Enhances soil texture and moisture retention. Adds organic matter
● Supports Beneficial Microbial Activity
● Sustainable: Utilizes fallen leaves, a readily available resource.
● Free renewable resource
Considerations:
● Production Time: It takes six months to a year to produce, requiring planning ahead.
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Scott’s modified Johnson-Su bioreactor set-up. Photo credit: Scott Hortrop
Creating leaf mold is straightforward. Collect fallen leaves and place them in a pile, a bag, or a bin, ensuring they are kept moist. Over time, the leaves will break down into a rich, crumbly material.
Scott Hortrop, member of Regeneration Canada, is using modified Johnson-Su bioreactors to produce compost and leaf mold from local fall leaves. At the end of the 19-month composting cycle, Scott makes a compost extract to apply to his crop in-furrow or via foliar spray. Earlier in the cycle, the leaves reach a leaf mold state that can be used as a peat moss alternative.
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Application In garden beds, leaf mold can be mixed into the top 6″-12″ of soil to improve soil texture. |
6. Hemp Mulch
Hemp mulch, also known as hemp straw, is a commercially available alternative to peat moss. It is processed from residue left over after harvesting hemp.
Hemp fibers are strong and slow to break down, with high water-holding capacity. Due to its water-holding capacity, hemp straw is reported to be especially effective in sustaining plants in times of drought.
Hemp compost, a mixture of hemp straw and cattle manure, has been shown to support significantly greater plant growth compared to conventional, peat-based potting soil mixes.
In the world of peat moss alternatives, hemp appears to be a newer option on the market and remains on the more expensive end of the spectrum as well. Additional studies are currently underway to further understand the potential for replacing peat moss with hemp straw in horticultural settings.
Advantages:
● Water Retention: High water-holding capacity, helping sustain plants during droughts.
● Durability: Strong fibers break down slowly, providing long-term benefits to soil structure.
Considerations:
● Cost: Hemp mulch is relatively new and can be more expensive compared to other alternatives.
● Availability: Additional studies are ongoing to understand its full potential, and availability may vary.
Regeneration Canada member David Ryan is currently testing out hemp mulch as an organic and water-holding amendment on his vegetable operation on the Sunshine Coast of B.C.
By making conscious choices in our farming and gardening practices, we can collectively contribute to preserving delicate peatland ecosystems and mitigating climate change.
Have another idea for a peat moss alternative? Want to share your first-hand experience with making your own peat-free mix? Shoot us an email at communications@regenerationcanada.org. We’d love to hear from you!
Special thanks to our amazing Regeneration Canada members: Scott Hortrop, David Ryan and Gail Winters who shared their knowledge on our online member community Hylo for this blog.
