By Diane Kennedy, for Let’s Talk Plants! February 2023.
Peat-Free, Why and How?
Any gardener is familiar with peat moss, made of the decomposing plants called sphagnum moss, but few know that it is bad to use and why.
Peat comes from moorlands, peat bogs, in Canada, Europe, Africa and in the Eastern U.S.
Moorlands are extensive ecosystems made up of thousands of species of rare plants and animals that have adapted to highly acidic, slow-draining soils. Peat bogs are one of the largest carbon sinks on the planet, storing about 25% of the world’s soil carbon, higher than all of the forests combined.
Peat farming scrapes the peat down to dirt, and there is no replacing it, as they have evolved over at least 10,000 years. Removing a yard of it is removing 1000 years of accumulation. The scraped ground is left bare and this delicate and important ecosystem dies. Modern harvesting practices release a minimum of two billion tons of carbon dioxide annually. Peat has been used for fires and smoking grains by local humans for centuries; however, the extensive mechanized farming of it by the peat moss industry destroys far more than the selected digging of it by small groups of people.
Using peat moss is problematical as well. It’s used to acidify soil, to add air into potting mixes, and is used decoratively on houseplants. However, it has very low nutritional value for plants, and as it has antimicrobial properties, it actually slows the release of nutrients to plant roots. Microbes are what change dirt into soil. Over the course of a year peat breaks down and actually compacts soil, so is often used with vermiculite and perlite (both unsustainably mined products). Also, if peat moss isn’t kept wet it becomes hydrophobic, repelling water rather than retaining it.
The United Kingdom’s government plans to ban the sale of peat products in every garden center by 2024. So, what to do? Look for products labeled "peat free."
In the U.K., many companies are switching to bracken, which is a renewable resource.
The best substitutes that you can use are worm castings, good compost, and biochar. Coconut coir also works, but its processing is not eco-friendly.
It is easy to make your own soil-less potting and seed-starting mix. You want a mix that drains well but also holds air and water and supports a plant. Experiment with a mix of 20 – 50% high-quality screened compost made from yard waste and kitchen scraps, mixed with bio char. The air space that holds oxygen and water should be more than half the mix (you are buying 50 – 80% air when you purchase potting mix!) In your garden, use compost and ground pine needles to acidify soil to help acid-loving plants such as blueberries and camellias. By burying old wood in the soil (hügelkultur) you not only acidify the soil but hold rainwater and sequester carbon for use by plants. (Read Diane's November 2020 Hügelkultur article here for more information: PERMACULTURE: Hügelkultur - Burying Wood [sdhortnews.org])
You can find out more about peat at PeatFreeGardeningUSA.org, and a list of some peat-free mixes at Gardenista. Remember that even if a package says organic, it doesn’t mean that it is peat-free or sustainable. There is a wonderful documentary called Magical Moors that is as enlightening as it is beautifully filmed and watching it will help you realize the beauty of the disappearing peat bogs.