Sphagnum moss is a garden product commonly used for its ability to retain water. It was once considered to be a green product because it was believed that it could be sustainably harvested from peatlands, but is becoming clear that when peatlands are restored after commercial harvesting, their characteristics change dramatically for many years. Fortunately, there are many alternatives to sphagnum moss, depending on the application.
One of the most common uses of sphagnum moss is to line metal plant baskets. In this capacity, the water-holding characteristics and stringy, tough fibers are vital to ensuring a good result. Long coconut coir fibers or woven mats, sheet moss, sections of used carpet pads cut to size or even plastic sheeting and newspapers can be used in much the same way. Plastic won't drain as well as the other materials, so be sure to leave an opening at the bottom of the basket for drainage.
Many orchid species cannot live without well-oxygenated roots -- they grow outside of the soil in a state of nature. Sphagnum is sometimes used as a growing medium for these epiphytic orchids because it is capable of keeping moisture near their roots without depriving them of oxygen. Mixes made of high levels of very coarse bark, charcoal, peat and perlite are excellent substitutes if your garden pantry is well-stocked.
Sphagnum is commonly used in seed-starting mediums for its ability to inhibit the fungus associated with damping-off disease in seedlings. Unfortunately, in this capacity, it has no equal, but inorganic products like sand, perlite, vermiculite and rockwool will increase drainage to help prevent the fungus from gaining a foothold. When using inorganic amendments in place of sphagnum, ensure you water them regularly and often, since they are unable to retain water for long.
Sometimes, dried sphagnum moss is ground and added to general-purpose soil mixes to help aerate the soil and hold onto moisture, much like its more degraded form, known as peat moss. Coconut coir powder will do the same job, is easier to wet and has a more neutral pH, but cotton gin trash or composted rice hull also make suitable substitutes. All of these products are the by-products of industry, making them inexpensive and readily available.
- Washington State University Extension: The Myth of Permanent Peatlands
- University of Florida IFAS Extension: Fact Sheet: Container Gardening
- Purdue University Cooperative Extension Service: Hanging Baskets
- University of Minnesota Extension: The Moth Orchid Takes Off
- University of Arkansas Cooperative Extension Service: Growing Media for Container Production in a Greenhouse or Nursery
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