Sphagnum moss is a type of moss that grows on the surface of soil or swamp. It has pliable, long spongy fibers that give it a soft and fluffy texture. Sphagnum moss is commonly used as a soil amendment because of its excellent water retention properties. It can hold up to 20 times its weight in water, making it ideal for plants that require a moist environment. Harvesting Sphagnum moss has less environmental impact as it is typically carefully harvested in order to ensure the approximate 5-6 years regeneration cycle.
Sphagnum Peat Moss
Sphagnum peat moss, aka peat moss, on the other hand, is a decomposed layer of sphagnum moss that has sunk below the surface of the plant. It has shorter fibers and a finer texture than sphagnum moss. Most of the peat moss sold in the US is harvested from the peatlands of Canada, northern US, or sourced from New Zealand.
Peat moss is a non-renewable resource and has significant environmental impacts when harvested. The bogs in which it grows are known for absorbing high amounts of carbon, helping to slow climate change. However, when peat moss is harvested, the process releases more carbon into the air, and it removes the resource that helps to absorb said oxygen, making it an unsustainable resource. Peat moss is also VERY slow growing due to the rate of decomposition which happens slowly from lack of air, so it takes generations to regrow peat moss bogs. According to several research studies, it can take from 5, to up to 20 years after the peat moss is harvested to return to an ecologically balanced environment. Furthermore, peat itself takes 15 to 25 years to form only a one-inch layer. Due to these reasons, gardeners choose to use more sustainable options, such as coco coir, as a substitute.
Purpose of Adding Peat Moss or Sphagnum Moss
The main purpose of adding peat moss or sphagnum moss to your soil mixture is to improve water retention. Both types of moss are ideal for plants that prefer a moist environment. However, depending on the pH level of the soil you are trying to achieve, using sphagnum moss is ideal for an alkaline environment, while peat moss is more acidic and can be used to neutralize or acidify your soil mix.
Another benefit of using either material is that they don't compact, which helps to protect your plant roots. However, if you plant solely in peat moss without other additives, this material can eventually become compacted. On the other hand, sphagnum moss creates an ideal environment for root growth and is commonly used when propagating plants. Additionally, it's important to note that peat moss lacks nutritional benefits. You cannot plant in just peat moss and expect healthy growth for your plant. Instead, you must add nutrients to peat moss to obtain an ideal environment for your plant.
Peat Moss Drawback
An additional drawback of peat moss is its longevity. After approximately 2 years, peat moss begins to dry out and become hydrophobic, making it impossible for your plant to absorb water no matter how much you may try to add. Because of this, you will need to change or refresh your plant's soil to help prevent soil compaction and root rot.
In summary, when deciding between sphagnum moss or sphagnum peat moss, it's essential to think about what specific environment your plant needs and decide from there. If you're concerned about sustainability and environmental safety, we recommend against using peat moss and substituting for a more sustainable option such as coco coir.