Peat Moss

If you garden, you’ve heard of peat moss. But what is it, really? And what role does it play in our gardens? Let’s find out!

'Sphagnum flexuosum' (James Lindsey) CC BY-SA 3.0

Peat v. peat moss
 
First, peat and peat moss are not the same thing.
 
Peat moss is a type of moss. Actually, several types.
 
And peat is a conglomeration of partially decayed organic matter that makes up bogs. Peat moss is a major component of peat, but not always.
 
Peat moss, the plant
 
Peat moss also goes by the name sphagnum. There are nearly 400 species of sphagnum moss. It can grow on pretty much anything.
 
Sphagnum has one rather odd characteristic: it alternates living cells with dead cells. Those dead cells are used to store water. Using this method, some mosses can absorb up to 20 times their own weight in water, which is why it is so popular in gardens.
 
How we use peat moss
 
Being able to hold so much water, peat moss helps keep our plants hydrated. Due to this characteristic, it is a common ingredient in potting soil and when growing microgreens. It is advertised as a soil amendment that improves soil structure and nutrient availability. You can overwinter tubers in a bucket of peat moss. Root cuttings are often stored in moist peat moss.
 
Contrary to popular opinion, adding peat moss (or pine needles) to your soil does not effectively alter its pH. That only works in laboratory settings and large-scale commercial enterprises.
 
Peat moss is used as fuel, in floral arrangements, and in crafts. Dried sphagnum moss has been used as a wound dressing. Note that peat moss can contain the fungus Sporothrix schenckii, which, according to the Centers for Disease Control and Prevention, can infect people with rose handler’s disease, or sporotrichosis, a potentially serious condition. As always, wash your hands after working with peat moss or in the garden.
 
But there is another problem associated with peat moss.
 
The problem with peat moss
 
Peat moss is harvested from peat bogs. Peat bogs cover approximately 3% of the Earth’s surface, store significant amounts of carbon dioxide, and are home to countless wildlife species.
 
Technically, peat bogs and peat moss are renewable resources. Some companies harvest peat responsibly, while others do not. [How can we tell by looking at a bag in the store?] It takes one year to generate one millimeter of peat on average. And we are using it at ever-increasing rates.
 
Instead of using peat moss to improve your soil, opt for more sustainable materials, such as aged compost, wood chips, coconut coir, and even shredded paper. These materials can be added to potting soil or used to top dress a garden bed without the drawbacks associated with peat moss.