First published November 2008, updated January 2011

Peat, which forms in wetlands, is a deposit of partially decayed vegetation matter. Peat moss (Sphagnum) commonly grows in peat bogs.

Peat and peat moss is sought after by gardeners for adding nutrients to poor soil and to assist with water retention. Peat moss is used in some hanging basket liners and as biodegradble pots for seedlings. Peat is also used as a solid fuel once dried in many places around the world.

The problem with peat

The wetlands (also known as peatlands) where peat is formed are unique ecosystems, so when it is dug up, those ecosystems are disrupted. As peat can take anywhere from a couple of hundred to thousands of years to form, the wetlands are pretty much irreversibly damaged. In the UK, most peatlands have now been destroyed and the government is taking action to preserve what remains. Peat deposits in southeast Asia could be destroyed within the next few decades

Peatlands are also massive carbon sinks - estimated to store anywhere up to 455 petagrams of carbon, which is 5 × 10 to the power of 11 short tons - in other words, a lot.

When peat is burned, it's like burning coal; much of the carbon content in the peat is released as carbon dioxide, the greenhouse gas of primary concern in relation to global warming. The burning of peat unlocks carbon that has been sequestered for centuries and by burning it faster than peat can be produced, we're just adding to our climate change woes.

The harvesting of the peat moss is also simply unsustainable. It's a slow growing plant and so much of it is needed to form the bricks that a favoured by gardeners.
 
According to data I found on Index Mundi, from the United States Geological Survey Mineral Resources Program, 936,000 tons of peat moss was imported into the USA in 2008 - that's an incredible amount of moss! In the same year, 6,100,000 tons of peat was consumed globally for horticulture and 16,100,000 tons for fuel use.

Peat alternatives

For the gardener, there's some good and economical alternatives to peat and peat moss.

The most popular choice is coconut coir, which is just a waste-product from coconut processing. It can be used as hanging basket liners, a potting medium, mulch cover or as a soil conditioner. Some research has also concluded that coconut coir is actually superior to peat moss and it retains more water. Bricks of coconut coir will expand up to 10 times their original size once soaked in water. Seed pots made from coconut coir are also available.

A replacement for peat itself is simple - compost - you can buy it (e.g composted manure) or make compost yourself - save some cash! Compost made from your kitchen refuse, bark chips or leaves are a good replacement.

Another alternative mulch material is cocoa-shell, which is a waste product from the production of chocolate. It has an added benefit of repelling cats.

Yet another alternative is dried alfalfa. Like peat moss and coconut coir, it retains a great deal of water and adds nutrients to the soil. Fine pine bark or pine straw is also said to provide good results.

For an ultra-rich soil conditioner, consider starting up a worm farm (aka vermicomposting) as the castings (worm poo) are prize fertilizers - worms will eat all sorts of household waste including cardboard and egg shells if you have children, they'll most likely love getting involved too!
 
Do you know of any other good alternatives to peat and peat moss? Please add them below.