Wool is part of the natural carbon cycle. Many textiles and fibres are made from carbon-based products, but only some, such as wool, are made from renewable atmospheric carbon. When wool is discarded, it will naturally decompose into the earth over months or years, slowly releasing important nutrients back into the soil. So wool acts like a fertiliser by slowly releasing valuable nutrients and carbon back into the earth.
How does wool biodegrade?
All materials from animal and plant origin have some element of biodegradability, meaning that they are able to decompose through the action of living organisms, such as fungi and bacteria.
Wool is composed of the natural protein keratin, similar to the protein that makes up human hair. When keratin is broken down naturally by microorganisms, the products do not pose any environmental hazard.
How long does wool take to decompose?
Wool biodegrades readily in as little as three to four months however the rate varies depending on soil, climate and wool attributes. This process releases key elements such as nitrogen, sulphur and magnesium back to the soil, which can be utilised by growing plants.
What are the best conditions for wool to biodegrade?
The unique outer structure of woollen fibres (keratin) are tough and water-repellent making them an extremely resilient and durable fibre in normal conditions. However, when disposed woollen fibres will easily biodegrade in warm, moist conditions and if buried in soil, fungal and bacterial growths develop which produce enzymes that will digest the wool.
In comparison, cotton takes at least five months to biodegrade and while still relatively good, slightly longer than wool. And, comparing wool to polyester fibres, well unfortunately, polyester fibres have a much harder time decomposing. They do eventually break down, but it does take many decades for the polyester fibres to do so.