One of wool’s greatest properties as a sustainable material is its biodegradability. Wool is made out of keratin, the same protein as human hair. Micro-organisms in soil or water can break down woollen matter and in turn, these micro-organisms also break down, sustaining a continuous biological life cycle.
In the right conditions, tests show that wool products will almost completely degrade after six months in the ground. Meanwhile, wool also biodegrades in aquatic environments. The latest research in New Zealand has demonstrated that by 90 days, different types of wool had biodegraded by 20%. In addition, wool can function as an effective soil conditioner and fertiliser, releasing sulphur, nitrogen, phosphorous and potassium as it biodegrades.
Wool’s biodegradation properties are in sharp contrast to synthetic fibres, which take much longer to break down and also release microplastics into the environment. Crucially, wool’s unique structure and water-repellent outer membrane mean that while a garment is being worn and cared for, the fibres are resilient and long-lasting. Wool starts to biodegrade in moist, warm conditions, which typically come into play after the lifetime of garments.