Keeping this short and simple - Yes, Tencel is 100% biodegradable/compostable. The fiber has a highly crystalline structure which means two things for us: it’s strong and does not biodegrade easily. The highly crystalline structure gives the end fiber an increased tensile strength that is stronger than cotton and other forms of regenerated cellulose fibers. However, having a highly crystalline structure also prevents it from easily biodegrading. While that might sound bad, it’s not. If consumers keep their clothes away from landfills, the high tensile strength of Tencel should give garments/products a long life! And because Tencel will biodegrade, when the fiber ends up in the ground, it will eventually do so! It just takes a little more time.
In surface soil, Tencel takes about 16 weeks to fully biodegrade. Rayon degrades in roughly 3 weeks and cotton in roughly 5½ weeks. If disposed in landfills, the amount of time is impossible to determine. The correct answer is: keep your items out of landfill by keeping them, selling them, donating them or disposing of them in other fashions. A few quick tips - ask the brand if they take back unwanted items, many (including us) do! You can also look for clothing bins!