Cotton Compostability
Cotton Compostability: Turning Textile Waste into Value
Cotton is a remarkable textile. Grown from sun, soil and water, cotton is a drought tolerant crop with a small water footprint. Unlike synthetic fibers, cotton’s natural fibers do not shed microplastics. Cotton fibers biodegrade in water,1 wastewater2 and soil,3 returning to the earth as a part of its circular journey.
Cotton waste can be valuable, with its ability to be turned into bioenergy, biofuel, biochar and even sugar for bio-based materials. It can also be composted, further demonstrating cotton’s circular lifecycle.
Composting is a sustainable solution for cotton at the end of its life, transforming scraps into nutrient-rich organic matter in less than 90 days.
What is Composting?
Composting is the process of converting organic matter into a nutrient-rich fertilizer. This is often done with organic materials like yard waste, plants or food waste. When it comes to textiles like cotton fabric or clothing, composting is defined more specifically. The Federal Trade Commission’s Green Guides, which provide guidance on environmental terminology and use, state that to claim a product as compostable:
- It should be clear whether the product can be composted at home or requires an industrial composting facility.
- The product must fully degrade into organic materials within a similar timeframe to other compostable materials in the facility.
- The resulting compost should be usable and free from inorganic or toxic materials.
Composting Fabric: Studies Show How Textiles Break Down in Soil
Compostable fabrics, therefore, must be made of biodegradable, natural materials that do not produce microplastics or release toxins. As a natural fiber, cotton has the ability to meet these criteria.
In a study from Cornell University in 2010, cotton and polyester were compared for biodegradability in both lab and industrial composting environments. Cotton fabric samples experienced significant biodegradation, with up to 77% weight loss within 90 days, while the polyester samples showed minimal degradation.3
Research around composting cotton is ongoing. In a 2023 study conducted by Cornell University, denim jeans (made of both cotton and synthetic materials) were buried in a compost pile. The cotton began to biodegrade within a month, and within 5 months, only the synthetic material remained.4
Unless Collective, a small brand focused on eliminating plastic waste in fashion, conducted a similar study. They sent 2,000 pounds of garment production cut waste to Agromin, a commercial composting facility. The composting test pile was checked within a month, and the fabric scraps were shown to have partially degraded. After seven weeks, the compost was separated into two piles so that any larger, undegraded pieces would continue to compost for a future batch. This study demonstrated to Unless Collective that composting is a viable option for their fabric scraps.
To learn more on the compostability of cotton, watch this webinar: Recent Webinar | Closing the Loop: Cotton Composting for a Circular Textile Economy | CottonWorks™.
Why is Cotton Composting Important to the Textile Industry?
Textile waste accounts for nearly 6% of municipal waste in the U.S., much of which includes non-biodegradable synthetic materials. To combat the waste and pollution often associated with the textile industry, circular, end-of-life solutions are needed. The studies above confirm that cotton can return to the earth, showcasing its potential, with the appropriate infrastructure, as a truly circular textile.
Do Consumers Care About Cotton Composting?
Globally, 86% of consumers are concerned about sustainability.5 According to Cotton Incorporated’s Global Sustainability Survey, 58% of consumers consider sustainability in their apparel buying decisions. This shift in consumer purchasing habits towards sustainability is evident, with an increasing preference for sustainable products. Consumers recognize compostability as a crucial aspect of sustainability. In the packaging industry, consumers rate compostability and plant-based packaging as the most sustainable option. Although composting textiles isn’t standard practice yet, consumers increasingly associate material compostability with sustainability, influencing their buying decisions.
Cotton offers many sustainability benefits for manufacturers looking to meet the expectations of their consumers. Pursuing cotton compostability can increase cotton’s reputation as a sustainable material for a variety of products.
What are the Environmental Benefits of Cotton Composting?
Composting can play an important role in making the textile industry more sustainable. It offers many benefits, including reducing textile waste, recovering useful materials, reducing greenhouse gas emissions, enriching soil health6, and contributing to a circular economy.
Does Composting Cotton Reduce Greenhouse Gas Emissions?
In 2018, 11.3 million tons of textiles ended up in U.S. landfills. There is a pressing need to reclaim these materials. Even if a complete shift to natural materials were feasible (which is unlikely in the near future), it wouldn’t resolve the issue of textiles filling up landfills. The problem goes beyond resource inefficiency; it’s about what happens when materials are discarded from the value chain and buried in landfills.
Biodegradable waste such as food scraps, yard waste and paper, makes up over half of the municipal waste that enters landfills in America. However, being biodegradable doesn’t guarantee, or even suggest, natural decomposition in landfills. Landfills lack oxygen, leading to anaerobic decomposition. This releases greenhouse gases like carbon dioxide and methane into the atmosphere. This methane emission is significant, with landfills contributing 14% of global methane emissions. Methane is 84 times more potent than carbon dioxide over a 20-year period, making its mitigation crucial for meeting short-term climate targets.
The promising studies above show that diverting cotton from landfills can help reduce methane emissions. Composting cotton achieves the opposite effect by storing methane in the soil instead of releasing it into the atmosphere. Furthermore, it also helps to reduce greenhouse gasses because the improved nutrient profile enriches the soil.6
Cotton Composting for Soil Enrichment
When organic waste breaks down with oxygen and microbes, it transforms into useful nutrients that can support healthy soil.6 Carbon, nitrogen and other nutrients and minerals from the soil are used by the cotton plants throughout their growing cycle and are stored in cotton fibers, textiles and apparel, even as they are worn and used. When cotton products biodegrade, they revert to organic components.
When they’re composted, the nutrients stored in the fibers can be released and used to enrich soil. These nutrients can then be reabsorbed by subsequent crops, creating a natural, circular system—from plant to fabric to compost and back to soil—that supports the growth of future plant generations.
Opportunities and Challenges in Cotton Composting
Recycling cotton waste for composting presents an opportunity to divert textiles and clothing from landfills, promoting waste reduction and supporting a circular economy. This concept is strongly aligned with the sustainability goals of the textile industry, fostering responsible practices that reduce environmental impact. Municipal composting programs, including the curbside collection of organic waste, encourage community-wide composting efforts, effectively reducing landfill waste and promoting sustainable waste management practices.
However, cotton textile composting poses its own set of challenges. The logistics associated with the collection, sorting, and transportation of cotton textiles at their end-of-life stages can be complex and costly. It is essential to ensure that cotton waste is free from synthetic material contamination, such as polyester, as non-compostable elements can disrupt the composting process. Education and infrastructure development are also key areas that require attention to fully unlock the potential of cotton textile composting.
Moreover, cotton composting offers a solution that extends beyond waste reduction. It addresses broader environmental issues such as climate change and soil degradation, making it a crucial component of regenerative agriculture practices. These efforts pave the way for the development of sustainable communities and a circular economy that values resource efficiency and waste reduction.
Select composted denim debris after 5 months
Cotton Composting for a Circular Textile Industry
As it stands, most cotton ends its life in a landfill, where it will break down slowly and cease to serve any further purpose. However, by composting cotton, the linear system is disrupted, and valuable materials are recovered.
Choosing cotton is a step towards embedding sustainability into the apparel, textile, and nonwoven industries. Cotton not only sequesters carbon throughout its lifecycle (as both a crop and a product), it also does not shed harmful microplastics. At the end of its life, cotton is biodegradable, and through composting it can return helpful nutrients to soil.
While composting cotton textiles is not yet widely practiced, there is significant potential to turn textile waste into a valuable commercial product that supports a circular economy. However, this first requires a shift towards choosing cotton for textiles and reducing the reliance on synthetic materials wherever possible.
Learn more about cotton biodegradability and connect with cotton suppliers. If you’re interested in learning about sustainability at the beginning of cotton’s life, discover resources about regenerative agricultural practices.
1. Zambrano, M. C., Pawlak, J. J., Daystar, J., Ankeny, M., Goller, C. C., Venditti, R. A., & (2020). Aerobic biodegradation in freshwater and marine environments of textile microfibers generated in clothes laundering: Effects of cellulose and polyester-based microfibers on the microbiome. Marine Pollution Bulletin, 151. https://doi.org/10.1016/j.marpolbul.2019.110826
2. Smith, M. M., Zambrano, M., Ankeny, M., Daystar, J., Pires, S., Pawlak, J., & Venditti, R. A. (2024). Aquatic aerobic biodegradation of commonly flushed materials in aerobic wastewater treatment plant solids, seawater, and lakewater. BioResources, 19(1), 1150-1164. http://doi.org/10.15376/biores.19.1.1150-1164
3. Li, L., Frey, M., & Browning, K. J. (2010). Biodegradability Study on Cotton and Polyester Fabrics. Journal of Engineered Fibers and Fabrics, 5(4). https://doi.org/10.1177/155892501000500406
4. Schwarz, M., Alwala, W., Perju, A., Bonhotal, J., Frey, M., Pires, S., Ankeny, M., & Daystar, J. (2024). The Effect of Denim Fabric as a Feedstock in Large Scale Composting of Manure/Bedding and Food Scraps. Compost Science & Utilization, 31 (1-2), 61-73. https://doi.org/10.1080/1065657X.2024.2349081
5. Cotton Incorporated and Cotton Council International. (2017). Sustainability: Concerned Customers. Cotton Incorporated Lifecycle Monitor. https://www.multivu.com/players/English/7972231-cotton-incorporated-global-sustainability-environment-survey/docs/SustainabilityConc_1512674738005-1565005957.pdf
6. Ho, T. T. K., Tra, V. T., Le, T. H., Nguyen, N. K. Q., Tran, C. S., Nguyen, P. T., Vo, T. D. H., Thai, V. N., & Bui, X. T. (2022). Compost to improve sustainable soil cultivation and crop productivity. Case Studies in Chemical and Environmental Engineering, 6. https://doi.org/10.1016/j.cscee.2022.100211
