June 18, 2024

First denim brand to successfully grow greenhouse cotton

4 min read

G-Star has unveiled its latest denim innovation, “Homegrown Denim”: a pioneering scientific collaboration with Wageningen University & Research (WUR) and Dutch Cotton. This experiment, funded by G-Star, explores how greenhouse-grown cotton could help drastically reduce the impact of cotton growing worldwide, and presents these findings for the benefit of the whole industry.

The challenges

Cotton is an easy crop to grow, but requires a lot of agricultural space and can take up to 10 000 litres of water to produce 1 kilogramme of cotton. Besides this, cotton growing also relies on a very specific warm climate, making cotton fields the starting point of a long and complex supply chain.

To add to these challenges, the global demand for responsible cotton is growing rapidly, but there is a huge shortfall. What if cotton could be grown better, anywhere?

“G-Star’s curiosity and drive for innovation led us to our partnership with Wageningen University & Research to study the feasibility of growing cotton in a greenhouse. This groundbreaking experiment could revolutionise cotton production by severely decreasing water consumption and land use, eliminating the use of chemical pesticides, improving the quality of cotton and drastically shortening the supply chain,” according to Rebecka Sancho, head of Sustainability at G-Star.

The research

For six months, a crop of greenhouse-grown cotton was studied at a research facility in Bleiswijk, the Netherlands. The research examined quality, yield and fibre properties, comparing its environmental footprint to traditional methods. Strategies like precision irrigation and renewable energy were explored for reducing impact, with economic viability and market potential also analysed.

The result: The first Dutch greenhouse-grown cotton

Overall, it was discovered that growing cotton in a greenhouse provides a controlled and protected environment that boosts crop productivity, quality and sustainability, and lowers the risks that come with outdoor growing.

Here are the top 8 benefits that were found:

  • Increased yields – Greenhouses boost cotton yield potential, with plants growing up to 4 metres tall and producing five to 23 times more cotton.
  • Extended growing season – Controlled environments in greenhouses enable cotton harvesting until for longer than usual.
  • Weather protection – Greenhouse-grown cotton is cleaner and whiter, with minimal contamination, and is shielded from weather damage.
  • Pest and disease management – Enclosed environments naturally deter pests and diseases, eliminating the need for synthetic pesticides.
  • Water efficiency – Greenhouse systems can save up to approximately 95% of water per kilo of cotton by using recycled rainwater for irrigation.
  • Soil conservation – Potted cultivation minimises soil erosion, preserving fertility and health without compromising quality.
  • Localised production – Greenhouses support local economies and sustainability by minimising transportation needs and enhancing community resilience.
  • Prolonged plant lifespan – Greenhouse environments enable multi-seasonal plant cultivation, improving sustainability and productivity.

“The biggest surprise for me in this research was how much cotton you can grow with how little water. We were able to harvest five to 23 times as much cotton with up to 95% less water,” notes Filip van Noort, crop specialist at WUR.

The supply chain

With greenhouse-grown cotton in place, G-Star joined forces with local suppliers to create the first ever fully locally sourced and manufactured jean. Every aspect of cotton processing and production of the garment was completed within the country: from ginning (separating cotton from its seeds) to spinning, weaving, sewing, dyeing and finishing. In addition, G-Star used electric vehicles between suppliers, creating the shortest possible supply chain with the least impact.

“This research allows us to rethink the way the entire industry is set up. And that is exactly what we need to do to find new and effective ways to improve our impact together. Therefore, getting involved in this project was an absolute must for G-Star, to support solutions for the future of denim,” comments Willeke Hendriks, chief product officer at G-Star.

The jeans

G-Star prototypes were created from the first greenhouse-grown cotton harvest. The jeans were garment-dyed and finished with G-Star trims. The limited pieces are not for sale, but will be available exclusively for press usage.

The future

This research and collaboration could be the first step in a promising journey toward more sustainable cotton growing. G-Star has committed to support the next phase for which new cotton is currently being cultivated in the greenhouse facility in collaboration with WUR.

G-Star and WUR have also invited two new partners, InnoGrowers and substrate company Grodan, to transition the research efforts into practical cultivation and scale up production. In addition to optimising growing methods, the primary goal this year is to enhance cotton yield per square metre, aiming to increase it from 1.2kg to 2.2–2.5kg. The next phase involves inviting other industry stakeholders to join forces, co-invest and amplify efforts – generating substantial impact and reshaping the fashion supply chain for the collective good.

The full findings report can be accessed here.

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