Hemp versus cotton: what the water and pesticide claims actually have to mean

Hemp is having a moment in sustainable fashion. Brands describe it as a low-water crop that needs almost no pesticides. Some of that is true. Hemp is a hardier plant than conventional cotton, and it generally needs less chemical input to grow. But "generally" is doing a lot of work in that sentence.

A fiber's footprint at the farm is one part of the story. What happens after the farm is another. And a brand saying its fabric is hemp — or organic cotton, or any other "natural" fiber — is not the same as a brand proving it.

What conventional cotton actually involves

Conventional cotton is one of the more chemically intensive crops grown at scale. It uses synthetic pesticides and synthetic fertilizers. Some of those inputs end up in soil and waterways. Some stay in the fiber and travel through the supply chain.

That is why the farm story matters. It also explains why a certification like USDA Organic, administered by the U.S. Department of Agriculture, is meaningful. USDA Organic prohibits synthetic pesticides, synthetic fertilizers, and genetically modified seeds. It sets real rules for how the cotton is grown and requires independent verification. It is not a brand promise. It is a documented standard with audits behind it.

The catch, as we have written before, is that USDA Organic stops at the farm gate. It certifies the fiber. It does not follow the fabric through spinning, dyeing, or finishing. A cotton garment can carry a USDA Organic fiber claim and still be dyed with chemicals that have no place near skin.

Where hemp sits in this picture

Hemp tends to grow well with fewer inputs than conventional cotton. It can also return nutrients to soil and grows densely enough to crowd out weeds without herbicides. Those are real agronomic advantages.

But hemp is not automatically certified organic. It is not automatically processed cleanly. A hemp shirt from a brand with no third-party standard behind it could still be finished with synthetic dyes, processed in a facility with no wastewater controls, and sewn by workers with no labor protections. The fiber being hemp does not change any of that.

What GOTS verifies across both fibers

This is where the Global Organic Textile Standard, or GOTS, becomes the right tool. GOTS is administered by the Global Organic Textile Standard International Working Group. It covers both hemp and cotton. And it does not stop at the farm.

To carry the GOTS label, a product must meet requirements at every stage of processing — not just at the source. That includes:

• Chemical inputs — synthetic dyes and finishing agents that are common in conventional textile production are prohibited or tightly restricted.
• Wastewater — facilities must treat wastewater before it is discharged. This is audited, not assumed.
• Social criteria — safe working conditions, fair pay, and the right to organize are required at every certified facility. Child labor and forced labor are prohibited.
• Traceability — each step of the supply chain must be independently certified. A brand cannot certify only the part it controls.

Independent certification bodies audit each facility. The brand does not grade its own work.

Why this matters when you are comparing fibers

Hemp and certified organic cotton are both better starting points than conventional cotton. That is a real distinction. But the fiber is just the beginning. Processing is where clean claims often fall apart — and where most brands go quiet.

When we evaluate materials at Poplar & Main, we look for a verifiable standard behind the claim, not just the claim itself. GOTS and USDA Organic are two we trust because they set documented requirements and require outside auditors to confirm them. Neither lets a brand be the judge of its own practices.

A greener fiber is a good start. A certified supply chain is what makes the start mean something.