Hemp

Hemp fiber is inert cellulose against skin, non-leaching, and no different from cotton in that respect - the cotton page covers the finishing chemistry that applies to any plant-fiber garment. Two claims specific to hemp deserve correction. The first is that hemp fabric is naturally antimicrobial and odor-resistant. The peer-reviewed antibacterial literature on hemp is about plant extracts and isolated compounds - cannabinoids, essential oils, seed oils - not about processed fiber or finished fabric, and results are inconsistent, with several studies reporting no activity at all. The US FTC has treated the equivalent claim for bamboo-derived rayon as deceptive advertising. Treat hemp's odor reputation as unproven. The second is that hemp needs no pesticides. It genuinely outcompetes weeds through dense fast growth, but the research is explicit that no evidence was found of the plant itself inhibiting insects or diseases, and hemp hosts plenty of pests - russet mite, aphid, flea beetle, armyworm. Part of why US fiber hemp carries so few chemicals is that so few are legally registered for it: the EPA has approved a single herbicide, ethalfluralin, for fiber hemp. Low-input is true; immune is not.

Nothing melts or migrates. Hemp burns rather than softening and takes hot washing well. As with cotton, the heat-sensitive component in a hemp garment is whatever synthetic was blended in for stretch.

Woven hemp has a visible slubby irregularity and a dry, crisp hand that softens as it breaks in; next to cotton of the same weight it feels stiffer and looks more textured. The label is the real test, because almost nothing sold as hemp is only hemp - blending with cotton is a technical necessity rather than a cost saving, since hemp's coarse stiff fibers spin badly on their own, and 55/45 or 50/50 hemp-cotton is the common construction. Watch also for the processing route. Mechanically processed hemp keeps the original bast fiber; regenerated cellulose spun from hemp pulp is not that fiber at all, and under US labeling rules any regenerated cellulose must be called rayon regardless of which plant the pulp came from. A fabric legitimately labeled plain hemp should be mechanically processed. Ask a brand whether the fiber was dew retted, water retted or chemically degummed - chemical retting uses sodium hydroxide, sodium sulfite and sodium carbonate, sometimes with EDTA, and a brand that cannot answer probably does not know its own supply chain.

Hemp is regarded as among the strongest and longest natural fibers and outlasts cotton in the same construction, which is why it holds up in canvas, webbing and rope. It creases readily and takes normal hot washing. Fabric hand is governed by how far the technical fiber bundles have been split into single fibers, which requires pectin and lignin to be broken down - that is what hackling and retting are for, and it is why two hemp fabrics of the same weight can feel completely different.

Pure hemp is cellulose and biodegrades on the same terms as cotton, quickly and completely. A hemp-cotton blend is still entirely biodegradable; a hemp blend containing elastane or polyester is not, and leaves the synthetic behind. There is no meaningful recycling stream for hemp textiles - the honest end of life is compost or landfill, where it breaks down.