Hemp Fibre

Industrial hemp is grown under legal restriction in essentially every jurisdiction that permits it at all. Typical elements of these regimes include licensing or registration of growers, restriction to approved varieties, limits on the plant’s cannabinoid content, and official sampling or inspection of standing crops. The particulars — which varieties, which thresholds, which authority, which paperwork — are set separately by each jurisdiction and are revised over time.

The consequence for the commodity is straightforward: hemp fibre supply is shaped by regulatory access as much as by climate or price, and a change in the rules can open or close a production region without anything agronomic having changed. This entry records that framing as a fact about the commodity and goes no further.

A hemp stem is a hollow cylinder: an outer layer carrying the bast fibre bundles, wrapped around a woody core known as hurd or shiv. The crop is grown densely and tall for fibre, since the object is a long, straight, unbranched stem, and it is cut rather than pulled — hemp stems are too tall and tough for the pulling that flax gets.

Hemp bast is not one thing. The bundles contain long primary fibres, which are what the traditional cordage and textile trade wants, and shorter secondary fibres formed lower down and later; separation quality determines how much of each ends up in a saleable stream. Hemp fibre is naturally coarser and less fine than flax, which is why the two are complements in the market rather than substitutes: linen’s territory is fineness, hemp’s is strength and durability.

As with flax, the fibre must be released from the core by retting, most commonly dew retting in the swath, where microbial action breaks down the pectins binding bast to hurd. The judgement is the same and the penalties are the same: too little retting and the fibre will not separate cleanly, too much and the fibre itself is degraded. Hemp’s heavier, coarser stems ret less evenly than flax straw, which is one reason hemp fibre quality has historically been more variable.

Retted straw is baled and taken to a decortication line, where mechanical breaking and beating shatter the hurd and separate it from the bast. What emerges is a fibre stream and a hurd stream, and both are sold. Hurd is produced in volume and has established markets in animal bedding, construction materials, and absorbents — enough that some hemp processing is run with the hurd stream firmly in the commercial calculation rather than treated as leftovers.

Buyers assess fibre length, fineness, strength, colour, cleanliness, and residual hurd content, with the intended application setting which of these dominates. A composites manufacturer cares about strength, consistency, and freedom from hurd; a textile spinner cares far more about fineness and length; an insulation or paper user tolerates a coarser, shorter product. There is no single international grading standard for hemp fibre, and specifications are set contract by contract.

• Cordage, twine, and rope — the traditional use, built on fibre strength
• Technical textiles, geotextiles, and nonwovens
• Composite reinforcement in moulded and pressed products
• Speciality paper and pulp
• Coarse apparel and household textiles where fineness allows

Uneven retting, high residual hurd, inconsistent fibre length, and contamination are the faults that recur across all of these markets. Because supply chains are small and fragmented relative to cotton or jute, consistency between lots is itself a quality issue for industrial buyers.