What Is Hemp?

How is hemp made?

Hemp is made by loosening the fibre bundles in the stems of the Cannabis sativa plant, most often by retting, then cleaning, combing or carding the fibres and spinning them into yarn.

The plant

Hemp is a bast fibre: it comes from the fibrous layer of the stem, as flax does for linen. The museum materials database CAMEO records hemp being cultivated in Asia for its fibre as early as 2800 BCE.

Hemp and marijuana are the same species; the line between them is legal. As of October 2026, US federal regulations define hemp as Cannabis sativa with a total delta-9 tetrahydrocannabinol (THC) concentration of no more than 0.3% on a dry-weight basis. Other countries set their own rules.

Retting

Retting frees the fibres from the stem. A 2022 review in the journal Materials lists five methods: dew, enzymatic, chemical, water and physical retting. Three matter most here:

• Dew retting: stems are left in the field for sun, rain and air to do the work. It is the most common method for flax and hemp.
• Water retting: stems are soaked, traditionally for 5 to 7 days. Most countries banned it from the 1960s to the 1990s over its wastewater and freshwater use.
• Enzymatic retting: takes 12 to 24 hours, but risks weakening the fibre and the enzymes are costly.

Decortication, mechanical stripping without retting, leaves impurities that need degumming before textile use.

From fibre to yarn

After retting, the stems are scutched to separate the fibre. Long fibres intended for finer textiles are then hackled, or combed. The short fibres left over from scutching are carded and spun into thicker yarns for thick fabrics. Hemp can also be cut and processed into cotton-like or wool-like fibres, so that it suits the spinning systems built for cotton and wool.

What are the properties of hemp?

Hemp is a strong, durable, lustrous and absorbent fibre that resists damage from water, light and insects, but it is somewhat stiff and is damaged by weak acids and bleaches.

• Strength: strong and durable, says CAMEO; the Materials review puts long hemp fibre's tenacity on a par with flax.
• Look: the fibre is yellow to brown and lustrous.
• Moisture: hemp takes up water and moisture readily.
• Stiffness: CAMEO describes hemp as high in cellulose and low in lignin, but the lignin it does contain stiffens the fibre and makes it harder to process.
• Resistance: it resists damage from water, salts, light, insects and alkalis, but weak acids and bleaches damage it.

CAMEO lists cordage, sailcloth, canvas and burlap among its uses.

What is the difference between hemp and linen?

Hemp comes from Cannabis sativa and linen from the flax plant; the two bast fibres are similar in structure, but hemp fibres are wider.

Under a microscope, CAMEO notes, hemp fibres are wider than flax, with a wide, flat central channel. Several other fibres also carry the name “hemp”, and the EU gives each its own legal name:

How is hemp graded or measured?

Hemp is described by the length, width and fineness of its fibres, and by whether it was spun from long or short fibre.

• Fibre length: CAMEO gives 1 to 2 m.
• Fibre width: 9 to 40 microns, averaging 25 microns.
• Fineness: the Materials review reports that a longer retting time gives a finer fibre, measured as lower linear density.

How does hemp appear on a clothing label?

In the EU, hemp must appear on the label as “true hemp” with its percentage by weight; in the US, it appears under its generic fibre name with its percentage by weight.

European Union

• Only the names listed in Regulation (EU) No 1007/2011 may describe fibre content. Hemp is listed as “true hemp”, the fibre from the bast of Cannabis sativa.
• Listed names may not be used for other fibres, even as a root or an adjective. A Manila hemp bag must say “abaca (Manila hemp)”.
• “100%”, “pure” or “all” is allowed only for products made exclusively of one fibre. Up to 2% of extraneous fibre is tolerated (5% for carded products) if technically unavoidable and not added routinely.
• Blends must give every fibre and its percentage by weight, in descending order.

United States

• Natural fibres must be identified by their generic names, with percentages by weight in descending order. The label must also name the manufacturer or give its Registered Identification Number (RN), and state the country of origin.
• Percentages may vary by 3%, but there is no tolerance when the label claims a single fibre, so “100% hemp” must be exactly that.
• The Textile Act does not cover tote bags or the textiles used in handbags, so a hemp tote bag needs no Textile Act fibre label in the US.

How do you tell good hemp from poor hemp?

Good hemp has a full fibre statement and a yarn that suits the cloth's weight; the label, not the look, tells you it is hemp.

1. Read the fibre line. In the EU, look for “true hemp” and a percentage. “Hemp blend” with no figures is not a full composition, because every fibre must be listed with its share.
2. Check which hemp. “Manila hemp” is abaca and “sisal hemp” is sisal, both leaf fibres from other plants. Neither is Cannabis sativa.
3. Don't judge it against linen by eye. The fibres are similar in structure and are told apart under a microscope, so rely on the label.
4. Match the yarn to the cloth. Thick yarn in a heavy cloth is expected, since short fibre is carded into thicker yarns for thick fabrics.
5. Look at the colour. Raw hemp is yellow to brown, so pure white hemp has been processed, and bleaches damage the fibre.
6. Expect some stiffness. Lignin stiffens hemp, so a new, unsoftened cloth can feel firm in the hand without being poorly made.

Red flags: “hemp” with no percentages; Manila hemp sold as hemp; and “carbon-negative” or “pesticide-free” claims with no certification or evidence.

How do you care for hemp?

Follow the care label, keep bleach of any kind away from hemp, and dry it fully before you put it away.

CAMEO lists hemp as damaged by bleaches and weak acids, so leave out vinegar rinses too. Store it clean and completely dry.

Is hemp sustainable?

Rain-fed hemp needed less water and land per kilogram of fibre than cotton, and few farm chemicals, in a 2005 study of UK-grown hemp, but the result depends on how it is retted and processed.

What the evidence says

The Stockholm Environment Institute (SEI) study, commissioned by the BioRegional Development Group with support from WWF Cymru, compared hemp, cotton, organic cotton and polyester:

• Water: UK hemp's 500 to 700 mm a season is met entirely by rainfall. The experimental hemp route totalled about 2,123 litres per kg of fibre, against about 10,229 for cotton including processing; around 73% of cotton comes from irrigated fields.
• Land: hemp yielded up to 3 tonnes of dry fibre per hectare, against 1.35 tonnes of cotton lint.
• Chemicals: hemp needs low inputs, including agrochemicals, and had not, to that date, been plagued by pests.
• Footprint: per tonne of spun fibre, 1.46 to 2.01 global hectares for hemp, against 2.17 to 3.57 for cotton.

The study warns that retting depends on the weather and can cause crop failure, that its experimental route was too costly and used a lot of energy, mostly to heat water for scouring, and that it covers only part of the textile chain. Some of its water and cotton-yield figures differ between pages. The Materials review adds that hemp suppresses weeds, so farmers can cut herbicide use and gain organic certification.

What it does not say

None of these sources supports claims that hemp needs no pesticides or that a hemp garment is carbon-negative. Scale matters too: Textile Exchange puts hemp at about 0.2 million tonnes in 2023, around 0.2% of the 124 million tonnes of fibre produced worldwide. For other fibres marketed on their impact, such as bamboo fabric, see sustainable fashion.