What it is
Cotton is a natural fibre composed mainly of cellulose, grown on the seed of the cotton plant and spun into yarn. It is breathable, absorbs moisture well, takes dye readily and feels soft against skin, which is why it dominates apparel. Its weaknesses are equally consistent: it absorbs water slowly and dries slowly, wrinkles, shrinks unless treated, and is vulnerable to mildew. The word "cotton" on a label tells you almost nothing about quality — staple length, growing origin, ginning, spinning method and finishing determine almost everything a buyer cares about.
Specification
- Category
- fiber
- Fibre family
- Natural cellulosic (seed fibre)
- Composition
- Cotton fibre is roughly 88–96% cellulose, with the remainder made up of waxes, pectins, proteins and mineral matter concentrated in the outer layers. The waxes are what make raw cotton water-repellent before scouring, and their removal during preparation is what allows the fibre to absorb water and dye.
- How it is made
- Cotton bolls are harvested mechanically or by hand, then ginned to separate fibre from seed. The lint is cleaned and opened, then carded — brushed into a continuous web — or combed, which removes short fibres and impurities. The resulting sliver is drawn, roved and spun into yarn. Yarn may be ring-spun for strength and softness or open-end (rotor) spun for speed and cost. The fabric is then knitted or woven, prepared, dyed and finished.
- Typical weight
- Knitted single jersey 120–220 g/m² · woven poplin 100–150 g/m² · denim 300–450 g/m²
- Also known as
- Cotton fibre · Gossypium fibre · Cotton lint
Properties
- Moisture absorption
- High. Cotton absorbs up to around 24–27% of its own weight in water before feeling damp, which is why it is comfortable in heat.
- Breathability
- High. Cotton does not trap heat the way dense synthetic fabrics do.
- Drying speed
- Slow. The same property that makes it comfortable in heat makes it slow to dry and unsuitable for performance wear where moisture management matters.
- Strength
- Moderate when dry, lower when wet — roughly 20–30% weaker wet than dry. This matters for garments that are washed frequently under tension.
- Elasticity
- Low. Cotton does not recover well from stretching, which is why pure cotton garments bag at the knees and elbows.
- Abrasion resistance
- Moderate. Better than viscose or acetate, considerably worse than polyester or nylon.
- Thermal behaviour
- Does not melt. It chars and burns rather than melting, unlike polyester, which melts and can fuse to skin.
- Dyeability
- Excellent. Cotton takes reactive, vat and direct dyes readily, which is why the range of achievable colours is wider than for most synthetics.
- Shrinkage
- Significant unless controlled. Woven cotton can shrink 3–10% on first wash. Mechanical compaction or resin finishing is used to bring this under control.
- Pilling
- Low to moderate, depending on staple length. Long-staple combed cottons pill less than short-staple carded cottons.
- Sun resistance
- Degrades slowly with prolonged UV exposure; less tolerant than polyester.
- Moth and mildew
- Resistant to moths. Highly vulnerable to mildew if stored damp.
Advantages
- Comfortable against skin, and the standard against which other fibres are judged
- Breathes well, making it suitable for warm climates and next-to-skin wear
- Absorbs moisture and takes dye exceptionally well, giving a wide colour range
- Does not melt, unlike most synthetics, which is a safety advantage in some applications
- Biodegradable, and compatible with mechanical recycling back into yarn
- Universally available with deep, competitive supply chains
- Predictable behaviour that mills, dyers and laundries understand well
Disadvantages and trade-offs
- Slow to dry, which is the main reason it loses out to synthetics in performance apparel
- Wrinkles readily and recovers poorly from stretching
- Shrinks unless it has been compacted or otherwise stabilised
- Vulnerable to mildew in humid storage, which is a real risk in hot, humid manufacturing countries
- Weaker when wet, which limits some applications
- Quality varies enormously under a single label — "100% cotton" is compatible with both excellent and very poor fabric
- Conventional cultivation carries significant water and pesticide impacts
- Cost considerations
- Cotton price is driven by the fibre market, then by what is done to the fibre. Between the cheapest and most expensive route from the same plant, the multiple is large. Carded open-end short-staple cotton is the low-cost path. Combed ring-spun long-staple cotton costs substantially more per kilogram, because more fibre is discarded during combing and ring spinning is slower. Organic and traced cotton adds certification cost and, depending on the market, a genuine premium at the fibre stage. Buyers comparing quotations should compare the fibre specification first — a large price gap between two "100% cotton" quotations is nearly always a specification gap, not a margin gap.
- Manufacturing considerations
- Cotton is forgiving to work with but unforgiving on specification. Three practical points account for most problems. First, shrinkage must be dealt with before cutting, not after — cutting greige or inadequately compacted fabric and then washing produces garments that no longer match the pattern. Second, sewing parameters need matching to the fabric weight; lightweight cotton jerseys are prone to seam pucker and needle damage if machine settings are carried over from a heavier fabric. Third, cotton's wet-strength loss matters in garment washing and finishing, where fabric is handled wet and under tension. Where a garment is to be piece-dyed or over-dyed, the dyehouse should see the actual fabric before the order is costed, because cotton's response to dyeing varies with its preparation.
- Sustainability
- Conventional cotton is a significant user of irrigation water and agricultural chemicals, though the picture varies greatly by origin and by whether the crop is rain-fed. Organic certification addresses cultivation inputs; it does not address water use, and a certified organic crop can be grown in a water-stressed region. Recycling routes exist — mechanical recycling produces shorter fibres suitable for lower-grade yarn, and chemical recycling can recover longer fibre but is far less established at commercial scale. Durability is the least glamorous and most effective sustainability lever for cotton: a garment that is worn for six years has a lower impact per wear than one that is worn for six months, regardless of the fibre's provenance.
Suitable garments
- T-shirts and jersey basics
- Polo shirts
- Denim jeans and jackets
- Shirts and blouses
- Bed linen and towels
- Underwear
- Workwear
- Children's wear
- Home textiles
What cotton actually is
Cotton is a seed hair. Each fibre is a single elongated plant cell, roughly 90%
cellulose, that grows from the surface of a cotton seed and is harvested along
with it. What the plant produces is not what the garment receives: the fibre
arrives coated in waxes and pectins that make it naturally water-repellent, and
almost everything done to cotton afterwards is a deliberate intervention.
The consequence that matters commercially is this: the difference between
cheap cotton and expensive cotton is not a matter of degree in one variable, but
a set of independent choices — where it was grown, when it was picked, how it
was ginned, whether it was combed, how it was spun, and how it was finished. Two
fabrics carrying the same care label can differ by a factor of several in cost
and behave nothing alike.
Fibre length is the first variable
Cotton fibre length, or staple, is conventionally grouped into three bands:
| Band | Approximate staple length | Typical use |
|---|
| Short staple | up to ~25 mm | Coarse yarns, denim, towels, industrial fabrics |
| Medium staple | ~25–29 mm | General apparel yarns |
| Long staple | ~29–34 mm | Fine shirting, premium jersey, high-quality knitwear |
| Extra-long staple | over ~34 mm | Luxury shirting, very fine yarns |
Longer fibres can be spun into finer, stronger, smoother yarns because more of
the fibre’s length is available to be twisted together. This is why
extra-long-staple cottons — Egyptian, Pima, Supima — attract a premium that
persists through every stage of production.
Named cottons are largely shorthand for a combination of origin, staple length
and, sometimes, a licensing or certification programme. The specific properties
should always be confirmed from the specification rather than inferred from the
name.
From boll to fabric
The chain runs: harvest → ginning → opening and cleaning → carding or combing →
drawing → roving → spinning → knitting or weaving → preparation → dyeing →
finishing.
Two stages do most of the work in determining what the final fabric will be like.
Ginning separates fibre from seed. Roller ginning is gentler and preserves
fibre length better; saw ginning is faster but more damaging. The choice is
usually determined by the crop and the machinery available locally, not by the
buyer.
Spinning determines the yarn’s strength, evenness and surface. There are two
main routes, and the difference is commercially significant:
- Ring spinning produces a finer, stronger, smoother yarn. It is slower and
more expensive.
- Open-end (rotor) spinning is considerably faster and cheaper, producing a
slightly weaker and hairier yarn that is entirely adequate for many end uses.
A buyer comparing two quotations without knowing which spinning route was
priced is comparing two different products. See
ring-spun cotton for the detail.
Where cotton fails
It is worth being blunt about the limits, because most cotton marketing is not:
- It dries slowly. This is the structural reason performance apparel uses
synthetics. In hot humid conditions, or during sustained exertion, a saturated
cotton garment stays saturated.
- It is weaker wet. Handling wet cotton under tension in a laundry or dyehouse
is a genuine process risk.
- It shrinks and wrinkles. Both are manageable, and both cost money to manage.
- It mildews. In humid storage conditions — which describes several major
manufacturing regions — damp cotton will develop mildew, and mildew damage is
permanent.
- Its quality is invisible on a label. “100% cotton” is a fibre content
declaration. It says nothing about whether the fibre is good.
Blends exist for a reason
Blending cotton with polyester is not automatically a cost-cutting measure. A
65/35 cotton–polyester blend is a genuine engineering choice: the polyester
reduces shrinkage and wrinkling, increases wet strength and speeds drying, while
the cotton preserves breathability and hand feel. In workwear and institutional
textiles, blends frequently outperform both pure fibres for the actual use case.
The problem is not blending. The problem is blending to reduce cost while
presenting the result as a quality alternative to pure cotton. The distinction is
detectable: blend ratio is testable under the ISO 1833 series, and any supplier
declining to state it precisely is telling you something.
Sourcing cotton fabric
For a buyer, the specification that removes most risk has six parts:
- Fibre content and staple class — not just “cotton”, but which cotton.
- Spinning route — ring or open-end.
- Construction — knit type or weave, and yarn count.
- Weight — GSM, at a named stage, by a named method, with a tolerance.
- Width — and whether it is measured on the greige or finished fabric.
- Test requirements — shrinkage, colourfastness, pilling, and the methods
they will be measured against.
A supplier who can answer all six is a supplier who will produce what was
ordered. A supplier who answers only the first is offering the cheapest fabric
consistent with the words “100% cotton”.