Material stories: what is cotton?

Cotton is such a ubiquitous fabric, you probably haven’t given much thought to where it comes from. But aside from picturing fields of fluffy cotton-ball plants, how much do you really know about this natural fibre?

Cotton is the world’s largest non-food crop - globally, we produce about 25 million tonnes of it a year. From fluffy towels to tough denim, it’s made into an enormous variety of fabrics. But even within these categories, cotton quality varies hugely - and it can be hard to tell what you’re getting.

For the latest instalment of our Material Stories series, we’re taking a deep dive into this brilliant everyday textile. We’ll be exploring the ways in which you can identify quality cotton, its unique properties and the intricacies of its sustainable credentials.

Where does cotton come from?

First, a quick rundown on how cotton gets from field to T-shirt. The cotton plant needs a warm climate, so it’s usually grown in tropical and subtropical parts of the world - primarily China, India, the Southern United States, Brazil and Pakistan.

Cotton fibres come from the fluffy white part of those iconic shrubs, which is actually a protective case that grows around the seeds. Under natural conditions, the fluff would blow away with the tiny seeds to help them spread.

To make cotton fabric, the cotton is harvested (either by machine or by hand) and the seeds are separated out. Then, the fibres are spun into yarn, and woven into a soft, durable fabric. Humans have been making cotton textile this way for thousands of years - since at least 6000 BC, in fact.

Properties of cotton fabric

The tiny individual fibres of cotton are fine and hollow, made almost entirely of pure cellulose. These characteristics give the resulting cloth a whole host of properties that make it ideal for wearing and living in:

What to look for in cotton

The specific properties you want from a cotton fabric will vary according to what your needs are. You won’t want a towel made of denim, for example. But because we’re sticklers for quality, we want to talk about the ways you can identify quality cotton:

100% cotton

As a baseline, if you’re buying something that seems like cotton, always check the label to make sure it isn’t a synthetic blend. Blending cotton with synthetic fibres makes the fabric cheaper, but the fabric won’t be as breathable or soft. It’s also usually more prone to pilling.

However, other fibres can give cotton extra benefits - for instance, a small amount of elastane provides stretch. A linen-cotton blend is extra light and breathable to wear, and a cotton-wool blend is warm and luxurious. As a general rule, look for fabrics made mostly from natural fibres.

Physical characteristics

But how to tell one 100% cotton fabric from another? Here are a few simple tests you can carry out.

Bear in mind that cotton is a relatively cheap fabric to produce, so it isn’t difficult to find 100% cotton products that are both affordable and long-lasting. Very poor quality cotton is usually only found at budget price points.

Organic cotton

Conventional cotton growing is a very chemical-intensive process. It makes heavy use of a variety of toxic pesticides and fertilisers - as well as a huge amount of water. Organic cotton is grown in a much more sustainable way, benefiting not only the environment, but the people who work in and live near cotton growing areas.

As well as being grown more naturally, organic cotton fabrics are treated and dyed with low-impact, non-toxic substances. Plus, organic cotton farmers are paid a living wage. We always recommend looking for organic cotton over non-organic cotton - look out for GOTS certification (Global Organic Textile Standard).

Extra-long staple, Pima or Supima cotton

These are all names for cotton made from a different species to the norm. These cotton plants produce particularly long, silky fibres (the ‘staple’). When these long fibres are spun into yarn and woven, the resultant fabric is very smooth, strong and durable. Extra-long-staple cotton is thus considered the highest quality cotton in the world, and accounts for around 10% of cotton grown worldwide.

Supima is a trademark that stands for ‘superior Pima’, and is grown exclusively in the United States. The quality and origin requirements of Supima are very strict, so it’s an extra assurance of a quality product (though generally much more expensive).

Egyptian cotton

Egyptian cotton is made from this same extra-long-staple cotton species, but is exclusively grown in the Nile Delta. Be careful about buying products marketed as ‘Egyptian cotton’ - often, they’ll only contain a small amount of genuine Egyptian cotton, or even none at all.

For genuine extra-long-staple Egyptian cotton, look for the symbol of the Egyptian Cotton Association:

The thread count myth

If you’re looking into cotton bedding, you’ve probably been thinking a lot about thread count. Put simply, thread count refers to how tightly woven fabric is - it’s the total number of threads woven into a square inch of fabric. Most people assume that the higher the thread count is, the better the bedding.

However, the reality is that there’s no perfect thread count - and once thread count gets very high, bedsheets can even become stiflingly heavy. Cotton quality is a far more important factor, and if you want light, breathable sheets, a lower thread count may suit you better. Generally speaking, the thread count of quality sheets ranges from 200-800, depending on the type of weave.

How sustainable is cotton?

Because cotton is a natural fibre that comes from plants, it should be a sustainable product - in theory. However, the realities of modern cotton growing mean most cotton isn’t sustainable at all.

Although cotton accounts for only around 2.3% of the world's arable land, it uses over 16% of global insecticides - many of which are known to cause cancer. Making enough cotton for a single T-shirt requires about 2500 litres of water. The intensive farming practices used to grow this crop permanently degrade soil and pollute waterways, harming both the environment and the people who work on and live near farmed land.

Organic cotton, however, is different. By not using toxic pesticides or fertilisers and using more natural systems to maintain soil, this way of farming cotton is much gentler on the planet and for people, too. Even though just 1% of cotton is organic, it’s becoming much more accessible - so we’d always recommend choosing it if you can.

Cotton versus linen

Here at Buy Me Once, we talk a lot about the benefits of linen. Like cotton, linen is a natural fibre that’s ideal for making clothing, bedding and other homewares. However, there are a few differences to consider.

Both cotton and linen are soft, breathable fabrics. Linen has the benefit of being extra moisture-wicking, feeling dry even after absorbing a lot of water. Once you start sweating in cotton, it has a tendency to feel damp. However, cotton has a softer feel than linen, which has thicker fibres.

Generally speaking, linen is a more sustainable crop than cotton. It requires much less water to grow, fewer pesticides and the fibres can be processed without chemical treatment. Even non-organic linen is a very low-impact crop.

However, linen is expensive - usually even more expensive than the best quality cotton. Linen is very long-lasting (it’s about 30% stronger than cotton), but quality cotton can last just as long. They’re both great materials to have against your skin - it’s down to personal preference.

Want to learn more about linen? Read our Material Stories article here.