Bamboo, Tencel, Organic Cotton, Hemp: A Plain Guide to Eco Fabrics

Pick up four T-shirts in almost any shop on the coast and the labels may say bamboo, Tencel, organic cotton and hemp. All four get called eco-friendly. They are very different materials, made in very different ways, and each has costs the hang tag leaves out.

Four fibres, one at a time

Bamboo

Bamboo the plant has a lot going for it. It grows fast, regrows from its roots after cutting and usually needs little or no pesticide.

Bamboo the fabric is another matter. Nearly all of it is viscose, also called rayon. The stalks are pulped, dissolved with strong chemicals including sodium hydroxide and carbon disulphide, and forced through fine nozzles to form fibre. What comes out is regenerated cellulose, much the same stuff whether it began as bamboo, beech or pine. In a poorly run mill those chemicals can harm workers and end up in waterways. This is why Canadian labelling guidance expects wording such as "rayon from bamboo" and not simply "bamboo".

• For: very soft, drapes well, breathes, made from a fast-growing crop.
• Against: chemically intensive processing; claims that the finished cloth is naturally antibacterial are poorly supported; it can pill and lose shape sooner than sturdier fibres.

Tencel and lyocell

Tencel is a brand name, owned by the Austrian company Lenzing, for its lyocell and modal fibres. Lyocell is also made from wood pulp, so it is a cousin of viscose. The difference is in the process. The pulp is dissolved in a less hazardous organic solvent, and almost all of that solvent is recovered and reused in a closed loop, so very little leaves the mill.

• For: smooth and cool on the skin, strong even when wet, absorbs moisture well, cleaner to produce than ordinary viscose.
• Against: still an industrial fibre that takes energy to make; the wood has to come from well-managed forests for the claim to hold; generic lyocell from other producers may not meet the same standard.

Organic cotton

Organic cotton is grown without synthetic pesticides or fertilizers and without genetically modified seed. That is better for the soil, for nearby water and for the people working in the fields.

It is still cotton, and cotton needs water. How much depends heavily on where it grows: a rain-fed field is a different proposition from an irrigated one in a dry region. Organic yields are often lower too, which means more land for the same amount of fibre. And the word organic describes the farm, not necessarily the dyeing and finishing. A standard such as GOTS covers processing as well.

• For: familiar, comfortable, easy to wash and mend, no synthetic pesticides on the crop.
• Against: water use, lower yields, and a claim that means little without certification behind it.

Hemp and linen

Hemp and linen, which comes from flax, are bast fibres taken from the stalk of the plant. Both crops do well in cool, damp climates, often on rainfall alone, and need little pesticide or fertilizer.

The cloth is strong, breathes well and softens with every wash, which suits a garment you plan to keep. The drawbacks are practical. New hemp can feel coarse, both fibres crease, and the supply chain is small, so choice is limited and prices run higher. Hemp is often blended with cotton to soften it, so read the percentages.

How to choose

No fibre is free of impact. A few questions sort the better options from the worse:

• Does the label name the real fibre, such as viscose or lyocell, or only the plant?
• Is there a recognized certification behind the claim?
• Is it blended with polyester or elastane? Blends are harder to recycle, and synthetics shed microfibres in the wash.
• Will it last? A sturdy shirt worn a hundred times beats a soft one that pills in a season, whatever it is made from.

The eco-friendly entries in the catalogue give the fibre content of each piece. In a shop, skip the hang tag and read the small label sewn into the side seam.