Sackcloth and elan: Kate Fletcher explains why there's more to hemp than a load of old rope - and no, setting fire to it won't bring a nice surprise

New Internationalist, June, 1998 by Kate Fletcher

Hemp's environmental credentials are indisputable. It grows better in organic systems than in conventional ones. It smothers weeds and controls pests, clearing the land for other crops. It improves the structure of the soil, with strong roots to prevent erosion. If processed in the field, it returns nutrients to the land and purports to `clean up' soil contaminated with heavy metals. It is one of a minority of textile-fibre crops that can be grown in temperate climates. What is more, the fibre is durable. In sixteenth-century England King Henry VIII even passed an Act fining farmers who failed to grow it. So why, given its potential, is so little hemp used today?

There are three main reasons. The first is that the market has been completely overwhelmed by cotton and synthetic fibres. The second is cannabis sativa, the recreational drug derived from hemp, which has made the cultivation of the plant illegal in many parts of the world. However, plant breeders have developed varieties which are low in the psycho-active compound, Tetrahydrocannabinol (THC), and farmers are beginning to grow these varieties under special licence.

The third and main reason is the process of extracting fibre from the plant's stem, or `retting'. In conventional treatments this process uses natural bacteria and fungi, or chemicals which break down the pectins that bind the fibres to the stem. Traditionally this is done in water. It can also be done by simply lying the crop on the ground, or `dew retting', which is preferable from an environmental perspective. But it depends on the right cocktail of heat and moisture and can take anywhere from one to six weeks. The weather's unpredictability makes this risky - farmers can easily lose their whole crop. Other retting techniques are being developed, but few have been perfected.

In conventional processing the stems are kept parallel throughout harvesting, retting and subsequent cleaning, but the mechanical method tangles the fibre up. The difference is crucial: only by keeping the stems aligned can a fine yarn and high-quality fabric be gained. Short fibres make a coarser, more rigid fabric, which perhaps is the reason why hemp is stereotyped as `sackcloth'.

Market image is all-important. Most designers will either not have heard of hemp, or know of its associations with the drug culture, or think its only use is for sacking. If garment producers realize the potential of hemp, and processing techniques are refined, hemp could begin to fulfil its promise as a local, environmentally responsible textile fibre with distinctive elan.

Kate Fletcher is a researcher in textiles/environment/design issues at Chelsea College of Art and Design, London, England.