Cultivating hemp fibre

Hemp Cannabis sativa produces good fibre for textiles and ropes. Easy to cultivate, the high-yield bast fibre is one of the longest of the Pon-wood fibres. It is superior to wood pulps and makes an ideal additive to recycled paper pulps to improve strength.

Hemp paper is tough and durable and can be finished to a creamy, desirable sheet with the addition of some shorter, softer fibre such as esparto or cotton. About 0.005 percent of the world's paper (by volume) is hemp, which is claimed to have many benefits over use of wood. Hemp is over 70% cellulose, compared with 25-50% for wood, and so fewer chemicals are needed. Hemp is lighter in colour and needs less bleaching than wood. Hemp is easier to grow that wood, taking four months to reach harvesting as opposed to twenty or thirty years, and can grow in all kinds of soil. Other uses for hemp include textiles, building materials and a seed oil.

Hemp fibre forms the sheeting for the Gutenberg Bible and the Declaration of Independence. In 1575, at the first paper mill outside Mexico City, a composite of hemp and cotton rags was the pulp of choice. US hemp paper production began in 1690. It was against the law for colonial American farmers not to grow fibre hemp. Hemp was extracted by retting (soaking to separate the fibre). During the American Colonial period, masters forced slaves to enter retting basins (even in winter) as the humanoid mechanical separators. So many died of pneumonia that slave-retting became illegal.

So far hemp has been labour-intensive. Mechanization of this unfamiliar (yet so familiar) crop needs research and development funds. The whole stalk (bast plus the shorter inner fibres) cannot compete with wood pulp under present market conditions: hemp costs two-and-a-half times more per ton. A new chemi-mechanical process that replaces older, purely chemical processes, may lower costs and help hemp grab a share of the higher-quality printing- and writing-grade paper market.

It is said that the male plants are best for fibre, the virgin females for psychoactive properties.

While marijuana is cosmopolitan, fibre hemp grows mostly in Europe (Hungary, Ukraine, and smaller amounts in France, Spain, and the UK) and south Asia. Despite rekindled interest, fibre hemp cultivation has been in long decline with shorter-term peaks during the world wars. This is partly because most "modern" nations prohibit fibre hemp cultivation. Hemp farmers may be required to have high fences with concertina wire and all-night lighting. Ironically, legal repression has given hemp fibre glamour and a larger market niche.

Globally, two hundred firms sell hemp products with a projected legal market of US $15 to $30 billion per year. Kentucky, USA (looking for tobacco substitutes), Canada, Ukraine, Germany and the Netherlands are all investigating markets. An Oregon company sells paper made from hemp fibre and cereal straw.