The use of flax fibre for cloth originated almost 10,000 years ago. Remnants of linen fishing nets and clothing, and unworked flax, have been found in Switzerland in the remains of Stone Age lake dwellings. The ancient Egyptians used linen shrouds, some of which are still preserved on mummies, and pictures of flax cultivation adorn the walls of various Egyptian tombs. Passages in the Bible refer to the manufacture of linen. Annual flax, which was cultivated in Mesopotamia, Assyria, and Egypt for about 5,000 years, still grows wild in the regions around the Persian Gulf, the Caspian Sea, and the Black Sea.
In Britain flax is still grown on a commercial basis in some areas. Fields of this crop are easily identifiable by the distinctive blue colour provided by the flowers.
Primarily a temperate-region plant, flax grows under a wide range of temperature and moisture conditions. High temperatures and high precipitation are, however, unfavourable for production of either flax or seed. Moderately fertile silt or clay loams are most satisfactory for cultivation.
Fibre flax is harvested by uprooting the plants, which are then piled in the fields to dry. The seed is removed to be used for feed or oilseed, or to be retained for planting. The straw is retted, a process that promotes partial decomposition of the stem to permit separation of the fibre from the woody portions. In retting, the straw is spread on the ground in order to subject it to the action of rain, dew, and micro-organisms, and to cyclic wetting, drying, freezing, and thawing. Another process, called water-retting, which is used in some countries, consists of immersing the straw in ponds, streams, or special tanks in which water and micro-organisms promote decomposition.
The retted stems are crushed and broken, and the fibre is separated from the woody fragments, called shives. This process yields relatively long and straight fibres, known as line fibres, and short, damaged, or tangled fibres, called tow. Flax tow is used primarily in upholstery. Having high tensile strength, line fibres are used in the manufacture of various threads employed in the bookbinding and shoe industries, and in such products as twine, fishing nets, and laces. Flax fibres are also used extensively in various types of linen cloth and other fabrics.
France and Belgium produce high-quality fibre. Flax fibre is also produced in eastern Europe, and on a limited scale in Ireland and Canada. Small amounts of fibre flax have been cultivated in the United States. The Soviet Union cultivated flax extensively; despite a large total yield, however, the quality of the fibre was usually inferior to that obtained from western Europe.
Flax for seed is produced and harvested in much the same manner as wheat and other small grains. The crop is most productive on loamy soils with moderate to high fertility. In California, India, and Argentina, seed flax is planted in autumn and matures in about 150 days. In the northern latitudes in Europe, the United States, and Canada, the crop is seeded in the spring and matures in 100 to 120 days. Yields and quality are best in relatively cool climates. High temperatures and drought during the time the seed is developing often reduce the crop yield and oil content.
Seed flax does not compete well with weeds. It is planted on clean firm seedbeds. The inability of seed flax to compete with weeds or other plants has made it valuable as a so-called nurse crop, or companion crop, for plantings of alfalfa (lucerne), clovers, and other forage legumes. Weeds in flax crops may be controlled by the use of herbicide sprays.
Flax seed yields from 30 to 40 per cent linseed oil by weight. The oil is used in the manufacture of paints and varnishes, linoleum, oilcloth, printing inks, soaps, and many other products. Since 1959 it has also been used as a coating for concrete road surfaces and bridge decks to prevent scaling and surface deterioration from heavy traffic, freeze-thaw cycles, and applications of salt or calcium chloride for snow and ice control. The oil cake, or linseed meal, that remains after the oil has been expressed contains 30 to 40 per cent crude protein and is a valuable feed for livestock.
In recent years the fibre from seed flax has been used in the manufacture of high-grade and special-purpose papers. For example, in the United States, most cigarette paper is manufactured from the fibre of domestically grown seed flax.