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Common Name: Flax

General Information

Linum usitatissimum is an annual plant that can grow up to 0.70 metres tall.
It is harvested from the wild for local use as a food, medicine and source of materials.

Known Hazards

The seed of some strains contain cyanogenic glycosides in the seed though the toxicity is low, especially if the seed is eaten slowly. It becomes more toxic if water is drunk at the same time[, ].
The cyanogenic glycosides are also present in other parts of the plant and have caused poisoning to livestock[].

Botanical References

Range

Possibly native to Europe. A rare casual in Britain, the original habitat is obscure.

Habitat

Not known in the wild.

Properties

Edibility Rating
Medicinal Rating
Habit	Annual
Height	0.70 m
Pollinators	Insects
Self-fertile	Yes
Cultivation Status	Wild

Cultivation Details

Prefers a light well-drained moderately fertile humus-rich soil in a sunny sheltered position[]. Plants grow best in a well-drained, loamy soil, those overlying a clay subsoil produce the best results[]. They prefer a pH in the range of 5 - 7[]. Very light highly fertile soils are not desirable as they produce tall rank growth tending to lodge[]. Plants are more sensitive to salt than most field crops[]. Prefers a cool moist climate during the growing season, dry weather making the plants short and woody[, ]. A very greedy plant, depleting the soil[, ] and requiring a rich, well prepared soil if it is to do well[]. Plants help to break up organic matter and prepare the soil for following crops[]. Cultivars selected for seed production succeed under a fairly wide range of conditions, but those selected for fibre production require abundant moisture and cool weather during the growing season, and warm dry weather during harvesting, especially where water-retting is practiced[].
The crop requires 15 - 20cm of rainfall if spread evenly over growing season, with 2.5 cm falling just before or after planting[]. The plant needs a relatively long ripening period between flowering and harvesting. Warm, dry weather is desirable at the heading stage to cause plants to branch and produce seed; after vegetative growth, dry weather is required for curing the seed[].
Linseed has a very long history of cultivation in temperate climates with evidence to show that it was being grown in Egypt over 5,000 years ago[]. It fell into almost complete disuse in Britain in the 20th century as artificial fibres were increasingly used, but it is once again coming into prominence both as a fibre and as an oilseed crop(1995)[]. Linseed is grown for its edible seed, the oil from the seed and for the fibres obtained from the stems[]. There are many named varieties, though these usually fall within with two classes. One class, generally known as flax, does not branch much and is grown mainly for the fibre in its stem, whilst the other class, known as linseed, branches much more freely and is grown mainly for its seed. Although classified as a species, linseed is possibly an ancient cultigen derived in cultivation from L. bienne[, ].
Flax crops take 3 - 4 months to reach maturity, though autumn or early spring sown crops can take 6 - 7 months[].
Lolium specis (Rye grasses) and Phleum species (Timothy grass) have allelopathic effects on Linum, reducing its carbohydrate synthesis[]. Linseed is a good companion plant for potatoes and carrots but is inhibited by Camelina sativa[, ].

Edible Uses

Seed - raw or cooked[]. The seed contains 30 - 40% oil, which comprises mainly linoleic and linolenic acids[]. The seed also contains cyanogenic glycosides (prussic acid). In small quantities these glycosides stimulate respiration and improve digestion, but in excess can cause respiratory failure and death[]. Cultivars low in these glycosides have been developed and large quantities of the seed would need to be eaten to achieve a harmful dose. The seed is used in breads and cereals, it can also be sprouted and used in salads[]. The seed is hard to digest and provokes flatulence[]. A nutritional analysis is available[].
The roasted seed is said to be a coffee substitute[].
A herbal tea can be brewed from the seed[].
An edible oil is obtained from the seed[, ], though it needs to be properly refined before it can be eaten. Some caution is advised in the use of the seeds for food since some varieties of this plant contain toxins.

Medicinal

Linseed has a long history of medicinal use, its main effects being as a laxative and expectorant that soothes irritated tissues, controls coughing and relieves pain[]. The seed, or the oil from the seed are normally used[].
The seed is analgesic, demulcent, emollient, laxative, pectoral and resolvent[, , , , , , ]. The crushed seed makes a very useful poultice in the treatment of ulceration, abscesses and deep-seated inflammations[, ]. An infusion of the seed contains a good deal of mucilage and is a valuable domestic remedy for coughs, colds and inflammation of the urinary organs[]. If the seed is bruised and then eaten straight away, it will swell considerably in the digestive tract and stimulate peristalsis[] and so is used in the treatment of chronic constipation[].

The oil in the seed contains 4% L-glutamic acid, which is used to treat mental deficiencies in adults[]. It also has soothing and lubricating properties, and is used in medicines to soothe tonsillitis, sore throats, coughs, colds, constipation, gravel and stones[, ]. When mixed with an equal quantity of lime water it is used to treat burns and scalds[].

The bark and the leaves are used in the treatment of gonorrhoea[].

The flowers are cardiotonic and nervine[].

An ethyl alcohol extract of the seed has shown interesting oestrogenic properties. In addition, it has been shown to reduce cell death from oxidation. The plant has potential as an active ingredient in preparations for the treatment of skin-ageing in post-menopausal women[].
The plant has a long history of folk use in the treatment of cancer[]. It has been found to contain various anticancer agents[].

Other Uses

A fibre is obtained from the stem[, , , , ]. It is of very high quality and is used in making cloth, sails, nets, paper, insulating material etc.The best quality flax fibre is used for making cloth. It is soft, lustrous and flexible, although not so flexible or elastic as cotton or wool[].. It is stronger than cotton, rayon or wool, but weaker than ramie[]. Lower quality fibre is used in manufacturing of towelling, matting, rugs, twines, canvas, bags, and for quality papers such as printing currency notes[]. The plant is harvested just after it flowers[]. The yield is 0.5 to 0.9 tonnes of fibre per hectare. When used for paper making, the stems are harvested in late summer or autumn when they are two thirds yellow and are then retted[]. The fibre is then stripped from the stem, cooked for two hours or more with lye and then beaten in a Hollander beater[].
The lower quality flax straw from seed flax varieties is used in the manufacture of upholstery tow, insulating material, rugs, twine, and paper. Some of the better quality straw is used in the manufacture of cigarette and other high-grade papers[].
The seed contains 38 - 40% of a drying oil[]. It has a very wide range of applications. The paint and varnish industries consume about 80% of all the linseed oil produced. The remainder is used in items such as furniture polish, enamels, linoleum, oilcloth, printer's inks, soap making and patent leather[, , , , ]. It is also used as a wood preservative and as a waterproofing for raincoats, slickers, and tarpaulins[]. The oil is also used in a spray on concrete roads to prevent ice and snow from sticking - it has the additional benefit of helping to preserve the concrete and prevent surface cracking and wear[]. Yields of over 4 tonnes of seed per hectare have been recorded in N. America, but yields of 2 tonnes or less are more common[].
A mucilage from the soaked or boiled seeds is used as a size for linen warps[].

Propagation

Seed - sow early to late spring in situ. Do not transplant the seedlings[].