In the past, flax was divided into two species, fibre and linseed, but these have now been merged into a single species, Linum usitatissimum, mentioned above. A single flax stalk contains about 20-30% fibre, with the aerial part yielding long fibre before branching, and the inflorescence twigs yielding a lower quality fibre, mainly used in sanitary ware. For this reason, flax growers strive to make the flax stalk, where the long flax fibre is found, as thick and long as possible.

To obtain the best quality fibre, flax should be grown when the weather is cooler and the sunlight is less, and weeded when it reaches its early yellow maturity.

Growers make sure that flax does not get too much moisture – it requires the most moisture during the flowering period, and then much less during the ripening period.