Hemp fiber is one of the strongest and most durable of all natural textile fibers.
It also has superior insulation properties, which means that clothing made from hemp keep you you warm in winter and cool in summer.
Generally it takes between 80 and 150 days for hemp to grow. Most hemp mature in 120 days. To secure the highest quality fibre, it is important to harvest at the proper time. Early harvesting produces weak fibre and later harvesting brings rough fibre with little luster.
Once hemp stalks are cut down, the bark need to be removed. However, it is almost impossible to remove the bark when it is still green. Therefore, hemp go through the process called "retting".
There are two methods of retting. One is called "dew retting". Hemp stalks are left out in the field so that they can be retted by the moisture in the air and bacteria.
The other method is called "water retting". The hemp stalks are submerged underwater for several days.
And finally hemp bark can be removed from the stalks.
Traditionally this was done by hand and still many parts of the world including China still use this method.
Once the hemp bark has been stripped, the fibers need to be separated from one another. The fibers are all held together by lignin which is a type of plant glue. By boiling hemp fibre in in a mild base of sodium hydroxide (NaOH) or “lye”, hemp fibres can be completely separated into their individual fiber bundles. This process to remove lignin is called "degumming".
After degummed, hemp fibre is separated into long ones and short ones. Generally long fibres are used for textiles as they have smooth and lustrous surface. Short fibres are usually blended with cotton to be spun. Blending hemp into cotton can add some stability and strength to cotton.
Hemp is blended not only with cotton but with other fibres such as wool, silk, flax, bamboo, tencel, nylon, rayon, and polyester.