As we know, hemp is the variety of cannabis sativa that does not contain enough amounts of Tetrahydrocannabinol (THC) to cause psychoactive effects. It has been fashioned into clothing for centuries. However, due to its relationship with marijuana, the high THC variant of the Cannabis plant, it has been marginalised for decades. Now hemp clothing is once again becoming popular since it is proving to be the most eco-friendly and durable option when it comes to making natural textiles.
In the first article of our ‘How It’s Made’ series, we thought we’d get into the Nitty gritty of how hemp clothing is made.
Step 1: Grow Hemp
Cannabis sativa is a tough plant that can be grown in most locations and climates. It does not need much aside from soil, sun and a little water. Once you put the seeds shallowly in the ground, your work is almost done. The planting should be quite dense so that they can compete for sunlight in a way that results in long heights rather than bushy, short sprouts.
Step 2: Harvest Hemp
Soon after the plant flowers, harvesting can begin. If left for too long, the fibres can become too coarse. Harvesting for fibre is much easier than doing so for seeds. Long stems could be challenging to harvest and may need PVC pipes to be placed near the moving parts to prevent wrapping.
Hemp can be swath or windrow cut when needed for fibre production. This is done at about 8” when the bottom leaves of female plants start to turn yellow. Fibre from male plants begin to die soon after pollination.
Step 3: Separate Fibers
After hemp is harvested it needs to undergo a process known as retting. This is the separation of the fibre from the rest of the plant. It is quite difficult but can be accomplished in a number of ways: moisture, chemicals or microorganisms can break the bonds between the non-fibre and fibre portions of the plant.
Windrow bales are taken for separation of bast and hurd fibers. The bark of hemp stems contain the highest concentration of bast fibres. Whereas hurd fibres which are high in lignin but short are more abundant in the rest of the stem. This means that stems with wider diameters are preferred. Fiber yields usually range from 15 to 22% of the dry weight of stems.
Step 4: Turn into Hemp Yarn
Hemp fiber is spun into yarn in a similar way to other natural fibres. It is usually spun without additional processing once decortication (removing the central woody core of the stem) has taken place. However, some manufacturers employ mechanical or chemical techniques which can improve the elasticity and softness of the fibres.
Lignin is a hard, woody biopolymer that constitutes about 10% of hemp fiber’s dry weight. It is why the fibres traditionally used to have a dry and scratchy texture. In the 80s, researchers discovered a means to eliminate lignin from the fibres by using enzymatic and microbial means.
During its conversion to yarn, it is twisted in long, continuous threads.This used to be done by hand with the help of a distaff and drop spindle to which the fibre is attached.These are then sealed with wax or something similar to create a end-product which is waterproof. Other fibres may be added during this stage to produce a blend.
Step 5: Weave into Fabric
Hemp is woven similar to flax (linen) using setts. It can be done industrially with automatic weaving or you can do it manually with a loom. With a loom, one can thread a piece of hemp through an embroidery needle. Start with smaller pieces of yarn which are easier to work with.
Continually weave the yarn over and under until you reach the other end of the loom. Make sure there is no slack by pulling the weft all the way through. Continue this until you run out of yarn then re-thread the needle and continue.
Step 6: Shape and Stitch Fabric
This is done in the same way with any other fabric. You use a scissors to cut and a machine or hand with thread and needle to stitch. Clothing made from hemp is so great because it gets softer and more comfortable with age unlike cotton which becomes dingy after a couple of washes.
Think about how much money you will save with a more durable fabric! It also saves the environment by reducing water waste and minimising the environment’s exposure to harmful pesticides since the crop has minimum pests.