A Deep Dive into Wool Fiber

As a shepherd, I’m a bit biased about wool but what other fiber can compete with all the things wool can do.

• Fertilizer

• Hold over 3 times its weight in water

• Insulate

• Regulate temperature

• Wick away moisture

• Repel bacteria which produce smells (don’t have to wash as often)

• Wool isn’t easily flammable and has a high ignition temperature

• Lanolin + wool is waterproof

• It felts

• Can be crocheted, knitted, woven…

• Compostable

Depending on the sheep breed, wool fibers range in micron count, length, crimp or curl, are rated from fine to course, and have a wide range of natural colors and luster. Wool from sheep can be used for clothing that is next to skin soft to rugs that are extremely durable.   

Try to top that cotton, linen, or man-made fiber! 

Wool is pretty amazing.

How does wool do it? Let’s start with the individual fiber.  (See picture above)   

The exterior of each fiber has cuticles similar to shingles on a roof which help shed water.  The addition of lanolin leads to a waterproof fiber. This double layer of protection helps sheep with all the elements from blizzards to rain. If yarn isn’t stripped of lanolin when it is made, outerwear made from this yarn is also waterproof.  Just these facts are pretty amazing but these fibers do even more.

Inside the wool fiber, a chemistry plant is working around the clock. If you are looking for a deep dive, check out the Hofmeister effect. (https://pubmed.ncbi.nlm.nih.gov/12425658/) For a simple explanation, wool adsorbs water. It does not absorbs water like the other fibers. (Did you pick up the difference between those words? Adsorbs not Absorbs). When a water molecule gets past the outer cuticle, it actually binds to the internal workings of the fiber.  This chemical reaction is called an exothermic reaction (heat producing). Studies have shown wool clothing becomes warmer when it goes into a higher humidity area due to this reaction. Think a fisherman with a wool sweater out on the sea and how this would help sheep keep warm on wet days!  Because the water molecules are bound inside the fiber, the wool does not feel wet. When the wool warms up, the bonds break between the water and the wool fiber producing a cooling effect. That is some pretty amazing natural chemistry happening 24/7. Wool is always working towards an equilibrium.

When we use wool pellets in the soil or use wool mulch, we take advantage of this natural chemical plant. If wool is in its driest state, it binds up to 35% of its weight in water! As the soil heats up around it, it slowly releases the water allowing the gardener to water less often.  As a mulch, wool helps to regulate the soil temperature underneath it which is helpful for the plant and the soil.

Another fun fact includes the molecules which make this fantastic fiber.  Nitrogen, Potassium and Sulfur are the three main elements.  A high amount of sulfur is located in the cuticles and is a fire retardant. Internally, Nitrogen is also a protector against fire. It takes a high amount of oxygen around wool and high heat to get wool to burn. Add in its water holding capacity and wool is a great choice for a fire retardant material. This probably doesn’t help us in the garden but it is a fun fact!

Last but not least, all of the elements are needed by plants.  As the wool slowly breaks down it leaves these elements to be transported by the soil microbiome to the plant’s roots. Wool pellets break down over 6-9 months.  A wool fleece takes a couple of years to fully break down.  Shredded wool mulch takes over 1 year. Adding all natural materials to soil improves the health of the soil. The soil loves wool!

Wool is a winner.  Wear it, make things with wool, or garden with it!  All natural fibers leave this world a better place.