The information below is an excerpt from my book, Dyeing by the Numbers.
Decide how long of a strip you want to hook. I prefer 36” (1 yard) but will occasionally dye 18” for smaller projects.
Measure 18” or 36″ along the selvedge of your wool, snip and rip. Never cut wool. Ripping keeps your edges on the straight of grain. No human with scissors can do as well. The straight of grain is important for the strength and durability of your strips.
Snip close to the selvedges and tear them off. If the exact amount of wool isn’t important to your formula, you can leave the selvedges on. Save the selvedges. They are great for testing dye baths (if undyed), tying up bundles of wool, etc. Selvedges are often used in prodding projects also.
Fold the wool in half; snip at the fold and rip. See the diagram above. You now have a fat 1/2 or a fat 1/4 yard.
Fold each section in half, in half again and in half once more as shown in the diagram below. Your folds will be parallel to the selvedge. Your finished bundle is approximately 3 ½” wide and 18” long.
Snip at each of the folds, two on one side and one thick one on the other.
This will give you a section of 8 swatches, the equivalent of ¼ yard if you originally measured 18” long.
Rip each ¼ yard piece into sections of the desired size. For sky and grass I use a piece 4 swatches wide @ 18″ long (a swatch set). If you need more to cover the space you are going to hook, use more swatch sets. For spot dyes and backgrounds I use the full ¼ yard piece.
Soak to wet the wool and dye as desired.
I recommend synthrapol or other wetting agent that is pH neutral. Soaking in soap will affect the pH level and require more acid to set.