My most recent natural dye experiment was natural indigo ice water dye for wool yarn. After standing in the garden and staring at a rather large patch of Japanese indigo, I searched for ways to use the fresh leaves for dye. Knowing that the color did not last long with fresh indigo leaves, I wondered how folks used the plant besides quickly dehydrating it for powder used in vat dyeing. In these situations, I am grateful we have the internet to search for information.
Indigo ice water dye came up in my search results. I had not heard of this method before. On two occasions I have worked with traditional indigo vat dye and loved the results. I knew that this method would yield something different but I had a surprise in store for me. Natural dyes demand that you expect the unexpected. I should have known better as natural dyes can be very surprising!
Reading through a few of the articles using the Indigo ice water dye, I saw photos and descriptions of lighter blue and aqua and teal results rather than the traditional blue jean shade of indigo. Ok, I could live with that. I grabbed a few skeins of our Finn wool yarn and the rest of the supplies.
Where Does Indigo Dye Come From?
Japanese Indigo, Polygonum tinctorium and sometimes referred to as Persicaria tinctoria, is an easy to grow annual. I started my indigo patch with one tiny seedling, purchased at a fiber festival. That tiny plant grew enough leaves for me to dye 600 grams of wool yarn. I saved the seeds, and next year I will plant a larger patch and try some of the other techniques for using indigo.
The process of using the fresh leaves from the indigo plant requires that you work quickly and don’t let the leaves start to dry out. I chose a cool day to attempt this, so ambient temperature would not help dry out the leaves. In addition, I gathered all the other tools and supplies I would need before I cut the fresh indigo. It took me about 8 minutes to strip the leaves from the stalks. You only want to use the leaves as that is where the indican, the precursor to indigo dye, is stored.
Materials and Tools for Indigo Ice Water Dye
A blender was the only tool I didn’t have on hand for this experiment, but I located an inexpensive blender quickly. Although Indigo is not a toxic plant, it is also not one that we eat. I prefer to keep my dye pots and utensils separate from our cooking gear, so I will be keeping this blender in my dye work area and not in the kitchen.
(you can watch the video of this process on my you tube channel and it’s further down in this post, too.)
In addition, you need a large bucket or stock pot, a large fine mesh strainer or fine mesh cloth for straining the leaf smoothie. Rubber gloves are a good idea, particularly if you have sensitive skin. Fresh cut indigo needs to be kept chilled. Have a container of ice water ready to stand the cut stalks in while you harvest the leaves from the stems. You also need more ice cold water or ice cubes and clean water to process the leaves.
I initially collected about five cups of the indigo plant leaves. Working in two batches, I put half the leaves into the blender filled halfway with ice water. Looking back, I probably had too many ice cubes in the blender and will pre chill the ice water next time. I mistakenly thought it needed ice and water, when in fact, it calls for ice cold water.
Blend the leaves and the ice water together to make a green smoothie. It will be a bright green liquid. Strain the leaf and water mixture through the fine mesh and into the large bucket or pot. Repeat with the rest of the leaves. Once you have all the leaves processed through the strainer, it is time to add the yarn or fabric. Pre-wetting is helpful in getting the yarn to sink into the dye liquid. Mordanting is not necessary with Indigo dye.
Push the yarn down into the dye liquid until it is saturated. Try not to agitate the fiber while it is in the dye pot. Let the yarn soak in the dye for at least 20 minutes. Pull the yarn out of the dye and feast your eyes on that gorgeous bright green color! I remember that with vat indigo techniques the yarn is green for a few moments as it oxidizes so I waited for the change to begin occurring.
And I waited, and waited and waited. The bright green subtly changed from bright to less bright. But it still remained green! The color darkened somewhat, but no blue was showing up. Did I do something wrong? Was this color even going to last?
I contacted two dye enthusiasts that have more experience than I do. Both of them reassured me that this was the common result from indigo ice water dye on wool. Silk will turn more turquoise or shades of light blue, but wool remains a green shade.
The remarkable thing about this is that green results from only one dye process. Most greens from natural dyes are the result of modifiers and mordants, as yellow is the predominant color from green plant matter.
Final Step in Indigo Ice Water Dye Method
To finish your yarn dyeing, allow the yarn to dry almost completely. Next, soak the yarn in a solution of 25% white vinegar and water for about 20 minutes, to set the color. Rinse completely. You can use a small amount of gentle soap or conditioner intended for care of fine wool.
Watch the Video of Making Indigo Ice Water Dye
Other Methods For Fresh Indigo Dye
One source I enjoyed reading, describes a method of creating a traditional indigo vat using the fresh leaves. While not as simple as the indigo ice water dye method, it is something that I will try next year when I have a larger crop. Katie, from Acanthus House blog also clearly explained the chemical process of the indigo vat dyeing method, in laymen’s terms.
The indigo ice water dye method is convenient and quick. If you grow a small patch of fresh Japanese indigo, this method is a great way to use the color grown in your own garden. It’s quick and easy, which is good, since indigo is easy to grow but frost sensitive. I am glad I harvested the leaves and saved the seeds from the flowers before the first frost.
Here are a few of my other favorite books on natural dyes.