by Jackie Heller
Last January I came across a small jar of indigo seeds from a harvest that I planted 3 years ago. I obtained the original seeds of Japanese Indigo (Persicaria Tinctoria) from my weaving/spinning/knitting mentor, Selma Miriam of Westport, CT. Not knowing if the seeds were still viable, I decided to plant all of them in peat pots to see if any of them would sprout.
I placed the pots in a sunny window and regularly watered them. Much to my delight, little sprouts started coming through the soil after about 1 month. By early March, I transplanted the seeds to a large, oblong, cast iron filigreed planter lined with a cocoa mat and filled with rich potting soil. I watered and protected the seedlings as they grew, netting them to discourage wandering deer and rabbits. The indigo grew very densely with regular watering. Flowers started to form by the end of August. Since I wanted more seed for next year, I let the indigo flower, but not for too long a period of time. Fresh leaves provide the best color
My harvest took place on September 11, 2021. I cut off the flowering leaves and will dry them out for seed. With a digital scale at the ready, I stripped 8 ounces of leaves from their stems (4 ounces at a time) and placed the leaves in 2 large glass pickle jar containers.
I filled the jars with hot tap water, enough to completely cover the leaves. I placed the lids on the jars and placed them in a large pot. I put a rack on the bottom of the pot so that the jars were not sitting directly on the bottom of the pan. I slowly heated the water to 160 degrees over a period of 2 hours. Using a candy thermometer keeps an accurate check of the water temperature.
In the meantime, I soaked my yarns in 2 pans with hot tap water. I used 4 ounces of a wool/silk handspun and 4 ounces of Faro singles wool. The yarns need to be very wet and saturated before dyeing. No other mordant is needed when dyeing with indigo.
Once the leaves had simmered for the 2 hours, the liquid was darker—a grayish brown color. This is called indoxyl. Wearing rubber gloves, I strained the dark liquid into a bucket, squeezing all of the moisture out of the leaves. It was sad to discard the leaves—but their job was finished. I added 1 tablespoon of ammonia to the liquid. This makes the solution more alkaline. With the help of Sharon Hussey, we proceeded to pour the liquid from one bucket to the other. As the liquid reacted with the oxygen in the air, its color turned to a dark blue/green. We kept pouring it back and forth for a few minutes. It’s actually very gratifying to watch the color develop.
The next step was to add a tablespoon of spectralite to the liquid. The Woolery sells it by the ounce. You may also use RIT color remover for this step. This is a color reducer. It will turn the blue/green liquid to a clearer yellow shade. We poured the liquid back into the pickle jars, covered them and placed them back into the water pot on the stove. This was heated to a temperature of 100 to 120 degrees for about 1 hour. Don’t overheat the water.
Now the fun part! We poured the liquid into a bucket, then added the yarn and let it sit for about 20 minutes. Sharon carefully lifted out the yarn, shaking it a bit, letting the air hit it. After a few seconds you could see the blue begin to bloom on the yarn.
We kept dipping the yarn and airing it until the dyebath became exhausted. From start to finish the procedure took about 5 hours.
