How to Extract Indigo Dye Pigment From Leaves

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How to Extract Indigo Dye Pigment From Fresh Leaves: A Step-by-Step Guide

In this post and video, I’m sharing how I extract indigo pigment from the leaves of the Japanese indigo plants (Persicaria tinctoria) that I grow in my dye garden. While I’m not a master or expert, I love practicing this ancient craft that has been passed down for a long time through many cultures. People have developed many different methods of indigo pigment extraction over thousands of years, and even today there are many natural dyers who have far more knowledge and skill than I do.

Everything I share here comes from my own experiments, combined with what I learned in greater detail from a course by The Dogwood Dyer. What I want to do in this blog is show you my experience and hopefully encourage you to try your own natural dyeing journey.

Enchanted by Natural Dyes

I’ve always been drawn to dyes. As a teenager, I loved using RIT dye and bleach to transform thrifted fabrics and old clothes into something new. Using plant-based colors was a natural extension of that love. When I discovered that people had been using plants like indigo, madder, and weld for centuries to create a brilliant blue dye or deep reds and yellows, something inside me lit up.

I didn’t start right away. I spent a year or so reading books, watching videos, and learning about different ways to set up a dye bath or prepare fiber. Eventually I bought an indigo dye kit, set up my first small indigo vat, and dyed a piece of white cloth. The moment it turned indigo blue was magical. The simple process of dipping fabric into what looked like green liquid and watching it turn dark blue when removed felt like alchemy.

From that first experiment, I moved into other plant colors—coreopsis flowers, madder roots, walnut hulls—and started dyeing raw protein fibers like wool, angora, and silk, as well as cellulose fibers like cotton and linen. Eventually I planted my own fresh indigo leaves in the garden. Growing indigo at home feels like connecting with an unbroken chain of artisans and farmers who cultivated indigo leaves for generations.

Indigo Pigment Extraction Methods

There are several indigo pigment extraction methods, and each one yields slightly different results. In this tutorial, I’m focusing on a traditional simple process of fermenting fresh leaves and binding the pigment with calcium hydroxide (commonly called pickling lime). This is a quick, gentle, and accessible method for home dyers, and it works beautifully even in small batches using plastic bins, a 5-gallon bucket, or even a mason jar or glass jar.

How to Extract Indigo From Leaves:

Equipment:

• a large plastic or glass container, with lid. I recommend a 5 gallon bucket or plastic trash can with wheels.
• a flat paving stone to weigh down the indigo leaves
• water (rainwater or tap water is fine)
• calcium hydroxide
• ph test strips
• mask
• gloves (this isn’t a toxic project, but the liquid is very drying to the skin and could irritate your skin)
• something to froth the liquid, such as a whisk, rake, or aerator pump.
• straining equipment. For small batches, a mesh strainer and coffee filter will work. For large batches, I like using this 25 micron strainer, or a large mesh strainer and a tightly woven silk or cotton bandanna.

Step 1: Harvest and Prepare

Wait until your Japanese indigo plants are about 2–3 feet tall. Cut them down to about 8–10 inches above the soil, leaving old leaves and nodes so the plant can regrow. This way, you’ll get another harvest in about a month.

Step 2: Ferment the Leaves

Place the freshly cut plant matter into a plastic bin or 5-gallon bucket. Cover with warm water or hot tap water if the day is cool, making sure all the stalks are submerged. If the weather is hot, you can just use water straight from the hose, as it will warm up quickly. Weigh them down with a stone or brick so no plants are floating at the surface of the water.

Cover and let ferment for about 24 hours. The exact time depends on ambient temperature—on a hot day it may be quicker, while in very cold water or cooler weather it can take longer.

You’ll know it’s ready when the water turns aqua and gives off a sweet, slightly sickly smell. This is a good sign that the indigo pigment has been released into the water. If left too long, the contents of the jars or buckets can over-ferment, leaving slimy, brown stalks and little pigment.

Step 3: Remove Plant Material

Strain out all the plant matter. At this point the indigo pigment has moved into the water. If you wait too long, the pigment can break down and you’ll get little pigment.

Step 4: Alkalize the Liquid

Slowly add pickling lime (calcium hydroxide) to the liquid. Stir well and check with pH strips until you reach a higher pH of around 10–11. Be sure to wear a face mask when using the pickling lime.

Step 5: Oxidize

Now it’s time to add oxygen. Stir vigorously, whisk, pump, or pour the liquid between containers. A metal rake or even your gloved hands can work. The liquid will froth and the aqua color will deepen into a rich dark blue. This usually takes 10–20 minutes.

Step 6: Let the Pigment Settle

Cover and leave the liquid undisturbed so the pigment sinks to the bottom of the container. You may see clear water or yellowish excess liquid at the top of the water and dense powdered pigment at the bottom.

This settling stage can take hours or even days, depending on how much pigment is present. To keep an eye on it, pour some into a glass jar or mason jar and set it where you can see the contents of the jar settle.

Step 7: Pour Off the Liquid

Carefully pour away the remaining liquid from the top of the water without disturbing the pigment at the bottom. Pour the liquid into a separate bucket and neutralize it with vinegar before disposing of it, since it’s alkaline. Use PH strips to check that the liquid you’re dumping is PH neutral.

Step 8: Filter and Dry

Filter the pigment through a coffee filter, silk cloth, or micron strainer. You’ll be left with damp, dense indigo paste. Let this dry at away from direct sunlight, until it forms a fine indigo powder.

Step 9: Store Your Indigo

Once dry, crush the pigment into a smooth powdered pigment and store it in a mason jar or airtight container. You’ve just made your own natural indigo dye!

Step 10: Repeat

When your Japanese indigo leaves grow back to about 12 inches tall, you can repeat the process. A healthy plant can give you multiple harvests, and next time you might experiment with different methods or try dyeing directly with fresh indigo leaves.

Using Your Homemade Indigo

Now that you have your own indigo powder, you can use it to make an indigo vat. The next step is combining the pigment with a reducing agent like fructose or henna to create a living vat for dyeing protein fibers and cellulose fibers alike.

Dyeing with indigo has a fascinating history—after all, it’s the color of blue jeans and one of the most recognized shades in the world. Unlike acid dyes or synthetic dyes, natural indigo dye connects you to the land, and the generations of farmers who tended indigo fields.

With your pigment, you can dye fabric, yarn, or fiber for spinning. I often use my homegrown indigo for making batts for handspinners, but it works just as well for a white cloth napkin, a mesh bag of wool, or even a simple bandanna.

Extracting Indigo: A Plant Lover’s Dream Project

All that work extracting indigo those beautiful green leaves, and I haven’t even started dyeing yet. But to me, extracting indigo pigment is just as fun as dyeing wool. I love working with raw materials -the rawer, the better. That’s why I felt drawn to natural dyes. Give me plants and flowers to play with! I would much rather handle those than chemical dye powders -it’s much more fun.

I exclusively use natural dyes in my shop. I regularly use indigo to dye fiber for making batts for hand spinners. I also dye fabric, bandannas, or yarn to use in weaving and knitting. It’s important to me that my batts and other products I sell always have close ties to the earth, and a strong human touch. Click below to purchase naturally dyed products from my shop!

Soulful Dyeing With Indigo

Extracting pigment may sound complicated, but it’s truly a simple process once you’ve done it a few times. Each stage—the fermentation, the frothing, the waiting—is part of a rhythm that connects you to the seasons and the plants.

Working with fresh leaves in my dye garden has given me not just jars of indigo powder, but also a deeper sense of connection. Indigo rewards patience: a little plant material, a few gallons of water, and some care can transform into the brilliant blue dye that colors the world.

I hope you feel inspired to try your own indigo project. Whatever method you choose, the reward is always the same: that first glimpse of good blues when the fiber turns indigo blue in the air.

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👉 Have you ever tried any indigo pigment extraction methods? Tell me in the comments—I’d love to hear about your experiments and what you plan to dye next time!