Growing Blue





Introduction: Growing Blue

The allure of indigo has always fascinated me. I've purchased blue powder and dyed yarns in the past, but always wanted to do some batik fabrics. This was the year. And to actually grow the plants that will produce the color blue. Blue is elusive in the plant world, a few flowers like forget-me-nots or hydrangeas are blue, but you can not extract a blue dye from them. There are several plants that contain the chemical indican from which you can produce a blue dye. They include woad, dyer's knotweed,  Indigo tinctoria, and I. suifruticosa.  I planted dyer's knotweed (polygonum tinctorium), as it was the easiest to obtain seed, and also to grow in my area of the Midwest. 

Step 1: Planting and Growing

I ordered seeds from an indigo project undertaken by Rowland Ricketts at Indiana University. I started the seeds indoors under florescent lights as they require a long growing season. It has definitely been that, this year, but one never knows. (We still have not had a frost the middle of October.) Because of a late wet and cold spring I did not plant them into the ground until the beginning of June. They grew well in my organic plot at the community garden. I perhaps planted them too close together, but they produced more than I needed for my first year of experimentation. 

Step 2: Harvesting the Plants

The information I read said to pick them in the August or September, when the leaves are starting to show a blue tint from crushing or insect damage. I cut a few plants and let them wither to see what would happen. Yep...starting to look blue!

Step 3: Direct Dye Processing

Now comes the tricky part. How to get that blue chemical out of the plants and useable as a dye that is light and wash fast. I chose the easiest method I could find. I just couldn't wait the months of fermentation and knowing it is a very smelly process I didn't want to run my husband off from the stench. What I did: I plucked the leaves and put them in a large pot. I added water to cover, and set it on an electric hot plate in the garage. I turned it to medium heat, as you want it to heat slowly for about 2 hours, keeping the temperature below a simmer...about 190 degrees. After about 2 hours, I turned off the heat and let it sit in the pot to cool down. It took on a metallic sheen, which I knew was correct. Then I strained it into a couple gallon jars through an old tea towel. If you dipped the fabric or yarn right in this liquid, or even simmered it, as you generally do with other natural dyes, you would get a color, but it would not be blue. Most likely green or yellow. Strange but true! You have to "reduce" the dye bath, or take the oxygen out of it. I accomplished that by using Rit Color remover. It's cheap and easily available. One and one-half tablespoons for the gallon of dye, stirred in and left to settle.

Step 4: The First Dip

Because I had to go to work, and sleep, and eat, and all that good stuff, my dye bath cooled off in the garage for a couple days. For the best dying you need the bath warm. For that I set the jar in a bucket of hot water. It only took about a half hour to come up to temperature, about 90-100 degrees. After the deoxidization the liquid becomes yellow. I dipped the yarn into the bath and it comes out yellow. As the yarn hit the air, the oxidation started immediately to turn green and then blue. 

Step 5: Now the Fun Begins...

With the test run of the yarn, it was time to try fabric dyeing. I used 100% muslin cotton fabric that I boiled for 2 hours to remove any chemicals or gums that are in the cotton to make it more receptive to dye. I tried a few things to create patterns. Wax resist and stitch resist were the most successful. For the wax I used soy wax. It comes out of the fabric easier, with hot water, melts at a low temperature, and is easy to find at a craft store. I used a few things to make patterns, a simple wire wound in a spring, a chicken wire piece of scrap I found in the garage, a tjanting tool, which is available from dye companies, like Jacquard, and a cookie cutter. I simply melted the wax in a small disposable tin baking pan and dipped the instrument into it, and then pressed it on the fabric. The tjanting tool is dipped in the wax to fill the reservoir and then you draw an image on the cloth. 

Step 6: Stitching and Resisting

Another method to use in creating a pattern is stitch resist. I drew some lines on the fabric and stitched a running stitch following the lines. Then I pulled it tight to gather up the fabric, making parts of it resistant to the dye. When the fabric is complete with stitches or wax resist it is simply dipped in the dye bath, pulled out to oxidize, and voila! decorated fabrics of your own making. After the first dip and oxidation you can dip again and again, each time letting the blue color come through before proceeding to the next dip. Each time will intensify the color. 

Step 7: Start All Over Again

And now what?  Well, save some seed and plant next year's crop for even more fun and beautiful indigo cloth. Let a few of the plants go to flower, and eventually seed. I've picked some to see if the seeds were evident. Yes, they are. I just hung them in bunches to dry and then rubbed the flowers to see seeds dropping out. I will keep these till next spring and start again. 

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    In step 3. After you strain the leaves out of the pot. Add the color remover and stir gently until it is dissolved. I let it sit for about 30 minutes to an hour for the reduction to take place.You can dip the yarn/cloth at this point, or I have let it sit for a day, and then warmed it up to to about 100 degrees before dipping. (I just did it again last week with this years' crop. Did you grow it?)

    At what step do you add the color remover?

    When you say to cover do you mean just covering leaves or to the top of the pot?

    1 reply

    The water should be deep enough to cover the leaves. You do not have to put a cover on the pot.

    Qué lindo el proceso que hiciste , fantástico

    1 reply

    Growing and using indigo was so exciting. Green leaves to blue dye. Just amazing. Give it a try!

    Where do you get it? How do you do it?

    oh just a harmless minecraft reference. In minecraft, you dye wool blue by combining a lapis lazuli ore with a wool block

    oh...that's too easy...a click and it's done!

    I think it would be cool to grow some but it's is easier to get my hand on some woad. It is an invasive species and is taking over some very big plots of land here in Utah.

    1 reply

    I grew some woad too. I did not have much luck with it. This dyer's knotweed seemed to have more indican in it. If it grows wild, definitely give it a try. I don't see it around here.

    Thank you SO much for sharing this. I have been dying for a natural dye for the cotton I grow on my patio here in the south. I can grow the indigo right next to my cotton, how cool. I have a small collection aizome fabrics from Japan and would love to make my own. Thanks and great 'ible. Your results are stunning and inspiring! Do you have any indigo seeds for sale?

    3 replies

    How exciting to grow cotton! The beauty of indigo is that it works on all natural fibers and doesn't have to be boiled like other natural dyes. I'm hoping to use it on linen soon. I wish I had thought ahead enough to save more seed, but only have enough for my small plot. Maybe next year. Glad you enjoyed the 'ible!

    Yeah I've been trying to find ways to dye my cotton balls before spinning, without mordant or commercial dyes. So I've been looking at turmeric, saffron, ochre, onion, and straight up iron oxide, all of which are in the yellow and orange tones and not the easiest to obtain. Growing indigo will make the pigment practically free and I love gardening so this is perfect. I can't wait to get my hands on some seed and try it. Thank you so much!

    I grew a few other dye plants in my little plot this year also. The most rewarding were weld (a very clear yellow) and dyer's coreopsis (which produced a rich rust color with varying shades of peach in lesser proportions) I over-dyed the weld dyed wool with indigo and got an interesting green. So many possibilities! Today we have snow flakes, so my gardening days are over for a few months...

    So cool how it changes colour as it oxidizes!

    You might try cooking the leaves in a crock pot so you could keep it going all night (assuming longer simmering time = stronger dye, which might not be true.)

    1 reply

    A crock pot is a great idea--less watching the pot. You have to have a dedicated pot, as you don't want to mix food with craft ware. Will have to go to some yard sales and find one cheap. I don't think longer time simmering would produce more dye. There's only so much pigment in the leaves. I know I will do a lot more experimenting next summer! It was so much fun.