Indigo: Magic of Dyeing

It was four months ago since I planted the indigo (polygonum tinctorium) or Japanese indigo. The plants were easy germinate, but I must say they do need a lot of care and attention. It was my first time growing them so I had to do it right. I had to water them daily and it wasn't easy when we went away at Christmas time. Luckily our dear neighbour kindly looked after them for me. I thought I had to wait until they flowered before I could harvest them, but after reading and reading I learned that if the leaves turned blue when bruised they are ready to be picked. The plants were starting to suffer from being in pots so I thought it was time to harvest them. 

I wasn't sure what I was supposed to do, but thanks to my friend Ingrid in the Netherlands for giving me some advice on how to process the fresh indigo leaves. I recently bought a book, A Handbook of Indigo Dyeing by Vivien Prideaux, from Ziguzagu. In the book there is a section on how to process fresh indigo leaves and it was coincidentally the same method as that given to me by Ingrid. I took the plunge and started cutting the branches from each plant. I did remember to leave two to three nodules on the plants as they should start growing more leaves after two or three weeks.   

The plants were all looking happy that morning because I had given them lot of water the night before. They are such thirsty plants I must say. 

It took me a couple of hours to cut all the branches and to strip the leaves from the stems. I didn't weigh the leaves so I don't know how many kilos of leaves I ended up with, but it was a lot. I now got all the stems left and I wander if they can be used in eco-dye! 

I read somewhere on the internet that I should cut the leaves into very fine pieces. Luckily I had hedge clippers that were perfect for the job. Then I added water and kneaded the leaves until the liquid turned dark green. That part was fun. 

Next I packed the chopped leaves in a glass jar and packed the leaves tightly in the jar filling the jar with cold water. I then stood the jar in a large saucepan on a trivet, forming a double boiler. I used my preserving boiler for the job. Over the course of an hour, I brought the temperature up to 71'C (160'F), certainly no higher than 82'C (180'F) and then turned off the heat. I strained the liquid into a plastic bucket.

To make the dye alkaline (pH 7.5-8) I added half a handful of washing soda. A few drops of ammonia will also work for this. The liquid will turn a dark green colour. Now I aerated this liquid by pouring it back and forth between two containers for about ten minutes. The liquid should turn greenish-yellow with a blue froth. I added half a teaspoon of sodium hydrosulphite per 4.5 litres (1 gallon), to reduce the solution. I left it standing for 30 minutes before starting to dye.  I have half as many leaves for the next batch.

I prepared some Shibori for dyeing. I didn't know how much fabric I would need for this batch so I prepared quite a bit of fabric for it. To my pleasant surprise it dyed beautifully. Also the smell of the vat was like walking on a newly cut lawn in a flower garden. It was late so I didn't have time to rinse what I dyed. The next morning I woke up and rinsed all the dyed pieces. This is the best part of dyeing - undoing the stitches of Shibori pieces!

The rest of the day I repeated the same process with the leftover leaves. I got a bit more adventurous with the second batch.  I used litmus test paper and discovered that the vat needed more washing soda and sodium hydrosulphite, so I added two tablespoons of washing soda and one teaspoon of sodium hydrosulphite to the vat.

Not wanting to waste any dye I stitched up my cotton t-shirt and put that in at the last minute. The colour is not that dark in real life. I took this photo when it was still wet. I also did some plain dying with the cotton fabric I have.

I have learned that recycled or vintage fabric is not suitable for indigo dye. Indigo dye shows every blemish on the surface of the cloth. Also you need pure white fabric to get a clear blue result. I did use some off-white fabric and it turned out a kind of dull blue. I also found that you must rinse the fabric as soon as you are happy with the colour. If you leave the fabric too long after the last 'dip' unwanted yellow streaks will appear. I also over-dyed some of my eco-dyed fabric, but nothing exciting happened to them.

Well it has been a lot of fun and quite challenging. At least now I can say that I grown my own indigo and dyed with them. I'm not sure if I will do it again though. I need a field full to grow enough indigo for a fermentation vat and it's not for me!!!

Until next time

Nat