06 September 2010

Woad: blue stuff from green stuff

This year, I grew some woad in the garden (seeds from Richters, of course).

Translation for non-fibre artists, and those unfamiliar with Celtic warriors:

Woad is a plant that contains the same blue ‘stuff’ as indigo, which is what your blue jeans are dyed with. Celtic warriors painted their faces blue to scare the enemy (Braveheart, anyone?) and as the indigo plant, which has higher concentrations of the dyestuff in it, won’t grow in colder climates, woad is how blue dyes and paints were made in the northern parts of the world for centuries.  

Yesterday evening, I picked some  of the leaves from the garden… and a good thing, too, as we had a hard frost last night (and woad doesn’t do blue after frost). This morning, I followed the instructions from here and here to extract indigo out of the woad.

The first batch I did turned out … the second didn’t. I heated the second batch differently, but more than that, I think it was that the leaves for batch #2 were harvested this morning … after the aforementioned killer frost. Hmmm.

The successful method worked like this:

  • harvest the woad leaves: in my garden, all kinds of stuff got mingled together so I wasn’t always sure what was woad … if you squish the leaves they bruise to a blue-green colour, so you can confirm what you’re working with
  • leaves sat on the counter overnight, wrapped in a damp tea towel
  • tore the leaves into bits
  • boiled a pot of water and when it was good and bubbling, scooped some into a glass jar which I set in the pot as a double boiler type contraption
  • added a glug of vinegar to the jar of hot water
  • added the leaves, handful by handful, stirring in with a spoon
  • got a bowl of cold water ready in the sink
  • after all the leaves were in and the whole mess heated for about 5 minutes, transferred the jar to the cold water to chill
  • stirred, added ice cubes to the water and replaced with cold water for about 10 minutes until the liquid was noticeably cooler
  • got the soda ready: dissolved a generous scoop of washing soda in hot water, cooled that as well
  • let the leaves sit in the cool water bath for a total of 20 minutes from when they left the hot water
  • strained the leaves out of the cooled mix
  • added soda mix to the leaves: everything went from green to brown!
  • poured from one glass jar to another back and forth until the liquid was very definitely blue
  • poured into 2 jars and let settle
  • 2 hours later, precipitation was obviously happening: blue granules were settling on the bottom

We now have 2 jars with a greenish liquid on top and blue granules on the bottom! Very awesome. I’ll let it sit overnight and then the instructions say to rinse the top liquid (remove and replace with clear water) repeatedly until it is clear on top and blue sludge on the bottom. Then we’ll remove the last of the water and let the powder dry out. I’ll probably try doing that directly in the glass jars.

This was the coolest mix of gardening and chemistry ever. I’m definitely growing more and trying this again next year! Of course, to dye wool or fabric with this requires a whole ‘nother adventure, but wow … I made blue stuff out of green stuff that grew from seeds! Too cool!


  1. That is very cool. Show us pictures when you've got some of your wool dyed. This is the first year I grew anything that was of little value as beauty or food. Comfrey for my compost and calendula for cream. Oh, and cabbage as chicken food, but I guess that's still food.

  2. I grow a fair bit of medicinal stuff, and nothing at all for beauty alone. :) It shows, too.

    However, I discovered that borage is super pretty - I'll be planting that out where it can spread and be admired! And we have calendula gone absolutely insane around here - I love it for ointment, and it is a dye plant and tea plant as well.


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