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Natural dyes – my first woad vat

I have been interested in natural dyes ever since I started making felt.

Apart from it being an obvious link between my two favourite activities (gardening and feltmaking), the colours are exquisite. Extracting dye from plants is as ancient a craft as feltmaking itself, and is a skill that needs to be kept alive. Besides I get an awful lot of enjoyment from gathering leaves and flowers.

As a partner in Vallis Veg Boxes – an excellent local veg box scheme! – I have easy access to plenty of vegetable waste and I had already tried my hands at dyeing with onions skins and other vegetable matter. But I was really intrigued by woad because of the lovely blue colour,

although slightly put off by what appeared to be quite a complicated process. At school, science was never my strong point and this seemed too … well… scientific!

Via a friend I heard about Caroline Griffiths, a local woad enthusiast and experienced dyer. I attended some of her dyeing demonstrations, which made the process seem much more accessible. Caroline kindly gave me plenty of pointers and advised me to grow “quite a few” plants to make sure I had enough for my needs

So, in spring 2011 I sowed 2 lots of seeds at an interval of 3 -4 weeks and ended up with 50 plants that were ready at different times, hoping to have at least 2 days to get to grips with the dyeing. The woad was very easy to grow and most unfussy about soil or other conditions; I grew them in quite compacted, clay soil with fairly generous addition of well rotted manure, on a very exposed and windy site. After initial watering in I hardly did any watering at all, and the rosettes quickly grew big enough to self-mulch. Had I grown them a bit closer together I reckon I would have had even fewer weeds to deal with.

On 25 July 2011 the time came for my first woad vat and my son Arran and I spent a beautiful sunny day making fire, gathering leaves and experimenting. All in all we harvested 7.7 kg of leaves with which we dyed 1kg of Shetland fleece and 0.7 kg or Romney fleece. We could have picked more leaves, but we ran out of wool to dye!

1) My 4 year old assistant in among the woadMy 4 year old assistant in among the woad

2) Rows of woad in between rhubarb (R) and tomatoes (L)Rows of woad in between rhubarb (R) and tomatoes (L)

3) Arran harvesting 7.7 kg of leavesArran harvesting 7.7kg of leaves

4) Weighing the leavesWeighing the leaves

5) 1st lot ready to be steeped in nearly-boiled rain water to extract pigmentFirst lot ready to be steeped in nearly-boiled rain water to extract pigment

6) After an hour, the water is brown and smells distinctly cabbage-y!After an hour, the water is brown and smells distinctly cabbage-y!

7) Straining off the liquid and squeezing excess fluid out of the leavesStraining off the liquid and squeezing excess fluid out of the leaves

8) Pouring liquid back & forth, after adding baking soda to make it alkalinePouring liquid back and forth, after adding baking soda to make it alkaline

9) Indoxyl reacting with oxygen in the air, changing it into indigoIndoxyl reacting with oxygen in the air, changing it into indigo

10) Adding reducing agent to prepare the liquid for dyeingAdding reducing agent to prepare the liquid for dyeing

11) Keeping the temperature even, whilst waiting for liquid to turn yellowKeeping the temperature even, whilst waiting for liquid to turn yellow

12) First batch of Shetland wool in the dye bathFirst batch of Shetland wool in the dye bath

13) When removing the wool, it react with oxygen and turns blueWhen removing the wool, it reacts with oxygen and turns blue

14) Extracting 2nd colour from the spent leaves, by boiling it with woolExtracting 2nd colour from the spent leaves, by boiling it with wool

15) Two colours from one plant, how amazingTwo colours from one plant – how amazing

16) Beautiful blueBeautiful blue…

17) And dusky pink… and dusky pink

18) Spent leaves after draining, ready to be compostedSpent leaves after draining, ready to be composted

19) All that's left on top of the compost heapAll that is left on top of the compost heap

20) Rows of woad ready to re-grow for the second harvestRows of woad ready to re-grow for the second harvest

  1. why is my woad giving me pink/lavender yarn?

    Reply

    • Did you aerate the liquid?

      Dyeing with woad is a type of indigo dyeing that incorporates a few more steps than ordinary plant dyeing. The following is not a recipe with exact amounts, just an indication of the steps in the process.

      First the dye has to be extracted from the fresh leaves by pouring almost boiling water over the leaves to scald them. Cover this container and let it stand for an hour or so.

      Strain off the liquid into another pot, squeeze the liquid out of the leaves into this pot (do not throw these leaves away, as they can be used to produce a pink colour from a second, ordinary dyebath). This liquid contains something called indoxyl, whih is a precursor to indigo. Add baking soda or ammonia to the fluid to make it alkaline (the liquid should be dark green), then whisk the fluid vigurously or pour it back and forth between 2 containers. The indoxyl will react with oxygen in the air and turn into indigo. This is the aerating process that I think you missed out. Keep aerating until for a few minutes after the froth has turned blue.

      Pour the dye liquid in a dyepan and warm to 50C. Dissolve some reducing agent (spectralite) into some warm water in a jar, and add to the dye liquid. Stir briefly. Cover the dyepan and keep it at a constant 50C. Do not stir. Meanwhile soak your yarn/wool in hot water (no need to mordant it first). When the dyebath has turned yellow, add your pre-soaked yarn by carefully lowering it in. Leave to soak for about 20 minutes or so, then gently lift it out of the bath. The yarn will turn from yellow to blue as it reacts with oxygen in the air. You can carry on dyeing successive batches of wool with the same dyebath until the colour is exhausted.

      For preccise recipes, consult a book such as:
      A dyer’s garden by Rita Buchanan
      The craft of natural dyeing by Jenny Dean

      Hope that help!

      Reply

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