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Plant Dyeing with Oak Galls

Oak Galls

Oak galls can be known under different names In the United Kingdom we have oak knopper galls. They are fantastic for natural dyeing as they contain high levels of tannin. Depending where in the world oak galls have been foraged from, their shape and size can be very different. 


Oak galls are formed when gall wasps lay their eggs on the branches of an oak tree, the tree reacts to this embedment of eggs by growing a hard ball which is the oak gall. The gall develops over the summer months and then falls to the ground around late August/early September. 


I foraged for oak galls in the last week of August. I’m fortunate to live near an oak tree however if you need to source them online, themazi natural dyes supply the most amazing products including oak galls.

What you need

  • The fabric which you have chosen to dye. This must be a natural material such as linen, cotton or silk. 

  • Soya milk to treat the fabric in preparation for dyeing. 

  • A container to soak the fabric in soya milk

  • Dye pot - I always you aluminium as this will aid the dyeing process. 

  • Oak galls - I use a ratio of 55grams to 200 grams of fabric (Depending on the desired shade of black the measurements can be altered). 

  • Muslin cloth and a second container for straining the dye.  

  • Wooden spoons - to stir the fabric in the dye pot. 

  • Scales to weigh your fabric and oak galls. 

  • Metal sieve


"I always use reusable gloves when handling dyed fabric"

Preparing the fabric for dyeing

The first thing you want to do is scour (wash) the fabric to remove any oils or dust, this step will aid the dye to attach to the fabric. I wash all my fabric in a domestic washing machine at 40°C  only for the first wash and to do a shrink test. I don’t use any detergent at this stage of the dyeing process.


Once your fabric has been scoured you are ready to mordant (pretreat) your fabric. I use soya milk to pretreat all my fabric (and on a good day I make my own soya milk). Shop bought or homemade the results are much the same from my experience. 


I add 500mls of soya milk to 1 litter of water and allow the fabric to soak for 12-14 hours. The fabric is then put back into the washing machine on a spin cycle and then hang to dry. I repeat this process 2-3 times, then label the fabric with the date and pencil in my diary when that particular batch is ready for dying.

"Always keep dyeing equipment separate for studio/dyeing use only"

Making the dye

Plant Dye Bath
  • To make your dye bath you will need 55grams of oak galls to 200grams of fabric. This will create a beautiful dark black shade.

  • 2 liters of water

  • 2 level teaspoons of ferrous sulphate crystals 

"I always soak my fabric in warm water a few hours before dyeing as this aids the colour to attach to the fabric and gives a more even coverage."

Let's get started.......!!

Oak Galls

Place the oak galls in the muslin cloth and crush them into smaller bits with a hammer. 


Add the crushed oak galls into your dye pot and add the water. 


Simmer for 30-40 minutes - watch carefully as you don’t want the oak galls to burn. You can add more water at this stage if needed. I tend to add about 100 mls more. 


Remove from the heat and allow the dye to cool down. I usually give 2-3 hours for the dye to completely cool. You can leave the dye for longer as this will intensify the colour/shade. 


Strain the liquid with a muslin cloth to collect all the crushed oak galls. This can be a bit tricky so I find using a metal sieve really helpful, as the sieve can sit over the top of the pot you are decantering into lined with the muslin cloth. 


If you want to reuse the oak galls, simple spread them out on a hard surface and place in a warm area to dry out. I reuse my oak galls about 2, at a push 3 times. I do find that the shade of black is less vibrant after a few goes. 


Add two level teaspoons of ferrous sulphate crystals to your dye. The crystals will dissolve in warm or cold water. I don’t reheat my dye as I like to use my hands to work the colour into the fabric by moving the fabric in and out of the dye bath and squashing the fabric under the dye bath water. This is an important stage in the process as it helps the colour to attach a more even coverage and really penetrates the dye into the fabric. 

This is the messy bit.......!!

Once the fabric is fully covered in the dye and you have spent some time working the dye into the fabric. You need to spin the fabric to drain off any exes water. Please note your washing machine drum will require cleaning after this step, as the dye will have left a black residue. I have invested in a portable hand spin dryer solely for dyeing oak galls. 


Your fabric is now ready to hang dry in a warm environment. When the fabric is damp, it can mark easy so be mindful where you place the pins to hang the fabric and keep out of direct sunlight as this can fade the colour that you spent time creating. 


Once the fabric is dry, you need to set the dye with a hot iron. Iron the full surface of the fabric. I usually wait 24 hours before putting the fabric on a cycle wash in the washing machine with a eco-friendly detergent. We use Ecover concentrate laundry detergent in the studio however any natural detergent is fine to use. 

Plant Dye Fabric

"The fabric is now colourfast and ready to enjoy!"

Audrey Bate


founder of Cosy Organic

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