Dyeing with Woad Seeds

Anyone growing woad plants probably knows that they are also prolific seeders. The flowers are really lovely and I have no problem with them seeding everywhere but it did seem a waste not to harvest the bountiful dangling seeds.

I’d heard that the seeds contained dye and so though I’d experiment as a good way of using up the excess. 


I had to clear some of the plants over the summer and autumn as they fell over or got tangled up in other things, so I ended up with a selection of both fully ripe (black) and under-ripe (browny-green) seed which were dried out and stored for future use.

Solitary bee enjoying woad in full flower
Woad seeds (semi-ripe)

Now apparently you extract the dye from the seeds in the typical way for dye plants (i.e. simmering) and don’t have to go through the rigmarole of pH changes, oxidation and reduction as when dyeing with the rest of the woad plant [lots of info online about this].


I had a small amount of alum mordanted Portland fleece which I wanted to try, and I also threw in some unmordanted Leicester longwool locks for comparison.


I ended up with 38g of ripe/unripe seed which I simmered for an hour or so to extract the colour. This got left for a day or so before I added the fleece which just happened to have been soaking in water for the same amount of time. Seed to wool ratio was roughly 1:1. The fleece then got simmered in the dye liquid for around an hour before I switched off the heat and let it cool.

Fleece in dye liquor- deep red colour

So, the colour is nothing impressive. I had suspicions it would be a greyish brown but it was definitely nearer grey. This was a little surprising given the rich red colour of the dye liquid. When dyeing with woad plants (leaves/stems) the dye liquid is a similar colour as this before you go through the mad-scientist phases to get blue, so I’m wondering if I could have gotten the same result if following this process with the seeds. Something to try in future?

An online article I saw from Jenny Dean [here] suggested a greenish colour could be obtained using an Iron modifier. This sounded very appealing so I removed the longwool locks from the pot to keep them as a reminder of the original/base colour, then added a glug of water from my trusty jar of rusty nails etc. One issue with this approach is that my iron solution is of a totally unknown concentration, but the dye liquid did change colour to a more greenish hue when I simmered again for another hour. However, when looking at the rinsed and dried wool I’m not convinced there was any ultimate difference in the colour of the fleece compared to the unmodified locks.

Well there you go. I’m not wowed by the colour but it was interesting to see what happened and it has opened up questions for next year’s seed crop and experimenting with the more convoluted woad dyeing approach. I wonder what would happen if you dyed with the woad plant and seeds together? I’ll probably add these fibres to my stash for wet felting as they’ll no doubt come in handy for a moody sky or stone wall etc.

Left: Leicester Longwool locks (no mordant, no modifier) Right: Portland fleece (alum mordant, iron modifier).


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