Natural dyeing with goldenrod & iron

Where I live, it's hard to think of any dyestuff more abundant than goldenrod. Fields upon fields of the stuff ripen every autumn, so there's plenty fresh dyestuff for the taking as long as you're ready for it at the right time of year. This was my first time dyeing with goldenrod, and also my first time dyeing raw (scoured) fiber rather than either finished skeins or store-bought roving. It went very well, all things considered.

The Process

I started with a cheviot fleece from the farm, which was full of a ridiculous amount of lanolin, VM (vegetable matter), and worse.  I put it through several rounds of scouring and got it mostly clean, but there was still a certain amount of lanolin in it when I decided it was ready to dye. 

I started by pre-mordanting the wool with alum & cream of tartar, and then set about preparing the dye. I collected about 2 lbs of goldenrod tops and simmered for an hour or two, in a large aluminum pot. An enamel pot would have been better, I suppose, but I use what I have.  I strained out the goldenrod from the dyebath, and added 8 oz pre-mordanted fiber while both were still quite warm.  Then I left it to soak and cool overnight.

The next day I rinsed the wool thoroughly with water and vinegar, and then with gentle soap. I was pleased to see that not much of the color rinsed out. It took a painfully long time for the wool to dry in the chilly weather, but I could enjoy marveling at the rich yellow color the whole time.  It's so satisfying when the dye holds fast! Since this experiment, I have found goldenrod to be very reliable as a natural dye.

Meanwhile, I dyed a second batch of wool, using the exhaust dye. The wool was from the same cheviot fleece, and also pre-mordanted with alum & CoT.  This time, I added a small amount of iron acetate to the dye bath as a color modifier. Since it was an exhaust dye it came out lighter, and the result is a pale yellow-green.

I am writing up this account at a later date, and I can't recall the exact amount of iron mordant that I used.  I do recall that I was very hesitant at first, but then poured in more of it later (still cautiously).  I have read that iron weakens the fiber dramatically; in antique textiles, the portions treated with heavy metals have often crumbled away entirely, while neighboring portions that were not so treated remain intact. If I were more scientific in my experiments, I would probably proceed with more confidence. I'm not even sure what the exact concentration of my iron acetate solution was, as I acquired it with the highly scientific process of dumping water and vinegar into a jar of nails. For now, I'm just trying things out to see what happens. 

The results

Fast forward a bit, and I've spun up all of the green iron wool and haven't yet finished with the yellow.  (This is not unexpected, since I like the color green more than yellow.)  The interesting thing is that the color has changed upon further processing. In the picture below, you'll note the difference in color between the two skeins.  Both were originally identical, with the pale luna-moth green color of the skein on the right. The one on the left has turned a brighter, yellower rockweed green. What happened? 

Still with a sticky trace of lanolin in them, all of my goldenrod skeins must be washed thoroughly after being spun and plied. The easiest way to get the lanolin out is to "melt" it with heat, and this process affected the color.  In the picture below, the rightmost skein sat in simmering, soapy water for an hour, and was then rinsed and hung to dry.  The remaining skeins have been spun and plied, but I have yet to put them through the final wash cycle.  Good to know for the future!