Dyeing Wool with Dried Weld and Dried Meadowsweet

Last month, while crawling around the darker recesses of the attic in search of boxes of Christmas decorations, I rediscovered some ancient bunches of dried dye plants. There was a bleat of horror when I carried them out to examine in daylight.
"Did the tinsel die of dandruff? What is that dusty, shrivelled mess? Oh, just look at the floor, all covered in bits!" My companion, Elinor Gotland broke off from unravelling the fairy lights. "Whatever you've got there, it can go straight in the bin."
"These look like stems of meadowsweet and I think the others must be weld spikes. The leaves are so brittle they're falling apart - can't remember how long ago I picked them, but I wonder if they might still have any dye to offer?"
Elinor grabbed at a tag dangling from one of the bunches. "Shouldn't think so, Beaut. This says 'Weld, May 2014'. Stop waving the stalks about, you're shedding seeds everywhere." She thrust the lot into a bag and gave me a push. "Make yourself useful and put that on the compost heap."

I hid the bag in the garage over Christmas. Last Sunday, I fetched it back out and put about 200g of dried weld and 200g dried meadowsweet in two buckets to soak. Looking for something cheap and cheerful to experiment on, some DROPS Merino wool that I'd bought at Wonderwool seemed spot on. There were balls of white, light grey and dark grey, which I was particularly pleased about, because lately, on the Plants to Dye For forum on Ravelry, several people have shown off impressively rich and intriguing colours from their dye work on grey yarns. Eight 25g skeins were scoured, soaked and left to mordant in a cold 10% alum solution for the next few days.

The soggy brown meadowsweet stems were simmered in a dye pot on Tuesday and left to stand. By Wednesday, the bucket of dried weld hadn't developed much of a froth or the evil smell typical of its fermentation phase, but I put it on to simmer anyway, while I was out with the dog. Himself was working from home and he assured me that the pot stank to high heaven by the time he carried outdoors. After sieving out the plant material, samples of both dye baths (meadowsweet on the left and weld on the right) showed a promising amount of colour.

Despite their years in the attic, the dried leaves had fermented once soaked. Both samples tested as acidic at about pH4 with indicator paper. Adding enough soda ash to bring the pH up to neutral 7 deepened the colour of the dye baths even more. On Thursday, I put skeins of each shade of yarn into the two dye baths and simmered them for an hour.

Eager to see the effect of overdyeing with yellow plant dyes on grey yarn, I hooked the skeins out to inspect while the pots were still warm.

"Elinor, come and see! I thought the grey yarns would make the yellow dyes come out in deeper tones, I never imagined it would turn them green! Wait til I show the others on Ravelry, they'll be amazed."

"Hold your horses, Beaut. That grey DROPS yarn can't have been natural wool."

I ran to check the ball bands.

"Yes it was, the label says 100% extra fine Merino."

"And it also says 'Dyelot 406833 '. I'd say the people at DROPS use quite a bit of blue in their grey dye." My companion took one look at my crestfallen face and started laughing. "Blue plus yellow makes green. What a muppet you are." 

"Well, at least I know that dried weld and meadowsweet are worth keeping for as many years as I like." I pondered over the yarns for a moment then looked at her speculatively. "Those colours are well saturated, there's obviously lots of dye still in the pots. All I need is some naturally grey wool to experiment upon." I picked up the kitchen scissors and snipped the air. "A nice bit of Gotland fleece would fit the bill."

Elinor stopped giggling.

"You wouldn't. You monster!"

I've never seen her move so fast.