A week ago I stood a tray of weld seeds in full sun on the greenhouse shelf because I'd decided long hours of daylight would germinate the seeds fast. No sign of life today, but no surprise because I found the compost dry as a Ryvita. My companion, Elinor Gotland, called from her deckchair on the lawn. "Were you right about a bit of sunshine getting your weld seeds started then, Beaut?" A full ten minutes watering the greenhouse had left me gasping in the humidity. I staggered out and veered across the lawn, attempting to dodge the question. "What a dramatic change this heat is from all the cool weather we've had." I reached the dye garden and stood there dripping sweat and trying to look nonchalant. "Rain then sun has really suited the weld plants, just look how many new flowers have grown."
Since its main flowering spike was cut two weeks ago, my biggest weld plant has sprouted over a dozen lateral flower spikes. Quite an impressive effort. That first main spike weighed 125g and has gone on to dye an even more impressive 250g wool yarn. Every batch of plant dye turns out a little differently, but since this one went particularly well, it seems a good point to record my current method.
I have found the strongest dye comes from chopping the plant material into large chunks and leaving it to ferment in cold water for at least three days, preferably a week. The water becomes faintly cloudy, slight frothy and properly stinky. Simmered for an hour, the dye bath looks only pale yellow and will test acidic at about pH 4 if you have indicator paper.
Adding enough dissolved soda ash to bring the pH up to neutral 7 will turn a weld dye bath deeper yellow and I think leaving the plant material in the pot while dyeing also adds to the strength of colour. Starting with 125g weld, I first added two 50g skeins of wool yarn mordanted with 10% alum, simmered them for an hour and left them to cool overnight. Next day, they were a deep golden yellow, more like the colour from Dyer's Chamomile than the acid yellow I usually get from weld. I heated one skein with some dissolved iron to sadden the yellow to green and repeated the whole process with another two skeins, which went a more typically lime yellow. A last 50g skein was simmered soaked for a few days while I was away from home and even that turned primrose yellow.
"I think the first flower spikes give the strongest dye, Elinor. As they've given me plenty of dyed yarn, do you think I should do some contact printing with this second lot or just cut the spikes and hang them up to dry?" "Best you let those flowers set seed, Beaut. Somehow I suspect you need to sow another weld seed tray."
I walked out into the garden thinking this could be the perfect day for sowing weld seeds and as I reached the greenhouse, my companion jumped up in delight. The miserable June weather has forced her to move her deckchair inside and while the interior of the new greenhouse does provide an exclusive orangery ambiance, mobile phone reception is so dodgy that the poor soul often has to trek back to the house to order her tea and biscuits. "Feeling parched and peckish again, Elinor?" A gust brought rain in through the greenhouse door and mud splattered the gravel as I dumped down half a sack of sodden seed compost. My companion shuddered and stepped back. "Do shut the door - if you care nothing for me, at least spare a thought for your chilli peppers. I can't think why you're bringing in compost, Beaut. This weather might feel like April but it's far too late to be sowing seeds." I wiped my hands on my jeans and the rain off my specs. "The summer solstice is upon us. Weld seeds germinate best with lots of light and since this is the longest day of the year, it must surely be a good time to start sowing next year's weld plants."
I usually sow all my dye plant seeds in March. The seed trays sit on the underfloor heating in the bathroom and within a matter of days, tiny shoots appear and off they go, out to the greenhouse to grow on. Weld is the only plant with delayed germination. I've found that even when seeds are sprinkled on the surface of the compost with no earth or vermiculite on top, they remain inert until they get not only warmth but really decent light. Still, sooner or later, weld seedlings do appear in the March sown trays and although officially a biennial, with an early start, most of the plants will flower the same summer.
This year's March sown weld plants are presently modest clumps of leaves, half of which have put up flowering spikes about 40cm high. They'll grow bigger and when I cut the main spikes, plenty more will shoot from the lower leaf axils. A few young weld plants won't flower, they'll just remain as low rosettes of leaves. Next spring, those will grow into plants 1.5m tall which start flowering by the end of May.
Weld flower spikes provide a great weight of material and thus a better harvest of luteolin dye than picking individual leaves from young clumps. Spikes are also simple to hang up in bunches to dry and dried weld leaves store their strong yellow dye for at least five years. Once they have finished flowering, the weld plants die. Since the second year plants grow so much bigger and generate ten times as much material as those that flower in their first year, it has become clear to me that though you have to wait longer, it's altogether more productive to cultivate weld as a true biennial. I've tried sowing fresh seed in September, straight from the last of the weld spikes, but once again, have found germination is uncertain. Maybe that's because the plant has been forced to go on flowering unusually long because I've picked spikes til the end of August and by September, the light levels are diminishing with the season. Left unpicked, early weld flower spikes would be setting seed already which would be scattered by the wind around the summer solstice. So theoretically, I reckon today could be the ideal time to sow weld. Even if there's little sunshine, we do have have long hours of daylight. Next week it's due to get warmer and I'll try to remember to put up another photo of that seed tray. See how long it takes the seeds to germinate.
Since salvaging dye from the neglected Japanese Indigo plants of 2017 proved such an unexpected success, I felt much less pressure to use all of last summer's harvest in fresh vats. Following Deb McClintock's method, whenever I had a surplus, I cut stems and tied them in bunches to dry in the greenhouse.
These have been stored in big paper bags under the spare bed. When I saw a beautiful pale blue shawl on a display at Wonderwool, I bought the pattern, thinking to myself I could recreate that colour using the dried indigo. Also, what a great excuse to buy some silk blend yarn to catch the light and show off the complex cabled border pattern. Once I dragged the first bag out and started to crumble the leaves off the stems, what appeared to be a large volume of dried indigo soon shrunk down to a modest net bag full weighing 200g.
Even so, that was twice as much as I had before. Once again, I followed John Marshall's instructions as described in Deb's blog, just doubling all the quantities. Previously I had dyed 200g wool tops with 100g dried leaves, so I expected a strong blue on my first 100g skein of yarn and a medium blue on the next and intended to dye a pale blue skein last. In practice, it took three dips each for two skeins to reach two shades of mid blue. Possibly the weight of dried indigo was deceptive, because I did leave lots of small stems in with the leaves. I exhausted the vat with a bit of wool blanket and have saved my other skein of fancy yarn for another time.
The dyed yarn is knitting up with stitch definition just as nice as I hoped and though this pattern takes all my concentration, it's a pleasure to make. Here's a link to an online source, Ravelry of course, the designer is Helen Kennedy and it's called Closer to the Edge.
My companion and I stood on the doorstep, bracing ourselves to step out into the June rain drenching the garden. "At least you won't have to water the pots, Beaut." "I never water the madder barrels, those roots need sharp drainage. Mind, I don't know if that hot summer last year might have been too dry, even for madder." "Well, you'll find out soon. Didn't you just use up the last of the dried roots?"
The remaining 100g of dried madder root from last spring's harvest had indeed been chopped in a food blender, covered with boiling water and left to soak overnight. In an attempt to replicate the success of my previous madder dye session, I followed the same minimalist process, simply adding more water next morning before putting in an equal weight of yarn mordanted in 10% alum. The pot was heated to more than hand hot but not boiling, kept hot for an hour, then left overnight. Despite the dye bath being naturally mildly acidic, the 100g skein of 4ply Falklands Merino/Silk blend came out a decent colour, though not as blood red as the alum mordanted skein of Blue Faced Leicester wool I dyed last week (shown balanced on top).
I had simmered the other half of that original skein of Blue Faced Leicester in the afterbath, just to see if the yarn itself might hold the key to success. Of course, there was less colour left in the dye bath for it to take up, but I do think it is somehow redder than the first. Apart from being a different kind of wool, I remember that that particular skein was among some that got neglected and accidentally left in a cold alum mordant bath for five days rather than two. It is dawning on me that the longer things soak in alum, the better they seem to dye, even though increasing the percentage of alum doesn't seem to make much odds. To exhaust the dye bath, two skeins of coarse wool yarn in pale shades of grey were heated briskly and left to fester for a couple of days before I poured the mouldy gloop onto the compost heap. By that time, it had fermented down to pH 5 and the yarn looked distinctly orange.
After we had walked the dog, I laid out the products of my two madder dye baths and sat back to contemplate them. Rain hammered on the skylight. "Were those madder roots worth waiting three years for, Beaut?" "Yes. I think so. I like all the colours and I'm a bit further forward with understanding the dye. Next time, I shall do an experiment dyeing yarn that has soaked in 10% alum for two days versus yarn soaked for five days." "So, when you're dyeing with the roots you dig out of the next barrel, you won't be trying calcium carbonate or bran or rinsing the roots or changing the pH or the temperature?" "Just adding water is good." Elinor emptied her Wellington boot out into the sink. "Not if you're a sock."
Since its main flowering spike was cut two weeks ago, my biggest weld plant has sprouted over a dozen lateral flower spikes. Quite an impressive effort.
I have found the strongest dye comes from chopping the plant material into large chunks and leaving it to ferment in cold water for at least three days, preferably a week. The water becomes faintly cloudy, slight frothy and properly stinky. Simmered for an hour, the dye bath looks only pale yellow and will test acidic at about pH 4 if you have indicator paper. 
Adding enough dissolved soda ash to bring the pH up to neutral 7 will turn a weld dye bath deeper yellow and I think leaving the plant material in the pot while dyeing also adds to the strength of colour. Starting with 125g weld, I first added two 50g skeins of wool yarn mordanted with 10% alum, simmered them for an hour and left them to cool overnight. Next day, they were a deep golden yellow, more like the colour from Dyer's Chamomile than the acid yellow I usually get from weld. I heated one skein with some dissolved iron to sadden the yellow to green and repeated the whole process with another two skeins, which went a more typically lime yellow. A last 50g skein was simmered soaked for a few days while I was away from home and even that turned primrose yellow.
Since its main flowering spike was cut two weeks ago, my biggest weld plant has sprouted over a dozen lateral flower spikes. Quite an impressive effort.
