Plant Contact Dyes on Cotton and Linen

The horseshoe border in the middle of the back lawn gets full sun (when there is any).  Last spring, it was dug over with sheep and cow manure from my friend Mary's farm and the dye plants got promoted to centre stage.  Dangerously exposed, although the dog is one year old and considerably less destructive than she
was last summer.  In the hope of improving her garden manners, I fixed some netting for sweet peas to stop her walking straight across the earth and apart from one rosemary bush which she uprooted three times, everything else has flourished, despite another cool, damp summer. These weld plants were only sown in March, here are the rosettes in June and though they are supposed to be biennial,

several spikes were about to flower at the end of last month.  I have become somewhat disenchanted with weld and didn't bother with a late sowing last autumn.  Thrilled with the powerful yellow dye I first had from fresh plants, I've been drying and storing most of the spikes ever since.  Soaking, fermenting and simmering dried weld indoors is not altogether a welcome winter sunshine fiesta, it makes the house smell rank and at the end of it all, yellow from dried leaves is not nearly so zingy. This unexpected 250g of fresh weld ought to have dyed 500g wool, if I had such an amount all spun up and ready.  I chopped it up and left it in a bucket of cold water to ferment for a day or so, while I pondered what to dye.

Past trials of dyeing cotton and linen fabric have suggested that weight for weight, they take up muted colours, compared to wool and silk.  My one attempt at mordanting with soya milk was a big waste of time, money and beans.  The classic mordant process for plant derived fibres involves simmering in tannin, before they can take up alum like wool does. Their greater weight also means far more

dyestuff is required.  One way and another, cotton and linen have seemed more trouble than they are worth.  Being possessed of 250g powerful dye plant and a second hand, but perfectly sound linen smock also weighing 250g, rather shifted the dynamic.  Plant fibres can be mordanted in one fell swoop, using 5% of their weight in alum acetate dissolved in water.  Since the fabric is so much thicker than silk, I supposed

that dye penetration would be reduced, so once my linen smock had had the mordant rinsed off, I turned it inside out and laid sprigs of coreopsis tinctoria and hardy geranium leaves within the body, so they would be pressed against the final outside surface.  The body section was rolled around a length of plastic downpipe and tied tightly with string which had been soaked in a solution of iron.  

The sleeves were tied across a wooden board and the whole thing was immersed in my weld dyebath, which always does look deceptively weak and weedy in colour.  A teaspoon of soda ash to alkalinise the bath brings up the yellow and shouldn't make linen feel harsh, as it can with wool.  

The pot was brought up to a simmer fairly quickly, kept below the boil for an hour and left to cool overnight.  The sodden bundle took several days to get anywhere near dry in this cool, dull summer. Once unwrapped, I was thrilled to bits.  What a result.  It looked even better after a machine wash at 30 degrees and a hot iron, only I can't show you, because my friend BG has it now.

The coreopsis flowers, leaves and stems have printed sharply on the rolled linen, which was indeed dense enough to keep out most of the colour from the weld dye bath and stop the intense coreopsis from bleeding through its layers.  The hardy geranium leaves have left a blur of greenish colour and the odd dark edge. On silk, they would have left a tracery of dark iron marks, but I assume the heavy linen also kept most of the iron on the string from reaching them.  Thoroughly enthused, I topped up the alum acetate in the mordant bath, bought a linen and cotton mix shirt in a charity shop and repeated the whole process using only coreopsis and whatever weld might be left in the afterbath.  Here is how it went.