Why Damp Weather Suits Dew Retting

Dew retting is the oldest and least fussy way to free linen fibre from flax stalks. It needs no pond, no tank, and no water you have to carry. All it asks for is flax laid out on grass, cool nights, and enough moisture in the air for dew to settle while the fungi get to work. In a British summer — or more honestly, a British autumn — that is rarely a problem.

The dew does two jobs at once. It keeps the stalks pliable so they do not shatter when you lift them, and it feeds the naturally occurring fungi that break down the pectin gluing the fibre bundles to the woody core. Retting in a wet season is slower than tank retting and far less controllable, but the fibre it gives you is grey-toned, robust, and full of character. For rustic linen yarns, that is exactly what you want.

Cutting and Laying the Flax

Pull or cut your flax when the stems have turned yellow for roughly a third of their height and the seed bolls at the top are still slightly green. Pulling gives you the longest fibre, roots and all, but cutting close to the ground is fine for a small plot. Tie the stems into loose bundles about the thickness of your wrist and leave them standing in stooks for a day or two to dry the leaves.

Then it is time to spread. Choose a patch of short, clean grass — mown lawn, rough pasture, or a spare strip of the allotment. Long grass shades the stalks and harbours slugs, so keep it short before you start.

• Lay the stalks in thin, even swathes, no more than two stems deep.
• Run them all the same way, so you can turn the whole swathe in one movement.
• Leave a gap between swathes for air and for your boots.
• Avoid hollows where water pools; standing water causes rot, not retting.

If rain is forecast, do not panic. Rain speeds retting up considerably. What you want to avoid is a fortnight of warm, dripping humidity followed by a sudden hot spell, which can leave the outside of the stalk over-retted while the middle is still woody.

What the Dew and Fungi Are Doing

Overnight, moisture condenses on the stalks and softens the outer skin. By morning, the fungi that live on damp plant matter — chiefly the grey and black moulds you will see dusting the stems — have begun secreting enzymes that dissolve the pectin between the fibre bundles and the shive, the brittle woody core.

You are not trying to rot the flax. You are trying to let the fungi nibble just far enough that the fibre slips free of the wood, and no further. This is the whole art of retting, and it is why damp, cool, misty weather is kinder than hot, wet weather. Cool nights slow the fungi down, giving you days rather than hours to judge the moment.

Judging the Ret: The Snap Test

Start testing after about ten days in damp weather, and every day after that. Take a few stems from different parts of the swathe, not just the ones that look ready.

Hold a stem at both ends and bend it gently. If it snaps cleanly like a dry twig, the ret is not finished — the pectin is still holding firm. If the woody core separates from the fibre and the stem pulls apart into a soft, stringy bundle, you are close. Take a stem, break the woody core near the root end, and grip the broken stub between thumb and forefinger. If the shive comes away in short, brittle pieces and the fibre slides off in a clean ribbon, the flax is ready.

Over-retting is the enemy. Stalks that have gone greyish-black, smell sour, or shed their fibre at a touch have gone too far and will give you weak, dusty yarn. The moment most of the swathe passes the test, lift it. Do not wait for the stragglers.

Drying, Breaking and the Grey Fibre

Lift the flax on a dry morning and stand it in loose stooks, roots down, so the wind can run through it. It needs to be bone dry before you store it, or it will mould in the barn. Two or three weeks of dry weather usually does it.

Then break, scutch, and hackle as normal. The difference is in the colour. Dew-retted fibre comes out a soft silver-grey to warm taupe, sometimes with darker streaks where the swathe lay unevenly. It is slightly coarser than water-retted fibre but noticeably stronger and more elastic, which makes it forgiving to spin and wonderfully hard-wearing in cloth.

Spinning and Dyeing Grey-Toned Linen

Grey fibre takes dye differently from creamy water-retted flax, and it is worth planning for that. The natural grey acts as a gentle base tone, muting bright colours into something softer and more lived-in.

• Madder over grey gives muted brick and rust rather than clear red.
• Weld turns a soft olive-yellow, excellent for working aprons.
• Woad over grey produces sage, slate, and soft teal, depending on dips.
• Onion skins give warm ochre and tan with almost no mordant fuss.
• Oak gall or tea deepens the natural grey to a rich charcoal-brown.

Linen is a cellulose fibre, so it needs a tannin step before the alum mordant if you want strong, lasting colour — sumac, oak gall, or a long soak in strong tea all work well. Spin a small sample skein first and dye that before committing a whole warp. Grey fibre is honest stuff: it tells you plainly what it will and will not take, and the colours it yields are the sort that look better with every wash and every year of wear.