Growing Dye Plants

Growing weld, madder, woad, and cosmos in the garden and how to extract and use the natural dye pigments on wool and silk.

Dyes from natural vegetable, animal and mineral sources were once the only choices for pigment. Until 1828, if it did not come from nature, it did not exist in the dyer's palate. With the advent of coal-tar derived dyes, and later chemically synthesized pigments, natural sources of dye gradually fell into disuse.

This is a shame, as some natural sources for dye produce truly exquisite shades and for less money than purchased chemical dyes. It is very easy to grow several of the very best and most famous dye plants in your herb garden. Some are so attractive that you will want them for their flowers alone.

WELD - Reseda luteola

Dyer's mignonette or weld produces an outstanding primary yellow on all protein fibers and cotton. This yellow is clear and intense, the yellow that all other yellows are judged against. The substance responsible for producing this color is luteolin and is present in all the green parts of the plant. Compared to other plant sources for yellow available to the home dyer, weld is very concentrated. Six or seven weld rosettes or two weld plants in bloom will dye a pound of wool an intense primary yellow color.

Weld is best grown from seed. Either start the seed indoors about six to eight weeks before the last frost or sow the seed directly where it will be grown in late summer or early spring. This plant prefers a sweet soil, but will grow in acidic soils as well. If allowed to flower and set seed, it will produce hundreds of volunteer plants in the spring. These can be weeded out where ever they are unwelcome and dried for use as dye later. Weld is a hardy biennial plant that produces attractive rosettes of slightly crinkled long and slender leaves the first season and long bloom spikes the second.

USING WELD IN THE DYE POT - Weld can be used fresh or dried with equal success. If you are only dying a small quantity of fiber, simply pick a few leaves from each plant, the same way you would harvest leaf lettuce. Chop the plant material and simmer for an hour to extract the pigment. Strain out the leaves and add your mordant and a small quantity of chalk or washing soda to the dye bath then the wet fiber or yarn. Simmer the fiber for an hour, stirring frequently. Luteolin is one of the few plant pigments that will settle out of solution after time so it is important to stir often.

Alum will give the best yellow but other mordants can be used to get gold, olive, and green. Remember to be very careful when using any mordant other than alum, especially chromium dioxide (chrome), as they are all toxic to some degree. Alum is very safe and will not harm your fibers.

The famous medieval colors, Saxon green and Lincoln green, were produced by over-dying weld yellow with woad blue. If you are interested in reproducing these colors today, it is very easy to do using indigo. Anyone interested in producing authentic colors for living history pageants will want to give this a try.

MADDER - Rubia tinctorum

The famous red, called Turkey red, was produced using madder root. The red coats of British soldiers also came from the madder plant. Once one of the only source of red pigment, madder is now only used by home dyers and heritage crafters.

All parts of the madder plant contain the pigment, alizarin, but the roots have the largest concentration. Madder is easy to grow but difficult to start from seed. If you cannot get plants from a friend, look for them in catalogs or at wool festivals. The annual Maryland Sheep and Wool Festival, held outside Baltimore the first weekend in May is a wonderful place to find dye plants (and other fiber-related items).

Once you have acquired your plants, you will want to put them in a bed about three feet by twelve feet. This rather coarse and sprawling plant needs to be grown for three years before the first harvest. As the plants spread, encourage more roots by burying sections of stem with soil. Madder likes full sun and deep rich, well-limned soil. You will get more pigment if your plants are grown under good conditions.

Harvest the roots with a digging fork. You will recognize them by their bright red color and they will be as thick as pencils or fingers. Save a few plants for a new madder bed. Because madder roots also contain yellow and brown pigments, you will want to take special care washing off all the soil. A brief soaking will leach out some of the undesirable pigments, also. Expect to get about six pounds of fresh roots from a dozen plants.

EXTRACTING THE DYE - After soaking the roots to remove as much yellow and brown as possible, chop the roots coarsely and run through a food processor or blender. The finer you grind the roots the more pigment will be released. If your water is not naturally hard, add some lime or a tablespoon of baking powder per gallon of water. Use about eight ounces of fresh root per pound of fiber for a good rich shade. After grinding the roots finely, soak overnight in the dye pot - the alizarin pigment should begin to run freely in the hard water. The next day, begin heating the dye pot slowly to between 140º and 160º F. This is very important! Use a thermometer. If you get the dye bath too hot you will destroy the red pigment and only get brown. Keep the dye bath at temperature for an hour then allow enough for easy handling so you can strain out the ground root. There is still a lot of pigment left in the roots, so save them in a jar of water for producing paler shades later.

Because it is much easier to grind fresh roots than dry ones, you might want to grind all of your roots at one time and save them in plastic bags in the freezer until you need red dye. When madder was used commercially to obtain red dye, it was often fermented with other ingredients then dried and the resultant pigment cakes were sold around the world.

Either premordant your fiber or add alum and tartaric acid to the dye bath. Immerse the pre-wetted fiber and bring the pot to 140º to 160º degrees and maintain the temperature for about an hour. Allow the fiber to sit in the dye bath until cold then remove, rinse and dry. The dye bath can be used as long as it shows color to dye paler shades. The tops of the plants can also be used for dye. An advantage to using the tops is that they also contain purpurin pigments which add brilliance and lustre to the dyed fiber. The plant tops can be harvested every year for dye even if the roots are still too small. About two pounds of dried tops will dye a pound of wool.

WOAD - Isatis tinctoria

Woad is one of the most ancient sources of the blue pigment, indican. This is the famous blue dye of the ancient Britons and was used to make green by over dying with weld. They also used the pigment to paint their faces blue, the better to frighten Roman conquerors.

The amount of indican in woad plants is woefully small compared with that in indigo, however, indigo is not reliably cold hardy and woad is. If you are really determined to be authentic and grow your own source of indican, plant woad. It is a member of the mustard family and is related to cabbage and broccoli. Woad grown in fertile soil will contain much more pigment than plants that barely get by. You should have no trouble getting seed from companies that specialize in herbs. Sow the seed where it is to grow in fall or early spring, Woad is also biennial and will produce a flat rosette of leaves the first season and a bloom spike the second.

EXTRACTING THE DYE - Harvest leaves all summer long, it takes two pounds of woad leaves to dye only four ounces of wool. Chop the leaves and cram them into a canning jar then pour almost boiling water over them until the jar overflows, cap the jar, excluding as much air as possible. After an hour remove the leaves and squeeze them dry. The indican will have been converted into indoxyl and the water will look brownish with a metallic sheen. This liquid can be used to dye small amounts of wool or silk. However, the results will be unsatisfactory, usually a pale blue or grayish blue and not particularly light fast.

If you want to dye large quantities of fiber a deep rich blue, use the same method as that used by Sturbridge Village in Massachusetts. Purchase ready to use indigo dye. This dye is made by dissolving dried indican in sulfuric acid and adding ground limestone to neutralize it. The fact is that the medieval dyers used essentially the same method. If anyone ever questions the authenticity of your woad-dyed textiles, just show them the jar of indoxyl and point out the plants in the garden.

During medieval times, the production of woad dye and dying were two separate occupations. Dye production was a major industry and thousands of tons of dye were made annually. People did not make their own dye but purchased it from professionals who spent their entire lives learning the secrets of fermenting woad and extracting the pigment. Exploration in the far east revealed the existence of indigo, a plant that contains ten times as much pigment as woad. Eventually, between imports from the far east and colonies in the new world, the European woad industry collapsed. Indigo dye was produced in South Carolina until the time of the Civil War.

COSMOS - Cosmos sulphureus

Diablo and Sunny Red are sold by most seed companies. These varieties produce beautiful reddish-orange flowers from seed planted in the spring. They will self-seed as well and return for years. The flowers from two dozen plants will dye about a pound of wool or silk a vibrant orange.

EXTRACTING THE DYE - snip the flower heads as they open and either use fresh or dry on screens for later. If you cut the flowers before they start to set seed you will get lots more bloom during the summer. When you have enough to dye your fiber, soak the flowers and simmer until the petals look pale and washed out.

Chalcones, the primary dye pigment in this flower, is very sensitive to pH. It is yellowish in an acid (vinegar) solution and reddish in a basic (ammonia or washing soda) solution. Keep in mind that wool and silk love acid but can be damaged by very basic solutions, so don't get the pH above 9. A teaspoon of ammonia or big pinch of washing soda will do the trick. The dye bath will change color instantly. Add alum and tartaric acid to your dye bath or use pre-mordanted fibers. Simmer for about an hour, until the desired depth of color is achieved.

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