Dyeing with weld. Photo by Flickr/underdutchskies
Natural dyes come in a rainbow of colors — as long as you know where to look. Plants, lichens, shells, and even insects contain all the compounds you need to make any color from soft yellow, to electric pink, to forest green. Many natural dyes also respond well to nontoxic dye-fixing mordants, such as alum and iron.
This article is the first of a two-part series on plants from which you can extract natural primary color dyes; red and yellow are covered here, and the second half of this series, to be published in our Spring 2020 issue, will focus on making blue hues with indigo and woad.
Red: The Root of the Madder
Madder (Rubia tinctorum), a perennial dye plant, displays clusters of small, yellow flowers in summer, and shiny, black berries in fall. Native to southern Europe, western Asia, and northern Africa, madder prefers loamy, moist soil, and plenty of sunlight. It offers a rambling groundcover, or grows like a vine with the right support. However, the plant’s best gifts hide underground; its medicinal roots can be processed to extract a red dye, with stronger red hues appearing in more alkaline soil conditions.
Wild madder. Photo by Getty Images/arousa
Madder needs 2 to 4 years to mature enough to produce the rich, lightfast (fade-resistant) reds that make the plant so popular among dyers. It spreads its underground roots and rhizomes, and produces rooted shoots wherever the trailing aboveground stems touch earth. But it’ll take over your garden unless you plant it in a deep (1-foot minimum) raised bed or a large, deep container. Plan to spend some time training the shoots back inside their bounds throughout the growing season as well.
If you’re itching to get started, you can sow seeds indoors 6 to 8 weeks before the last frost, or sow them directly when the soil warms up. Plant the seeds about 1⁄4 inch deep, and keep them evenly moist. The seeds should germinate within two weeks. Transplant seedlings or starts as soon as they have a few sets of true leaves, when the soil outside is warm and the risk of frost has passed.
Because the roots need at least two years to develop, you can ensure a constant supply of mature roots by establishing a rotating harvest schedule. Establish three sections in your reserved madder bed, and plant all three starts the first growing year. In fall of the second year, you can harvest one section of 2-year-old roots. The next year, harvest the next section, and the third year, harvest the third section. Continue rotating the section you harvest from every year, and you’ll always have roots.
Dyeing with madder. Photo by Flickr/Stranded YarnsUK
Madder has both true roots and underground stems, so you’re likely to dig up both. But it’s the true roots — more twisted than the underground stems, with a small or absent woody core — that contain the rich red pigment. Cut the roots and stems from the plants’ crowns, leaving about 4 inches of root attached to support the plant in the coming year. Shake the dirt off the harvested roots and stems, and then wash and scrub off the thin outer bark, revealing the orange-red flesh.
Chop the roots into small pieces with a knife, pruning shears, or a food processor you no longer use for food. Smaller pieces will make future dye extraction easier, so take your time with this step. Spread the chopped roots on screens or newspaper to dry, and turn them frequently to stave off mold. You can still use moldy roots for dyeing, but the color will be duller and the dyebath won’t smell pleasant. While you can use fresh roots, drying encourages the creation of more of the dye compounds alizarin and purpurin, and will help you achieve stronger reds. Dried roots kept in a cool, dark spot will store more or less indefinitely.
Variations on Red
Madder responds colorfully to both pH and temperature. You’ll get the truest reds with an alum mordant and alkaline dyebath. Acidic dyebaths produce oranges to browns, and an iron mordant can produce a range of purples.
- More orange: An acidic dyebath will favor lighter, more orange results. You can add a few tablespoons of vinegar or lemon juice to the dyebath itself to modify the color, or dip the freshly dyed material in a pot of water with vinegar or lemon juice.
- More red: If you’re already getting oranges and want true reds, you need a more alkaline dyebath. Add a few tablespoons of washing soda to the dyebath, or dip the freshly dyed material in a pot of water with washing soda added.
- Purple: Iron is a “saddening” mordant, meaning it makes colors bluer or grayer; if you mordant with iron, you don’t need to use alum. You can wet your dyeing material in an iron pot, or use a nonreactive pot and add pieces of iron to the mordant bath. Or, you can simmer pieces of iron in a pot of water and dip freshly dyed material in it to modify the color.
Yellow: Shoots of Weld
Weld (Reseda luteola) is a biennial plant native to much of Eurasia and northern Africa. Most plants in the genus Reseda produce strongly aromatic flower spikes, and some quantity of the dye compound luteolin. R. luteola produces the largest quantity of luteolin, thus making it the most common species for dyeing. The plant prefers recently disturbed alkaline soil, moderate to light moisture, and full sun.
Sow seeds indoors 2 to 3 weeks before the last frost in deep, firmly packed cells of potting soil. Mist the soil to keep it moist until the seeds germinate; pouring water on the seeds risks washing them out entirely. Plant them outside after the risk of frost has passed, but before the taproot reaches the bottom of the cell to avoid stunting the plants. Weld plants don’t appreciate having their roots disturbed. You can also direct-sow the seeds after the last frost.
Photo by Getty Images/Whiteway
First-year plants have long taproots and will produce a basal rosette of strappy, unlobed leaves. You’ll want to harvest second-year plants when the flowering stalk shoots up to 5 feet tall, with blossoms from top to bottom. The small, green-to-yellow flowers smell sweetly, and pollinators love them.
It’s the flowering tops of the plant you’ll harvest for dyeing. If you want to save seeds, allow the bottom third of the stalk to bloom and set seed, and then cut the stalk down. Tie the stalks in small bundles, and hang them upside down to dry. Chop or cut dried stalks into small pieces, and store them in a paper bag until you’re ready to use them.
Variations on Yellow
With an alum mordant and an alkaline dyebath, weld produces bright, clear yellows; iron turns the dye an olive green.
- More yellow: If you’re getting dull yellows or pale browns, your dyebath needs to be cooler or more alkaline. If a dyebath has been overheated, dump it out and start again with new weld. To make the dyebath more alkaline, add a few tablespoons of washing soda, or dip the freshly dyed material in a pot of water with washing soda.
- Olive green: Iron makes colors bluer or grayer; so it’ll turn a yellow a more olive green color if you wet your dyeing material in an iron pot, or use a nonreactive pot and add pieces of iron to the mordant bath. Alternatively, simmer pieces of iron in a pot of water and dip freshly dyed material in it to turn your material more olive-colored. When you mordant with iron, you won’t need to add alum.
- Orange: You can overdye weld-dyed material with a weak madder dyebath to get a wide range of oranges. You don’t need to mordant the material again.
Dyeing with Madder and Weld
If you soak the dried plant matter overnight, you’ll be able to get more dye out of it. The dyeing processes for madder and weld are similar, but note that the percentage of plant material required for madder dyeing is greater than that required for dying with weld.
Madder: Make sure your dying materials are dry, and then weigh them. You’ll need 12 to 20 percent of this weight in alum for the mordant, and 50 to 100 percent in dried madder root for the dye. For 1 pound of fiber or fabric, that’s 1.92 to 3.2 ounces (about 5 to 8 tablespoons) of alum, and 1⁄2 to 1 pound of madder root. After dyeing, you can save the used madder roots for future, lighter dyebaths; just spread them out to dry thoroughly before you store them, and separate them from unused roots.
Photo by CarlaTilghman
Weld: Weigh your dyeing fabric while it’s still dry. You’ll need 12 to 20 percent of its weight in alum for the mordant, and up to 50 percent in dried weld for the dye. For 1 pound of fiber or fabric, that’s 1.92 to 3.2 ounces (about 5 to 8 tablespoons) of alum, and up to 1⁄2 pound of weld, depending on the depth of color you want. If you’re using 50 percent weld to weight of dry material, there’ll be enough pigment in the bath after your first dye to create lighter shades in subsequent dips.
Photo by Carla Tilghman
Fill a large pot with lukewarm water, stir in the alum until it’s fully dissolved, and submerge the material you want to dye. Swish it around to saturate it evenly with the mordant. Let it sit until you’re ready to move it to the dyepot.
To create your dyepot, fill a second pot with lukewarm water, leaving room for the plant soaking liquid. Stretch a piece of cheesecloth or muslin over the pot. Pour the plant material and soaking water into the pot, catching the plant bits in the cloth. Tie the cloth into a “teabag” and leave it in the dyepot while you bring the dye solution up to just below a simmer (about 180 degrees Fahrenheit). Madder and weld dye both turn brownish if overheated, so be mindful of the temperature, and when in doubt of the temperature, turn down the heat.
Squeeze out the wet material you want to dye until moist but not dripping. Add it gently to the dyepot, and swish it around to saturate it with the dye. The longer the material stays in the dyepot, the deeper the color turns, to a point. Remember that the color will lighten as the material dries.
Drying your dyes
Squeeze the excess dye water out of your material gently, and hang it up on a clothesline or drying rack. It’ll likely drip as it dries, so if you’re worried about stains on the floor, lay down cardboard or a folded towel to protect it. Sunlight will fade natural dyes over time, so you can re-dye your material to keep it vibrant, or enjoy the softer hues of a well-loved item.
Caitlin Wilson is an Heirloom Gardener editor, and lifelong textile enthusiast. You can find her projects, successes, and failures at Sunshine And Roses.