To Dye For

Kelli Caldwell is using an abandoned lot in West Philadelphia to grow an unusual garden, one that provides the raw materials for her dyes.

By Jacqueline Boytim | April 23, 2013
Natrually dyed fibers

An array of naturally dyed fibers. Dyes used include marigold, ponderosa pine, and madder.

Flickr user Desertsong

The lot at the corner of 36th Street and Haverford Avenue in West Philadelphia was once abandoned, overgrown with weeds, and heavily strewn with garbage. In 2011 Kelli Caldwell hatched plans to transform this forgotten space into a community garden. Today, a chain-link fence encloses flowerbeds tended by neighborhood volunteers. But this garden is no ordinary one; it’s a chemistry garden, a throwback to the days when fabric dyes came only from plants, animals, and minerals.

Plants provide a broad spectrum of color: marigolds yield golden yellow dyes; apple-tree bark, dahlia petals, onion skins, and ivy berries produce dye colors ranging from warm mustard to springy chartreuse. Other plants—traditionally, indigo leaves for blue, madder roots for red—round out the plant-dye spectrum, and until the second half of the 19th century all were used to dye fabric, leather, and paper. Then, in 1856, William Henry Perkin created the first synthetic dye, mauve, from coal tar. Mauve was soon joined by a range of colors that displaced their plant-based counterparts.

Today most textiles are dyed with synthetics, which allows clothing manufacturers to color their products consistently and inexpensively; the dyes remain stable through extended sun exposure and are resistant to microbial attack. But the properties that lend synthetic dyes their commercial and aesthetic appeal also pose environmental and health issues. Resistance to microbes—a positive feature in clothing—reduces the effectiveness of wastewater-treatment plants and allows these dyes to persist longer in the environment. The 19th-century coal tar technology on which these dyes are based does pose health issues, such as cancer. In the wake of modern environmentalism artisans and activists alike find plant dyes a compelling alternative.

A 2011 webinar on the production and sustainability of vegetable dyes hosted by Caldwell provided the seed for the West Philly garden, which belongs to a project called Dyed Green Tomatoes (DGT). Caldwell is a program associate for the National Association of Sustainable Fashion Designers (SFD), the institutional driver of the project. After SFD acquired the abandoned lot in December helpers began clearing debris, and SFD then enlisted the University of Pennsylvania’s Environmental Studies department to plan the garden’s layout. With plant and lumber donations from the Pennsylvania Horticultural Society and a local Home Depot, as well as volunteer labor from the West Philadelphia Community Center, DGT had seeds in the ground by June 2012.

Owing to its summer start DGT was able to grow only marigolds. But next year Caldwell plans to relocate to the nearby Awbury Arboretum and expand the garden inventory to include indigo and madder. Then she will begin community workshops on natural fabric dyeing. Though methods vary with different plant sources, each process follows the same basic sequence. First, plants are harvested and prepared for a water bath. Then the fabric to be colored is treated with a mordant to help the dye stick to fibers. The mordant most commonly used with natural dyes, and also the most environmentally friendly, is alum (potassium aluminum sulfate). Treated fabrics are then added to a pot containing the dye plant and water. These components are heated together and allowed to simmer for an extended period. Once the desired color has absorbed into the fibers, the fabric is removed, rinsed, and hung to dry.

Adapting this traditional process to suit large-scale manufacturing is a tall order, and Caldwell recognizes the trade-offs in using natural dyes. Though she delights in the complexity of colors produced by natural dyes, she appreciates the consistency of synthetics and their low cost. Another tradeoff: the production of synthetic fibers can be less harmful to the environment than irresponsible cotton cultivation.

Ultimately, Caldwell wants synthetic dye technologies to become as ecologically viable as the old plant-based technology. But until then there’s the DGT project. This summer, when the new garden yields enough flowers and vegetables, Caldwell envisions getting community members involved in dyeing their own cloth. She hopes this educational experience will encourage them to consider more carefully the dyes used in their own clothing. She’s particularly excited about youth involvement: “Seeing their eagerness to learn about this process and willingness to get dirty and work in the garden—then their appreciation for the end result: priceless!”