Sustainable Cultivation of Plant-derived Indigo for Diversification and On-farm Value-added Dye Pigment Production

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2010: $9,871.00
Projected End Date: 12/31/2011
Region: Southern
State: Tennessee
Principal Investigator:

Annual Reports


  • Miscellaneous: Indigo


  • Crop Production: biological inoculants, nutrient cycling
  • Education and Training: farmer to farmer, on-farm/ranch research, workshop
  • Farm Business Management: new enterprise development, cooperatives, budgets/cost and returns, value added, agritourism
  • Pest Management: mulches - living, mulching - vegetative
  • Production Systems: general crop production
  • Soil Management: green manures, soil analysis

    Proposal summary:

    Growing global and local markets for natural dyes suggest that growers and grower-led cooperatives can spur rural economic development through the cultivation and processing of plant-derived natural dyes, but more research -- specifically organic and sustainable agriculture centered research -- is needed before these alternative crops can be an economically viable or logistically feasible option for Southeastern growers.
    While alternative crops or value added products can help a small farm increase income, these crops carry the additional cost of obtaining information on cultivation and production needs, identifying willing buyers for a new product, and integrating a new crop into an existing farm rotation.

    As the market for naturally dyed organic clothing continues to grow, natural dyeplant cultivation can be a productive value-added enterprise for small farms in the South. The organic fiber and sustainable textile market is growing. Global sales of organic cotton increased by 63% in 2008 to $3.2 billion and are expected to reach US $5.3 billion in 2010 according to Reuters in April 2009. As this market evolves, there is an increased demand for plant and earth based colorants (rather than those derived from synthetics or petroleum). I would like integrate small farmers into this value chain.

    In addition to providing a valuable source of year-round income, natural dye crops can increase sustainability in a diversified cropping system. Plants that produce blue dye pigment, Indigo-containing plants, for example, are low nutrient feeders and have few pest problems. One specific indigo containing plant, the Indigofera species are leguminous plants that frequently serve as a green manure and a summer cover crop across the world. However, some of the largest recent studies of natural dye plant production -- the SPINDIGO Project in the European Union, for example -- have focused on conventional farming methods, rather than investigating how to integrate natural dye crops into a sustainable farm system.

    Project objectives from proposal:

    The lack of comprehensive data on production, yields, post harvest processing, and storage and market needs makes it risky for Southeastern farmers to enter into growing natural dye plants, since there is minimal producer level information, whether about which plants to select, what conditions to grow in, or how to process natural dyestuffs into a value added product. Research is needed to determine best practices for cultivar selection, cultivation, processing and pricing, as well as accurately assessing production costs and income per acre.

    Southeastern growers need research to determine suitable natural dye crops for our region, and to establish best practices for cultivation and processing of these plants. This project will provide a baseline of cultivation, production and cost data for working with the three most promising indigo-containing plants -- specifically indigo (Indigofera suffructosa and Indigofera tinctoria), and Japanese indigo (Persicaria tinctoria) -- to create storable, value-added dye products that can be sold from the farm-gate across the region as a natural alternative to synthetic indigo. In addition to assessing the most profitable production techniques, we will focus research on post-harvest handling and processing -- often the most discouraging aspects for farmers entering alternative crop cultivation. We will finalize techniques for on-farm processing of indigo-containing plants into powdered natural indigo. Processed natural dye material ready for dyeing demands a higher price point and permits better storage, branding, and marketing than raw plant material.

    Little information exists on larger scale - not homegarden - natural
    dye production, so yield and value per acre is very difficult to assess. A 2001-2004 European Union collaboration called Spindigo started research on two of these plants, woad and Japanese indigo, but Indigofera species did not grow in their region. This project will allow us to establish which indigo-containing plants will grow best in our region of Middle Tennessee, and how they may be best processed to yield products of high market value.

    Natural indigo powder currently sells for between $46 (The Dyeworks, CO) and $60 (Earth Guild, NC) per pound. Research suggests yields of 60lbs/acre for Indigofera species, thus garnering between $2760 per acre and $3600 per acre of indigo after processing. According to the Spindigo Project, woad can produce indigo in quantities of up to 100 kg/ha or 89.2 lbs/acre. Woad currently retails on the internet for 20g/10 euros (Bleu de Lectoure) or 19.50 British Pounds for 20 g (Woad-inc). These sell for much higher than we think our market could currently bear in the Southern US, at an equivalent of $283.75 per pound (given a 1.25 Dollar to Euro Exchange rate), which would garner $25,310 per acre. These extremely high value products are the result of branding, marketing and EU customer trust. However, it does show how small farms can be profitable in this niche market.

    This project has long-range potential as a jumping off-point for cooperation in researching and growing other dyeplants. I have spoken with farmers in Kentucky and Alabama about cooperating to grow, process, and market other natural dye plants (such as Hopi dye sunflower, zinnias, or marigolds, which are already successfully grown in this region for other market outlets), in order to produce a wide variety of colors and to provide consumers with "one stop shopping" for natural dye products. On-farm processing and pigment extraction would mean vertical integration of indigo dye and other pigments, as well as a regional branding initiative through the creation of a unique product -- color from seed to shirt.

    This one year study will investigate the feasibility of cultivating and processing plant-derived indigo in the Southeastern US. Based on preliminary trials in 2008 and 2009, we have identified the indican-containing plants most likely to be profitable and successfully grown in our region: dyer's knotweed (P. tinctoria), and two types of indigo (Indigofera suffruticosa and Indigofera tinctoria), to determine the best cultivation and processing techniques for each.

    For the research trials, I plan to grow and process 100 row-feet of each of the variables the three cultivars utilizing organic practices, with varying inoculation, mulch and fertilizer variables. We will test to determine the most suitable methods for cultivating the selected crop(s), based not only on green vegetative yield but also isolated pigment yield. By investigating different nutrient regimes I can determine maximum profitability based on the volume and purity of final product (pigment) yield after taking into account input costs. For each row we will determine production costs and compare this to final yields and the market value of indigo end product. Indigo will be harvested in batches based on variety and processed along side each other so date of harvest and conditions are the same. Our method of processing uses non-specialized equipment.

    After the harvest and processing, our partner ASK Apparel will do comparison testing of the quality of the natural indigo pigment from the different production methods and plants by making dye vats and testing the strength and clarity of the dye. Additionally, project collaborator ASK Apparel will perform market analysis and research in order to establish appropriate markets for the finished dyestuff in future years.

    Outreach goals include:
    - Host field days at farm to correspond with dyeplant harvesting and processing; host "open houses" to promote natural dyes

    - Cultivate institutional and farm partnerships. Host an out of town information session and dye workshop.

    - Create website to host instructional videos, factsheets, and other project-related information

    - Create downloadable factsheets on cultivation and processing for three test crops

    - Create online technical instructional videos on:
    * best practice cultivation techniques for plants selected for second-year study
    * best practice processing methods for high-quality yields
    * processing of raw plant material into indigo pigment

    - Informational booth at SSAWG conference; recruit attendees for future dyeplant workshops and as potential grower network members

    -Create a Southern natural dye growers' network that will serve to explore and share best practices in the cultivation and processing of plant-based indigo and other natural dyes. According to C.Martin, Agriculture Specialist at NM State University, and lead researcher on a 2006-2007 WSARE grant Growing and Marketing Dye Plants as Alternative Crops, in the Southwest US in order to meet the wide range of colors and plant materials, [researchers] recommended in the report that growers form a co-op or coordinate their production to be able to provide a wide range of colors, and not create a glut of a single crop.

    The ultimate goal of our outreach is to create a grower cooperative that lower barriers to profitable dyeplant growing and provide resources for obtaining dye seeds, sharing processing equipment and methods, and increasing awareness of natural dyeing and regional dye sourcing options.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.