Turning Food Waste Into Gold 

By Elena Bilheimer, EcoNews Journalist

The fashion industry is notorious for its damaging effects on the environment, unfair labor practices, and promotion of endless consumerism and throwaway culture. Synthetic dyes,  most of which are carcinogenic and toxic for ecosystems, are a core practice in the industry and are widely used and disposed of into the environment. Learning how to naturally dye using food waste or invasive plants is an empowering and rewarding activity that is environmentally friendly and can help bring new life to clothes that would otherwise be thrown away or donated. Dyeing with onion skins (Allium cepa), a readily available food waste that often ends up in the garbage or compost, is an accessible, cheap, and easy introduction into this craft and the process of upcycling.

According to the United Nations, the fashion industry is responsible for 8-10 percent of the world’s greenhouse gas emissions, while also producing 20 percent of wastewater. In contrast, natural dyes that are derived from plant or fungi sources have a low environmental impact, are safe for human health, and don’t release any harmful chemicals during the dyeing process. Natural dyeing has a long history, and until synthetic dyes became widely accessible in the mid-19th century, using plants and minerals to dye textiles and other objects was the standard practice. Tracing the history of dyeing with onion skins is difficult — as onions now grow throughout the world — but the vegetable itself seems to have originated in central Asia

Dyeing with onion skins is relatively easy compared to other dyes, as use of a mordant (a substance that is used to improve the color fastness and durability of natural dyes) is not required to help bind the dye to natural fiber. This is due to the high tannin content found in onions, which work similarly to mordants. Onion skins produce a beautiful range of earthy colors, sometimes even producing shades of gold. Many dyers consider the colors produced from natural sources to be “living colors”, meaning that they capture and transmute the essence of the alive material that made them. Whether or not you agree with that assessment, this practice can help you create a more intimate relationship with the plants you use and surround yourself with everyday.

How to Dye with Onion Skins


  • Lots of dry red or yellow onion skins  
    • The skins can be mixed together or done separately. Experiment to see which colors you like.
    • A general rule of thumb is a 1:2 ratio between the weight of fabric and the weight of onion skins. The more skins you have, the stronger the end color. 
  • Natural fibers 
    • Natural dyes are not usually successful at dyeing synthetic fabric. Give new life to clothing items you already have or find new pieces made of natural fibers to experiment with at your local thrift store.
      • Wool and silk are examples of natural protein fibers.
      • Cotton, linen, and bamboo are examples of plant fibers.
  • A big pot (the bigger the better depending on the amount of items you are wanting to dye) 
    • Some dyers (including this one) claim aluminum pots increase color saturation. Although onion skins are non-toxic and food safe, it is a good idea to avoid using the same materials you use for cooking for natural dyeing (especially when experimenting with any other sort of dyestuff). You can either get a pot and utensils from the thrift store or designate cookware you already have for all future dyeing processes.
  • A big spoon 
    • Be aware that wooden spoons will turn yellow throughout this process, so sometimes stainless steel spoons are preferable.
  • A colander or strainer
  • A kitchen scale (not completely necessary, but helpful for knowing how many skins to add)


  1. Wash fabrics (either in the washing machine or by hand for delicate fibers). Scouring, the process of thoroughly cleaning the fabric to remove any grease, dust or dirt that will inhibit the fabric from uptaking the dye, is another step you can take to improve results. If you are interested in this step, there are many resources online that explain how to do this.
  2. Weigh fabric and onion skins in grams and write down the amounts. Again, this is not a necessary step but will help if you ever want to repeat the process of experiment with different weights. 
  3. Soak fibers in hot water for a few hours or overnight to aid in their ability to extract color from the dyestuff.
  4. Rinse onion skins and remove any stickers or moldy/discolored spots. 
  5. Put onion skins in the pot and add enough water to cover them.
  6. Bring the pot of water to a boil and then reduce to a simmer for around an hour, until the water has turned a deep saturated color.
  7. Let the dye bath cool down and then remove the skins with the colander (another pot or big bowl can be helpful).
  8. Add enough water so that your fibers can swim around without crowding each other (the less you are dyeing at once the better)
  9. Add pre-wet fibers to the dye bath.
  10. Slowly reheat the dye bath with fibers for another hour.
  11. Stir fabric continuously for at least the first five minutes after adding them to help with an even dye coverage and to remove air bubbles. 
  12. Stirring every once in a while throughout the process can also be helpful in ensuring evenness. 
  13. Let your fibers cool in the dye bath. Leaving the fibers in the bath overnight can increase the brightness and depth of colors. 
  14. Remove the fibers from the dye bath and rinse with cold water until water runs clear.
  15. Hang fibers to dry and then let them cure for a few days or weeks before gently hand washing them with cold water and a pH neutral soap. Continue to wash with cold water and a gentle soap throughout the lifecycle of the item. Remember to enjoy  and admire your beautiful handmade creations!

Other Helpful Hints:

  • The dye bath can be kept in the fridge for about a week or in the freezer for six months to a year. Use your senses to tell when it’s gone bad and is better suited to feed the plants outside.
  • Onion skins can be collected over time and stored in a cool dry environment either in a paper bag or a jar. If putting them in a jar, make sure they are completely dry before closing the lid to avoid any mold growth. 
  • Some restaurants, grocery stores, or even friends and family can be convinced to save their onion skins for your dye purposes. 
  • Turmeric powder can also be added to the dye bath to achieve extra bright yellows. Add the turmeric at the same time as the onion skins, and be sure to stir extra when adding the fibers as sometimes the powder can settle. 
  • Although mordants  are not required to dye with onion skins, they can sometimes brighten the colors or make them last longer. Check out this website for more information on how to pick the right mordant for the type of fabric you have and how to do the process safely and effectively. 
  • It is possible to create patterns with different household items. Try using clothespins (which create little white squares) or tying different strings or rubber bands to create interesting circles. Have fun and be creative!
  • Avoid placing your dyed fabrics in direct sunlight. Although onion binds to fabric relatively well, non-synthetic dyes will naturally fade over time. You can always dye items again to brighten faded colors. 
  • The pH of your water can affect the results. Play around and experiment to see what you like.
  • Other food waste dyes that are relatively easy to learn how to use include avocado pits and skins, pomegranates, and used coffee grounds. Dyeing with invasive plants like eucalyptus is also possible. The journey has just begun!
  • Be a good scientist! Write down the date, the weight of the onion skins and fiber, and how it turned out. This will help if you ever want to repeat the process. 
  • Natural dyeing is an exploration of imperfection, inviting us to practice becoming comfortable with results that are not always what we intended or hoped for. As Prentis Hemphill, a therapist and somatic healer, said, “Perfectionism is a commitment to habitual self-doubt”.  Enjoy the creative process and know you can always try again if it doesn’t turn out exactly like you were hoping it would.