Dirt Shirt “Recipe”

---

Supplies

• Colored, fine-textured soil (not sand): Bright colors work best, especially reds and yellows, but other colors work, as you can see below.
• Clean, white cotton: tee or button-down shirt, or cotton swatch, can be knotted for tie-dye.
• Small-scale, as below: 1-qt zipper-seal freezer bags.
• Large-scale: Bucket or tub to mix soil with water to make slurry. I typically use a 5-gallon bucket; the high sides help contain the mess.
  • Broomhandle, stick, rod, paddle or other object to stir the mixture.
• Vinegar. The vinegar alters the pH of the mixture, which causes the iron pigments in the soil to be more soluble, and so more easily transferred to the fibers. The end result is a more colorfast dye.
• Heat source for soaking and/or drying, if desired.
• If not outside, a tarp or drop cloth to protect the floor or carpet.

---

Method

• Wear something you do not mind getting stained, otherwise, wear an apron to protect your clothes (and take your chances with big splashes).
• If not outside, put down a tarp or drop cloth to protect the floor or carpet.
• Small-scale: Add 250 ml water to bag.
• Large-scale: Add 4 to 6 liters of water to bucket.
• Add vinegar (250 ml vinegar to 4 liters water, 15 ml vinegar to 250 ml water)
• The amount of soil varies with the soil texture.
  • What is soil texture?
  • How can I know? Using Texture-by-Feel.
  • Sands settle out of suspension and do not form a slurry.
  • The amount of water required increases with increasing clay content; it normally ranges from 1 to 3 times as much water as soil, though it could be more.
  • High clay content soils also tend to stick together and are difficult to get to a slurry consistency. Grind or crush aggregates (clumps) and add clay very slowly while stirring/mixing.
• Stir continually while slowly adding soil.
• Add cloth/tee/shirt. Mix it into the soil slurry until totally covered. Turn it inside out and repeat the process.
• Soak for several hours. If possible, heat (simmer) the mixture while soaking.
• Rinse thoroughly several times.
• Line or tumble dry on medium or high heat. Use a moist cloth to wipe the inside of the dryer after removing the shirts.
• After drying, I sometimes repeat the soaking process, and have gotten deeper colors.
• After the dye job is complete, machine wash the shirt by itself in cold water. The color will bleed onto anything in the washer with it. Use a moist cloth to wipe the inside of the washing machine tub to remove soil particles, then run the machine through a rinse cycle with nothing in it.

---

---

The instructions above incorporate the following comments from Susan Letcher who used my original recipe to make dirt shirts while she was a graduate student at U Conn. “I want to thank you for your dirt shirt web page. I’m a PhD student in ecology, and I just made a very successful batch of dirt shirts with some soil samples I brought back from my field site in Costa Rica. In order to dispose of my soil samples in accordance with USDA regulations, I had to sterilize them either by autoclaving or boiling. Not wanting to bring down the wrath of everyone in the department by filling the autoclave with fine red dust, I elected to boil them– and what better use for a big pot of boiling mud than to make dirt shirts? I invited a bunch of friends over for a dirt shirt party. Your recipe worked really well. My only suggestion would be to add the vinegar during the soaking step–this is what I’ve done while dyeing fabric with other reagents in the past, and it seemed to work really well in this case, too. We simmered the shirts in mud and vinegar (c. 1 cup per gallon) for about four hours, and rinsed in plain water. The color is great, and has lasted through one washing so far with no perceptible fading.”

---

This can easily be adapted to the experimental method for a science class.

• Have the students make a hypothesis about what will happen when white cotton material is submerged in mud (of various colors). For the scientist, This is called the null hypothesis, or hypothesis of no difference. The scientist will then have an alternative hypothesis that says the soil will change the color of the cloth and what color they think it will be.
• Determine the variables to test. Some suggestions include:
  • Soil color, soil texture
  • Vinegar – with and without
  • Use of heat during soaking or drying.
  • Soaking time and amount of agitation.
  • Use a mordant (fixative, pretreatment) such as soda ash, http://www.pburch.net/dyeing/FAQ/sodaash.shtml
  • Use your imagination.

---

I would be interested in your results or comments. Are there changes you would suggest? Email me.

Updated: 14 October 2024