The Amish dye fabric with what they find in gardens and forests.
Colors
Yellow: onion skins, turmeric, chamomile. Brown: walnut shells, oak bark, tea, coffee. Blue: indigo (grown or bought), blueberry. Pink/red: beet, elderberry, madder root. Green: nettle, spinach (but pale and fugitive). Gray/black: alder bark + iron mordant.
Process
1) Mordant: soak fabric in alum (potassium aluminum) solution — fixes dye. Without mordant, color washes out in 2-3 washes. 2) Extraction: boil plant material 1-2 hours. Strain. 3) Dyeing: fabric in dye bath 1-12 hours (longer = deeper). 4) Rinse cold.
Durability
With mordant — dozens of washes. Without — 3-5. Walnut and indigo — most durable. Berries — least.