I’ve been growing my own Japanese indigo plants to dye with for the last 5 years. There are many reasons to grow your own:
1. Magic. It is magical that a leaf can make this beautiful color. But it gets more magical. The dyebath is yellow-green and so is your yarn when you add it. But when you pull the yarn out, the color changes in the air to a beautiful turquoise blue! Magic.
2. There is no need for a mordant. A mordant is an additive that you must use with plant dyes usually to fix the color or achieve something beyond a light yellow-tan. Common mordants that are fairly safe are alum, (a salt that has aluminum) and iron (a metal). While these are fine if used properly, I prefer to not use any mordants if possible. And indigo fixes its own color, no mordants needed!
3. Japanese indigo is easy to grow. Nothing special is needed but they do love a nitrogen rich soil and regular water.
4. Doable amount of gardening. About four plants will yield enough dye for a bulky yarn women’s sweater, more if you harvest multiple times. Totally doable amount of gardening for anyone interested.
5. The blue is unusual and beautiful. Blue is rare in the natural world of colors, and it is accessible to you when you grow you own indigo plants.