Last year at the end of the gardening season, before the first frost killed off my Japanese indigo crop, I harvested a bunch of stalks to save. I hung some to dry; I took the leaves off of some, bagged the leaves in a freezer ziplock, and stuck them in the freezer; and I took the leaves off of some, laid them out on a flat pan, put the pan in the freezer, and left them to not only freeze, but to dry out (freeze-dry).
About a month ago, I tried brewing up a Japanese indigo dye pot in the usual manner (like I would for fresh leaves), but I used some of the freeze-dried leaves. It didn't work out. I meant to toss all of my frozen and dried leaves but couldn't quite bring myself to do it.
I'm glad I didn't because I just came across the book, A Garden to Dye For, by Chris McLaughlin. In it there is a recipe for using dried Japanese indigo leaves in an ice-water preparation to dye silk. Yippee! Of course I tried it right away.
The recipe calls for 4 ounces of J. indigo leaves, half air-dried, half microwave-dried. These are blended up with ice-water in a blender, the mixture is strained through a cloth (like a flour sack towel) and a strainer, and then the pre-wetted silk is placed in the thick mixture for 10-20 minutes. This is supposed to yield a light, turquoise-like blue on the silk. I didn't have any microwave-dried leaves, but I used all of the dried and frozen leaves I did have on hand. They totaled about 3.5 ounces.
The author of the book left her silk scarf in the liquid for 40 minutes. I didn't have any scarves, but I have lots of silk hankies, so I used some of those. Although I did see the blue color on the hankies at about 10 minutes, I left them in for 40 minutes. I also tossed in a small knitted swatch of wool I had on hand. After soaking, the silk should be rinsed and left hanging to dry.
I rinsed my hankies, and although I caught glimpses of that pretty turquoise for a moment, what I ended up with in the end was green. I don't know if that's because I left the hankies soaking for too long, because of the chemistry of my water (well water, run through a softener), or because some of my leaves were frozen, but not dried. The color is pretty, nonetheless.
Here are the hankies soaking in the thick liquid:
And here they are after drying overnight. The turquoise ones on top are some hankies that were dyed in an actual J. indigo dyebath last summer. The little woolen swatch is to the right of those hankies, and the green hankies from last night's experiment are below those:
It's a nice color, especially on shiny silk, but not the pretty turquoise I was hoping for. I've used up all of my leaves from last year now, but fear not! I have another crop growing in the dye garden as we speak. I will, of course, repeat the experiment again in hopes of attaining that wonderful turquoise in the future from dried J. indigo leaves.