Gio's class dyed wool with marigolds in the sun. They left these jars outside for several days and then one day when I dropped Gio off at school there was a big tub of warm water on the picnic table and all the jars were line up next to it. As each child arrived they poured out the liquid and petals, then rinsed the wool in the warm water, rung it out and hung it on a nearby bush to dry. The color ended up being a pale yellow.
The next day the big tub was filled with a dark liquid. His teacher told me it was indigo. As each child arrived they donned rubber gloves and dipped their wool into the liquid. Then they rung it out and placed it on a lined cookie sheet to dry. At first it looked black but as it dried it started to turn a grayish green. I can't wait for next week to find out what the color ended up being. I'm thinking green.