We grow a lot of marigolds. I pick them and dry them and we sell them as natural dye material. I know they give good color. Every year we do a color test on the marigolds we sell but it's usually early to mid summer and the colors have always been wonderful. We've never been disappointed. But, here it is mid-October and I'm still picking marigold blossoms and drying them.
Dyeing with natural dyes is always magic. And a bit of a crap shoot. The color you get from any plant varies with the amount of sun, the amount of rain, the heat, the cold, etc. Basically anything that can change in the plant's life can and will change the color you get when you use that plant as a dye. So marigolds picked in mid-October probably won't give the same color as they would have if picked in July.
We only want to sell dye materials that will give color so I thought I would do a test. The last bucket full of marigold blossoms I picked and dried, I boiled up to make a dye bath. As long as I get good color, regardless of the exact color, then I will keep picking and drying and selling the blossoms.
I'm really pleased by the results! Despite my inability to photograph this yarn true to the colors I can see when I look at them, the yarn mordanted with alum (on the left) is a bright clear yellow. The yarn mordanted with copper (on the right) is a darker but still lovely golden color. The only surprise was the superwash Merino Kona Coast (in the center) mordanted with alum. It is a deep golden yellow not as dark gold as the copper mordanted yarn but deeper and richer than the alum mordanted yarn.
OK. We are good to go. I'll continue to pick marigold blossoms for a while longer. At some point, the temperature will drop and the plants will stop making flowers. That will definitely be time to stop picking flowers. In the meantime, I think there is enough color in the dye bath to do another batch of yarn. I'm sure the color will be paler but hopefully no less gorgeous.