Cosmos

Cosmos are native to Mexico, and eventually made their way to the United States. They have a history of being used for attracting beneficial insects, such as lacewings, that feed on pest insects and provide pollination for surrounding plants.

Sow cosmos directly into soil after the last frost, or sow indoors 4-6 weeks prior to the last frost. If sowing indoors first, transplant seedlings outdoors once the last frost has passed. Cosmos require full sun. Sow seeds 1/4 inch deep and thin the seedlings 12-18 inches apart when they are a few inches tall. Flowers should bloom at about 7 weeks when growing from seed. Cosmos can grow 18-60 inches tall, so stakes may be necessary for support. Water regularly, but do not overwater; cosmos are draught-tolerant.

When harvesting, cut the flower off the stem to use for natural dyeing.

The petals of a cosmo plant are where their dye color comes from. Flowers are placed in a dehydrator for 8-12 hours and then stored in a cool, dry area until they were ready to be used for dyeing.

When creating a dye concentrate with Cosmos, it is important to use hot water rather than cold. 

Fabric should be mordanted before dyeing with cosmos. 

The fresh or dried plants work well with bundle dyeing as well. 

Dye concentrate recipe:

24 grams dried orange cosmos

16 grams dried yellow cosmos

72 ounces water 

Simmer mordanted fabric in dyestuff for 1 hour at 140° Fahrenheit. 

Let fabric soak in dye bath for 24 hours at room temperature, then strain and rinse.

Sources:

Johnny Seeds

The Spruce

Colour Cottage

The Micro Gardener

Almanac