Cosmos are sometimes referred to as the flower paint of the Aztecs as they were historically used during rituals by the Aztecs in South America, where the plant originates. Cosmos is thought to have received its name from the Spanish priests that grew it in their gardens during missions in Mexico. The symmetrically placed petals led them to call the flowers cosmos after the greek for universe. There are many varieties of cosmos that are popular for growing in the garden as ornamental and cut flowers, but Cosmos sulphureus produces flowers that are shades of yellow, orange and red and can be used as a natural dye. The fresh or dried flowers produce yellows, oranges and browns.
Cosmos seeds are best sown in April on a sunny windowsill or warm greenhouse, the seeds are fairly large and usually germinate within a week or two if they are kept at approximately 20C. The seedlings require plenty of light in the first few weeks of growth. If you are growing your coreopsis seeds in one of our soil pods, sow approximately 3 seeds per pod, allow the seedlings to grow until they have formed the first true leaves, then separate and select the strongest seedlings to plant on into larger pots or directly into the garden after the risk of frost has passed.
Space plants with about 20-30cm between them. Cosmos plants prefer fertile soil with added organic matter, but their main requirement is plenty of sun, so plant them in a sunny spot. Keep the plants well watered and they should grow very quickly. To promote the plants to bush out and produce more flowers, pinch out the growing shoot when they reach 20-30cm. Harvest the cosmos flower heads when the flower has opened completely by snipping or snapping them off. This way the plant will continue to produce more flowers throughout the rest of the season.
Once you have harvested the cosmos you are ready to dye! You can also dry them out in a sunny spot on a windowsill to save them for use during the winter.