Cosmos bears single white, pink, lavender, or burgundy blooms from summer through frost. Dwarf cultivars, such as ‘Sonata’, tend to bloom earlier than taller-growing types.
To start seeds indoors: About 4 to 6 weeks before the last frost date, sow the seeds, covering them with about 1/8 inch of medium. Keep the temperature at about 70°F. When seeds sprout (5 to 7 days), lower the heat to about 60°F and provide bright light to keep them from becoming “leggy.” Transplant seedlings outdoors around the last frost date.
Photo: (cc) Ragnar Jensen/Flickr