Cosmos Seeds,
Black Magic

Sow cosmos seeds after the danger of frost has passed, as this variety is not frost-hardy. The soil temperature should be at least 60 F. In areas with short growing seasons, start seeds indoors 3-4 weeks before the last expected frost and transplant them once outdoor temperatures have stabilized. In warmer climates, it may overwinter as a perennial if protected from frost. For the best planting window, check your local area's frost dates. If you're not sure how to do that, refer to our blog post 'Our Experts Answer Questions, Share Resources.'

Lightly press the seeds into the soil at a depth of 1/8-1/4 inch. Plants should be spaced about 10 inches apart for proper air circulation and room to grow. For earlier blooms or colder regions, start seeds indoors in a well-draining seed-starting mix. Keep temperatures between 65-75 F for optimal germination. After 3-4 weeks, harden off seedlings before transplanting them outdoors. Handle with care to avoid disturbing the delicate roots.

Make sure that the Black Magic cosmos receives 6-8 hours of direct sunlight daily. It flourishes in light, well-draining soil and can tolerate nutrient-poor conditions. Overly fertile soil can actually result in excessive foliage growth at the expense of blooms. This variety is drought-resistant once established, needing only occasional watering. Avoid overwatering, as it can lead to weak stems. Taller plants may require staking or support, especially in breezy locations.

• Cosmos are insect pollinated, and there may be some crossing between varieties in the garden. You can enjoy the mixing or use caging techniques and hand pollination to avoid crossing.
• Saving seeds from cosmos is easy: simply allow the heads to brown and dry on plants and collect seeds. Store in a cool, dry, dark place over winter.