Cosmos Seeds,
Velouette

Plant cosmos only after all chance of frost has passed when soil temperatures have warmed to at least 60 F. In colder regions, seeds can be started indoors 3-4 weeks before the last frost and transplanted outside once temperatures are suitable. In warmer climates, cosmos can be direct sown in late spring or early summer. For best results, check your local last frost date to determine the optimal planting time. Check out our blog post ‘Our Experts Answer Questions, Share Resources’, if you’re not sure how to do that.

Sow the long, slender seeds horizontally and cover lightly with a thin layer of soil, as they need light to germinate. Space plants about 10 inches apart for good air circulation and to prevent overcrowding. Seedlings emerge in 7-14 days, depending on temperature and moisture. Maintain a temperature of 70-75 F for optimal germination. If transplanting outdoors, handle seedlings carefully to avoid disturbing their delicate roots.

Avoid excessive fertilization, as this encourages leaf growth over flower production. Once established, cosmos are drought tolerant and need minimal watering. Overwatering can lead to weak, leggy plants. If plants become too tall or leggy, trim them back by one-third for a bushier habit.

• 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.