Collection: Cosmos Seeds

planting cosmos seeds in your garden

Cosmos bipinnatus, commonly known as garden cosmos, is considered a half-hardy annual, although plants may reappear via self-sowing for several years. Let the sunny disposition of cosmos, waving to and fro in the wind, brighten your day. Cosmos flowers will present themselves just 50 to 60 days after being sown. Once in bloom, cosmos height varies from two to six feet tall and can become top-heavy. Avoid this problem by planting in groups, or as a thick border along a fence line. The leaves will interlock, the colony will support itself, and you will reap the benefits of their show. If you can't decide on a favorite, try Eden Brothers' Crazy for Cosmos Seed Mix!

Cosmos is actually a Greek word meaning "harmony" or "balanced universe." It is a Mexico native flower and is one of the simplest flowers to grow. These beauties are suitable for all zones and are perfect for beginners and even children gardeners!

When to Plant Cosmos Seeds

Plant your cosmos seeds in the spring when the soil can easily be worked. Cosmos prefer full sun or partial shade. These blooms are incredibly adaptable and will thrive in average to poor soil quality as well as dry conditions.

Scatter cosmos seeds after the threat of frost has passed. Seeds may be covered about 1/4 inch with soil, as they do not need direct light to germinate. Water your seeds, keeping the soil moist but not soggy for about 10 days. Germination can occur in just a few days, or it may take up to two weeks.

caring for cosmos flowers

Once the seedlings begin to sprout, cosmos require little to no attention. Only water your cosmos during hot, dry spells. You can add a general purpose fertilizer once or twice a season to improve flowering if desired, however, these blooms are very self-sufficient for the most part. If you want your cosmos plants to continue blooming throughout the entire summer season, be sure to deadhead old blooms as they wilt. In warmer climates, cosmos may be cut back to 12 inches after blooming; they will start blooming again in one to two months. Divide flower clumps about every three years or so.

For more information about planting, growing, and caring for cosmos flower seed, see the Cosmos Seeds Planting Guide.