With their bright, daisy-like flowers in shades of pink, orange, white and red, cosmos add cheerful color to summer gardens. After the blooms fade, the cosmos plants develop seed pods bursting with hundreds of seeds. But what do cosmos seeds look like?
Cosmos seeds have a very distinctive appearance. Learning to recognize them allows you to harvest and save seeds to plant more cosmos for free in future seasons.
The Appearance of Cosmos Seeds
Inside the dry brown seed heads, cosmos seeds are elongated and skinny. They resemble tiny blackened canoe paddles.
The seeds are around 5-6 millimeters long. They have a flattened oval shape and pointed tips. The seed coat starts off light brown when fresh, then turns darker as the seeds dry.
When mature, the seeds detach easily from the central disc within the faded flower head They readily fall out with the slightest shake or touch This is why birds love feasting on ripe cosmos seeds!
When Are Cosmos Seeds Ready to Harvest?
Cosmos seeds reach maturity around 2-3 months after the flowers finish blooming. Check seed heads in early fall for ripeness.
Signs seeds are ready for harvest:
- Flower heads are dry and brown
- Seeds fall readily from pods when shaken
- Seed coats have darkened from light to dark brown
Pick seed heads once the morning dew has dried for the best dry, mature seeds. Use scissors or pruners to snip off the spent flowers just below the faded blooms.
Collecting Dry Cosmos Seeds
Step 1. Harvest dried flower heads and place in paper bags. Collect from your best plants for seeds true to type.
Step 2. Crack open pods over a paper towel to release seeds. Flick pods to remove all seeds.
Step 3. Spread seeds on a paper towel-lined box. Place in a warm, dry spot for 4-6 weeks. Gently shake box daily to mix seeds.
Step 4. When thoroughly dry, pour seeds into envelopes labeled with variety and date. Add silica packs or dry milk powder to absorb moisture.
Step 5. Store envelopes in a sealed glass jar or tin in a cool location until planting time next year.
Saving Cosmos Seeds for Replanting
With proper harvesting, drying and storage methods, cosmos seeds remain viable for 2-3 years.
Start seeds indoors 6-8 weeks before your last spring frost. Or sow them directly in prepared garden beds after danger of frost has passed.
Space cosmos plants 8-12 inches apart in full sun and well-draining soil. Water when top few inches of soil are dry. Deadhead spent blooms to encourage more flower production.
Reasons to Save Your Own Cosmos Seeds
Here are benefits of collecting and replanting your own cosmos seeds:
-
It’s free! No need to buy new seed packets every year.
-
Maintains genetics. Saves seeds perfectly adapted to your growing conditions.
-
Promotes biodiversity. Heirloom and native species disappear without seed saving.
-
Satisfaction. Rewarding to grow plants from seeds you harvested yourself.
-
Seed exchanges. Extra seeds can be shared with other gardeners.
Tips for Successful Cosmos Seed Saving
Follow these guidelines for the best results harvesting and reusing your own cosmos seeds:
-
Choose heirloom varieties, not hybrids, for seed saving.
-
Allow pods to fully ripen on plants before collecting.
-
Dry seeds thoroughly before storage to prevent mold issues.
-
Store seeds in envelopes labeled with variety and date in a cool, dark place.
-
Use dried milk powder or silica packs when storing to absorb moisture.
-
Sow recycled seeds within 1-3 years for highest germination rates.
Watch for Cross-Pollination
Different cosmos varieties can cross-pollinate if planted near each other. This results in hybrid seeds that won’t grow true to type.
To prevent accidental hybridization, only grow one variety for seed saving or separate different types by at least 1 mile.
Enjoy an Endless Cosmos Supply
With their fine-textured, colorful flowers and carefree growth habit, cosmos are must-have annuals for most gardens. Saving your own seeds ensures you’ll have an ongoing supply of these beauties for free.
Just be sure to let pods fully mature on plants before harvesting those paddle-shaped seeds. With proper drying and storage methods, they’ll germinate readily the following year.
So plant some cosmos this season and get ready to collect and replant their unique seeds again and again. Your flower beds will overflow with gorgeous blooms year after year thanks to seed saving.
Tips for Collecting Cosmos Seeds
Need to know how to harvest seeds from cosmos?
Before you can start collecting cosmos flower seeds, you need to decide which flowers you want to grow next year. Pick out some samples that look especially nice, and then tie a short piece of yarn around their stems to remember them.
Once the flowers begin to die back, the cosmos seed harvest can begin. When the flower dies and the petals start to fall off, bend one of the marked stems to see if it works. If the stem snaps easily in half, its ready to pick.
Remove all the dried flower heads and place them in a paper bag to capture loose seeds. Break the pods open with your fingernail over a paper towel-lined table to get the seeds out.
Flick the inside of each pod to make sure you remove all the seeds. Line a cardboard box with more paper towels and pour the seeds into the box. Place them in a warm spot where they wont be disturbed. Each day, shake the box to move the seeds around. Then, let them dry for six weeks.
Cosmos Seed Harvest Info
When you collect cosmos seeds, the only hard part is figuring out if your plant is an heirloom or a hybrid. Hybrid seeds wont reproduce faithfully the traits of their parent plants and arent good candidates for seed saving. The cosmos plant seeds from an heirloom, on the other hand, and are ideal for this project.
How to Grow Cosmos Flowers From Seed – How to Prune For More Flowers and General Care
FAQ
Can I just throw cosmos seeds on the ground?
Will cosmos self seed?
What does cosmos flower seed look like?
What do Cosmo flower seeds look like?
Cosmo flower seeds look like small, pointy sticks that are slightly curved with tapered, pointed ends. They are generally dark brown in color and may be thin or slightly thicker in girth. Some cosmo flowers produce seeds that are longer while others produce shorter seeds. Generally speaking, cosmos will germinate readily from healthy seeds.
How do you identify Cosmos seeds?
Labels to identify the seeds, such as a post it note to stick to the inside of the container, or a marker to write on the outside of the bag. Harvest cosmos seed at the end of the growing season in early fall, when the seed heads have matured and you notice that the seeds become loose and begin to fall away from the pods.
When do Cosmos seeds form?
The cosmos seeds will form on the flower head after the petals have dropped. At first it will look like this: The above is an immature seed head. They are not ready for picking yet and are still quite green. You want to wait until the seed head opens up and is completely brown and dry.
Are Cosmos seeds Hardy?
These plants have grown in your own environment, and endured your weather patterns throughout the growing season. If you harvest flower seeds and save your seed from year to year, over time the seeds will become more hardy and adapted to your garden space. Cosmos seed is no exception.
Do Cosmo flowers produce seeds?
Some cosmo flowers produce seeds that are longer while others produce shorter seeds. Generally speaking, cosmos will germinate readily from healthy seeds. Lots of Cosmos Seeds on a piece of construction paper
Do Cosmos seeds go to seed?
Though cosmos are an annual flower, they go to seed very readily. While you can allow the seeds to drop and see if new ones will sprout the following spring, you can also collect cosmos seeds to save and plant the following year. Collecting and saving cosmos seeds is very easy and in just a couple of minutes you can have tons of seeds.