Do you love planting cosmos in your flower garden every year? Learn how to collect cosmos seeds so you can plant more every year!

Cosmos are one of my favorite flowers. They are perfect in a wildflower mix or to plant in a field or around a mailbox or birdhouse.

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They are simple flowers, but are great for bringing more butterflies, bees and hummingbirds to your yard. They also make a great flower to plant in the vegetable garden!

Cosmos are most commonly seen in either yellow/orange or pink/white, though there are a lot of other varieties to choose from as well.

The pink/white varieties can get quite tall- 4 feet or more! I prefer to plant the shorter orange/yellow varieties which only get a couple feet tall. Either one is beautiful though!

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.


how to collect cosmos seeds


How to Collect Cosmos Seeds for Future Planting

Collecting and saving cosmos seeds is very easy and in just a couple of minutes you can have tons of seeds. Which will turn in to tons of flowers you can plant next year for free!

Here’s how to do it:


With many of the flowers I grow, such as calendula or zinnias, I pick the blossoms as they grow or deadhead them after the blooms have faded. With cosmos, I just leave the flowers alone and just pick as I feel like it to enjoy indoors.

The cosmos seeds will form on the flower head after the petals have dropped.

At first it will look like this:

cosmos with immature seeds


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.

It will look like this when the cosmos seeds are ready to be collected:


mature cosmos seeds ready to be collected


When the seeds are fully mature they come off very easily. I like to use a bowl to hold under my hand when I am collecting so that I catch all the cosmos seeds that fly off the plant when I disturb them!

Collect all the dry seeds that you can find- but watch out for spiders! They love to live on the flower and seed heads!

If you aren’t certain the seeds are 100% dry you can keep them in an open container for a few days to allow them to dry before storing them.


a close up of hands collecting cosmos seeds to saving


How to Store Saved Cosmos Seeds

Make sure the cosmos seeds are completely dry before storing, otherwise you might end up with mold in your jar which can ruin your entire seed collection!

It’s best to keep your dried cosmos seeds in an air tight container with an air tight lid. This prevents the seeds from collecting moisture from the air around them.

Mason jars are perfect for storing seeds!

Another option is to seal the dry seeds in a plastic Ziploc bag or a sealed envelope.

No matter which container you choose, be sure to label your container with the name of the seed and the year collected.

Seeds are best stored at a temperature of 30-40 degrees, so storing them in the refrigerator or freezer can work well to keep them dry and mold free, thus expanding their shelf life.  You can also just store them where ever you store the rest of your garden seed collection!

If you don’t want to collect them, you can always leave the seeds on your cosmos and see if they will self seed the following spring. I usually do a little bit of both!


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