Buy One Package of Cosmos Seeds and Harvest Your Own Lifetime Supply

How many things in life can you buy one of and then make thousands more for free? Not many.

That's the magic of seed production. You grow a couple of cosmos flowers, harvest the seeds, plant those seeds next year, and repeat. You never need to buy another seed packet again (unless, of course, there's another color you really want).

If you're new to growing cosmos, you're in for a treat. Cosmos are like zinnias and marigolds—they just give and give and give. These low-maintenance flowers with their lacy leaves come from the daisy family and are super easy to grow from seed. You can literally just sprinkle seeds in your pollinator garden. You'll find flowers in shades of pink, purple, orange, yellow, and burgundy, and even some candy-striped ones.

These flowers will not only attract pollinators to your space, they'll also draw in a whole host of beneficial insects like lacewings, hoverflies, tachnid flies, and parasitic wasps. These bugs might not sound like a good thing, but trust me, they are. They'll take care of pest issues for you, which means growing cosmos can improve the overall health of your garden.

And the seeds are super easy to save!

What Do Cosmos Seeds Look Like?

Cosmos seeds look a bit like little swords, at least the swashbuckling cartoonish kind. They're each about five or six millimeters long, and they start off light brown and then fade to charcoal.

Now, let's look at how to harvest your own cosmos seeds.

Cut Cosmos Flowers as They Fade

Cosmos flowers will bloom prolifically from summer all the way to your first frost. The best time to harvest your cosmos flower heads is when the flowers are past their prime. This is when the magic of seed formation starts happening. The flowers might not look so charming anymore, but they're busy creating tons of seeds for you.

You can snip spent flowers at any time to save seeds from, or you can wait and do a big haul right before you're expecting frost. Make sure to use a clean pair of pruners to cut the stems a couple inches beneath the spent blooms. I recommend focusing on flowers from your favorite plants, and make sure to grab at least one flower head in every different color you want to grow again. (Though if your flowers were cross pollinated, the next generation won't be true to the original. That's never really bothered me. You're sure to end up with something beautiful no matter what.)

Cosmos are masters at self-sowing the following year, so know that you're likely to get new plants in the spring anyways. Saving seeds is just your way of having a little more control over where the majority of your flowers end up.

Let Cosmos Flowers Dry

Hang your blooms upside down to dry somewhere dark and dry for about a month until they are completely dehydrated. You don’t want any moisture left when you store them or you risk growing mold. If the stems are too short to hang, you can also spread the flower heads out on a drying rack.

Store Dried Cosmos Flowers Over Winter

Once the flower heads are dry, it's easy to separate the seeds from the petals by rubbing them between your fingers.

These seeds need to rest a little bit before they're ready to grow again, so you'll want to store them in some seed-saving packets or a glass jar for the winter. This is the beginning of your lifetime supply of cosmos seeds. Whatever you don't use next year can be saved for up to five years or so before losing viability.

Sow Cosmos Seeds

Wait until your final frost has passed before you sow your new round of cosmos seeds.

Pick a spot in an in-ground pollinator garden, a flower bed, or your raised garden beds that gets full sun. Cosmos prefer at least 8 hours of direct sunlight to bloom to their fullest potential.

You can use what I call the Lazy Woman's Method of Planting (trademark pending... just kidding). To plant this way, you'll literally scatter the seeds by shaking them from the palm of your hand. You can be as wild or methodical as you want while you scatter your seeds. 

Use a small shovel or a hand rake to cover the seeds up a little bit. Water your seeds in really well. 

And Wait for Blooms!

Cosmos take about 50 to 60 days to bloom. When they do, get ready for lots of cottage charm.

That, my friends, is how you have thousands of cosmos, enough to last you a lifetime, enough to give to friends, family members, your kids' teachers, even strangers on the street so the garden doesn't stop with you. Let's cover the world with flowers! And cosmos are so prolific and easy to grow from seed.

Thanks for being here and making gardening ordinary again!