Flowers | Seed Starting

Cosmos Seeds – Growing Cosmos from Seed to Flower

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Cosmos are one of the easiest flowers to grow! We planted our first Cosmos seeds in 2020 and were dazzled by the beautiful and prolific blooms. Cut flowers all summer long!

Attractive to people and pollinators alike, cosmo flowers can be a beautiful, low-maintenance flower with many benefits.

  • Enjoy cut flowers all season long!
  • Attract pollinators to your garden.
  • Add beautiful, long-lasting color to your garden and outdoor spaces.
  • Relax with a flower that doesn’t require much maintenance.

With so many benefits and ease of growing, cosmos make a great choice for your garden!

What Is the Cosmos Flower Meaning?

The cosmos flower is indigenous to Mexico but also popular in the United States and beyond. The name “Cosmos” comes from the Greek word “kósmos,” which translates to world and also tends to refer to order.

With this in mind, the cosmos flower meaning gives a nod to harmony and order. Other flower meanings for cosmos refer to decorative and ornamental appearances, peacefulness, and modesty.

The cosmos flower meaning also connects with love and care for someone else. Some say the flower is considered a “love flower.”

Picture a single flower symbolizing the purest and gentlest most unassuming love! I see a girl and a boy walking on a beach with a single flower in hand – so dreamy!

What Do Cosmos 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.

Cosmos flower seeds scattered on a piece of paper

How Tall Do Cosmos Grow?

Cosmos flowers can grow as tall as five feet. Generally speaking, cosmos grow between one and five feet high.

Our cosmos in 2020 were as tall as I am – five feet two inches!

It will be interesting to see how tall different varieties grow and I will come back to update this post with that information.

How to Grow Cosmos from Seed

Growing cosmos from seed is so easy and it’s a wonderful child-friendly gardening activity, too. It’s so rewarding to teach them how to plant cosmos seeds.

Cosmo flowers produce profuse blooms that kids will love to pick or cut during the summertime.

Planting Cosmos Seeds - Woman's Hand Holding Cosmos Seeds above Cosmo Seed Packets

How to Sow Cosmos Seeds

If you want to get a jump on things, start your flower seeds indoors. Teach your kids how to sow cosmos seeds in egg cartons for a fun and easy gardening activity.

  1. Cut the top off of an egg carton.
  2. Turn the bottom upside-down and poke holes in each of the egg compartments.
  3. Place the bottom of the egg carton on top of the lid, like a tray.
  4. Fill all of the egg carton cavities with potting soil.
  5. Select your cosmos seeds and decide how many seed cells you would like to fill.
  6. Place two to four seeds per seed cell. (I find cosmos seedlings fairly easy to separate and very forgiving during potting up and transplant.)
    • Tip: I practically surface sow these guys with great results! I basically scratch them in just like zinnias, just a little bit of potting soil dusted on top or around the edges of the seeds.
  7. Write directly on the egg carton to label the type of cosmos you planted. (You can also write on masking tape, a popsicle stick, or plastic plant tags.)
  8. Spray with a water spray bottle or mister to wet the soil.
  9. Keep the soil moist and check daily for growth and watering needs.

Cosmos generally germinate pretty quickly. In most cases, your little ones should enjoy that first peek of green within less than a week!

Cosmos Plant Seedlings

Cosmo seedlings seem to grow rather quickly in my experience. I love watching them grow and look forward to seeing the flowers that bloom!

By the way, consider pinching off the growing tip on your cosmos seedlings when you transplant them outside. They should respond by growing bushier and a bit more compact.

We’re going to try this, as ours were very large and sprawling last year. I’m excited to see how it goes!

How to Harvest Cosmos Seeds

When cosmos produce seed heads, you can wait for them to dry and then snip them off to save the seeds.

Last year I read that the first blooms to go to seed contain the most seeds, so be sure to collect those if nothing else.

I can vouch for this! We found larger, nicer and more seeds inside the dried, spent blooms that finished up first.

Here are some tips on how to harvest cosmos seeds:

  1. Wait until the bloom is fully spent. It may take on a shade of brown.
  2. Use scissors to snip off the old bloom above the last set of leaves.
  3. Continue to collect spent blooms so you can save many seeds.
  4. Pull the spent cosmos flowers apart over a tray or lid to reveal the seeds.
  5. Save the seeds in a paper envelope or paper lunch bag until you are ready to trade them or plant them in the future.

Final Thoughts: Cosmos from Seed to Flower

Growing cosmos from seed will likely be a part of our garden plan for a long time to come. We found so many benefits growing these pretty flowers from seed.

In 2020, we didn’t even plant our flower seeds until June! We received some Cosmo seeds in a swap and happily grew seashell cosmos and sensation cosmos last year.

When they bloomed, we enjoyed lovely shades of purple, pink, and wine, along with pure white cosmos. The petals of the seashell cosmos had a tubular appearance.

This year, I am so excited to see how much sooner we get to enjoy blooms having started our cosmos from seed in April.

Now we are growing even more cosmos since we loved them so much!

Various different seed packets of cosmos flowers - Bright Lights, Daydream, Picoti, and more

Cosmos Seeds 2021

Here’s what we’ve planted so far:

  • Apricot Lemonade Cosmos – from Swallowtail Garden Seeds (You can also get them at Etsy!)
    Apricot Lemonade Cosmos, Available for sale on Etsy - Photo courtesy of the seller, MossHallSeeds (https://tidd.ly/3coO5YJ)
    Apricot Lemonade Cosmos, Available for sale on Etsy – Photo courtesy of the seller, MossHallSeeds.
  • Cosmic Orange Cosmos from our seed swap friend Jenny on Instagram
    Cosmic Orange Cosmos, available for sale on Etsy at RobinSeeds - https://tidd.ly/3x0FvHl (Photo courtesy of RobinSeeds.)
    Cosmic Orange Cosmos, available for sale on Etsy at RobinSeeds – (Photo courtesy of RobinSeeds.)
  • Cosmos Picoti – white cosmos with a dark pink edge we bought from Nikitovka Seeds online
    Beautiful cosmos picotee flowering with white petals and pinkish purple edges. Available for sale at Etsy - photo courtesy of seller, ZellajakeFarmGarden. https://tidd.ly/3z5hWPu
    Beautiful cosmos picotee flowering with white petals and pinkish purple edges. Available for sale at Etsy – photo courtesy of seller, ZellajakeFarmGarden.
  • Daydream Cosmos – from a swap within a Facebook seed swap group with Jamie C.
    Daydream Cosmos Seeds - beautiful white with pink and yellow centers, available for sale on Etsy. Photo courtesy of seller, DaisyHeader. https://tidd.ly/3iikcgp
    Daydream Cosmos Seeds – beautiful white with pink and yellow centers, available for sale on Etsy. Photo courtesy of seller, DaisyHeader.
  • Cosmos Seeds we saved from 2020 – can’t wait to see if they’re hybrids or what!

I still have plans to plant a few more seeds once I get around to it. Hopefully we will have space to plant some Bright Lights, which are yellow, orange, and red cosmo seeds, according to the packet.

Are you growing cosmos for the first time this year? Or maybe you are a long-time grower of this beautiful flower! Let’s chat all about cosmos in the comments – what’s your favorite type of Cosmo flower?

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6 Comments

  1. I have a love hate relationship with cosmos. I wasn’t warned how prolific they are and the first year they kept reseeding and took over an entire flowerbed. The seeds blew into neighbors yards and they had cosmos. Mine also grew to over 5 ft tall but were trampled by a Texas rain storm. Then they looked horrible.
    I’ve learned to pinch them back before they bloom and to dead head before they reseed.
    You can count on cosmos returning each year and I’ve learned to appreciate their efforts to remain in my garden.
    My neighbors constantly compliment the cosmos more than any other of the other flowers.

    1. Hi Steven! Thanks so much for your thoughtful comment – I too was very surprised last week to see several cosmos have reseeded themselves!
      I thought my daughters and I meticulously saved every seed head, but it turns out we got a few surprises!
      (Although, I can imagine taking over an entire garden would be quite a different scenario! I am still trying to decide where to plant all of our flowers this year. 🙂
      Did any of yours cross to form different colors or features from the parents? We are excited to see what we end up with!
      Our 4 o’clocks also had a few volunteers this year and I am equally excited to see if they crossed or will resemble the original plant where the seeds must’ve dropped.

      Deadheading cosmos and Pinching are excellent ideas – I saw photos from a gardening friend of mine where she was able to double propagate her cosmos seedlings by pinching and replanting the top few inches of the plants. She placed them under grow lights and they grew a beautiful new root system! I definitely plan to try this on any flowers that I pinch this year. (It sounds like you already have plenty to spare! But this sounds like a fun experiment to try if you have other flowers you wish to multiply.)

  2. I was smitten by Cosmos when my very first exposure was to a 2 acre roadside field! I began searching for seedlings at my local greenhouses and nurseries. When I innocently inquired about Cosmos daisies, I was emphatically informed that they are NOT daisies, simply Cosmos! That’s the moment that I realized that they were indeed highly regarded by professionals and commoners (like myself) as well. I am so influenced by Cosmos that I actually wear an original, colorful tattoo that has had hundreds of compliments over the years. Long Live Cosmos!!!

    1. Hi Lisa! That’s sounds like such a wonderful tribute to the Cosmos Flower! Thanks for sharing your story – I love the origin stories with meaningful reasons about how a flower or plant gained its significance for someone. 🙁 I have a friend on Instagram who grows an entire field of Cosmic Orange Cosmos and has people come for the flower experience – photos, bouquets, etc. She sent us some seeds and I can’t wait to see how beautiful these orange ones are! The Cosmos really brightened up our backyard last year and I can’t wait to see what they do this year, since we got a few volunteers in the same garden bed! 🙂 I also love how easy they are to grow with my kids!

  3. Thank you for sharing valuable information about the cosmos. I love reading your article that gives additional knowledge about plants. Keep sharing more articles like this.

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