Flowers | Seed Starting

Starting Dahlias Indoors from Seed – Don’t Be Intimidated!

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Dahlias offer breathtaking beauty in the garden or spilling over a vase. Starting dahlias indoors from seed ended up being one of my absolute favorite things last year. Such an impressive flower comes from such an unimposing seed.

Last year (2021) was our first time growing dahlias at all. I was very excited to experience the whole process from planting dahlia tubers and seeds to dahlia seed collection.

Pink and Yellow Dahlias started from seed indoors
Pink and Yellow Dahlias started from seed indoors

At first, I was a little intimidated, I’ll admit. I had seen the beauty of other gardeners’ dahlias all over Instagram.

Who am I to think I can even come close to that?

But, I shrugged it off because everyone starts somewhere, and truly, the gardening community is very welcoming and supportive at large.

If it’s your first time starting dahlias indoors from seed, don’t be intimidated! I am happy and honored to help you through the ropes.

Let’s get started!

What does a dahlia sprout look like?

When planted from seed, a dahlia sprout is bright green in color and tends to have two rounded, oblong leaves. You may see a fine line down the center of each leaf. These first leaves are the cotyledon.

Once the true leaves grow, you may see more of a pointed and serrated edge to the leaves.

Starting Dahlias Indoors from Seed - Dahlia Seedlings in a Blue Egg Carton with Seed Coat still attached to cotyledon
Starting Dahlias Indoors from Seed – Dahlia Seedlings in a turquoise egg carton with seed coat still attached to cotyledon

How long do dahlia seeds take to germinate?

Dahlias may take 3 days to 3 weeks to germinate, depending on the type, seed quality, and growing conditions. Under grow lights with lots of eager attention, our first dahlia sprout appeared in 3 to 4 days only.

Sowing Dahlia Seeds Indoors

In my humble opinion, growing dahlias from seed is just as easy as growing any other flowers from seed.

I used the same exact process of using egg cartons to start seeds as I always do for zinnias, calendula, marigolds, and others.

For me, the big difference came when it was time to transplant the tiny dahlia seedlings from the egg trays to nursery pots or the ground.

Some of them had been growing for so long that they’d already created their own miniature tubers!

They were so cute and amazing to see. I happily upgraded their growing space!

Unwins Mix Dahlia Seeds I received in a seed swap in 2021!
Unwins Mix Dahlia Seeds I received in a seed swap in 2021!

How to: Starting Dahlias Indoors from Seed

Here are the exact steps I use to grow dahlias from seed in egg trays inside.

  1. Prepare an egg carton for planting. (You can use my exact process on planting seeds in egg cartons.) Cliff Notes: Poke holes, fill with soil, plant seeds, water, wait!
  2. Select the seeds from dahlias you wish to grow. I’ll be planting ones I’ve saved from my 2021 dahlias, but you may wish to choose from a wide variety available. You can find dandy dahlias, cactus dahlias, or others. I’ve also grown unwins dahlia mix, white ribbon dahlias, and a variety of large dahlias from seed. (I’ve only grown dinnerplate dahlias from tubers I purchased.)
  3. Sow dahlia seeds about ¼-inch deep. You can poke small holes in the soil or just brush it aside with your fingertip or a popsicle stick.
  4. Cover the seeds up with soil. Replace the soil lightly over the seeds.
  5. Water the soil with a spray bottle. Thoroughly moisten the soil enough to get down to the seeds.
  6. Place the trays in a sunny window or under grow lights. I love the grow rack I’ve created! First, I purchased an awesome shelving setup with a basket for supplies. Then, I ordered Monios LED grow lights.
  7. Check daily for moisture needs and progress. Our seed-grown dahlia sprouts were some of the first flower seeds to germinate for us in 2021!

The Mystery of Seed-Grown Dahlias

The best beauty of growing dahlias from seed is that you never quite know what you’re going to get. (Well, maybe if you are a professional grower with a controlled environment…)

It’s amazing to plant a saved seed and see what comes of it. You may have favorite flowers that grow this way. If that’s the case, give them a name and save the tuber!

(If you live in a cool climate where dahlias aren’t perennial, be sure to save and store dahlia tubers indoors for next year.)

White Ribbon Dahlia started from seed indoors with a bee pollinating it
Here’s a White Ribbon Dahlia started from seed indoors with a bee pollinating it – Bees LOVE dahlias!

Do you have any awesome dahlias you’ve started from seed? Love to hear your stories!

Also, feel free to ask any questions or share any other tips you may have. We love hearing from you!

Happy Gardening!

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4 Comments

  1. This is a great article thank you after reading this I don’t feel as nervous growing dahlia seeds lol. This is my first time and your article helped a lot!!!!

    1. Hi Jennifer, thanks for your kind and amazing comment – it means so much to me hearing that my article helped! I loved growing dahlias and can’t wait to try them again this year. I wish you so much luck and hope they grow beautifully for you. Thanks again for taking the time to drop a line. Happy Gardening!

  2. Thank you for your dahlia seed post! I collected dahlia seed last year for the first time and I’m excited to give it a try!
    I’ve read that LED lights need to be kept further away from the emerging/growing seedlings. What is your experience with this?
    Thank you!

    1. Hi Barbara! Thanks so much for your note – so happy you’re growing dahlias from seed this year! They were one of my favorite things to grow last year. I kept my dahlia seedlings on the same racks / distances from grow lights as the rest of my seedlings. I started them with the lights just a few inches above the trays and only raised the lights as the plants grew. How’s it going for you? Best wishes for your garden this year!

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