Yes, Virginia, dahlias from seed do exist. You can grow dahlias from seed and even save tubers from them.
This is how I got started with dahlias in the first place.
It was the dead of winter and I decided I was going to grow dahlias because so many people in my feed were raving about them.
I looked up the price of one tuber and said, nope.
Then I stumbled on dahlia seeds. These seemed way more affordable and low risk.
I bought a pack called “Showpiece Mix,” and, with very low expectations, planted them out and got them to flower.
I fell in love immediately.
Each bloom was unique and beautiful. And once I’d gained confidence growing dahlias, I did eventually invest in a few tubers!
But I’m getting ahead of myself.
Before we get further into this post, there’s one thing worth knowing upfront: dahlia seeds are a genetic melting pot.
Seedlings won’t be identical to the parent plant. Instead, they’ll be something entirely new.
For some gardeners that’s a dealbreaker.
For me, it’s the whole point.
Dahlia Seeds vs. Tubers: Which Is Better?
Starting dahlias from tubers or from seed each have their own advantages. Here’s what I think is great about each.
Growing from seeds:
- Cheaper than tubers (or free if you’re saving from your own plants)
- Every seedling is genetically unique, which means surprises (both beautiful and questionable!)
- A great way to experiment and potentially discover something special
- Seeds are easy to trade, share, or buy (also less expensive to ship)
Growing from tubers:
- Plants are clones of the parent—you know exactly what you’re getting
- More reliable; stays true to color and form if it’s a named variety
- Tubers can be reliably saved year after year
For a cutting garden where you want to know exactly what you’re going to get: tubers win.
But if you have extra space, a smaller budget, or just want unique surprises, growing from seed is your best bet.
I grow both. I can’t help it!
There are special varieties that I don’t want to be without, but the allure of discovering a new flower and giving it a fun name draws me to plant at least a few dahlia seeds each year.
Oh yeah, did I not mention that before? You get to name your new varieties! How cool is that?
If you’re new to dahlias and have a small garden, I’d suggest starting with tubers. Here’s how I plant my dahlia tubers.
How to Grow Dahlia Seeds: Starting Indoors
Growing dahlias from seed is similar to starting other tender annuals indoors.
If you start tomatoes indoors, the process is like that. See my post on growing tomatoes from seed for a refresher.
However, there’s one big difference.
My preferred method for starting dahlia seeds involves pre-sprouting them.
Dahlia seeds can be a little spotty in germination, and each seed is precious, especially when saved from a favorite flower.
Pre-sprouting them helps me know exactly which seeds are viable before planting and allows me to plant a single seed per cell so I don’t waste any by having to then them out.
We’ll get into that soon.
When to Start Dahlia Seeds Indoors
Start dahlia seeds indoors 4–6 weeks before your last frost date.
They don’t need a long head start as they’ll grow quickly once germinated.
You also don’t want to let them get too big unless you’re prepared to up-pot them to keep them from becoming stressed.
Six weeks is my sweet spot.
My last frost date is on April 25. I typically start dahlia seeds in early March, around the same time as my tomato seedlings.
What You’ll Need
- Good quality potting mix
- Small cells or seed trays
- A grow light
- A spray bottle or gentle watering can
- A paper towel
- Plastic bag or plastic wrap
Sprouting Dahlia Seeds Step-by-Step
1. First, pre-sprout your dahlia seeds. Moisten a paper towel and squeeze out excess water. It should be damp, but not dripping.
2. Space your dahlia seeds out evenly on the paper towel. Fold up the paper towel with the seeds inside and place in a plastic bag. Label each bag.
3. After a week, start checking your seeds regularly for sprouting. A sprouted seed will have a little white “tail” coming out of the pointy end of the seed.
4. Plant one sprouted seed about 1/4″ deep in each pot or cell filled with moist potting mix. Keep the pots or trays under a strong grow light for 14 hours per day.
5. Mist your planted dahlia seeds daily. Never let it dry out completely, but don’t let it get waterlogged either. Seeds will continue to grow and you should see a sprout above the soil in a few days.
Dahlia Seed Germination Time
Dahlia seeds typically germinate in 7–14 days under average room temperature conditions (65°–75°F).
Don’t give up if yours are slow. Some groups may take up to 21 days to sprout, especially if they’re older seeds.
Once seedlings emerge, place them under strong light for 14 hours a day.
Growing On: From Seedling to Transplant
After germination, dahlia seedlings grow fast. Here’s what to expect in the weeks between sprouting and planting out:
Week 1–2 (post-germination)
Cotyledons (the first two seed leaves) appear. They’ll look like small, rounded, slightly ruffled leaves. Happy birthday, baby dahlia!
Week 2–4
True leaves emerge. This is when seedlings start to look like actual dahlias. Once you have two sets of true leaves, you can pot up to a slightly larger container to give those babies room to grow their itty bitty tubers.
Week 4–6
Seedlings should be sturdy and a healthy green. This is the window before it’s time to harden off and transplant.
Week 6–8
Hardened off seedlings can be planted outdoors once the last frost date has passed. If you want to force seedlings to branch and produce more stems, pinch the tips off the plant once it has 4 sets of leaves.
Read more on how to pinch cut flowers for more stems in this post.
Hardening Off
Before moving dahlia seedlings outside permanently, they need to be hardened off, or gradually introduced to outdoor conditions.
This takes around 7 days.
Start by setting them outside in a sheltered, shady spot for a few hours, then bring them back in. Each day, increase their time outside and gradually expose them to more direct sun. By the end of the week, they should be able to handle a full day outside in direct sun.
When to Plant Dahlia Seedlings Outdoors
Transplant dahlia seedlings outside after your last frost date, once nighttime temperatures are consistently above 50°F. Dahlias are frost-tender and will die if hit by a late freeze.
I keep frost fabric on the porch in the spring to cover seedlings if a freeze is expected.
Before planting, select a spot with:
- Full sun (at least 6 hours, ideally 8+)
- Well-draining soil (dahlias are prone to root rot)
- Good air circulation (to prevent powdery mildew)
Plant seedlings at the same depth they were growing in their cell and space them 12 inches apart.
Water in well and keep them consistently moist for the first week or two while they establish.
I usually add a handful of organic fertilizer plus mychorrizae (like Espoma) into the planting hole before planting each seedling.
Then I set up my stakes around the dahlias. I use the corral method where I simply tie a cord to form a pen of sorts around the dahlias to keep them from flopping over.
For more in-depth notes on how I plant and stake dahlias, read my post on how to plant and grow dahlias.
Will Dahlia Seeds Grow Into Tubers?
This is one of the most common questions about growing dahlias from seed.
In short, the answer is yes… but there’s more you need to know.
Dahlia plants grown from seed will form tubers by the end of the growing season, just like plants grown from tubers do. You can dig them, store them over winter, and replant them next year.
However, first-year seedlings tend to produce smaller, fewer tubers than established plants. That’s normal.
Give them a full growing season and they’ll build up a good root system. By year two, you’ll have a proper clump to divide just like any other dahlia.
Variations from Tubers Planted from Seed-Grown Dahlias
One more thing to note, is that if you save tubers from seed-grown dahlias and replant them, they may look slightly different the next year.
Not always, but sometimes. You may notice a small variation in color, petal count, closed vs. open center, etc.
For this reason, professional dahlia breeders grow out new varieties for at least 3 years to monitor for changes like this.
What to Expect: Timeline for Dahlias from Seed
Here’s a realistic picture of the full season:
| Stage | Timing |
|---|---|
| Start seeds indoors | 4–6 weeks before last frost |
| Germination | 7–14 days after sowing |
| Transplant outdoors | After last frost date |
| First bloom | 90–120 days from seed (midsummer to late summer) |
| Seed heads ready to harvest | Late September – October |
| Dig and store tubers | After first frost kills foliage |
Starting dahlias from seed 6 weeks before last frost should give you plenty of time for them to mature and bloom before first frost.
I start my seeds in mid-March and expect to see blooms by the Fourth of July at the latest.
For the fastest blooms, do not pinch your dahlias, plant them in a spot where they get unfiltered sun all day long, and feed them with a balanced fertilizer (NPK numbers are all the same or close, like 5-5-5, 4-3-4 or similar).
Too much nitrogen, and you’ll end up with a ton of leaves.
Saving Seeds from Your Seedlings
Once your seed-grown dahlias bloom, the cycle starts again. If you find a seedling you love, then you can save seeds from it just like you did from the parent plant.
Keep in mind that its seeds also won’t grow exactly like the parent, so each generation is a new roll of the dice.
Some dahlia breeders spend years selecting and crossing plants this way to develop new named varieties.
Now that I grow dahlias from tubers and seeds, my favorite seedlings have come from seeds saved from named tubers, notably Cornel, Cornel Bronze, and Thomas Edison.
I’ve noticed seeds grown from them are more likely to have a similar form to those parent flowers.
Frequently Asked Questions
No. Unlike some perennial seeds that need to be exposed to cold for some time to break dormancy, dahlia seeds will germinate readily without stratification. Provide warmth and moisture and those babies should sprout!
No. Bury seeds about 1/4 inch deep and firm the soil over the seeds.
You can, but your season may not be long enough to get blooms before frost. As with tomatoes, starting indoors before last frost gives you a head start and earlier blooms.
Seeds are the result of pollination. Each seed carries a unique combination of genetics and will grow into a plant that may look complete different from the parent. Dahlia tubers are essentially clones. A plant grown from a tuber wil be identical to the one it came from. Learn to grow dahlia tubers in this post.
Your Turn to Grow
It’s your turn to grow dahlia seedlings in your own garden.
Raising dahlia seedlings of your own is an accessible way to get into growing dahlias and fill a garden for less.
The world of dahlia breeding is an exciting adventure, and any of us could discover a new favorite dahlia!