How to Grow Dahlia Seeds

There’s something so exciting and satisfying about growing dahlias from seed. It feels a little like magic — these tiny seeds evolve quickly into little sprouts, then tiny plants, and eventually into beautiful blooms. And, because dahlia genetics are so complex, the new flowers which grow are always unique. You never know what they are going to look like in terms of color, and even form.  Even if both seed parents are the same type, like two collarettes for example, seedlings may decide they want to be an informal decorative (eg. closed centre), formal decorative, single or peony dahlia bloom. 

That said, in my own experience, I find my collarette seeds are about 70-80% collarettes when both parents were. However, you really never know until the first flower blooms.

If you’ve never tried starting dahlias from seed before, the wet paper towel method is an easy, low-pressure way to begin.

Here’s how to do it — and why it works so well.

Why Start Dahlias This Way?

Dahlia seeds don’t need anything fancy to sprout. What they need is consistent moisture and warmth. The wet paper towel method lets you:

• See exactly which seeds are viable
• Avoid overwatering (a very common problem)
• Get a head start before planting into soil
• Feel like a proud plant scientist check on your little experiments

It’s simple, affordable, and surprisingly fun.

What You’ll Need

• Dahlia seeds
• Paper towel
• Water
• A resealable plastic bag or container; I use simple ziploc baggies
• A warm spot in your home

That’s it. No grow lights, no seed trays — at least not yet.

Step-by-Step: The Wet Paper Towel Method

1. Moisten (Don’t Soak) the Paper Towel

Wet a paper towel and then gently squeeze it out. You want it damp, not dripping. If water runs out when you pick it up, it’s too wet.

2. Lay Out the Seeds

Spread the dahlia seeds on one half of the towel. Give them a little space so roots don’t tangle later.

3. Fold and Seal

Fold the other half of the towel over the seeds and slide the whole thing into a resealable bag or container. Don’t seal it 100% airtight — a tiny bit of airflow helps.

4. Keep Warm

Place the bag somewhere warm (around 18–22°C is perfect). On top of the fridge or a warm shelf works beautifully.

Now you wait (always the hardest part). 

 

What Happens Next

In about 5–10 days (sometimes sooner!), you’ll start to see tiny white roots emerging. It’s genuinely exciting the first time you spot them.

Check daily to make sure the towel stays damp. If it starts drying out, lightly mist it.

If you notice any seeds that haven’t sprouted after about 10–14 days, they may not be viable — and that’s okay.  Dahlia seeds tend to have a 70-90% germination rate, depending on the seeds and growing environment. They like to be snuggled in a damp and warm (room-temperature environment).

One of the benefits of using the wet paper towel method is that it allows you to know which seeds have germinated. You can then gently take the sprouts off the paper towel and move them into seed trays knowing that they are viable and are going to grow.  Plant the sprout with the roots facing down and the little leaves popping above the soil.  

You can plant the seedlings into a general potting mix. Keep the soil damp, but not soggy. Check seed trays daily, and water as needed. 

 

Baby dahlias transplanted into seed trays last year. 

 

Transplanting to Soil

Once the root is about ¼–½ inch long, it’s time to move the seed into soil.

• Fill small pots with a light seed-starting mix
• Make a shallow hole
• Gently place the seed root down; tweezers help if you have them
• Lightly cover with soil
• Water gently

Within a week or so, you’ll see the first little green leaves pushing up. That’s when the excitement really begins.

A Few Encouraging Notes

• Not every seed will sprout. That’s normal. Expect germination rates generally between 70-90% with optimal set up.
• Every seed-grown dahlia is unique. You might get unexpected colours or petal shapes. Be ready for "dahlia Christmas" as blooms start to open throughout the summer. It's so much fun!
• Seed-grown dahlias form tubers by the end of the season, which you can save and overwinter. You can plant overwintered-tubers next spring. Dahlias grown from tubers will always be an exact genetic replica of their parent plant. If you like a particular dahlia seedling, you can overwinter the tuber and expect to see the same parents when the tuber is planted next year. Sometimes, you will also see second season flowers change (often, I've seen form is even better after the first year).

 

There’s something special about growing dahlias this way. You’re not just planting a flower — you’re discovering one. Each bloom really feels like a fun gift.