Growing Dahlia Flowers From Seed
Have you managed to get your hands on some dahlia seeds? You might wonder ‘what’s the big deal? Gardeners grow from seed all the time!’ but growing dahlia flowers from seed offers many unique opportunies.
I’m by no means an expert, but today I’ll be sharing how I grew dahlia flowers from seed as my growing experiment in 2021. If you are just starting out growing dahlias, you might want to check out my Tips for Growing Magnificent Dahlias as well.
Where can I buy dahlia seeds?
I have dahlia seeds from a few different places, but my favorite dahlia I grew came from a pack of Triple Wren Farm seeds. Floret Flowers also sells dahlia seeds I believe. This year I saved some seeds from my patch, and I hope to make those available to subscribers soon (update: we are sold out of dahlia seeds for the year, but make sure you are subscribed so you don’t miss out next time)!
Growing Dahlia Flowers From Seeds vs. Tubers
The only way to know for sure what kind of dahlia you will be growing is to purchase a tuber from a vendor (cuttings are another way to propagate dahlia copies, but most vendors don’t sell cuttings). So, if you see a dahlia flower variety online that you want to grow, you’ll need to purchase tubers. Dahlia tubers are the bulbous root of the plants that produce an exact copy of the parent plant. In fact, tubers are great for beginners who want to start their dahlia collection and My Tips for Growing Magnificent Dahlias article focuses on growing from tubers if you need some additional tips.
Growing dahlia flowers from seed provides a certain element of excitement since dahlia seeds do not grow flowers identical to their parents! You could end up with small little dahlias, thin or scraggly plants, random colors, and some really stunning specimens! If you read on, you’ll see the dahlias I ended up with after starting about a dozen plants. It’s such a fun experience!
Additionally, dahlias grown from seed do produce tubers. In other words, you will have tubers at the end of the season to save and grow the next year!
Some Notes on Dahlia Breeding
While most of us are growing dahlias for fun, I’ve been reading more about dahlia breeding and thought I’d share some facts. Again, I’m not an expert, but here are some interesting things to know:
Growing dahlia flowers from seed is how breeders create new dahlia varieties.
Before a variety can be “claimed” it needs to be grown throughout several seasons to make sure it is stable (some dahlias have genetics that can present differently over time).
Not all dahlia flowers will produce seeds. For example, my cafe au lait dahlias don’t produce seeds while others make a lot! I’ve read this can have a lot to do with pollination, genetics, etc.
Breeders can actually pollinate certain dahlias by hand to try and get specific characteristics or traits to combine. This process also involves covering the flowers to isolate the pollen from bees or other pollinators.
For an in-depth guide to breeding dahlias, definitely check out Kristine Albrecht’s book Dahlia Breeding for the Farmer-Florist and the Home Gardener. Kristine has years of experience, and her dahlias are incredible! I’m new to this process, but I think it goes to show that you can get involved as much as you’d like to—whether it’s just for fun or if creating your own personal dahlia variety is your goal!
Time to Start the Dahlia Seeds!
Every season I grow something new to me. Instead of a tutorial, it felt more appropriate to just write about growing dahlia flowers from seed as I experienced it so, each week that passed, I wrote down notes on what I’ve observed, what surprised me, and the discoveries along the way.
It was New Year’s weekend 2021. After such a warm and dry Winter, I couldn’t resist wanting to start my dahlia seeds. Yes, it was a risk to start this early, but I saved some seeds to start in February as well. Dahlias are warm season plants that don’t tolerate frost well, so starting even later is fine too.
I started the seeds by placing one per cell, using six-cell trays filled with my DIY seed starting mix. If you are looking for seed trays that will last for years, check out these 6-cell seed starting trays. Each seed was carefully buried about 1/4″ deep. Due to the cold weather outside, I kept my seeds indoors to start. Literally five days later, I had about 3/4 of the seeds germinate. It was amazingly fast!
About 10 days later, I planted more seeds in each of the cells that didn’t germinate. Honestly, I knew there was always a risk of a seed being sterile or not germinating.
Up-potting Dahlia Seedlings
It’s very imporant to make sure you keep your seed starting medium moist while seeds are germinating. After what was only about a week, it became obvious that these fast-growing seed babies were going to outgrow the tiny six-packs quickly. Therefore, I decided to up-pot them into 4″ seed pots to prevent the seedlings from getting root bound. In retrospect, I probably should have started my seeds in the 4″ pots to begin with because dahlias grow so quickly.
Caring for Dahlia Seedlings
The most beautiful thing I noticed once the first true leaves started forming on my seedlings, was that each leaf-shape was different. Some leaves were smooth and slender while others had jagged edges or almost looked like feathers. I truly enjoyed watching each plant grow into something unique from its brothers and sisters.
By the end of January, I did my first feeding of fish emulsion. To feed seedlings, I simply make a weak solution of water and emulsion and then water the seedlings from underneath using a tray. You can see a demonstration video of how I feed my seedlings in Tips for Stronger Seedlings.
I continued to care for the dahlia seedlings, taking them outdoors during the day and indoors at night. All of a sudden, the dahlias were getting too big for the 4″ pots I had them in! If you remember in my Tips for Stronger Seedlings article, root bound plants can slow in growth and become unhappy. Therefore, it was time to think about transplanting the dahlia seedlings. In my garden climate, this would be too early to plant any frost-sensitive plants, but the dahlias grown from seed in 2021 were destined for a spot in my mom’s garden where she never truly gets to freezing due to her microclimate closer to the ocean.
When growing dahlia flowers from seed, as with all seedlings, you need to follow a hardening off process to prepare your seedlings to be transplanted outdoors. The process can vary depending on how you’ve been growing, but I share a simple 10-day process HERE on the blog.
On Feburary 7th, I decided it would be more beneficial to the root bound seedlings to transplant them in my mom’s garden now, but with frost cloth to keep them safe. In retrospect, seeing how fast dahlias grow, this was definitely an early start. In the future, when growing dahlia flowers from seed, I’d probably start in March.
Planting dahlias in the garden
Before transplanting the dahlia flowers grown from seed out into the garden, we amended the garden soil. I followed my usual steps for How to Amend Soil Organically but also did some more specific things for the dahlias:
First, I used an organic all-purpose flower fertilizer per the package instructions.
Second, I added bone meal which is an amendment high in phosphorus that I add to a majority of my flowering bulbs or tuberous plants to promote blooming year after year. My daffodils, anemones, and ranunculus also love bone meal at planting time.
Third, we setup a drip line system to water the dahlias. Luckily, my mom’s garden already had the proper connections for it, so we just needed to purchase the drip line tubing. If you’re curious about the various types of irrigation we use in the garden, I wrote up a full post on that HERE. There are lots of options!
Lastly, since the temperatures were still somewhat cold at night, I brought some wire hoops and Agribon frost cloth to create our DIY fabric row covers for the dahlias. I don’t think this is necessary if growing dahlia flowers from seed at a more proper time, but since I was pushing the limits of the climate, it seemed like a good idea.
Pinching Dahlia Seedlings for Blooming
Since, this year, I decided to go after dahlia growing “like the pros,” I decided to pinch my seedlings to promote more bushy growth and blooms. This is a practice that professionals use often because their goal is more blooms in a controlled setting, but in the past I’ve only done this sometimes and don’t mind letting my dahlias do their own thing in the landscape sometimes. If you’d like more information, I share how to pinch dahlia seedlings in Tips for Growing Magnificent Dahlias.
Observations of Dahlias Grown From Seed
Remember how I said “some might grow scraggly, some not at all, etc.”? Well, right away I could see the strongest and most vigorous ones. One specific dahlia didn’t grow at all for MONTHS only to produce a really terrible looking flower. It’s not really the gardener’s fault, but more about the genetics of that dahlia.
The majority of my dahlias grown from seed produced pleasant flowers with open-centers for the happy bees. They were fun to have as a pop of color, but not the swoon-worthy dinnerplate or ruffly and romantic blooms that many dahlias are known for. Here are the various dahlia blooms that I got:
What next? Growing & Breeding Dahlias
From this experience, I did decide to keep four of my dahlias to grow out for 2022. I guess I should say “keep” because technically my mom refused to let me destroy any of the tubers, and insisted on keeping them all in various areas of her yard—so we are “keeping” them all.
The following year, growers are supposed to continue documentaion and see if your saved tubers grow in the same color, pattern, and form as the previous year. Essentially, this is all to determine if the genetics are stable because there could be a totally different presentation the following year. This is my next step for 2022, and I’m excited to see if the dahlias I chose to keep and observe look good this year.
Are you excited for growing your own dahlia flowers from seed?