Most gardeners buy dahlia tubers. But what if you grew your dahlias from seed — and then harvested the tubers at the end of the season? That's exactly what we did at Diamond Field Blooms, and the results were remarkable.
Starting from Seed
Growing dahlias from seed is the road less travelled. Most dahlia varieties don't come true from seed — meaning the seedlings won't be identical to the parent plant. But that's part of the magic. You get variation, surprise, and the thrill of discovering what each plant becomes.
We sowed our dahlia seeds in summer, nurtured the seedlings through the growing season, and watched them bloom. But the real surprise came at the end of the season when we lifted the plants.
The Tuber Harvest: What We Found
Each plant yielded 6 to 10 tubers.
To put that in perspective: you start with one seed (essentially free, or a few rands each), and end the season with up to 10 tubers per plant — each one capable of producing a full flowering plant next season.
Is 6–10 tubers per plant good?
Yes — it's very good. A healthy, well-fed dahlia grown from seed in its first year can produce a modest clump. Getting 6–10 tubers from a first-year seed-grown plant is a strong result, especially in the South African climate where our warm summers give dahlias a long growing window.
For comparison:
- A tuber purchased from a nursery typically produces 1 clump of 5–15 tubers after a full season
- A first-year seed-grown plant producing 6–10 tubers is performing on par with — or close to — a purchased tuber
Seed vs Tuber: The Key Differences
| Seed | Tuber | |
|---|---|---|
| Cost | Very low | Higher |
| Predictability | Variable (surprise blooms) | True to variety |
| First year blooms | Yes, but later | Yes, earlier |
| Tuber yield (year 1) | 6–10 (good result) | 5–15 |
| Year 2 potential | Excellent — now you have tubers | Excellent |
| Best for | Experimentation, volume, budget | Specific varieties, reliability |
What to Do With Your Harvested Tubers
Now that you have your tubers, here's how to handle them:
- Clean and inspect — remove excess soil, trim damaged roots, and check for rot
- Cure briefly — leave them in a cool, dry spot for a day or two to dry the cut ends
- Store correctly — in SA's mild winters, store in a breathable bag or box with dry vermiculite, sawdust, or newspaper in a cool, dark place
- Label everything — note the flower colour and form so you know what to expect next season
- Replant in spring — once the risk of frost has passed (August–September in most of SA)
The Bottom Line
Growing dahlias from seed and harvesting your own tubers is one of the most rewarding things you can do in the garden. It's budget-friendly, endlessly surprising, and by the end of your first season you've gone from one seed to a whole collection of tubers ready for next year.
At Diamond Field Blooms, we stock dahlia seeds so you can start your own tuber-building journey. One packet of seeds could give you dozens of tubers by autumn — and a garden full of colour along the way.