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Growing Dahlias Made Simple

I love pottering in the greenhouse and garden and listening to classic rock with my Labradoodle, Florrie.


When I was a child, my parents grew dahlias. It seemed such a difficult task. I remember complex geometric rows of canes and cotton to support flower heads. Emerging blooms were protected by small brown paper bags.

Woe betide you if your football went flying and neatly severed a flower from its stem! The pom pom shaped flowers always seemed to be full of earwigs. They were always ready to jump out and nip any passing young fingers!

So when it was suggested last year that we might grow dahlias in our current garden, Florrie Labradoodle and I looked at each other with some trepidation!

Florrie at the garden centre

Florrie at the garden centre

Off to the Garden Centre

Florrie and I started our venture at the local garden centre. Florrie enjoys the garden centre as they have a pet section. She likes to sniff the treats and meet other furry friends!

We asked about dahlias and were directed to the tuber section. We found some strange looking objects that looked like dried out carrots all tied together! They came in plastic bags full of wood shavings. Growing them looked difficult! They weren’t cheap either!

So we retreated to the seed section. We soon found a reasonably priced packet of mixed dahlia seed. Success!

Florrie and her seedlings

Florrie and her seedlings

Growing Dahlias From Seed

Growing dahlias from seed is quite easy. Simply place the seed on compost in a seed tray. Lightly cover with a dusting of compost and water. Then I put mine in the greenhouse, but any sunny place with a temperature around 20C will do.

I like to use seed trays that are divided into individual cells. That way you can pop out the young plant when it is ready without disturbing the roots.

A week later, our first seedlings appeared! Just a few weeks later and the seed tray was a mass of young green plants! At this stage you can pinch out the tip of each shoot to encourage the plants to bush out.


Hardening Off

Our dahlias were now ready to plant out. I gradually ‘hardened them off’.

Leaving the warmth of the greenhouse can be a shock for young plants. So it is best to do this gradually. First put the tray of plants outside of the greenhouse for an hour or two each day. Then keep increasing the time until they are out for all daylight hours.

When the risk of frost has passed, you can leave the tray out all night as well. This is called ‘hardening off’!

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Planting Out

There were two options for planting out. Either plant straight into the ground or into containers. We decided to try both methods to see which faired best.

We found that planting the dahlias straight into the ground was like putting out a plate of chocolate biscuits for the slugs and snails. Within a couple of days, the plants had been completely stripped of foliage. Only the stalks remained!

Encouragingly, planting into containers was more successful. Use new compost to maximise nutrients as dahlias are hungry eaters! I could place the containers on our patio, which was less of a slug and snail jungle than the rest of the garden.

Then it was just a case of regularly watering and watching them grow!


Feeding and Staking

As I mentioned earlier, dahlias are hungry plants. I feed them with Miracle Gro plant food. Simply dissolve a scoop of crystals in your watering can and water as normal.

It was very exciting when flower buds appeared at the end of long stalks. I was worried about them flopping over once the flowers opened up. So I pushed a garden cane into each pot then looped some string loosely round each plant and cane. This seemed to do the trick!



The beauty of mixed seed is never quite knowing what colour and type of flowers you are going to get! Reds, yellows, pinks and apricots all soon appeared! Simply snip off the flower heads when they start to die back to stimulate the plant to grow more!

Some people have difficulty in telling the difference between the flower buds and the spent flower heads. They both have a similar shape. Just give them a squeeze! The spent flower heads are soft and squishy!

Dahlias regrowing the following year

Dahlias regrowing the following year

Save the Best for Next Year

Florrie and I were very pleased with the outcome of our dahlia experiment. We had lovely flowers all summer long! The first frost finally finished them off.

There are complicated instructions about lifting, cleaning and storing dahlia tubers over winter. We didnt bother! We chose our favourites and simply left the pots on the floor in the greenhouse as they were.

Then the following spring, they burst back into life again. Regular feeding with Miracle Gro and we will have more of the same this summer! And not an earwig in sight!

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.


RTalloni on June 14, 2019:

Thanks to our daughter we planted 8 varieties of dahlia tubers early this spring. 7 are up and we are hoping for the best on the 8th. I was wondering about watering with miracle grow so thanks for sharing your experience. Florie's a cutie.

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