Monty Don’s top tip for growing dahlias is a must-try this February

Bold, beautiful, and oh-so-dramatic, we've long had a soft spot for dahlias – especially as they're an easy way to fill our gardens with colour. Still, they can be expensive, which is why Monty Don's top tip for growing dahlias is a must-try this February.

Now, whether he's teaching us how to deadhead or overwinter dahlias, Monty is a pro when it comes to this particular flower. It makes sense, then, that he's full of tips on how to get more dahlia blooms for free.

Here's the thing, though: you'll need to act fast if this is something you want to do on top of, say, learning how to grow dahlias in pots, as it's very much a gardening job to tick off in February. You've been warned...

Monty Don's top tip for growing dahlias

If you're a true fan of this flouncy flower, you'll likely already know how to plant dahlia tubers for non-stop blooms all summer and autumn long. 

Still, Monty has suggested breaking the rules somewhat this month and ignoring the official guidelines on when to plant your tubers – going early, it seems, is the easiest way to fill your garden borders with dahlias for free.

'Dahlia tubers can be potted up towards the end of the month and forced into growth with extra heat to produce material for making cuttings,' explains Monty via his official gardening blog. 

'These cuttings will then grow on and make flowering plants by the end of summer, which both extends the season and replenishes tired stick.'

Basically, Monty is pushing a trick used by seasoned gardeners up and down the country: you can bring dahlias into growth outside of their natural growing season, which will leave you plenty of time to take and propagate cuttings ahead of the summer. 

So, how to do it?

What you'll need

Thankfully, there isn't much equipment involved when it comes to forcing dahlias – although it's a good idea to have the following to hand:

• A good quality peat-free compost, like Miracle-Gro Premium All Purpose Peat Free Compost from Amazon
• Some dahlia tubers (we're big fans of the Dahlia 'Café au Lait' from Crocus)
• A 30cm pot (this Round Bell Pot from Homebase is a great option)
• A warm spot indoors with good light (you can always try this Plant Heat Mat from Amazon if you're worried about temperature dips)

Step-by-step guide

Now that you have everything you need, it's time to get to work making Monty Don's top tip for growing dahlias a reality. And we suspect you'll be pleased to know there really isn't much to this gardening hack, too.

'It's actually pretty easy to force your dahlia tubers,' says Christopher O'Donoghue, one of the co-directors at Gardens Revived. 

Christopher O'Donoghue

A gardener with over a decade of experience under his belt, Christopher set up Gardens Revived with his brother, Andrew, in 2018  to create a thriving family business. Together, they have worked on residential gardens, listed buildings and gardens, flower shows and large estates with some exceeding 70 acres – many with historical significance.

'It's something I've done many times before, will likely do many times again, and have always had great results from,' he adds. 

'Honestly, I think it's a great and inexpensive way to source more dahlia plants for cuttings!'

1. Plant your tubers

According to Monty Don himself, all you'll need to do to tick off this step is fill a pot with 'any peat-free compost', making sure to use just enough to cover the tubers. 

'Remember that dahlias prefer moist, yet free-draining soil,' adds Christopher, noting that it's always easier to save an underwater plant than an overwatered one.

2. Keep them warm

If you want to tackle Monty Don’s top tip for growing dahlias in exactly the same way the gardening guru himself does, all you have to do next is 'place the pot on a heated mat or window sill and keep [it] moist'. 

'Make sure they're in a spot that gets lots of sunlight,' advises Christopher, noting that you can always supplement with fluorescent lighting if necessary.

3. Watch and wait

According to Monty Don, 'new shoots should appear after about 10 days', although you'll want to wait until they're about 7.5cm long before they can be taken for cuttings.

4. Take your cuttings

While Monty Don’s top tip for growing dahlias simply states that you should force tubers to grow early and take cuttings, Christopher is more than happy to advise us on the finer details of the process.

'You'll want to take your cuttings from the healthy, non-flowering shoots,' he says, noting that you should use a clean, sharp knife and make the cut as close to the crown of the tuber as possible (without severing it).

5. Show your cuttings some TLC

Next, Christopher says that you will need to remove the lower leaves of your dahlia cuttings, before dipping the cut end in a rooting hormone like Munnie Rooting Formula for Robust Root Growth from Amazon.

'Plant them in a well-draining potting mix, and be sure to keep them moist,' he continues, explaining that they will need indirect light and a warm environment to thrive. 

6. Plant them outside

Once roots develop on your dahlia cuttings, Christopher says it's time to transplant them to larger pots before planting in the garden.

'You'll want to harden them off first,' he explains, adding that it's a good idea to give them a dose of a general fertiliser (try Growmore from Amazon) to help give them a boost.

If you're planting them directly into soil, be sure to plant your cuttings a few millimetres lower than they were in the container, water them in well, and mulch them, too.

And, just like that, Monty Don’s top tip for growing dahlias is our new favourite thing to do this February – especially if it means we'll be treated to an array of gorgeous flowers come summer.

If you'll excuse us, then, we're off to coax our tubers into life (like a sort of horticultural Frankenstein). Wish us luck...