Dahlia Watering Requirements Can Be Contentious – Here’s What The Experts Say
Elizabeth is a Permaculture Garden Designer, Sustainability Consultant and Professional Writer, working as an advocate for positive change. She graduated from the University of St. Andrews with an MA in English and Philosophy and obtained a Diploma in Applied Permaculture Design from the Permaculture Association.
Reviewed By COLIN SKELLY
Colin is a Horticulturist and Horticultural Consultant with experience in a range of practical and managerial roles across heritage, commercial and public horticulture. He holds the Royal Horticultural Society’s Master of Horticulture award and has a particular interest in horticultural ecology and naturalistic planting for habitat and climate resilience.
Contributions From JUNE NASH
The current Secretary for The National Dahlia Society, June is known for her extensive dahlia knowledge and has even been recognised by the American Dahlia Society for her contributions.
David is the Director at Halls of Heddon, which is a dahlia nursery established in 1921. David has a large following on social media and runs a YouTube channel, where he shares updates on the dahlias he grows each year.
Simon Lycett is one of the UK’s most highly sought-after Florists, designing arrangements for Royal Weddings and other highly prestigious events in the country. He is an RHS Floristry Ambassador, author of ‘The Flower Market Year’ and has appeared on several TV and Radio shows. Currently, he is the Host of Channel 4’s Full Bloom.
Dahlias are popular plants to grow in UK gardens.
These cottage garden favourites are relatively easy to grow as long as they are grown in the right location.
“At the moment I am obsessed with dahlias and can’t get enough of them,” shares Florist Simon Lycett.
However, they do have to be cared for correctly and one important element of their care is watering.
Dahlias are not necessarily difficult flowers to grow and getting the watering right can be an important piece of the puzzle – read on to understand clearly just what your dahlia will need.
| Difficulty | Easy |
| Equipment Required | Watering can or hose |
| When To Water | Throughout the year, especially during the summer |
How Much Water Do Dahlias Require?
One important thing to understand when growing dahlias is that they do need consistent moisture and plenty of water throughout the summer season once they are mature.
Another detail to remember is that dahlias like moist but not waterlogged growing medium.
Maintaining this consistent water availability is a key component in growing these plants successfully.
However, the water needs of dahlias will differ throughout the year and will depend on the location of the particular garden in which they are grown.
“For dahlias planted in the ground, the soil conditions will play a key part in how often you’ll need to water your dahlias in hot, dry weather,” shares Master Horticulturist Colin Skelly.
“Dahlias in sandy soil will need far more watering than those in clay soils, which hold more soil moisture for longer.”
How much you will need to water will also depend on how much rainfall there is in your area and on the light levels, temperature and other environmental factors.
The size and age of the plants will be important too, as June Nash from The National Dahlia Society explains:
“Water sparingly at first but gradually increase this as the plant grows.
“Each pot will eventually need to be watered every day, usually in the evening, even if it has rained.”
You’ll also have to consider whether you are growing your dahlias in containers or in the ground.
Plants in containers will generally need to be watered a lot more frequently.
When growing in the ground where you live, you’ll need to understand the soil type and other soil characteristics because some soils retain water a lot more easily than others.
“A good free draining compost is essential and I personally had some very good results with Dahlias in pots last year using peat-free compost,” says David Hall, the Nursery Manager at Halls of Heddon.
“Dahlias need plenty of water without getting waterlogged – they won’t like that!”
When To Water Dahlias
Mature dahlias should be watered when the top few centimetres of the soil or growing medium feels dry.
However, it is best when you are planting dahlias to avoid excessive watering too early.
Tubers can easily rot if they are in saturated soil or growing medium.
Don’t water unless the soil or medium is very dry.
Wait until the roots have formed and become well-established before you start to water during dry periods.
Once your dahlia has established a good root system, water consistently when the weather is dry and pay attention to drainage, ensuring that while moisture remains, the soil does not become saturated and excessive water can drain away.
The Watering Process
When you are watering your dahlias, it is important to remember that fewer deeper waterings are better than providing water little and often.
This helps the plants develop deeper, healthier roots.
How you water is also important, as well as the quantity and regularity of watering.
One other important thing to think about when watering dahlias is where the water is actually required.
Rather than sprinkling water from above, which soaks the foliage and flowers of your dahlias, think about how you can direct the water to where it is actually required.
Water the soil at the base of the plant rather than the plant itself, so that the water can be taken up from the soil by the roots of your plant.
Try to keep splashes onto the foliage and flowers to a minimum.
By thinking about the above, you should be able to keep dahlias happy when it comes to their water needs.
