If you’re new to growing dahlias, WELCOME! We are glad you are here. Dahlias are one of the most rewarding flowers you can grow. However, there are a few tips that I’d like to share with you before you get started.
Trust me, I’ve made plenty of mistakes myself. When you grow as many dahlias as we do here at Russells Mills Flower Company, I’ve learned pretty quickly what works…and what absolutely does not.
Here are some of the most common beginner mistakes we see (and how to avoid them).
1. Following Every Piece of Internet Advice
Ah yes, the internet. A magical place where you can learn anything…including how to accidentally torture a perfectly good dahlia tuber.
One of the biggest mistakes we see is starting tubers indoors to get a “head start.” It sounds logical, especially if you live in a cooler climate. But in reality, this often creates more problems than it solves.
Indoor conditions usually mean less light, fluctuating temperatures, and stressed tubers. Then when those tubers finally go outside, they experience transplant shock and need time to recover.
Meanwhile, the tubers planted directly in warm soil outside are just living their best lives and quickly catch up.
Our rule on the farm is simple:
Warm soil = happy tubers.
Also, while we’re on the subject…we strongly advise against the infamous plastic bag method. If you’ve never heard of it, please forget I mentioned it. If you have heard of it…try planting your tubers the old-fashioned way this season and watch how much happier they are.
2. Overwatering Tubers
This one surprises a lot of beginners.
Dahlia tubers do not want to sit in wet soil. In fact, one of the fastest ways to rot a tuber is by watering it before it has even started growing.
On our farm, we don’t water newly planted tubers at all until we see the first green shoot coming up through the soil.
Once plants are established, dahlias prefer deep, infrequent watering instead of light watering every day.
Think of it like this: Dahlias don’t want wet feet. I mean, who does?!
3. Planting Dahlias in Too Much Shade
Dahlias love sunshine. Like…a lot.
If you plant them somewhere with too much shade, they’ll stretch and grow tall and floppy trying to find light. The stems become weak, and the number of blooms drops dramatically.
For the happiest plants, aim for full sun. Your dahlias will reward you with stronger stems and way more flowers.
4. Overthinking the Planting Process
Plant tubers about 4–6 inches deep, and they will grow no matter which way they’re facing. Laying them horizontally is usually easiest, but orientation isn’t critical. Dahlias are actually pretty forgiving.
The bigger thing to pay attention to is timing and soil conditions:
~ Plant after all danger of frost has passed
~ Avoid soggy soil
~ Wait out heavy rain if necessary
Cold + wet soil = BAD
5. Forgetting Support
Some dahlia varieties grow tall. Like…really tall.
Without support, wind or heavy rain can easily snap stems. It’s heartbreaking when a plant you’ve been nurturing all summer suddenly folds in half like a lawn chair.
The easiest solution is to install stakes or netting when you plant the tubers. That way, plants grow naturally around their support system.
Future-you will be very grateful.
6. Not Cutting Flowers Often Enough
Here’s a fun fact: dahlias love being cut.
When flowers stay on the plant too long, the plant shifts its energy toward producing seeds instead of new blooms.
When you harvest regularly, the plant says, “Well I guess I better make more flowers.”
This is why dahlias are such amazing cut flowers for home gardens.
So go ahead, enjoy the cut flowers. Fill the house with them. Give them to friends.
7. Thinking Dahlias Are Always Perennials
Garden centers often label dahlias as perennials, which can be confusing.
They are perennial in Zones 8–11, where the ground doesn’t freeze.
But in colder zones, tubers usually need to be dug up in the fall and stored for winter to prevent freezing or rot.
It’s an extra step, but it’s also how many growers build up their collections year after year.
8. Thanks for Reading This FAR!
The truth is, every dahlia grower makes mistakes…even experienced ones. Gardening is always a mix of science, hope, patience, and a little trial and error.
The good news? Dahlias are surprisingly resilient.
And once you grow one successfully, it’s very hard to stop.
Trust me. I’ve tried.
