How to Grow Dahlias from Tubers

Your step-by-step guide on how to grow dahlias from tubers. Filled with tips and tricks for having blooms all season long.

How to Grow Dahlias

Dahlias are one of the most beloved cut flowers. They’re a workhorse in the garden with their long stems, incredible variety of colors and forms, and nonstop blooms (they’re a cut-and-come-again flower, meaning the more you cut them, the more they bloom for you), dahlias are a standout in any cut flower garden or bouquet. While they may look intimidating, dahlias are surprisingly easy to grow once you understand a few basics.

I grow dahlias in Zone 8b, and with proper planting, care, and harvesting, they can produce beautiful blooms from early summer until frost! This guide walks through all of my tips and tricks for growing dahlias from tubers all season long.

When to Plant your Dahlias

Dahlias can be grown from both seeds and bulb-like things called “tubers.” They can also be grown from cuttings, but that’s a story for another time. The best, most approachable way would be to grow from tubers! 

Dahlia tubers, in most places, should be planted in the spring when the threat of frost has passed. However, if you live in a zone like mine (8b), you can probably get away with planting them a little bit earlier. In fact, while most dahlia gardeners have to dig up their tubers at the end of the season and store them somewhere warmer, I can typically leave my dahlia tubers in ground over the winter because our temperatures are more on the mild side. 

The main thing is to get to know your growing zone, and specifically your typical first and last frost dates, as these will help you determine when to plant your dahlia tubers!

Where to Plant your Dahlia Tubers

Dahlias will perform best in an area that gets full sun and good airflow. 

Look for a spot in your garden or yard that offers:

• 6–8 hours of sunlight per day

• Well-draining soil – I plant my dahlia tubers in raised beds which are great for growing dahlias. You can choose your location and you can your soil, and they typically have great drainage.

• Enough space for mature plants to grow without crowding – I plant my dahlia tubers 12 inches apart. This is a safe distance to ensure each dahlia plant has enough room to prevent disease and grow healthy!

How to Plant your Dahlia Tubers

As I said above, dahlia plants like to have a little bit of space (I do about 12 inches apart) for a good chance at growing well with lots of blooms. When you receive a tuber in the mail, you’ll want to plant them roughly 4 to 6 inches deep. Lay them horizontally with the growing eye facing up. When you receive the dahlia tuber in the mail you may even have a sprout growing, just make sure that sprout is facing up when you plant it.

Most importantly: do not water your tubers after you plant them! Dahlias are very prone to rotting, and there should be enough moisture in the soil to help the dahlia begin to root and grow.

When you start to see growth popping through the soil, you can begin to water your dahlias.

Watering and General Dahlia Care

Watering your dahlia tubers

Once established, dahlias benefit from consistent, deep watering. This means that if you get a good rain, no need to water that day. Sometimes I think it’s easiest if you water when the soil looks particularly dry. Pay attention to how your plant it looking as well – if the leaves are drooping and wilting, give them a good water. If they aren’t, maybe wait until the next day to water. As I said earlier, dahlia tubers are prone to rotting, so you don’t necessarily want to overwater them either.

Staking

Dahlia plants can get very large. This means that they benefit from staking early on. I like to buy these wood stakes from Lowe’s. They’re affordable and really good quality! Just make sure that when you add your stakes you place it some ways away from the dahlia tuber. The last thing you want is to stake your tuber!

Pest Control

If you’re new to gardening and don’t know much about pest control, I cover this topic in more depth on my How to Start a Cut Flower Garden post!

Growing Dahlias in the Heat

Dahlias are a flower that typically love the heat. However, the plant originated in the mountains of Mexico where the climate is very hot but dry. If you live in the South where the climate is very hot and the humidity is high, you may experience some struggles with your dahlia production. The plant will typically shut down in the heat of the summer, meaning it will not produce many blooms, but then will increase again when the weather begins to cool down again in the fall.

Many people use shade cloth in the heat of the summer to help their dahlias continue to produce blooms, and some even cut their plants back to about 12 inches off the ground and just focus on getting their blooms in the fall. Or, you can do what I do and just let your plant slow down in the hot months of July and August, and look forward to the months of September and October when the blooms really take off!

Digging your Dahlia Tubers/Dahlia Storage

Once your dahlia plants are finished for the season, proper end-of-season care is key to enjoying healthy plants again next year. Dahlias are not frost-hardy, so the foliage will die back after the first frost. This is your signal that it’s time to decide whether to dig and store your tubers or leave them in the ground.

How to store your dahlia tubers overwinter

Dahlia tubers need a cool, dark, and dry environment during storage. I store mine in the garage next to a wall that receives ambient heat from inside the house.

Here’s how I store my dahlia tubers when I dig them out of the ground:

• Placing tubers in plastic bins or boxes filled with wood shavings, peat moss, or vermiculite. I personally use peat moss, but any of the 3 will work!

• Check your tubers once a month and remove any that show signs of rot. Quick tip: Keep an eye on the condensation on the sides of your storage container, and if you see a lot of moisture, crack the lid and leave it cracked for a couple of days until the condensation dwindles.

Growing Dahlias from Tubers

Dahlias are one of the most rewarding flowers you can grow. With a little planning and regular care, they will provide months of stunning blooms for bouquets and garden enjoyment alike. Whether you’re growing a single plant or an entire row, dahlias quickly earn their place in the garden. If you implement these tips into your own garden, chances are you’ll become just as dahlia-obsessed as I am in just one growing season!

Dahlia Growing Resources

Here are a few resources I love for growing dahlias and just cut flowers in general!

1. Floret Farms Cut Flower Garden – This is a great resource for general flower and gardening knowledge. I had this thing out all the time when I was first starting out! Erin (the author) also has great resources on YouTube and Instagram (@floretflower).
2. Backyard Bouquet Podcast – I’ve learned so much from this podcast and it’s a great resource for a flower garden beginner!
3. For growing dahlias specifically, there is a dahlia group on Facebook called “Dahlia growers,” and I use this as a resource very often!