How to Plant Dahlia Tubers

• Written by Holly Hughes on July 09, 2022

With their many-petaled beauty coming in almost all colors of the rainbow, who wouldn’t want dahlias to brighten up their garden?

An exceptional cut flower – just browse dahlia arrangements at sensational flower delivery service SendFlowers.com to see for yourself – dahlia varieties offer you the opportunity to enjoy romantic grandeur or geometric splendor with their kaleidoscopic color and marvelous petal patterns and shape. Dahlias also happen to be Mexico’s national flower!

In this article, we will look specifically at growing dahlia tubers, providing you with everything you need to know to enjoy planting dahlia tubers in the ground or in pots for a colorful, thriving, and eye-watering outdoor space.

Want to know how to plant dahlia tubers? Keep reading for the best tips and tricks to do so!

How to plant dahlia bulbs

To ensure a show-stopping display of dahlia flowers, it’s pivotal to plant their tubers correctly.

The first step in planting dahlia tubers is guaranteeing the tubers themselves are in top condition, with no potential signs of rot or damage.Home and Gardens cites three essential elements that determine a healthy dahlia tuber.

These elements are:

• The main body: This retains all of the nutrients and energy necessary to produce the following year’s plant;
• The eye(s): These will become the stalks of a new dahlia plant once they sprout and should be pink or have signs of green growth;
• The neck: This needs to be unbroken and durable and is what connects the two other parts.

Once your dahlia tubers have all of these elements, all you have to do is find the place in your garden with their ideal growing conditions. These are: fertile, well-draining soil with a pH of 6.0 – 7.5; 6-8 hours of sunshine; and a place where they can get adequate watering.

Once you’ve chosen your spot, plant your dahlia tubers with the eye facing towards the sky. Dahlia tubers are quite delicate so be sure to handle them carefully.

Given the fact that dahlia tubers can grow 4-5 feet in height, be sure to stake each tuber with a strong support when planting to support them as they sprout upwards.

Once you’ve covered the tubers in soil and watered, you can expect to wait two to three weeks before seeing the first of your glorious dahlia shoots appear.

What is the best time to plant dahlia bulbs?

Dahlia planting time is important to get right to ensure your plants will grow strong and healthy right through to fall. These colorful delights, despite their vivacious color, are delicate little tubers and cannot withstand cold. Therefore, dahlia tubers should only be planted in springtime, when any risk of frost has passed and ground temperatures are at least 60°F (15°C).

Depending on where you live in the US, this might be from April onwards, while colder climates might need to wait until June and warmer areas can start earlier. If you happen to be a tomato grower, one general rule that can be followed in any location is that dahlia tubers should be planted at the same time as tomatoes.

For those eager to start your dahlia tubers as early as possible, it’s possible to plant them in pots or containers first indoors, before moving them outside when the ground is warm enough. Keep reading to find out how to plant tubers in pots.

Tips for planting dahlia bulbs in pots

If planting your tubers in pots to store indoors, you can do this in March. This means you will then be able to transplant them outside by mid spring.

Alternatively, if you are short on space and want to keep your dahlia tubers in containers to complete a balcony garden, your townhouse patio, or a small backyard, you can follow outdoor planting guidelines and pot smaller dahlia tuber cultivars in late spring once ground temperatures are again at 60 or above.

Choosing the container for your dahlia tuber is important – choose one that is well-draining with plenty of drainage holes, at least 15 inches deep and a foot in diameter.

Fill with multi-purpose, peat-free potting compost and then plant your tubers as you would in the ground, watering well and adding a stake if needed. Place the pot in a sunny aspect either indoors or outdoors depending on the time of year.

How deep to plant dahlia tubers

A common question people ask when reading dahlia bulbs planting guides is ‘how deep do you plant dahlias?’

It’s an important question as dahlia planting depth is important to tuber’s growth.

When planting tubers in the ground, dig a hole 3-4 inches below the surface and place the tuber in it with the ‘eye’ facing upwards. Depending on the variety you have chosen, dahlias should be planted a minimum of 15 inches apart though larger varieties should be placed 30 inches from one another.

If planting your tubers in pots, they should be 1-2 inches below the surface for adequate coverage.

How to water dahlias

Dahlia tubers enjoy a soil that is moist and are generally thirsty plants. Once you’ve planted your dahlia tubers, give them a good watering and then leave them (unless the soil dries out) until their green shoots appear above ground. This will avoid tubers rotting in the ground.

Once your tubers begin shooting, you want to keep your soil evenly moist (without being sodden) and so watering will depend on your own garden’s conditions. However, most plants will need a deep watering once or twice a week.

Those tubers growing in pots will need more consistent watering as potted soil tends to dry out much quicker. Just make sure your container is well-draining to avoid your plant becoming waterlogged and rotting.

How to care for dahlias after planting

Your tubers should begin sprouting after a few weeks and when this happens and they have developed three pairs of leaves, it’s necessary to pinch out the tips. This will ensure a bushier, healthier plant with much more growth.

It’s also important to remove most of the shoots sprouting from the tuber (we recommend leaving five). Use a clean and sharp pruners to do this, removing a few inches from above a set of leaves. This will give you far more flowers to enjoy!

And this is one of the best things about dahlias: the more you cut them, the more they will flower! This means you can enjoy them as cut flowers right through until autumn. Of course, to make them last longer, it’s imperative to keep them in a clean vase. Discover our tips for keeping your vaseware clean for healthier and longer-lasting arrangements here.

Of course, if it’s not possible for you to grow tubers right now, don’t forget there are lots of ways to enjoy fresh summer blooms at home. Treat yourself or a loved one to a monthly subscription to flower delivery services like BloomsyBoxwho specializes in farm-fresh, sustainably-sourced flowers, or MonthlyClubs, who delivers the best in seasonal arrangements.

Or get a one-off treat from EnjoyFlowers for a summery delight.