We all know how beautiful dahlias get when they grow in the garden with their colorful blooms and tubers that continue to develop even when the crown looks to be all dead.
But can you grow those bushy perennials in pots? And what about those tubers?
How many dahlia tubers per pot? Only plant one dahlia tuber per pot. The dahlia root system is robust and needs at least 1 foot of space to develop all those fat and healthy tubers. To encourage healthy growth both above and under the soil, plant the dahlia tuber in a large container with at least 2 feet of space between the tubers.
It takes more than just enough space and a healthy tuber to grow a successful dahlia plant in a pot. Read more to find out the necessary prerequisites for a thriving potted dahlia.
Planting Dahlia Tubers in Pots
Planting dahlias in pots can have many advantages. It insulates the temperature-sensitive plants against unpredictable weather conditions and the dangers of frost.
However, you also have to pay extra attention to the soil, watering, light, and feeding as part of the plant’s maintenance and care.
Repotting and dividing the tuber clumps are both essential for the survival of the potted plant.
Do Dahlias Do Well in Pots?
Dahlias, like many other small plants, do well in pots as well as in the garden so long as the growing conditions are favorable and the plant is getting enough light.
Since potting soil dries out faster than its counterpart in the garden, you need to water the plant regularly since drought has damaging effects on the roots and tubers. As the plant produces more tubers, you need to repot it regularly.
Best Dahlias for Pots
Not all dahlia varieties are suitable for growing in pots. To make sure your dahlia doesn’t outgrow the container too fast, choose a small variety with a relatively slow growth rate.
The following are some of the best dahlias to grow in containers.
- Dahlia ‘Ellen Huston’
- Dahlia ‘Impression Fantastico’
- Dahlia ‘Happy Single First Love’
- Dahlia ‘Impression Fabula’
- Dahlia ‘Happy Single Party’
- Dahlia ‘Happy Single Wink’
- Dahlia ‘Happy Single Romeo’
- Dahlia ‘G.F. Hemerik’
- Dahlia ‘Impression Festivo’
Best Soil for Dahlias in Pots
When planting dahlia tubers in pots, make sure to fill the pot with regular garden soil. As long as the soil is loamy with a loose texture and drains quickly, the dahlias will have the perfect medium to grow.
Avoid using potting mix or compost with peat. These mediums could dry out the tubers and stunt the growth of the dahlia. If you want to use a potting mix, add it to garden soil at a 2:1 ratio in favor of the garden soil.
Dahlia Tuber Spacing
Although it’s recommended to plant a single tuber per pot, sometimes you can have a large planter that can take more than one tuber.
Here, spacing is of the utmost importance to ensure each dahlia has enough space to develop its own tubers. Allow between 1 and 2 feet between each dahlia in the planter or large container.
Number of Dahlia Tubers Per Pot
The average 12-inch pot should only have one dahlia tuber in it. That’s the minimum required space for a single dahlia plant to grow successfully without getting overcrowded, competing over resources, or having its sunlight exposure limited.
How Deep To Plant Dahlia Tubers in Pots
When planting a dahlia tuber in a pot, make sure the tuber is between 4 and 6 inches deep into the soil. The neck of the tuber where the eyes are should be pointing upward while the tail end of the tuber with the roots should be buried deep in the soil.
If in doubt as to which end of the tuber should be up, plant it lying down at 4 inches deep, and cover it with soil.
How To Plant Dahlia Tubers in Pots
Planting a dahlia tuber in a pot is quite straightforward and can be done in just a few minutes. Follow these steps to get your dahlia tuber to a good start.
- Choose a suitable pot between 12 and 14 inches in diameter and the same in depth. Make sure it has lots of drainage holes at the bottom.
- Fill the pot with garden soil, or add one portion of potting mix to every two portions of garden soil.
- Mix in slow-release organic compost as long as it doesn’t have peat.
- Dig a deep hole in the middle of the soil between 4 and 6 inches deep, and place the tuber in the hole so that the neck is up. If in doubt, place the tuber on its side.
- Cover the hole with soil, and pack it to push out any air pockets.
- Water the pot until water flows out of the drainage holes. Then keep it in a sunny place.
- If you’re worried about frost, keep the pot indoors until the threat of the last frost is over.
How Often To Water Dahlias in Pots
Dahlias in pots need more watering than those growing in the garden. That’s because the soil in the pot dries out fast. Water the dahlia between 2 and 3 times a week on average. In the peak of summer, you might need to water it every day.
Best Fertilizer for Dahlias in Pots
Avoid high-nitrogen fertilizers since they inhibit the growth of flowers and encourage leaf growth instead.
A fertilizer high in phosphorus and potassium (like this blossom booster) is recommended for perennial dahlias. Side-dress with slow-release organic compost and homemade fertilizers to keep the soil rich.
Can You Leave Dahlias in Pots Overwinter?
In the winter, the dahlia dies back, and you need to overwinter it to protect the tubers deep in the soil until the next spring.
Cut back the plant to about 4 inches above the ground. If you get frost or frigid temperatures in the winter, bring the pot indoors, and keep it in a cool and dry place.
Planting Dahlias in Pots in the Ground
Some people prefer to plant dahlias in pots and then place the pots in the ground. The idea is that when the weather changes, they can dig up the pot and move it indoors until the next spring.
Having the dahlia in the pot makes it easier to move indoors and outdoors without having to dig up and divide the tubers every year.
Growing Dahlias in Pots Indoors
If you want to grow dahlias in pots indoors, make sure they get between 6 and 8 hours of sunlight and that you water them regularly. When the weather warms up, bring the pots outside.
Transplanting Dahlias From Pots
You can transplant the young dahlia as long as it’s still under 1 foot tall.
- Prepare the soil in the new site, and mix in organic compost or bone meal.
- Dig a hole as deep as the height of the root ball of the plant, and place it in the hole.
- Fill back the soil, and pack it.
- Water thoroughly.
Do You Soak Dahlia Tubers Before Planting?
If the dahlia tuber is shriveled and dried out, you can soak it in water before planting. However, a healthy tuber doesn’t need soaking.
Can I Plant Dahlia Tubers in July?
The cut-off date for planting dahlia tubers is mid-June. The plant needs warm temperatures to grow and establish. July planting is too close to the winter.
You can plant one dahlia tuber per pot and water it regularly. Feed it with a phosphorus-high fertilizer and side-dress it with organic compost. Overwinter the plant to protect the tubers.