Growing Dahlias in Containers: How to Grow & Care Guide

5 Min Read

Dahlias are visually striking flowers that are even in small spaces, easy to appreciate when grown in pots. From July until autumn, you can have an abundance of blossoms if you use the proper soil, watering methods, and sun exposure.

Dahlias work well as filler or thriller plants in containers and also make wonderful cut blooms. In a mixed planting in a large container, their foliage offers a wonderful architectural framework. Continue reading for information on growing dahlias in pots as well as planting, caring, and other advice.

How to Plant Dahlias in Pots

Plant dahlias in pots outside as soon as there’s no possibility of frost where you live. Make sure every pot is at least 12 inches deep, 12 inches tall, and 12 inches broad to allow plants ample space to develop their roots. Use a pot that has lots of holes for bottom drainage.

When to Plant

If you plan to plant dahlias in pots outside, wait until after the last frost date in your area, or make sure you have enough time to take your pot inside in case of a late frost. A minimum temperature of 60 degrees should be present in the soil.

Dahlias can be planted indoors around six weeks before the last frost if you live in a colder climate and would like them to bloom early. When the plant emerges from the dirt, it’s a good idea to provide extra illumination if you put it indoors.

Use plant-specific grow lights or shop lights with one warm and one cold fluorescent bulb light designed for plants.

Pot Size

Make use of a pot that is at least 12 inches deep and 12 to 14 inches in diameter. To prevent them from toppling over in a strong wind, plant taller species in hefty pots. The tubers will rot if they are left to sit in water, so make sure the pot has adequate drainage. When the dahlia grows too big for its original container, repot it in a sturdy plastic container.

Tuber Spacing

Dahlia tubers might be a little awkward to handle because of their size, so plant no more than one tuber per container to prevent overcrowding. Plant tubers with their stem ends pointing up in the ground. Fill in the top of the stem end with soil so that it is slightly below the soil line.


Follow the guidelines on the package when using an all-purpose, quickly-draining potting mix that has been supplemented with slow-release fertilizer granules. Add a small amount of potting soil to the bottom of the pot, creating a small mound, and then place the tuber on top of the mound.

Next, carefully add potting soil to the area surrounding the tuber, firming it in place so as not to break the tubers. Ensure that there are no air pockets around any portion of the tuber and that the potting mix completely encloses it.

How to Care for Dahlias in Pots


When dahlia tubers are planted in containers, water them right away. Once you observe green growth above the soil’s surface, wait to water it. Tubers might decay if you water your dahlias excessively before they have established a root system.

Water the seedlings once they have sprouted, ideally once or twice a week, just enough to keep the soil damp but not waterlogged. To prevent the soil from drying up entirely, check the moisture content of the soil frequently. You might need to water container plants more frequently—possibly even every day—if summertime temperatures are exceptionally high and dry.


Dahlias may not perform well in extreme heat, but they do prefer full sun. Make sure the location of your potted dahlias receives six hours or more of direct sunlight each day. If you live in a warm, sunny area, you might want to keep your dahlias shaded during the hottest part of the day by placing your container in an area that receives some afternoon shade.

Stakes and Support

Stakes are necessary to prevent most full-sized dahlias from toppling over, especially those with enormous blooms should be added just after planting. To make sure your plants will stay upright, use strong pegs made of wood, bamboo, or even metal rebar.

Even tomato cages will do in a pinch. If you’re using bamboo poles, you might require more than one stake for each plant. As the plant grows, add loosely-fitting twine, garden clips, or twist ties to your stakes.


Dahlias should be pinched off at the tips when they are around 16 inches tall. Eliminate the growth situated just above a group of robust leaves at the very tip of the stem. As a result, the pinched center stem will be replaced by several new stems.

Best Dahlias to Grow in Pots

Dahlia tubers are available online, at nurseries, and certain big-box stores. Dahlias that have been started in containers are also sold by many nurseries. Dahlias are available in an enormous variety of plant and bloom sizes. Look for “dinner plate” dahlias if you’re seeking huge blossoms.

Look for miniatures or “low-growing” dahlias if you’re searching for shorter plants. The finest dahlia kinds to grow in pots are those that are compact, dwarf, and short.

Sunshine: Up to 24 inches tall, with yellow petals and orange centers.

Star’s Favourite: Up to two feet tall, pink petals.

Scura: Up to 18 inches tall, compact with tangerine blossoms.

Park Princess: Up to 24 inches tall, with pink petals.

Impression Fuego: Up to 20 inches tall, with vibrant red and gold petals.

Starting Dahlia Seeds Indoors

Plant dahlia seeds indoors 6–8 weeks in advance of the final date of frost in your area. Utilize seed trays with drainage and potting mix designed for seed beginning. Apply a small amount of water to the growing medium, press the seeds into the soil, and then lightly cover them with dirt.

To ensure you have enough plants, it’s a good idea to sow more seeds than you’ll need because dahlia seeds can have a germination rate as low as 30%. Use plastic wrap or clear plastic covers to trap moisture in the growing medium, and spritz the soil to keep it moist. Use a heat mat or keep the seedlings in a warm area while they germinate.

After seeds sprout, place a grow lamp two inches away from the seedlings and program it to run for fourteen to sixteen hours per day. Start dahlia seedlings’ hardening off a few weeks before the anticipated last frost date. Transplanting seedlings outside should wait until the soil reaches a minimum temperature of 60 degrees.

You should expect some variety in dahlias grown from seed because they are not exact clones of their parent plants, unlike dahlias grown from tubers.

Overwintering Dahlias in Pots

Dahlia tubers should ideally be overwintered in pots if you reside in a cold area. After a few fall frosts, wait and take the following actions:

  • Cut off any dead leaves that are a few inches above the ground.
  • Take the pots inside your shed or garage to allow them to dry out.
  • Remove any superfluous dirt and dig up the tubers. Put the tubers in a bin, cardboard box, paper bag, milk carton, or other airtight container.
  • Dahlias should be kept dry, cool, and dark all winter.
  • Examine the tubers in the spring and only replant those that are solid—not soft or dehydrated.


What’s the lifespan of potted dahlias?

The tubers can survive for several seasons or longer if they are properly overwintered. Dig them up or store them in a pot in a cool, dry, dark spot that won’t freeze over the winter. Since the tubers are dormant, you can let them dry in the pot without watering them.

 Will dahlias in pots return each year?

Dahlias may thrive as perennials in USDA zones 8 and above and are regarded as cold-hardy plants. If the tubers are properly overwintered and replanted in the spring, dahlias will reappear every year in cooler climes.

Do dahlias prefer the light or the dark?

Dahlias grow best in full sun. If you live in a really hot, sunny region, you might want to plant them where there is some afternoon shade to keep them from being overheated.


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