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The ultimate guide to planting, growing, and caring for your Dahlias!

If you're looking to add some stunning color to your garden or want to create a beautiful bouquet for your home, dahlias are a perfect choice. These beautiful, easy-to-grow flowers come in a wide range of colors, sizes, and shapes, and with a little bit of care, they'll bloom all summer long. 

Whether you're a seasoned gardener or just starting out, this comprehensive guide will provide you with everything you need to know to get started with dahlias, from choosing the right varieties to planting, feeding, and caring for your plants. So, let's dive in and discover the beauty and joy of growing dahlias!

 

How to plant your dahlias?

To plant dahlias, follow these simple steps:

  • Choose a location with full sun exposure (they need at least 6 hours of direct sunlight) and well-draining soil.
  • Dig a hole that is about 4-5 inches deep and wide enough to accommodate the dahlia tuber.
  • Mix some compost or well-rotted manure into the soil at the bottom of the hole.
  • Place the dahlia tuber in the hole with the "eyes" or growing points facing upwards.
  • Cover the tuber with soil, leaving about 2 inches of space between the soil surface and the top of the tuber.
  • Water the tuber thoroughly after planting, and then keep the soil moist but not waterlogged during the growing season.
  • As the plant grows, provide support using stakes or a trellis, and deadhead spent flowers to encourage more blooms.
The ultimate guide to dahlias

 

When to plant dahlias?

Dahlias are typically planted in the spring when the soil has warmed up and there is no longer a risk of frost. In most areas, this is between the end of April and mid-May.

However, the exact planting time can vary depending on your location and local weather conditions. It's important to wait until the soil is at least 60°F before planting dahlias to ensure they have the best chance of growing and thriving. 

In areas with warmer climates, such as UDSA zones 8 or higher, it is perfectly fine to plant dahlias earlier in the season. You can even leave them year-round in the ground, as long as you protect them from the harshest conditions with a layer of extra mulch.

 

Should I soak dahlias tubers before planting?

Soaking dahlias tubers is a popular technique that some gardeners swear by, while others skip it altogether. So, should you soak your dahlias tubers before planting? The answer is not straightforward, as it depends on the condition of your tubers and the environment in which they will be planted.

Soaking tubers can help rehydrate them and remove any dirt or debris that may have accumulated during storage. It can also help jumpstart the growth process and give your plants a head start. However, if your tubers are in good condition and have been properly stored, soaking may not be necessary.

When soaking, be sure to use lukewarm water and avoid leaving them in for more than an hour, as prolonged soaking can lead to rotting. Once you've soaked them, pat them dry and plant them in well-draining soil.

 

Where to plant dahlias?

They thrive in areas with well-draining soil, plenty of sunlight, and protection from strong winds. Here are some tips on where to plant dahlias:

Sunlight: Dahlias require at least 6 hours of sunlight per day. Choose a spot in your garden that receives full sun for most of the day.

Soil: Dahlias prefer soil that is well-draining and rich in organic matter. Amend the soil with compost or other organic matter to improve drainage and nutrient content.

Water: Dahlias need regular watering, especially during the hot summer months. Make sure to water deeply to encourage strong root growth.

Wind protection: Dahlias have a tendency to snap in strong winds, so choose a location that is protected from strong gusts. Planting dahlias near a fence or wall can provide additional protection.

Planting dahlia tubers

 

Do Dahlias do better in pots or on the ground?

Dahlias can be grown both in pots and in the ground, depending on the growing conditions and the gardener's preferences. When planted in the ground, dahlias tend to have a more extensive root system and can reach their full growth potential, producing larger and more abundant blooms. 

However, if the soil in your garden is not suitable, or if you have limited space, growing dahlias in pots can be a great option. Potted dahlias require regular watering, feeding, and a well-draining potting mix. Regardless of the growing method, it is essential to provide adequate sun exposure, as dahlias thrive in full sun conditions.

 

How to grow dahlias?

To grow dahlias, start by planting the tubers in well-draining soil in a sunny location after the last frost date in your area. Dig a hole that is twice as deep as the tuber and place it with the "eye" facing up. Cover with soil and water thoroughly.

As the plants grow, provide support with stakes or cages to prevent them from falling over. Water deeply and regularly, but make sure the soil doesn't become waterlogged.

Fertilize the plants with a balanced fertilizer every few weeks to promote healthy growth and abundant blooms. Deadhead regularly to encourage continuous blooming. In the fall, after the first frost, dig up the tubers and store them in a cool, dry place for the winter. 

 

How long does it take for dahlias to start growing?

The bloom time for dahlias varies depending on several factors, such as the planting time, growing conditions, and climate. In general, it takes about 2 months for dahlias to bloom from the time they are planted. However, this can vary based on the specific variety of dahlia and the growing conditions. It does take about 2-3 weeks for them to sprout. 

Dahlias typically bloom from mid-summer to early fall, with peak bloom times occurring in late August and early September. To ensure the best bloom time for your dahlias, it is important to plant them in a location that receives full sun and to provide them with adequate water and fertilizer throughout the growing season.

Field with beautiful dahlias

 

How do I keep dahlias blooming?

However, many gardeners struggle to keep their dahlias blooming throughout the growing season. Fortunately, there are a few simple steps you can take to ensure your dahlias continue to produce blooms all season long.

  1. Plant in the right location: dahlias need full sun and well-drained soil. Make sure to plant them in a spot that gets at least 6 hours of direct sunlight per day.
  2. Water regularly: dahlias need consistent moisture, so water them deeply once or twice a week depending on weather conditions.
  3. Fertilize: dahlias are heavy feeders and benefit from regular fertilization. Use a balanced fertilizer every 4-6 weeks throughout the growing season.
  4. Deadhead regularly: remove spent blooms regularly to encourage new growth and more blooms.
  5. Provide support: dahlias can grow quite tall and may need staking or support to keep them upright.

 

Should you deadhead Dahlias?

While deadheading can be beneficial for many types of plants, it is not strictly necessary for dahlias, including dahlias. However, deadheading can help prolong the blooming season and promote bushier growth in dahlias. 


If you choose to deadhead your dahlias, it is best to do so regularly, removing the spent flowers as soon as they start to fade. This will encourage the plant to produce more blooms and can also prevent the formation of seeds, which can divert energy away from flower production. Plus, don’t your dahlias look nicer when all of the spent blooms are removed?


If you don't deadhead dahlias, the plant will divert its energy into producing seeds instead of growing new blooms. Deadheading, which involves removing spent flowers, promotes the growth of more flowers by encouraging the plant to produce new buds.

 

How long do Dahlias last once they bloom?

Dahlias can last in the ground for several months, but the exact duration depends on several factors such as weather conditions, soil quality, and overall care. Under optimal growing conditions, Dahlias can bloom from mid-summer through the fall. The flowers typically last for several months, and with deadheading, the plant can continue to produce new blooms throughout the growing season.


With proper care, dahlias can last for up to two to three years in the ground, but they may require lifting and storage during the winter months in colder climates. It is essential to provide adequate water, sunlight, and nutrients to the plant to ensure its longevity. Regular maintenance, such as fertilizing and pruning, can also help extend life.

Dahlia flowers

 

Do dahlias multiply?

Dahlias are propagated by dividing their tubers, which are underground storage organs. This means that the plant does not produce offspring from seeds like other plants. However, over time, dahlias can produce multiple tubers, which can be separated and planted to create new plants.

In addition to providing optimal growing conditions, gardeners can encourage dahlias to multiply by dividing their tubers every few years. This not only helps to create new plants but also ensures that the original plant remains healthy and vigorous. These new tubers can be removed in the fall after the first frost or in the spring when new growth appears.

 

How many dahlias can you grow from one tuber?

This depends on the quality of the tuber and the number of eyes. Healthier tubers will of course produce more growth than damaged ones. Then it is important to check how many eyes (tiny buds) your dahlia tuber has because this is where the plant grows from. 1 eye gives 1 dahlia plant. Most tubers have multiple ‘eyes’, but it is common that dahlia tubers only have one eye. We check the tubers carefully that they have at least 1 eye.


1 dahlia plant gives several blooms. Keep in mind that the smaller the dahlia variety, the more blooms it will give. For example, Dinnerplate dahlias have huge blooms, but there will be less than for example, the border dahlia.

 

How to care for dahlias?

Here are some tips on how to care for dahlias.

  1. Soil: dahlias require well-draining soil that is rich in nutrients. Amend your soil with compost or other organic matter to improve soil quality.
  2. Water: dahlias require regular watering, but do not overwater them as this can lead to root rot. Water deeply once or twice a week, depending on the weather.
  3. Fertilizer: use a balanced fertilizer that is high in phosphorus to promote blooming. Apply fertilizer once a month during the growing season.
  4. Pruning: pinch off the top of the plant when it reaches about 12 inches tall to encourage bushier growth. Deadhead spent flowers to promote new blooms.
  5. Winter care: in colder climates, dahlias should be dug up and stored indoors during the winter. Cut back the foliage and allow the tubers to dry before storing them in a cool, dry place.

By following these tips, you can enjoy a beautiful and healthy dahlia garden. Remember, the key to successful dahlia care is to provide them with the right growing conditions and regular maintenance.

Gorgeous dahlia blooms

 

Can you leave dahlias in the ground year-round?

The short answer is that it depends on your climate zone. Dahlias are not frost-hardy, and if you live in a region with harsh winters, leaving your dahlias in the ground year-round can result in the bulbs freezing and dying. If you do leave them in the ground, the roots will freeze, get damaged or destroyed, and eventually rot away.

This is what you should do before the first frost signs: cut the dahlia down to 4 inches, dig it up, and plant it in a small pot. Bring this pot with the dahlia tuber indoors and store it in a cool and dark place like a basement or a garage.  

However, if you live in a milder climate zone, like USDA zone 8 or higher, you will be able to leave your dahlias in the ground year-round. Mulching around the plants in the fall can also provide extra insulation to protect the bulbs from freezing temperatures.

 

Do dahlias come back every year?

The good news is that dahlias can indeed come back year after year, but only if you take the right steps to care for them. 

In colder regions, dahlias will need to be dug up and stored indoors during the winter to protect them from frost and freezing temperatures. To ensure their survival, it is important to dig up the tubers after the first frost, clean and dry them, and store them in a cool, dry, and dark place until the next planting season. 

In areas with mild winters, such as in USDA climate zones 8 or higher, dahlias can be left in the ground over the winter months. After blooming time, just cut back the dead foliage and the stem till there are 6 inches left, and cover the dahlia with an extra layer of mulch.

 

When should Dahlias be cut back?

The best time to cut back dahlias is after the first frost has occurred, usually in late fall. The frost will cause the leaves to turn black and wilt, indicating that it is time to cut them back. This is important because cutting them back too early can lead to the plant not having enough time to store enough energy for next year's growth.

To cut back your dahlias, start by removing any dead or damaged leaves and stems. Cut the remaining stems to about 6 inches from the ground. You can then carefully dig up the tubers, shake off any excess soil, and store them in a cool, dry place until the next planting season.

It is important to wait until after the first frost to cut back your dahlias. This will ensure that the plant has enough time to store enough energy for the next year's growth.

Dahlias in the garden

 

What is the best fertilizer for dahlias?

One of the essential aspects of growing healthy and vibrant dahlias is choosing the right fertilizer. Fertilizers are essential as they provide nutrients that the plant needs to grow healthy and produce beautiful blooms.

The best fertilizer for dahlias is one that is rich in potassium and phosphorus. Potassium helps to promote strong stems, while phosphorus is essential for the development of healthy roots and flowers. Nitrogen is also important for dahlias, but too much of it can result in weak stems and foliage growth at the expense of blooms.

When choosing a fertilizer for your dahlias, it is essential to look for one with a balanced NPK (nitrogen, phosphorus, potassium) ratio, such as a 5-10-10 or 10-20-20 fertilizer. You can also use organic fertilizers like bone meal, fish meal, or compost to provide your dahlias with the necessary nutrients.

It's important to apply fertilizer at the right time. You should apply a slow-release fertilizer once in early spring and again after the plants have started to bloom. Over-fertilizing can lead to the burning of the roots.

 

Do dahlias multiply on their own?

The answer is yes, dahlias can multiply on their own. Dahlias have tubers, which are similar to bulbs, that store nutrients and allow the plant to survive through the winter. When the tuber grows, it produces new tubers that can be removed and replanted, essentially multiplying the plant. These new tubers can be removed in the fall after the first frost or in the spring when new growth appears.

In addition to multiplying through tubers, dahlias can also self-sow. This means that if the flowers are left on the plant, they will produce seeds that can grow into new plants. However, the resulting plants may not have the same characteristics as the parent plant, and it can take a few years for the plant to produce flowers.

It is important to note that while dahlias can multiply on their own, it is still recommended to divide and replant the tubers every few years to prevent overcrowding and ensure healthy growth. This can also be an opportunity to propagate the plant and create new plants to enjoy.

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