August 25


A detailed guide on cultivating delphiniums from seed: step-by-step instructions and essential tips

How to grow delphiniums from seed

Delphiniums are beautiful flowering perennials that can add a stunning touch to any garden. Growing delphiniums from seed can be a rewarding experience for any gardener. Although they require some special care, delphiniums are relatively easy to grow and can provide abundant blooms if properly taken care of.

Before you start growing delphiniums from seed, it’s important to choose a suitable location. Delphiniums prefer full sun, but they can tolerate some shade during the hottest part of the day. The soil should be well-draining and rich in organic matter. It’s a good idea to prepare the soil by adding aged manure or compost before planting.

Once you have prepared the soil, you can start planting the delphinium seeds. It’s best to start the seeds indoors in containers before the last frost of the season. Delphinium seeds should be planted 1/8 inch deep and should be spaced about 12 inches apart. Keep the soil moist but not waterlogged, and make sure the containers have good drainage.

After the delphinium seeds have germinated and the seedlings have grown to a suitable size, you can transplant them into the garden. When transplanting, make sure to space the delphinium plants about 18 inches apart to allow for their mature size. Delphiniums can be quite tall, so you may want to stake them for support.

Delphiniums require regular watering, especially during the hot summer months. They also benefit from a weekly feeding of a balanced fertilizer. It’s important to thin out the plants each year to ensure good air circulation and prevent overcrowding. This can be done by cutting back some of the older stems at ground level.

Delphiniums are prone to certain pests, including aphids and slugs. Regular inspection and the use of organic pest control methods, such as introducing beneficial insects or handpicking, can help keep these pests at bay. It’s also important to remove any dead or dying foliage to prevent the spread of disease.

Delphiniums are known for attracting bees and butterflies with their vibrant flowers. They can be a beautiful addition to any garden or flower border. With the right care and attention, delphiniums can provide stunning blooms year after year.

Why grow delphiniums from seed

Delphiniums are beautiful flowering plants that add grace and color to any garden. While you can buy delphinium plants from nurseries, growing them from seed is a rewarding and cost-effective option. Here are a few reasons why you should consider growing delphiniums from seed:

1. Cost-effective

Buying delphinium plants can be quite expensive, especially if you want a large number of them. Growing delphiniums from seed is a much more affordable option, allowing you to have a larger quantity of plants for a fraction of the cost.

2. Wide variety of options

When you grow delphiniums from seed, you have access to a wide variety of options. You can choose from different types, such as double or belladonna delphiniums, according to your preferences. Starting from seed gives you the freedom to select the specific type of delphinium that you desire.

3. Early start

Starting delphiniums from seed allows you to begin the growing process early, giving you a head start on the flowering period. This is particularly important for double or belladonna delphiniums, which require a longer growing period before they start to flower.

4. Thriving in suitable conditions

Delphiniums are hardy plants that can thrive in a variety of growing conditions. Whether you have a large garden or a small balcony, you can grow delphiniums in containers or directly in the ground. They adapt well to different climates and can be grown in both sunny and partially shaded areas.

5. Low maintenance

Once established, delphiniums are relatively low maintenance plants. They require regular watering, especially during dry periods, and occasional feeding with a well-rotted organic fertilizer or seaweed solution. They also benefit from staking to support their tall stems.

6. Long flowering period

Delphiniums have a long flowering period, providing you with beautiful blooms for several weeks. The flowers come in a range of stunning colors, adding a touch of elegance to your garden. By planting a mix of early and late blooming varieties, you can enjoy delphinium flowers for an extended period of time.

7. Attracting pollinators

Delphinium flowers are loved by pollinators, particularly bees and butterflies. By growing delphiniums in your garden, you can help support the local ecosystem and attract beneficial insects to your yard.

In conclusion, growing delphiniums from seed is a cost-effective and rewarding way to add beauty and elegance to your garden. With a wide variety of options, thriving in suitable conditions, and a long flowering period, delphiniums are a popular choice among both experienced and novice gardeners. So why not give it a try and enjoy the beauty of these stunning flowers in your own backyard?

When to plant delphiniums

Delphiniums are beautiful flowering plants that can add grace and color to any garden. They are mostly grown as herbaceous perennials, but some varieties are biennial. If you are a gardening enthusiast looking to grow delphiniums from seed, it’s important to know when is the best time to plant them.

In heavy frost areas, it’s best to start the delphinium seeds indoors before the last frost of the season. This will give them plenty of time to grow before they are ready to be transplanted into the garden. Start sowing the seeds 6-8 weeks before the last expected frost date.

Direct sowing

If you live in a mild climate where the winters are not too harsh, you can also direct sow the delphinium seeds in the garden. In this case, sow the seeds in early spring or late summer, before the first frost of the season.

Before sowing the seeds, prepare the soil by loosening it and removing any weeds or rocks. Delphiniums prefer well-draining soil, so make sure to amend the soil with aged manure or compost to improve its fertility. Also, note that delphiniums like a slightly acidic soil with a pH of around 6.0-7.0.

Watering and feeding

Once the delphinium seeds are sown, water them regularly to keep the soil moist. During the germination period, it’s important to provide them with plenty of water, but be careful not to overwater as it can lead to rotting of the seeds.

When the seedlings start to grow, thin them out to give each plant enough space to develop. This will also help prevent overcrowding and improve airflow around the plants, reducing the risk of diseases.

As the delphiniums grow, they will require regular feeding to support their growth and flowering. Use a balanced fertilizer, or one that is high in phosphorus, to promote blooming. Follow the package instructions for the proper dosage and frequency of application.

Staking and pruning

Delphiniums are tall plants that can reach a height of 4-6 feet, so it’s important to stake them to provide support. Insert the stakes into the ground near the plants and tie them loosely to prevent the plants from bending or breaking.

During the growing season, delphiniums may require a haircut to promote bushiness and keep them looking tidy. After the first flush of flowering, cut back the plants to encourage a second bloom. Remove any dead or dying parts of the plant to maintain its overall health and appearance.

Final thoughts

Delphiniums are a beautiful addition to any garden and can bring a touch of elegance and color to your outdoor space. By following the proper planting and care instructions, you can enjoy these stunning flowers year after year. Just make sure to provide them with suitable growing conditions, regular watering, and feeding, and you’ll be rewarded with a stunning display of delphinium blooms.

How to grow delphiniums from seed

Delphiniums are beautiful tall perennial flowers that can add a touch of elegance to any garden. While it’s possible to buy delphinium plants from nurseries and garden centers, growing them from seed is a cost-effective way to establish a large number of plants. Here’s how you can grow delphiniums from seed:

1. Start with good quality seeds

Begin by purchasing delphinium seeds from a reputable supplier. Look for seeds that are fresh and of high quality to ensure successful germination.

2. Choose the right time to sow

The best time to sow delphinium seeds is in early spring, around March or April. This will give the plants enough time to establish themselves before the flowering period in summer.

3. Prepare the soil

Delphiniums prefer well-draining soil that is rich in organic matter. Before planting, amend the soil with compost or well-rotted manure to improve its fertility.

4. Sow the seeds

Sow the delphinium seeds in a seed tray or individual pots, covering them lightly with soil. Keep the soil moist but not waterlogged and place the tray/pots in a warm location.

5. Provide support

Delphiniums are tall plants and will require support as they grow. Install stakes or plant supports around the seedlings to prevent them from toppling over.

6. Transplant the seedlings

Once the seedlings have developed a few true leaves, they can be transplanted into the garden. Space them at least 12-18 inches apart to allow for proper growth.

7. Water regularly

Delphiniums need regular watering, especially during dry periods. Water the plants deeply and consistently, aiming to keep the soil evenly moist.

8. Provide proper care

8. Provide proper care

Delphiniums are hardy perennials but may require some care during the growing season. Remove any weeds or competing plants around them, and consider thinning the plants if they become overcrowded.

9. Protect from harsh conditions

Delphiniums are vulnerable to harsh winter conditions and may not survive in certain regions. If you live in an area with severe winters, consider providing winter protection by covering the plants with mulch or burlap.

10. Enjoy the flowers

With proper care and attention, your delphinium plants should start flowering in their second year. These tall and majestic flowers will attract bees and butterflies to your garden, adding beauty to your outdoor space.

Remember, delphiniums are hungry feeders, so don’t be afraid to give them an occasional dose of well-rotted manure or a liquid feed of seaweed extract to enhance their growth.

Follow this advice from expert gardener Simon Nicholls, and you’ll soon have a garden full of thriving delphiniums, bringing color and grace to your flower beds.

Where to grow delphiniums

Delphiniums are beautiful flowering plants that can add a splash of color to any garden. When deciding where to grow delphiniums, there are a few key factors to consider.

Soil: Delphiniums prefer fertile, well-drained soil. A traditional garden bed with loamy soil mix is suitable for these plants. If you don’t have a garden bed, you can also grow delphiniums in containers. Make sure to use a good-quality potting mix that drains well.

Light: Delphiniums thrive in full sunlight, although they can tolerate some shade. They need at least 6 hours of direct sunlight per day to grow and flower well.

Space: Delphiniums are tall plants that can reach a height of up to 6 feet. Make sure to space them at least 2 feet apart to allow for proper air circulation and growth.

Watering: Delphiniums require regular watering, especially during dry spells. They prefer to be evenly moist, so water them weekly or whenever the soil feels dry to the touch. Avoid overwatering as this can lead to root rot.

Feeding: Delphiniums are heavy feeders and benefit from regular feeding. Apply a balanced fertilizer once a month during the growing season to promote healthy growth and abundant flowering.

Attracting pollinators: Delphiniums are attractive to bees and butterflies. If you want to attract these pollinators to your garden, planting delphiniums is a wise choice.

Overwintering: Delphiniums are perennials, meaning they will come back year after year. However, they may not survive harsh winter conditions in some areas. To protect your delphiniums during winter, apply a layer of aged manure or compost around the base of the plants before the first frost. This will provide insulation and help retain moisture.

Overall, delphiniums are relatively easy to grow and will reward you with beautifully colored flowers year after year. Whether you have a garden bed or limited space in containers, these plants are sure to add a touch of beauty to your home.

How to grow delphiniums in pots

Growing delphiniums in pots is a great way to enjoy these beautiful flowers in more confined spaces, such as balconies or patios. While delphiniums are traditionally grown in the ground, they can also thrive in containers if the right conditions are provided. Here’s how:

Choosing the right pots

When growing delphiniums in pots, it’s important to choose the right containers. Opt for larger and deeper pots, as delphiniums have long roots and need ample space to grow and spread. Make sure the pots have drainage holes at the bottom to prevent waterlogging.

Preparing the soil

Delphiniums prefer moist, well-drained soil. Use a high-quality potting mix enriched with organic matter, such as compost or well-rotted manure, to ensure good drainage and fertility. Additionally, adding a handful of seaweed meal to the potting mix can provide extra nutrients for your delphiniums.

Planting the delphinium seeds

Start by sowing the delphinium seeds in a seed tray or small pots filled with seed compost. Moisten the compost before sowing the seeds and press them lightly into the surface. Cover the tray or pots with a plastic bag or glass lid to create a mini greenhouse effect and place them in a warm, well-lit area.

Note that delphiniums can be quite finicky when it comes to germination, so it’s wise to consult an experienced gardener for advice on the best techniques specific to your climate and conditions. Seeds should germinate within a couple of weeks, and once they have reached about 2 inches in height, they can be transplanted into larger pots.

Caring for delphiniums in pots

Delphiniums in pots need regular watering to keep the soil consistently moist, but not waterlogged. During the growing season, feed your delphiniums with a balanced liquid fertilizer every two weeks to ensure they receive sufficient nutrients for healthy growth.

As delphiniums grow taller, they will need support to prevent their stems from bending or breaking. Use bamboo stakes or other suitable support structures to prop up the plants. Gently tie the stems to the supports, being careful not to constrict their growth.

In terms of pests, delphiniums can attract aphids and slugs. Keep an eye out for these pests and take appropriate measures, such as using organic insecticides or creating natural barriers to protect your plants.

Winter care for potted delphiniums

Delphiniums are herbaceous perennials that die back to the ground during winter. In colder climates, it’s best to bring potted delphiniums indoors or to a sheltered area to protect them from freezing temperatures. Trim back the foliage and reduce watering, allowing the soil to dry out slightly between waterings. Re-introduce regular watering and feeding in early spring to encourage new growth.

By following these steps, you can successfully grow delphiniums in pots and enjoy their beautiful flowers in even the smallest of spaces. Whether you choose to grow them from seeds or purchase young plants, delphiniums will grace your container gardens with their vibrant colors and tall, elegant spires.

How to care for delphiniums

Delphiniums are beautiful flowering perennials that can add grace and color to any garden or border. Once you’ve grown your delphiniums from seed, it’s important to provide them with the proper care to ensure they thrive.


If you’re growing delphiniums from seed, Simon Nicholls, an experienced gardener, advises starting them off in a potting mix aged over a year. This will give the seeds the best chance of germinating and growing into healthy plants. Once your delphinium seedlings have developed their second set of true leaves, they can be transplanted into your garden or a larger container.

Location and Soil

Delphiniums prefer full sun but can tolerate some shade, especially in hot climates. They also require well-draining soil, as they are susceptible to root rot in heavy, waterlogged soil. Simon says, “Look for a location in your garden that gets around 6-8 hours of direct sunlight per day.”



Delphiniums have high water requirements, especially during their flowering period. Water them deeply once a week, or more often if the weather is particularly hot and dry. Make sure the soil gets evenly moist, but avoid overwatering, as this may lead to root rot.


Delphiniums are heavy feeders, so it’s important to provide them with regular fertilization. Simon recommends using a balanced, slow-release fertilizer once a month during the growing season. Additionally, applying a fertilizer high in phosphorus prior to the flowering period can help encourage larger and more vibrant blooms.


Delphiniums can grow quite tall, and their stems may become top-heavy, causing them to bend or break. To prevent this, it’s wise to stake your delphiniums. Place the stakes around the plants early in the growing season, before they get too tall and floppy. Use garden twine to gently tie the stems to the stakes for support.

Deadheading and Cutting Back

To prolong the flowering period of your delphiniums, it’s important to deadhead the spent flowers. This will prevent the plants from putting energy into producing seeds and encourage them to produce more blooms. Once your delphiniums have finished flowering for the season, cut them back to ground level. This will help ensure healthy regrowth the following season.

Pest and Disease Control

Delphiniums, particularly the traditional blue varieties, can be susceptible to powdery mildew. To prevent this fungal disease, make sure your plants have adequate spacing and good air circulation. Applying a fungicide labeled for use on delphiniums can also be beneficial. Additionally, keep an eye out for aphids and other pests and take appropriate measures to control them.



Delphiniums are hardy perennials and can withstand cold winter temperatures. However, it’s a good idea to provide some protection for your plants during the winter months. Applying an aged compost or mulch around the base of the plants can help insulate the roots and protect them from freezing temperatures.

With the right care and attention, your delphiniums will reward you with beautiful flowers year after year. Just remember to provide them with plenty of water, sunlight, and fertilizer, and they will thrive in your garden.

Types of delphiniums

Delphiniums are a popular choice among gardeners, with their tall spires of colorful flowers adding height and drama to any garden. There are several types of delphiniums that can be grown from seed, each with its own unique characteristics.

1. Belladonna Delphiniums

Belladonna delphiniums are herbaceous perennials that grow to a height of about 3 feet. They produce beautiful, delicate flowers in shades of blue, pink, and white. These delphiniums are well-suited for planting in borders, where their tall spikes can provide a focal point.

2. Pacific Giants Delphiniums

Pacific Giants delphiniums are known for their stunning range of colors, including deep blues, purples, pinks, and whites. They can reach a height of up to 6 feet, making them an impressive addition to any garden. These delphiniums are especially suited to areas with cooler summers.

3. New Millennium Delphiniums

New Millennium delphiniums are a favorite among gardeners for their large, showy flowers and sturdy growth. They come in a wide range of colors, including blues, purples, pinks, and whites. These delphiniums are the result of years of breeding and selection, resulting in plants that are both vigorous and disease-resistant.

4. Magic Fountains Delphiniums

Magic Fountains delphiniums are a dwarf variety, reaching a height of about 2-3 feet. They produce an abundance of flowers in shades of blue, purple, pink, and white. These delphiniums are well-suited for growing in containers or in smaller garden spaces.

5. Black Knight Delphiniums

Black Knight delphiniums are known for their dramatic, dark purple flowers. They can grow to a height of about 4-5 feet and are often used as a backdrop in garden borders. These delphiniums are especially suited to well-drained soil and can be prone to powdery mildew if not given proper care.

When choosing delphiniums to grow from seed, be sure to consider the growing conditions in your garden and choose a variety that is suitable. All delphiniums require plenty of sunlight and well-drained soil. They also benefit from the support of stakes or other structures to help prevent the tall flower spikes from toppling over.

Do delphiniums grow back every year

Delphiniums are beautiful flowering plants that can add height and color to your garden. They are known for their tall spikes of flowers in shades of blue, pink, purple, and white. If you’re considering growing delphiniums from seed, you may be wondering if they will grow back every year.

Mostly, delphiniums are perennial plants, which means they will come back year after year. However, they are not always reliable in all climates and conditions. In some colder regions, delphiniums may not survive the winter and will need to be replanted each spring.

To increase the chances of your delphiniums surviving the winter and growing back every year, there are a few steps you can take:

1. Planting

Delphiniums should be planted in well-draining soil in a sunny spot in your garden. They prefer slightly alkaline soil, so you may need to amend your soil if it is too acidic. Make sure to space the plants at least 18 inches apart to allow for good air circulation.

2. Staking

2. Staking

Tall delphiniums may need to be staked to prevent them from bending or breaking in strong winds. Use a suitable stake and tie the plants to it using soft twine. This will help to keep the plants upright and prevent damage.

3. Thinning

When the delphiniums start to flower, you may need to thin out the crowded stems to encourage better air circulation and prevent diseases. Remove any weak or damaged stems, leaving only the healthiest ones to flower.

4. Feeding and Watering

Delphiniums are heavy feeders and need regular feeding throughout the growing season. Use a balanced fertilizer and follow the instructions on the packaging. Water the plants regularly, especially during periods of dry weather, to keep the soil consistently moist.

5. Cutting back

After the delphiniums have finished flowering, you can cut them back to the ground. This will help to encourage new growth and prevent the plants from becoming too leggy. You can also divide the plants every few years to keep them healthy and prevent overcrowding.

In conclusion, while delphiniums are mostly perennial plants that will grow back every year, their ability to survive over winter depends on the specific conditions in your garden. By following the planting and care tips outlined above, you can increase the chances of your delphiniums thriving and returning year after year.

Do you cut delphiniums after flowering

Delphiniums are beautiful flowering plants that can bring grace and color to any garden. Once they have finished flowering, many gardeners wonder whether to cut them back or leave them as they are. Here is some advice on what to do with delphiniums after flowering:

  1. Some gardeners choose to cut back delphiniums after flowering to encourage a second flush of blooms later in the season. This is especially true for newer hybrid varieties, which tend to bloom more than once. Cutting back the plants after their first flush of flowers ensures that they remain compact and bushy, rather than leggy and untidy.
  2. Others prefer to leave the plants standing after the first flush of flowers. This is because the dead flower spikes of delphiniums can be quite ornamental, especially when covered in dew or raindrops. Additionally, the seed pods that form after the flowers have faded can be attractive and can add interest to the garden.

When deciding whether to cut back delphiniums, it is also wise to consider your local climate. In areas with mild winters, delphiniums may continue to flower and provide color in the garden during the fall season. In colder climates, cutting back the plants after their first flush of flowers can help prepare them for winter dormancy.

Advice for cutting back delphiniums:

If you decide to cut back your delphiniums after their first flush of flowers, here are some tips to follow:

  • Wait until after the flowers have faded before cutting back the plants. This allows the flowers to set seeds, which can be collected for future planting or left to self-sow in the garden.
  • Cut the flower stalks down to the base of the plant, using sharp and clean pruning shears or scissors. Be careful not to damage the emerging new growth at the crown of the plant.
  • Remove any yellow or diseased foliage from the plant. This helps prevent the spread of diseases and keeps the plant looking tidy.
  • If the delphinium has become tall and leggy, you can cut it back by half to encourage a more compact and bushy form.
  • After cutting back the plants, water them well to help them recover and stimulate new growth. Adding a slow-release fertilizer or aged compost to the soil can also be beneficial.

Whether you choose to cut back your delphiniums after flowering or let them stand, it’s important to remember that these plants are hardy perennials that can grace gardens with their beautiful blooms year after year. With the right care and proper planting, delphiniums can be grown in both traditional borders and containers.

If you’re a new gardener looking to grow delphiniums from seed, be sure to give them plenty of space to grow and stake them early on for support. Delphiniums prefer a rich, well-drained soil and benefit from regular watering and fertilizing during the growing season. With these tips in mind, you can grow delphiniums that will attract attention and add beauty to your garden.

For the latest gardening advice and tips, subscribe to our newsletter and have the information delivered straight to your inbox!


You may also like

Leave a Repl​​​​​y

Your email address will not be published. Required fields are marked

{"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}

Direct Your Visitors to a Clear Action at the Bottom of the Page