How to Grow Stunning Dahlias from Seed in 7 Easy Steps

Dahlias are one of the most popular and versatile flowers that you can grow in your garden. They come in a wide range of colors, shapes, and sizes, from tiny pompons to giant dinner plates. They also bloom from midsummer to late autumn, providing a long-lasting display of beauty and charm.

But did you know that you can also grow dahlias from seed? Growing dahlias from seed is not only fun and rewarding, but also economical and easy. You can start your own dahlia collection from a packet of seeds, or create your own new varieties by crossing different types of dahlias.

In this article, we will show you how to grow stunning dahlias from seed in 7 easy steps. We will cover everything from sowing, germinating, caring, transplanting, enjoying, and harvesting dahlia seeds. By following these steps, you will be able to grow healthy and beautiful dahlias from seed in no time.

How to Sow Dahlia Seeds

The first step to growing dahlias from seed is to sow them properly. Here are some tips on how to sow dahlia seeds:

• Time: The best time to sow dahlia seeds is in late winter or early spring, about 6 to 8 weeks before the last frost date in your area. This will give your dahlia seedlings enough time to grow and harden off before planting them outdoors.
• Place: You can sow dahlia seeds either indoors or outdoors, depending on your climate and preference. If you sow them indoors, you will need a warm and bright spot, such as a windowsill or a greenhouse. If you sow them outdoors, you will need a sheltered and sunny location, such as a cold frame or a cloche.
• Method: You can sow dahlia seeds either directly into pots or trays, or into seed starting mix. If you sow them directly into pots or trays, make sure they have drainage holes and are filled with moist and well-drained potting soil. If you sow them into seed starting mix, make sure it is sterile and fine-textured. You can use peat moss, vermiculite, perlite, or coco coir as your seed starting mix.
• Preparation: Before sowing your dahlia seeds, you may want to soak them in water for 24 hours to soften their hard shells and speed up germination. You may also want to nick or scratch them with a knife or a nail file to help them absorb water better.
• Sowing: To sow your dahlia seeds, simply scatter them thinly over the surface of the soil or the seed starting mix. Do not bury them too deep, as they need light to germinate. A good rule of thumb is to cover them with a thin layer of soil or mix that is equal to their size. You can use a sieve or a shaker to distribute the soil or mix evenly over the seeds.
• Watering: After sowing your dahlia seeds, water them gently but thoroughly with a fine mist or a spray bottle. Make sure the soil or the mix is moist but not soggy. You can also cover the pots or trays with clear plastic wrap or a glass lid to create a mini greenhouse effect and retain moisture.
• Labeling: Don’t forget to label your pots or trays with the name and date of your dahlia seeds. This will help you keep track of their progress and identify their varieties later.

How to Germinate Dahlia Seeds

The second step to growing dahlias from seed is to germinate them successfully. Here are some tips on how to germinate dahlia seeds:

• Temperature: Dahlia seeds need warm temperatures to germinate, between 18°C and 24°C (65°F and 75°F). You can use a heating mat, a radiator, or a sunny spot to provide the necessary warmth. Avoid placing your pots or trays near cold drafts or vents, as they can lower the temperature and slow down germination.
• Moisture: Dahlia seeds need moist but not wet conditions to germinate. You can check the moisture level of the soil or the mix by touching it with your finger. If it feels dry, water it lightly with a fine mist or a spray bottle. If it feels wet, remove the plastic wrap or the glass lid and let it dry out slightly. Do not overwater or underwater your dahlia seeds, as both can cause rotting or damping off.
• Light: Dahlia seeds need light to germinate, but not direct sunlight. You can place your pots or trays near a bright window, under a grow light, or in a shady spot outdoors. Make sure they receive at least 6 hours of light per day, but avoid exposing them to harsh or scorching sun rays, as they can damage the delicate seedlings.
• Ventilation: Dahlia seeds need fresh air to germinate, but not strong winds. You can provide ventilation by opening the plastic wrap or the glass lid slightly, or by placing your pots or trays in a well-ventilated area. Make sure they are protected from pests and animals, such as birds, squirrels, or mice, that may eat or disturb your dahlia seeds.
• Time: Dahlia seeds can take anywhere from 2 to 4 weeks to germinate, depending on the variety and the conditions. You can expect to see the first signs of germination when tiny green sprouts emerge from the soil or the mix. Do not lose patience or give up on your dahlia seeds if they take longer than expected to germinate. Some dahlia seeds may be dormant or slow to sprout, but they will eventually germinate if you provide them with the right environment.

How to Care for Dahlia Seedlings

The third step to growing dahlias from seed is to care for them properly. Here are some tips on how to care for dahlia seedlings:

• Watering: Dahlia seedlings need regular watering to grow and thrive. You can water them once or twice a week, depending on the weather and the soil condition. You can use a watering can, a hose, or a drip irrigation system to water your dahlia seedlings. Make sure you water them deeply and evenly, but avoid splashing water on their leaves or stems, as this can cause fungal diseases. You can also mulch your dahlia seedlings with organic matter, such as straw, leaves, or compost, to conserve moisture and prevent weeds.
• Fertilizing: Dahlia seedlings need occasional fertilizing to boost their growth and flowering. You can fertilize them once a month, starting from when they have 2 to 3 pairs of true leaves. You can use a balanced fertilizer, such as 10-10-10 or 20-20-20, diluted at half strength according to the label instructions. You can also use an organic fertilizer, such as fish emulsion, seaweed extract, or compost tea, applied at full strength according to the label instructions. Make sure you fertilize your dahlia seedlings after watering them, and avoid touching their roots with the fertilizer solution, as this can burn them.
• Pruning: Dahlia seedlings need light pruning to encourage bushy and compact growth. You can prune them when they have 4 to 5 pairs of true leaves, by pinching off the tip of their main stem just above a pair of leaves. This will stimulate the growth of lateral branches and more flowers. You can also prune off any weak, damaged, or diseased stems or leaves that may affect the health of your dahlia seedlings.
• Protecting: Dahlia seedlings need protection from pests and diseases that may harm them. Some of the common pests that may attack your dahlia seedlings are aphids, spider mites, thrips, slugs, snails, and caterpillars. Some of the common diseases that may affect your dahlia seedlings are powdery mildew, botrytis blight, bacterial wilt, and mosaic virus. You can prevent and control these pests and diseases by using cultural methods, such as removing any infected plants or parts; using clean tools and pots; avoiding overhead watering; providing good air circulation; rotating crops; and applying organic pesticides or fungicides if needed.

How to Transplant Dahlia Seedlings

The fourth step to growing dahlias from seed is to transplant them into their final location. Here are some tips on how to transplant dahlia seedlings:

• Time: The best time to transplant dahlia seedlings is when they have 3 to 4 pairs of true leaves, and after the last frost date in your area. This will ensure that your dahlia seedlings are strong enough to survive the transplanting process, and that they will not be damaged by cold temperatures.
• Location: You can transplant dahlia seedlings either into the garden or into larger pots, depending on your space and preference. If you transplant them into the garden, make sure you choose a sunny and well-drained spot, with rich and fertile soil. If you transplant them into larger pots, make sure you use a good quality potting mix, and that the pots have drainage holes and are at least 30 cm (12 inches) in diameter.
• Method: To transplant your dahlia seedlings, follow these steps:
  • Water your dahlia seedlings well before transplanting them, to reduce the shock and stress.
  • Prepare the planting holes or pots by digging or filling them with soil or mix, and adding some organic matter or slow-release fertilizer if needed.
  • Carefully remove your dahlia seedlings from their original pots or trays, by gently squeezing or tapping the sides and bottom, and lifting them out by their roots. Do not pull them out by their stems or leaves, as this can damage them.
  • Place your dahlia seedlings in the planting holes or pots, at the same depth as they were growing before. Do not bury them too deep or too shallow, as this can affect their growth and flowering. A good rule of thumb is to plant them so that the soil or mix level is just below the lowest pair of leaves.
  • Fill in the gaps around your dahlia seedlings with soil or mix, and press it firmly but gently to eliminate any air pockets. Water your dahlia seedlings thoroughly after planting them, to settle the soil or mix and establish contact with the roots.
  • Stake your dahlia seedlings if they are tall or floppy, by inserting a bamboo cane or a metal rod next to each plant, and tying it loosely with a soft string or a twist tie. This will support your dahlia seedlings and prevent them from breaking or bending in the wind.
  • Label your dahlia seedlings with their name and variety, if you want to keep track of them or share them with others.

How to Enjoy Dahlia Varieties from Seed

The fifth step to growing dahlias from seed is to enjoy their beauty and diversity. Here are some tips on how to enjoy dahlia varieties from seed:

• Types: One of the advantages of growing dahlias from seed is that you can discover new and unique varieties that may not be available in nurseries or catalogs. Dahlias from seed can produce different types of flowers, such as cactus, pompon, single-flowered, anemone-flowered, collarette, waterlily, peony-flowered, ball, decorative, or orchid-flowered. They can also vary in color, size, shape, and pattern, creating a stunning display of diversity and charm.
• Selection: To enjoy the best of your dahlia varieties from seed, you may want to select the ones that suit your taste and preference. You can do this by observing their performance and appearance throughout the season, and marking or tagging the ones that you like best. You can also compare them with other dahlias from seed or from tubers, and see which ones stand out or complement each other.
• Harvesting: To enjoy your dahlia varieties from seed as cut flowers, you may want to harvest them at the right time and in the right way. You can do this by following these steps:
  • Cut your dahlias early in the morning or late in the evening, when they are fully open but not faded or wilted. Avoid cutting them in the heat of the day, as this can reduce their vase life.
  • Cut your dahlias with a sharp knife or scissors, at an angle of 45 degrees, about 5 cm (2 inches) below the flower head. Leave some foliage on the stem for photosynthesis and aesthetics.
  • Remove any lower leaves or buds that may be submerged in water, as this can cause rotting or bacterial growth.
  • Place your dahlias in a bucket of clean water as soon as you cut them, and let them rest for a few hours in a cool and dark place. This will help them hydrate and last longer.
  • Arrange your dahlias in a vase or a container of your choice, filled with fresh water and some floral preservative if available. Change the water and recut the stems every 2 to 3 days, to prolong their vase life.

How to Harvest Dahlia Seeds

The sixth step to growing dahlias from seed is to harvest their seeds for future use. Here are some tips on how to harvest dahlia seeds:

• Time: The best time to harvest dahlia seeds is when the flowers are fully mature and dry, usually in late autumn or early winter, before the first frost. This will ensure that the seeds are ripe and viable, and that they will not be damaged by cold temperatures.
• Method: To harvest your dahlia seeds, follow these steps:
  • Cut the flower heads from the plants, leaving some stem attached. You can use a sharp knife or scissors, or simply snap them off by hand.
  • Place the flower heads in a paper bag or a cardboard box, and label them with their name and variety. You can also use a mesh bag or a basket, but make sure they have good air circulation and drainage.
  • Store the flower heads in a cool and dry place, such as a garage, a shed, or a basement, for 2 to 4 weeks. This will allow them to dry completely and release their seeds.
  • Break open the flower heads and shake out the seeds. You can use your fingers, a fork, or a sieve to separate the seeds from the chaff. The seeds are thin and black, and look like small grains of rice.
  • Sort out the seeds and discard any that are damaged, discolored, or moldy. You can also test the viability of your seeds by placing them in water. The ones that sink are good, and the ones that float are bad.
  • Store your seeds in an envelope or a glass jar, labeled with their name, variety, and date. You can also add some silica gel packets or rice grains to absorb any moisture and prevent mold growth.

Conclusion

Growing dahlias from seed is a rewarding and enjoyable hobby that anyone can do. By following these 7 easy steps, you will be able to grow stunning dahlias from seed in no time:

• Sow your dahlia seeds in late winter or early spring in moist and well-drained soil.
• Germinate your dahlia seeds in warm and bright conditions for 2 to 4 weeks.
• Care for your dahlia seedlings by watering, fertilizing, pruning, and protecting them from pests and diseases.
• Transplant your dahlia seedlings when they have 3 to 4 pairs of true leaves, preferably after the last frost.
• Enjoy your dahlia varieties from seed by selecting, harvesting, and arranging them as cut flowers.
• Harvest your dahlia seeds when the flowers are fully mature and dry, usually in late autumn or early winter.
• Store your dahlia seeds in a cool and dry place until next season.

We hope you found this article helpful and informative. If you have any questions or comments, please feel free to share them below. We would love to hear from you.

Happy gardening! 

About The Author

Samantha

I’m Samantha, a plant enthusiast who has been growing plants for years. I believe that plants can make our lives better, both physically and mentally. I started growit.wiki to share my knowledge about how to grow plants. I want to help others enjoy the beauty and benefits of plants.

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