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Growing Beautiful Dahlias from Seed – A Guide

January 21, 2024

Christmas in the Spring – Dahlias From Seed

Last year was the first year we grew dahlias from seed and I am hooked! This method of dahlia propagation is simple, and creates a great surprise in spring as the dahlia seed turn into amazing flowers. Why? Dahlia seeds are not true to the mother plant, so every seed is a new and unique variation. You never know what kind you will get! The only way to get a true replica of your mother plant is to divide the tuber, or take cuttings (Dahlia Propagation Through Cuttings article). You get such a broad and wide range of dahlia flowers from planting seed, it is truly amazing, and you can keep the variations you like, dig up that dahlia tuber, and propagate for more.

dahlia plants from seed
Growing Dahlias From Seed is Like Christmas in Spring

Growing dahlias from seeds and from tubers are two different methods, each with its own advantages and challenges.

Growing Dahlias from Seeds

  1. Variability – Seeds can produce a wide range of flower colors, shapes, and sizes, making them ideal for those who enjoy surprises and diversity in their garden.
  2. Cost-Effective – Seeds are generally less expensive than tubers.
  3. Availability – A wide variety of seeds can be easily obtained from nurseries or online.
  4. Growing Season – Dahlias grown from seeds may take longer to flower. They are typically started indoors before the last frost date and transplanted outside when the weather warms.
  5. Lifecycle – Plants grown from seeds may not produce viable tubers in their first year, meaning they often can’t be overwintered and replanted next season.

Growing Dahlias from Tubers

  1. Predictability – Tubers will produce flowers that are identical to the parent plant, allowing for more control over the aesthetics of your garden.
  2. Quicker Blooms – Dahlias grown from tubers tend to flower earlier in the season compared to those grown from seeds.
  3. Overwintering – Tubers can be dug up at the end of the season, stored over winter, and replanted the following year.
  4. Cost – While initially more expensive than seeds, tubers can be a better long-term investment since they can be reused for several years.
  5. Ease of Growth – Growing dahlias from tubers is often considered easier and more reliable, especially for beginner gardeners.

Dahlia Seed or Tubers?

  • For Experimentation and Diversity – Choose seeds.
  • For Predictability and Perennial Growth – Opt for tubers.

Your choice will depend on your gardening goals, budget, and the level of effort you’re willing to put into your dahlia garden.

The Steps – Growing Dahlias with Seed

The dahlia from seed method is simple, and the dahlia seeds grow fast. Here is how to propagate dahlias from seed:

  1. First off, don’t buy cheap seed! Buy some high quality Hybrid Dahlia Seed, with high germination rates. If you buy cheap seed, you’ll reap what you sow ;). You can buy what we use on our flower farm here, from a top seed producer: Hybrid Dahlia Seed.
  2. Find a pot or seed tray and fill it with a seedling mix or a mix of soil and vermiculite.
  3. Wet the medium and poke holes with a seed planter/dibber that are about 1/2″ deep, and about an inch or so apart.
  4. Place your seeds in the holes and cover with soil mix.
  5. The seeds will germinate in about 2 weeks, but if you apply bottom heat with a seed mat, it will speed up the process (This season mine popped in 7 days).
  6. Water daily, and provide plenty of light, either with a grow light or place in a south facing window.
  7. Soon you will have a whole set of seedlings.
  8. Once they are about 2-3 inches or their leaves are touching, you can move them to small pots (3 inches) and continue to grow.
  9. Before you move the little propagated dahlias to the garden, “harden them off” by exposing them to the outdoors, gradually over a week more and more.
  10. Pro Tip – When the dahlias you grow from seed are 12-18″ tall, snip the center growth bud with garden snips/scissors. This will encourage branching and give you a bush with more flowers!
  11. Wait for the fun!
Propagating and Growing Dahlia From Seed
Dahlia seedlings sprouting

Seed to Tuber: Making Sure You Get Treasure at the End

Ensuring that a dahlia grown from seed produces a viable tuber for the following season involves several key steps:

  1. Select High-Quality Seeds – Start with high-quality dahlia seeds from a reputable source. This increases the likelihood of healthy plant growth and tuber development.
  2. Proper Germination – Begin by sowing seeds indoors, preferably in a seed-starting mix, 6-8 weeks before the last frost date. Provide adequate warmth (about 70°F or 21°C) and light to encourage germination.
  3. Transplant Carefully – Once the seedlings have developed true leaves and are strong enough, transplant them into individual pots. This allows the roots to develop without competition.
  4. Adequate Sunlight – Dahlias thrive in full sunlight. Ensure your plants get at least 6-8 hours of direct sunlight daily for optimal growth.
  5. Regular Watering and Feeding – Water the plants regularly, keeping the soil moist but not waterlogged. Feed them with a balanced, slow-release fertilizer to provide the necessary nutrients for growth.
  6. Proper Soil and Drainage – Plant your dahlias in well-drained soil. Excess moisture can lead to root rot, which can be detrimental to tuber development.
  7. Pest and Disease Management – Keep an eye out for pests and diseases. Address any issues promptly to prevent damage to the plant and its developing tuber.
  8. Allow Full Season Growth – Allow the dahlia plants to grow for the full season without cutting back. This gives the plant ample time to develop a strong root system and, subsequently, healthy tubers.
  9. Post-First Frost Care – After the first frost in autumn, the above-ground part of the plant will die back. Wait about a week, then carefully dig up the tubers. This timing allows the skin of the tuber to toughen up, making it more viable for storage.
  10. Proper Storage – Clean the tubers gently and store them in a cool (40-50°F or 4-10°C), dark place over winter. Use slightly moistened sand, peat moss, or vermiculite to store them. Check periodically for rot or drying out.

Remember, not all dahlia plants grown from seed will produce viable tubers in their first year. It can vary depending on the variety and growing conditions. Patience and proper care throughout the growing season are key to success.

These dahlias from seed will grow an amazing tuber you can lift if you like the variety you have produced. This tuber will produce the exact flower, and you can then use tuber division to multiply you bounty. Here is some additional info on the specific of growing dahlias and seed charateristics:


3-5 days at 65-70°F (18-21°C)


Transplant (recommended) – Sow your dahlia seed 4-5 weeks before last frost. Cover your seed with soil/medium and keep soil surface moist until dahlia seed emergence. When seedlings have true leaves, transplant into larger growing trays or pots. To maintain healthy seedlings, do not allow plants to become root bound and do not disturb roots during the early growing process. Direct seed in the garden – After last frost when soil is 65–70°F (18–21°C), sow thinly, 2 seeds/ft, 1/4″ deep. Cover lightly but tamp the soil. Keep surface moist, but not soaked, until emergence. Thin to 9-12″ after first true leaves appear on the dahlia plants.


Full Sun.






Winter Hardy 8-11

Annuals 3-7


Before dahlia blooms are completely open.


Dahlia plants that are propagated from seeds will produce tubers that can be saved, stored and planted the following spring. In the fall, after plants have died back but before the ground freezes, cut dahlia plants back to 2-4″ above the soil line and carefully dig up the tubers and remove all excess soil. Let tubers dry and cure for 1-3 days in warm location with some humidity, out of direct sunlight with proper air flow. Pack tubers in peat moss or vermiculite inside perforated plastic bags, boxes with holes or crates.


Dahlia variabilis