Growing Dahlias From Seed Indoors – Secrets To Success

Last Updated on December 29, 2021 by Guillermina

Are you thinking of growing Dahlias from seed indoors? These are all secrets of success that you need to know.

Dahlias come in almost every color imaginable, from pale pastels to hot, vibrant shades. Their flowers have a wide range of shapes, from small tight balls all the way to lily-like blooms the size of dinner plates. They will certainly enrich the space in which they are located and add a jungle or exotic scheme.

Although traditionally grown from tubers and outdoors, did you know that you can opt for growing Dahlias from seed indoors? Keep reading to find out all the secrets to success.

Dahlia Flowers – In General

Dahlia is a genus that has about 40 species of flowering plants from the aster (Asteraceae) family. There are thousands of dahlia cultivars that are classed into a variety of types. Some of them are single, double, peony-flowered, cactus, waterlily, pompon, and dinnerplate dahlias.

Dahlias are native to the higher elevations of Mexico and Central America and were first introduced to Britain from Spain in 1798. About six of the species in the Dahlia genus have been bred for cultivation as ornamental flowers.

They are tuberous perennials, and most have simple leaves that are segmented and toothed or cut. As for colors and hues, flowers may be white, yellow, red, or purple in color. Dahlias grow well in most garden soils but are also too tender to be left in the ground all winter in zones 7 and below.

It is important to remember that they are not a one-size-fits-all plant. Dahlias are usually divided into large, medium, and small varieties. Although they can be grown in containers, large dahlias are not practical container plants because of their size and structure. Therefore, it would be best to opt for medium or small varieties that have enough space to grow happily in a pot.

 dahlia seeds

These varieties are ideal for containers and indoor cultivation:

  • Park Princess
  • Happy Single Romeo
  • Jan van Schaffelaar
  • Impression Festivo
  • Pulp Fiction

Dahlia Seeds – What Do They Look Like And How To Get Them?

The seed of the Dahlia flower is located inside a ripe seed floor. You will recognize them by the fact that they are extremely thin, black, and under ½ inches long.

This is what dahlia seeds look like:

The seeds are very easy to obtain. Do you know someone who has a Dahlia in their garden? Just ask him to collect a few seeds for you. Or get your seeds from the store.

How To Grow Dahlias Indoors?

The process of growing Dahlias from seeds indoors begins with planting 6-8 weeks before your last frost date. This will allow them enough time to grow so they can bloom in the warmer months. Expect it to take about 100-120 days for the seeds to produce flowers.

 dahlias plant care

Methods Of Planting Dahlias Indoors

There are several methods and ways of planting and germinating Dahlias from seed, these are the two most common.

Method 1 – Paper Towels

This method is very simple and involves the use of two pieces of paper towels. Take two wet paper towels and place the dahlia seeds straight on one and cover it with another paper towel.

Then, put them inside a zip lock bag and place them on the top of your refrigerator. Feel free to leave the seeds for 3-5 days. After the time has elapsed, start checking the bag daily for signs of germination.

When you notice the germination has begun, carefully plant the seedlings in a seed pot and place them under the growing lights.

Method 2 – Seed Trays

Another method involves planting your seedlings directly on your seed trays. The process is also simple and consists of filling the seed starting trays with a seed starting mix and poking holes in which you will place one Dahlia seed.

Then, bottom water the seed tray and cover with a clear acrylic dome and set on a heat mat and underneath grow lights. You can expect to see your seedlings in the next 3-5 days.

When Is The Right Time To Transplant Dahlia Seedlings?

When you notice that your dahlia seedlings have true growing leaves, it is time to transplant them into larger pots. Their transplant is very important as it will allow them not to become root-bound.

Dahlias Plant Care


Dahlia flowers require a lot of sun, preferably at least 6 to 8 hours a day. Therefore, it would be good to place it somewhere by the window so that it can enjoy enough sunlight.


When choosing soil for growing Dahlias from seed indoors, choose rich, loamy, and well-draining soil with plenty of organic matter. Also, make sure it is fairly neutral with a pH of around 6.5.


In the early growing stages, Dahlias do not prefer excessive watering. This is because the seeds and then the tubers don’t need water until they germinate and develop a root system. Moreover, you can leave the soil to dry out completely before your next watering.

Once the plants are established and you have filled the pot with potting soil, it is time to start watering regularly. In terms of frequency, once or twice a week will suffice. Also, try watering your dahlias deeply as some large tubers are planted six inches deep and water needs to reach the root system

 growing dahlias from seed indoors


Dahlia flowers adore fertilizing. The more food they get, the more the plant will grow, and accordingly their flowers will be more numerous. Try using a fertilizer with a higher percentage of phosphorus (ideal ratio 10-30-20) to encourage blooming.

Pests & Plant Diseases

The most common pests are slugs, earwigs, caterpillars, and thrips. Also, they are prone to powdery mildew and other fungal diseases. Therefore, try to space your plants to provide for good air circulation and try to keep the foliage as dry as possible. Infections are usually treated naturally, with neem oil or some other natural solution.

To Wrap Things Up

There is something so rewarding about growing Dahlias from seed indoors. Just try to imagine that feeling of having your own fresh-cut Dahlia flowers in a vase.

Follow these tips and you will have thriving dahlia flowers in as many posts as you want. On the other hand, your plant will endow you with so many flowers that it will keep you smiling all season long.

Was this dahlia guide helpful to you? Let us know in the comments below.

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