How To Start Dahlias Indoors

March 24, 2023 6 Comments

How To Start Dahlias Indoors

Dahlias are a magnificent flower and beloved amongst gardeners everywhere due to their vibrant colors and stunning blooms. Starting dahlia tubers indoors is an excellent option for those looking to get a head start on the growing season. But, when should you start dahlias indoors?

Dahlia tubers lined up at Rooted FlowersTuber to flower at rooted flowers.The ideal time to start dahlias indoors is in early April, about six to eight weeks before the last frost date in your area. This gives your dahlias enough time to grow and develop before they are transplanted outdoors. To begin, fill a 4-inch-diameter pot or larger about one-half full with a potting mix.

Planting a dahlia tuber at Rooted Flowers.Place your dahlia tuber vertically in the potting mix so that you can see the neck, and cover the rest of the pot with potting soil. Be careful not to water the soil immediately, wait until you see eye development (see below) before watering. Tubers left in cool, damp soil can rot, so make sure the area you have it in is at least 65F consistently. Using a heat mat is best to keep the soil temperature up.

Eye development on dahlia tubers.Once your dahlias start to grow, place them in a sunny window or under artificial lighting. Dahlias require at least six hours of sunlight each day, so ensure they receive enough light. Keep the lights on for about 14-16 hours a day and turn them off at night if you're using artificial lighting.

Sprouted dahlia tuber at Rooted Flowers.As your dahlias continue to grow, keep the soil evenly moist but not waterlogged. When the sprouts reach about 4-6 inches in height, pinch off the top growth to encourage bushier growth.

When the weather warms up, and the threat of frost has passed, transplant your dahlias outdoors into well-draining soil. Plant them so that you bury the neck under the soil and space them at least 12 inches apart. Only the green sprout should be visible above the soil line. Our rule of thumb is that when it’s time to plant tomatoes, it’s time to plant dahlias!

Field of dahlias growing at Rooted Flowers.Dahlia process at Rooted Flowers.Starting dahlias indoors is an excellent way to get a head start on the growing season and ensure that your plants are healthy and strong before transplanting them outdoors. Planting tubers directly outside can be risky, especially when there is a sudden downpour of rain. Getting your dahlias started indoors ensures beautiful blooms all season long.

Field of dahlias at Rooted Flowers.Do you have any tips for starting dahlias indoors that have worked well for you? Share your thoughts and experiences in the comments below!

To learn more about what we offer and the next sale, check out our Dahlia Tuber Collection.

6 Responses

Rebeccca Sadlowski
Rebeccca Sadlowski

October 09, 2023

Franziska — Sluggo works well for slug problems and isn’t a problem for all growers.

Franziska
Franziska

October 09, 2023

I’m surprised that when it comes to talking about the challenges of growing dahlias outdoors nobody ever mentions slugs and snails but only frost!

Pamela
Pamela

June 01, 2023

Thank you for the indoor planting tips. I’m gonna fill my pots and place my tubers in them today I have artificial lighting so they should get off to a good start. The 65° is the hard part my room is about 60 at all times. Maybe I’ll have to put a little heater in there. Thanks again here’s to season 2023 may could be a super Duper one.

Shelley
Shelley

April 17, 2023

This is great, I have not always had the best luck with Dhalias when I plant them right into my gardens. I’m going to try your advise this weekend…thank you

Anne Mastrototaro
Anne Mastrototaro

April 04, 2023

I’m so excited for gardening season to get underway. I love seeing the transformation of the dreary gray landscape to vivid color as Spring progresses. I add to my gardens each year and look forward to growing more dahlias this year.

Liz Krieg
Liz Krieg

March 25, 2023

PERFECT! Thank you for posting this, Becky!

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