Café au lait dahlia

How to start dahlia tubers inside

Are you looking to get a head start on your dahlia garden this year? Starting dahlia tubers indoors can give you a jump on the growing season and lead to earlier blooms. It is also a great idea if you have lots of slugs or earwigs in your garden that can damage young, vulnerable plants.

Follow these expert tips to successfully start your dahlia tubers indoors.

What are Dahlia Tubers?

Dahlia tubers are similar to bulbs but have a different structure. They are called tubers and are from the same family as the potato. Dahlia tubers are the starting point for growing beautiful dahlia flowers in your garden.

When to Start Dahlia Tubers Indoors?

Start your dahlia tubers indoors about 4 to 6 weeks before the last frost date in your area. This will give the tubers enough time to sprout and develop before they are transplanted outdoors.

How to Start Dahlia Tubers Indoors?

1. Choose a well-draining potting mix and fill a container (a small pot, or sandwiches-sized zippy bag) with it.

2. Place the dahlia tuber in the container with the eyes facing up.

3. Cover the tuber with 2-3 inches of soil, leaving the eyes exposed.

4. Place the container in a warm, sunny location like a sunny window sill or under plant lights. 

5. Don't water the tuber until you see green growth. Then, keep the soil moist but not waterlogged.

6. Once the danger of frost has passed, you can transplant your dahlia tubers outdoors for a beautiful display of flowers.

How to know when to plant dahlias outside

Dahlias do not do well in cold weather. You can plant them in the soil once all the danger of frost has passed, usually in mid-May in our area (Zone 6b, Mississauga). Another great way to know is to wait until the crabapple tree petals have fallen. Then you will know it is reliably warm outside. You can also look up the last frost date in your area. 

Dahlias like it when the soil is warm, around 10 degrees Celsius. 

Look for our next post on how to plant your tubers and follow us on Instagram to get updates tips and tricks. 

By following these expert tips, you can successfully start your dahlia tubers indoors and enjoy an early and vibrant dahlia garden. Happy gardening!

Back to blog