Waking up and planting tubers for a new season.
As our dahlias orders arrive and we wake up last year’s tubers let's think forward to our 2024 dahlia growing season.
Place your stored tubers in a warm room for about two (2) weeks and you will see them begin to " eye up ". After they "eye up" you can plant them in a mixture such as Pro - Mix to start them growing. Don't over water them and don't let them be exposed to cold temperatures. A small inexpensive greenhouse works really well and protects them from colder night temperatures during the spring. A light cover of plastic or sheet will also work, anything to give them some protection.
When soil temperatures begin to warm up about the third (3rd) week in May you can think about planting them in your dahlia garden. They like soil temperatures to be about 60 degrees. I like to start my plants in pots before planting because I can regulate the amount of water they receive as they start to grow. If we get to much rain sometimes the developing tubers can rot out before they get a chance to start growing.
Plant your tubers about 4" - 6" deep and about 18” apart. You can mix in a small amount of 10 -10 -10 fertilizer if you like. Don't forget to put your stake at the head of the dahlia. By staking while planting, you will not risk piercing the tuber when it is covered up with soil. I like to cover up the tuber or plant as it grows until the filled hole is level with the rest of the garden soil.
And just like that our thoughts turn to spring …. March 2024
Reminder, Long Island hardiness zone is now 7B with last frost predicted for the last week of April.
Starting Dahlias from Seeds
Growing dahlias from seeds isn’t any harder than growing most other annuals from seeds. However, there are a few things to keep in mind.
The flowers of dahlia seedlings rarely look like their seed parents. Due to the octoploid genome (8 sets of chromosomes), countless combinations of different genetic traits can occur in seedlings.
Some of the dominant traits that tend to prevail in seedlings are open disc centers, low petal count, small blooms, tall plants, poor form, weak stems, downward facing blooms, or a single set of petals. Thus, most seed dahlias don’t look like the flashy big show dahlias most of us admire. But seed plants are usually much more vigorous and healthier than plants grown from tubers. They will do great in a garden border and are a fall favorite of many pollinators. Most seed dahlias will also make tubers that can be overwintered.
Desirable traits such as high petal counts, strong stems, good tubers, large blooms, and closed centers are far less common. It’s estimated that only 1 out of 1,000 seedlings has the right combination of desirable traits to become a show flower variety.
Seed germination typically takes between 3 days to 1 week and up to 2 weeks. However, due to the complicated genetics, even fat looking seeds might not sprout. Germination rates can sometimes be very low. Seeds can be pre-sprouted between wet paper towels in plastic bags to save space. Paper towels need to be checked daily and sprouted seeds have to be transplanted immediately and very carefully into pots with soilless growing medium.
Alternatively, sow seeds densely into soilless or seed starter mix and prick them out into larger pots as they germinate.
Dahlia seeds are very cold sensitive and should be started indoors 4 to 8 weeks before planting outside. Keep seedling trays or wet paper towels at a temperature of 70°F or higher.
Plant seedlings outside in late May. They should be well rooted and have at least 3 sets of true leaves.
Space plants 12 inches apart. If you want to increase the number of seedlings to evaluate, plant them 4 inches apart and then cull seedlings with undesirable traits as they bloom.
You can save your own seeds or buy seeds. However, many fully double show dahlia varieties make no or only few seeds. Therefore, high quality seeds from experienced dahlia hybridizers may cost $.50 to $2 for each seed.
Seeing a completely novel dahlia bloom, one you cultivated from seed, is a joy beyond measure.
Copyright © 2024 New England Dahlia Society.
All rights reserved.
Waking up Tubers for Cuttings ONLY
Copyright © 2024 New England Dahlia Society
February is generally too early to plant tubers indoors in pots
—> wait to pot up tubers until March/April - unless you have a heated greenhouse available
Timing for dahlia cuttings (approximate – differs by variety)
Waking up tubers: 2 to 5 weeks (some varieties need longer)
Root cuttings: 3 to 6 weeks (visible roots)
Grow on cuttings to planting size: 3 - 4 weeks
Read the full article. (with photos) here.
Winter 2024 notes (January)
We have recently checked on the condition of the stored Eisenhower Park and Cornell/EMF tubers in the root cellar at Planting Fields. Most were in excellent condition but as seen by the photos some were not. The rotten tubers were removed and dusted with sulfur and diatomaceous earth to prevent further rotting. One box had wet (not damp) paper which was a result of a very damp location and rotting tubers. This box was discarded and the tubers cleaned up. The cleaned- up tubers were then put in a new lined (newspaper and wax paper) dry apple box.
If the newspaper is bone dry, check the tubers for any shriveling. If there is some shriveling, you should add some moisture to the box by spraying some water between the newspaper and the box. Do not spray water directly on the tubers, as this will promote rot.
It is very important for you to check on the condition of your winter stored tubers. Failure to do so can result in complete tuber loss and even worse, the loss of the surrounding tubers as the rot spreads.
