If you live in a place with a short growing season, you should put your dahlias and gladiolus to seed early to make sure you get blooms before the season ends. After being planted, dahlias and glads take about 90 days to bloom. However, they are very sensitive to frost, so if you wait until there is no longer a chance of frost, your flowers might not be able to bloom before the end of our 100-120 day growing season.
Dahlias are beloved for their showy, colorful blooms that light up gardens from midsummer into fall. To get the most flowers from your dahlias, it’s important to properly wake up the tubers in spring Here’s a step-by-step guide to pre-sprouting dahlia tubers for healthier plants and maximum blooms
Why Pre-Sprout Dahlia Tubers?
Dahlia tubers are the storage organs that the plants use to survive winter. In spring, they must be coaxed to wake up from dormancy and begin actively growing again.
Pre-sprouting tubers indoors gives them a head start on the season. It allows the small new shoots to establish before being planted outdoors. This minimizes transplant shock and results in stronger, more vigorous plants.
If tubers are planted outside too early while soil is still cold and wet, the sprouts may rot or fail to thrive. Pre-sprouting for 3-4 weeks indoors avoids this issue.
When to Start Waking Up Tubers
Time your pre-sprouting to occur 4-6 weeks before your average last spring frost date. This gives outdoor soil time to warm up before sprouted tubers are planted
For most regions, mid to late April is ideal. If you start too early, the young sprouts may grow spindly and weak before they can be planted out.
Aim to have sprouted tubers ready to plant around early to mid May in all but the warmest climates. Check your specific frost date to schedule perfectly.
Step-by-Step Guide to Pre-Sprouting Dahlias
Follow these steps for waking resting dahlia tubers and getting them primed for planting:
1. Retrieve Tubers from Storage
- Carefully remove tubers from their winter storage containers.
- Avoid damaging any small sprouts that may have already begun growing.
- Remove any rotted or desiccated tubers that won’t be viable.
2. Place in Trays
- Arrange tubers together in trays, bins, or pots with drainage holes.
- Plastic seedling trays or aluminum roasting pans work well.
- Partially cover with moist vermiculite, potting mix, wood shavings, etc.
3. Provide Warmth and Light
- Place containers in a warm, sunny spot indoors like a south window.
- A greenhouse or cold frame also works if protected from frost at night.
- Ambient temperatures around 70°F (21°C) are ideal.
4. Keep Moist
- Check moisture levels daily. Damp but not soggy soil is needed.
- Mist or water lightly when the sprouting medium becomes dry.
- Avoid having tubers sit in overly wet conditions.
5. Watch for Sprouts
- Check for small pinkish sprouts emerging at the tuber necks in 1-3 weeks.
- Some varieties take longer – don’t discard any firm tubers too soon.
- Once sprouted, ensure they get bright light to avoid leggy growth.
6. Hold Off Planting Out
- Let sprouts grow to 2-3 inches (5-8 cm) before moving outdoors.
- Time planting for roughly 4 weeks after starting waking process.
- Wait until nighttime temperatures are above 50°F (10°C).
What to Expect When Waking Dahlias
Here’s what to look for as your dahlia tubers emerge from dormancy:
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Small pinkish/red sprouts form at the tuber necks around 1-2 weeks into pre-sprouting. This is where the stems will grow from.
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Most varieties will show sprouts in 2-3 weeks. Some take longer – up to 4 weeks. Discard any mushy tubers.
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Let sprouts grow to about 2-3 inches (5-8 cm) tall before planting out. Avoid leggy, weak growth by providing sun.
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Tiny white nodules on the tuber are new roots beginning to form. This is a great sign of an active, healthy tuber.
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Leaves will not form until plants are up and growing in garden soil. Do not wait for leaves to transplant.
Troubleshooting Problems
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No sprouts forming: Be patient – some tubers take 4 weeks or longer. Discard any softened or rotting tubers. Ensure temperature is at least 65°F.
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Tips die back: Likely caused by cold damage if tubers got chilled. Cut back to healthy growth and replant. Avoid frost risk.
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Leggy, weak sprouts: Insufficient sunlight during waking period. Move to brightest spot or under grow lights to strengthen growth.
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Moldy tubers: Excess moisture – reduce watering and provide good airflow. Dry out sprouting medium and discard any rotted tubers.
Key Tips for Success
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Start waking 4-6 weeks before outdoor planting time.
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Provide bright light once sprouts emerge to prevent lanky growth.
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Time outdoor planting for after danger of frost when soil warms above 60°F (15°C).
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Take care not to overwater during pre-sprouting phase. Damp but not wet soil.
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Gently plant pre-sprouted tubers outdoors with sprouts facing upward. Avoid disturbing the emerging roots.
Waking up dahlia tubers properly gives them the best start to the growing season. Follow these guidelines for pre-sprouting your tubers and you’ll be rewarded with vigorous, floriferous dahlia plants this summer.
How to Pre Sprout Gladiolus
- A tray, like the bottom of a seed tray, old plastic food containers, or pie plates made of aluminum
- Water
Directions:
- After putting your glads away, take them out and check to see if the bulbs have mold growing on them or if they are soft or rotting in any way.
- Put the corms on the tray so that the flat side is at the bottom and the pointy side is at the top.
- Just add enough water so that the corms’ bottom 1 or 2 cm are submerged. Watch how much water is in it and add more as needed.
- Wait for the corms to sprout on a windowsill, under a grow light, or in your heated greenhouse.
- Plant your corms in the garden after the risk of frost has passed. Digging deep enough to cover the sprout’s white part as well
- Every week, only pre-sprout a small part of your corms so that the flowers last longer during the summer. This is known as successive planting. I’m going to sprout once a week in April and maybe even the first week of May so that I can have flowers from July to September.
Waking Up Dahlia Tubers | Easy Guide to Starting Dahlia Tubers Indoors | Maple Leaf Barn
FAQ
How long does it take to wake up a dahlia tuber?
How to get dahlia tubers to sprout?
How to activate dahlia tubers?
How to wake up dahlia tubers in ziploc bags?
Can you revive Dahlia tubers?
Reviving dahlia tubers is an essential step and can help ensure your dahlias grow well in your garden. With the right techniques, you can easily revive dahlia tubers. They should be planted in late spring or early summer, in rich and well-draining soil.
How should I care for dahlia tubers?
Dahlia tubers require a rich and well-draining soil and at least 6 hours of direct sunlight. Water them regularly, but avoid over-watering. Use a balanced fertilizer every couple of weeks throughout the growing season. The best time to begin waking up dahlia tubers is when the soil temperature reaches 60°F (15°C).
When should you plant dahlia tubers?
Dahlia tubers should be planted in late spring or early summer. Plant them in an area that receives at least 6 hours of direct sunlight. The soil should be rich and well-draining. Water the dahlia tubers regularly, but avoid over-watering. Use a balanced fertilizer every couple of weeks throughout the growing season.
How should dahlia tubers be stored?
To store dahlia tubers, they should be kept in a cool and dry location. This is important because tubers can rot in overly moist or wet conditions. Store them in a cool, dry room or basement, or even in a refrigerator.
How do you grow a dahlia plant from a tuber?
To grow a dahlia plant from a tuber, first, place the container in a warm, bright location and allow the tuber to soak for several hours to activate its growth hormones. Then, remove the tuber from the water and place it in a shallow container filled with potting soil. Lightly cover the tuber with more potting soil and water the soil until evenly moist.
When do dahlias start sprouting?
After a long winter in storage, it’s time to pull those dahlias from their slumber and get them ready to go into your garden. I always start this process around the end of April , to give my dahlias about 4 weeks to wake up and start sprouting before I plant them into the garden the first week of June.