Spring is an exciting time for gardeners as we start preparing our gardens for the upcoming growing season. If you grow dahlias, spring is a critical period for caring for the tubers to ensure beautiful blooms later in the year. In this article, I’ll provide a comprehensive guide on what to do with dahlia tubers in spring.
Inspect and Prepare Tubers
The first step is to take out your stored dahlia tubers and inspect their condition Carefully remove any excess soil and debris from the tubers. Look for signs of damage, rot, or pests Damaged tubers likely won’t survive planting, so it’s best to discard them. If you find some rot, cut it away with a clean, sharp knife. Allow any cut tubers to dry for a day or two before planting.
Proper winter storage is key for healthy dahlia tubers. Cool temperatures between 40-50°F in a dark, well-ventilated area prevent rotting and diseases. If tubers seem soft, shriveled, or moldy, they may not sprout well. Consider purchasing new tubers for planting.
Planting Dahlias
Once spring arrives it’s go time for planting your dahlia tubers. Select a sunny spot with at least 6 hours of direct sunlight. Dahlias need well-draining soil so add compost or manure to improve drainage and nutrients.
Dig holes 12-18 inches apart and 2-4 inches deep depending on tuber size. Place the tubers with the eyes pointing up. Cover with soil and water thoroughly after planting. Add more soil if needed after watering to prevent tubers from being exposed.
Spring Care Tips
Here are some tips for caring for newly planted dahlias:
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Watering: Dahlias need consistent moisture, so water tubers regularly, especially right after planting. Avoid overwatering.
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Fertilizing: Use a balanced fertilizer at planting time. Switch to a fertilizer higher in phosphorus as plants mature to promote blooming.
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Pests/Diseases: Watch for signs of aphids, spider mites, powdery mildew and other issues. Treat promptly to avoid spread.
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Staking: Add stakes or supports for dahlias once they reach 10-12 inches tall to prevent damage from wind/rain.
Dividing Dahlia Tubers
Dividing tubers in spring helps increase your dahlia stock for this year’s planting and beyond. Here are the steps:
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In early spring, carefully dig up the entire clump of tubers from last year.
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Gently remove any excess soil and separate tubers, making sure each piece has at least one “eye.”
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Allow the divided tubers to dry for 1-2 days. This prevents rot and aids healing of any cuts.
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Dust cut surfaces with a fungicide powder before replanting.
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Replant the divided tubers following the guidelines above. Water thoroughly after planting.
You can also propagate dahlias from cuttings for more plants. Take 4-6 inch stem cuttings in spring, remove lower leaves, and dip in rooting hormone before planting in potting mix.
Troubleshooting Issues
Even if cared for properly, dahlia tubers can still run into problems in spring:
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Rot – Caused by excessive moisture. Improve drainage and avoid overwatering. Cut away any rotten parts of the tuber before planting.
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Poor germination – Could be from cold temps, damage, or improper storage. Try new tubers if issues persist.
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Slow growth – Usually due to insufficient water or nutrients. Ensure regular watering and fertilizing.
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Pests/diseases – Treat any issues promptly to avoid spread. Be vigilant about monitoring plants.
Important notes about dividing dahlias:
- Make a solution of bleach water and sanitize your pruners between every clump to prevent the spread of potential disease.
- Discard any suspect clumps. It’s hard to throw away a prized tuber, but it’s not worth risking the spread of sickness and disease in your soil and other tubers. A small loss now is nothing compared to a major loss later.
- There are some dahlia diseases, like gall, that are pretty clear to identify. Other times, tubers can look strange from what is known as lenticels. If you are ever unsure you can call your local extension office for further advice and possible testing.
Dahlia Tuber Check / Dividing Dahlia Tubers in Spring / Dahlia Storage
FAQ
How do you prepare dahlia tubers for spring?
Dig them up before the first frost, shake of the soil and let them dry – a dry paintbrush helps to remove soil. I then put mine on newspapers in cardboard boxes in the garage. As long as they stay dry, they’ll not rot. By “growing” them now, you will build up the tubers a bit, and make them stronger for next season.
How do you wake up dahlia tubers?
So how do you it? It’s very simple- Take your tubers from their storage location and move them to a frost free place that’s around 65-70 degrees.Mar 14, 2024
Can I plant a whole clump of dahlia tubers?
Does Tuber Size Matter? The short answer is no. As long as you plant a clump or tuber that has at least one eye, it will grow into a plant.
Should I soak dahlia tubers before planting?
Before planting, soak the tubers in a bucket of tepid water for an hour so they can fully rehydrate.Mar 2, 2025
How do you care for dahlia tubers?
Care of tubers starts with proper treatment during the growing season. While most dahlias start producing tubers in the spring, the roots do not mature until late in the growing season. Before digging, go through the garden and throw away any weak stock.
When is the best time to divide dahlia tubers?
The best time to divide dahlia tubers in spring is when new shoots begin to emerge and the soil has warmed up. This is usually around late March to early April, depending on your climate. How do you divide dahlia tubers in spring? To divide dahlia tubers in spring, start by carefully digging up the dahlia clump with a garden fork.
How do you divide dahlias in spring?
To divide dahlia tubers in spring, start by carefully digging up the dahlia clump with a garden fork. Once the clump is out of the ground, gently separate the tubers by carefully pulling them apart. Be sure to keep some stems attached to each tuber as this will help with identification and planting.
How do dahlia tubers survive winter?
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.
How do you divide dahlia tubers?
Dividing dahlia tubers involves separating these storage structures into smaller sections, each of which can grow into a new dahlia plant. The best time to divide dahlia tubers in spring is when the plants have started to emerge from the ground, but before the new shoots have grown too large.
Do dahlia tubers keep well?
However, tubers from some dahlia varieties tend not to keep well, and some cultivars tend to give very sparse tubers. For these varieties, one should consider planting extras and growing pot roots. Care of tubers starts with proper treatment during the growing season.