Tucking Your Dahlias In for Winter
I learned this lesson the soggy PNW way: two years in a row, I bought gorgeous dahlias in summer, tucked them into the ground, mulched them heavily in winter, crossed my fingers… and they never returned. Not a sprout, not a stem, nothing. Just empty soil and heartbreak.
That’s when I discovered the truth: in our climate, dahlias don’t usually die from cold — they die from wet. A long, damp winter turns those lovely tubers into mush underground. So now I think of overwintering them like tucking sleepy little creatures into a safe burrow until the sun returns.
Why Dahlias Need Extra Winter Care (PNW-specific)
Our winters are mild but soaked — exactly what tubers hate.
Even in zones 8b–9a, leaving tubers in the ground is a gamble.
Digging them up protects your investment (and your favourite colours!).
Bonus: you can divide, label, and grow even more next year.
Step-by-Step Guide: How to Overwinter Dahlia Tubers
- 1
Wait for the first frost
Let the leaves blacken — that signals the tubers to go dormant.
- 2
Cut stems down to 4–6”
Prevents water from funneling down the hollow stalks.
- 3
Dig carefully
Use a fork and lift from the outside edge — tubers snap easily.
- 4
Gently clean them
Brush soil off; avoid blasting with water.
- 5
Cure for 1–2 weeks
Cool, dry, and airy — this toughens their skins.
- 6
Label everything
Trust me, future-you will not remember which is “the peachy one”.
- 7
Store in a breathable medium
Shavings, vermiculite, peat, or coir all work well.
- 8
Keep at 40–50°F
Basement, garage, or unheated cupboard.
- 9
Check monthly
- Wrinkled = needs a very light mist
- Moldy = remove bad bits + refresh medium
- 10
Wake them in early spring
Move to a slightly warmer spot; pot up or plant once frost danger is past.
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