Cleaning and Storing Summer Bulbs and Tubers in December

As December’s chill settles in, it’s time to make sure your tender summer bulbs and tubers—like dahlias, cannas, begonias, gladiolus, and calla lilies—are safely stored away. Proper handling now will protect them from rot and frost, and reward you with strong, healthy growth next year. Here’s a step-by-step guide to cleaning and storing summer bulbs and tubers this December:

1. Lift Before Deep Freeze

• If you haven’t already, lift all tender bulbs and tubers as soon as the top growth is blackened by frost. Don’t delay if hard freeze is forecast.
• Use a garden fork to dig carefully around clumps, lifting with plenty of soil to avoid snapping tubers.

2. Gently Clean Off Soil

• Brush off loose soil by hand; avoid washing, as excess moisture can cause rot during storage.
• For stubborn soil, wait for it to dry and gently shake or rub it off later.
• Remove lingering stems, cutting 3–5cm (1–2in) above the crown.

3. Inspect and Sort

• Check each bulb or tuber for rot, wounds, soft spots, or pest damage.
• Use healthy, firm, undamaged ones for storage; compost or bin anything soft, moldy, or rotten.
• Separate different types and varieties for easier labeling later.

4. Dry the Bulbs and Tubers

• Cure them for about 1–2 weeks in a cool, dry, frost-free place (like a shed or garage) out of direct sun. Spread in a single layer with some airspace between.
• Turn occasionally for even drying.

5. Store Properly

• Place in cardboard boxes, wooden crates, or paper bags (never sealed plastic).
• Layer with dry material—sawdust, peat-free compost, perlite, vermiculite, sand, or shredded newspaper—to avoid direct contact and promote airflow.
• Label each batch with plant name and color.

6. Pick the Right Location

• Keep somewhere cool (ideally 4–10°C/39–50°F), dark, and dry—cellar, garage, or frost-free shed.
• Avoid places prone to damp, frost, or big temperature swings.
• Check the bulb/tuber bags every 3–4 weeks—remove any showing mold or shriveling.

7. Overwintering Tips

• For cannas and begonias, don’t let tubers dry out fully—just keep them barely moist.
• For dahlias, gladiolus, and callas, drier is best.
• Some bulbs (e.g., crocosmia, eucomis) may survive outside in mild areas with a thick mulch for protection.

By cleaning, curing, and storing your summer bulbs and tubers well in December, you guarantee gorgeous displays next year—without the heartbreak of winter loss.