Fall sets the terms for next summer’s garden. Hardy spring bulbs such as daffodils, tulips, iris, and hyacinths go into the ground now, while tender summer bloomers including dahlias, cannas, gladiolus, and calla lilies must come out of it. Tender bulbs cannot survive a hard freeze in the soil, so gardeners in zones 7 and below dig them up and store them indoors until the ground warms again. Replacing store-bought bulbs every spring costs more than storing them, and stored bulbs often flower earlier because they have already started developing roots before planting.
Winter preparation reaches beyond the flower beds. The same weeks spent digging bulbs are when roofs, foundations, and outbuildings get their cold-weather check. An unheated garage shelf full of bulb crates sits under a roof that can shed ice dams when snow melts and refreezes along the eaves, so the steps for preventing ice dams belong on the same to-do list as the garden fork. Handle both and the whole property comes through winter intact.
Which Bulbs Need Winter Storage
Not every bulb comes out of the ground. The decision hinges on whether the plant’s native climate matches the local winter, and that match is what the hardiness zone system measures. Order and variety matter less than condition: a firm, unbruised bulb from a local grower stores far better than a shriveled bargain-bin find.
Hardy Versus Tender Bulbs
Hardy bulbs evolved in cold climates and need a period of winter chill to trigger flowering, so they stay in the ground. Daffodils, crocus, snowdrops, and most tulips fall into this group; the cold is part of their life cycle. Tender bulbs evolved in frost-free regions and die when frozen. Horticulturists recommend removing tender bulbs from the garden in zones 7 or below, where the ground freezes solid for much of the winter.
Plants with tender bulbs include:
- Asiatic lily
- Caladium
- Calla lily
- Canna
- Crocosmia
- Dahlia
- Elephant ears
- Freesia
- Gladiolus
Reading Your Hardiness Zone
The USDA hardiness zone map is the starting point for the decision. Gardeners in zones 8 and warmer can often leave cannas and dahlias in the ground under a thick mulch, while zones 7 and colder should treat them as tender and store them. The microclimate of the planting bed matters too: a north-facing bed against the house stays colder longer than an open south-facing slope, so a marginal zone can tip either way depending on where the bulbs sit.
Digging day usually lands on the first frosty morning, when the top inch of soil is frozen and slick. The same studded traction for construction boots that keeps crews planted on icy job sites works on a garden path, so pull on grippy footwear before you start lifting bulbs.
How to Dig Bulbs Without Damage
Timing and technique decide how many bulbs survive storage. Dig too early and the bulbs have not stored enough energy for next year’s bloom; dig too late and frost may already have damaged them.
When to Dig
Wait until the foliage has yellowed and flopped, roughly six to eight weeks after the flowers fade. The leaves are the bulb’s food factory, and cutting them early shrinks next year’s flowers. If frost nips the foliage first, the bulbs are usually still sound as long as the ground has not frozen hard.
The Digging Technique
A garden fork does less damage than a shovel because it disturbs a wider, looser area:
- Loosen the soil with a garden fork 6 to 8 inches away from the plant stem.
- Lift a wide root ball instead of yanking on the stem.
- Shake off loose soil, then clip the stems back to 2 to 4 inches.
- Let the bulbs cure in a dry, airy spot for a few days.
- Brush off the remaining soil, but do not wash bulbs that will be stored dry.
A clean cut at the stem reduces the chance of rot. Bulbs with soft spots, cuts, or mold go to the compost pile rather than the storage crate, because one decaying bulb can rot an entire box.
While the clump is out of the ground, separate the offsets, the small bulblets attached to the parent bulb. They need an extra season or two to reach blooming size, but they are free plants that multiply the value of the original purchase.
Shake off as much soil as possible before curing, then store the crates somewhere rodents cannot reach. A galvanized trash can or a hardware-cloth shelf keeps mice and squirrels out of the stash.
Storage space is the limiting factor in most homes, and the same tricks that hide winter gear in plain sight, such as under-bed bins, hanging racks, and stackable crates, work for bulb storage. The sneaky ways to store winter gear shown at Bob Vila demonstrate how to reclaim closet and garage space that can be borrowed for the bulb stash between November and April.
Curing, Cleaning, and Prepping Bulbs
Preparation separates bulbs that sleep through winter from bulbs that shrivel or rot in the crate.
Curing Times by Type
Different bulbs cure at different rates, and each type prefers its own temperature band in storage. The table below summarizes the common tender bulbs:
| Bulb type | Curing time | Storage temperature | Humidity |
|---|---|---|---|
| Dahlia tubers | 3 to 5 days | 40 to 50°F | Moderate |
| Gladiolus corms | 2 to 3 weeks | 35 to 45°F | Dry |
| Canna rhizomes | 3 to 5 days | 45 to 55°F | Moderate |
| Caladium tubers | 1 to 2 weeks | 50 to 60°F | Dry |
Cure in a single layer on newspaper or a screen, never in a pile, and turn the bulbs once a day so moisture escapes evenly. A warm, shaded spot works better than direct sun, which can cook the outer skin.
Treating Cuts and Pests
Dust cut surfaces with sulfur powder or a bulb fungicide, then inspect for thrips and mites before storage. Gladiolus corms in particular carry thrips that survive the winter inside the corm, so a labeled insecticide dip or a warm-water soak before storage breaks the cycle.
Dahlia clumps can be divided before storage or in spring. Dividing in fall gives each cut surface time to callus over before the tubers go into the crate, which reduces rot during the storage months.
Crates and bins stack neatly on a shelf unit, and the same design logic that goes into a custom-built ski locker, sized slots, ventilation, and sturdy framing, applies to a bulb storage rack. Build a slatted shelf rack so air moves around every crate and the weight stays on the framing rather than the bulbs.
Storing Bulbs: Containers, Temperature, and Checks
The goal is steady, cool, dry conditions that keep bulbs dormant without drying them out.
Container Rules
Choose containers that breathe and keep varieties separated:
- Use cardboard boxes, mesh bags, or wooden crates; avoid sealed plastic bags.
- Layer bulbs in peat moss, vermiculite, or sawdust so they do not touch.
- Label every container with the variety and the digging date.
- Keep crates off the concrete floor, where cold and damp migrate upward.
Where to Store
An unheated basement, attached garage, or cool closet that stays between 40 and 55°F works well for most tender bulbs. Check the crates monthly and remove anything that has sprouted, shriveled, or rotted. Sprouting in midwinter usually means the space is too warm; shriveling means it is too dry. A shallow bowl of water or a damp sponge on the storage shelf raises humidity without wetting the crates.
A shriveled bulb is not always a dead one. If the base is still firm, mist the storage medium lightly and move the crate a few degrees cooler. Bulbs that recover stay dormant for the rest of the winter; bulbs that keep shrinking go out.
The fork, trowel, and pruners used for digging need their own winter routine. Clean off the soil, dry the metal, and oil the pivots, because the cold-weather tool care that keeps equipment operating in winter also stops rust from eating the blades before spring.
Winterizing the Rest of the Property
With the bulbs tucked away, the same effort extends to the house and outbuildings, where standing water and cold air do their own quiet damage.
Closing Down Water and Heat Leaks
Drain garden hoses, shut off exterior faucets, and close the vents and valves that let cold air into the crawl space. A full shut-down sequence, from draining the irrigation system to sealing drafts, is laid out in our house winterization guide, and most of it fits into a single weekend.
Protecting the Foundation
Bulb beds drain naturally, but the strip of soil against the foundation does not. Grade the soil away from the house and keep downspout extensions clear so melting snow does not pool against the wall. Container-grown bulbs can be stored in their pots if the garage stays above freezing, which frees the crate space for the bulbs that need it most. Check the gutters at the same time; a blocked gutter dumps meltwater straight down the foundation wall and undoes the grading work.
Frozen ground pushes water sideways instead of letting it soak down, and the drainage fixes described in our foundation drainage in winter article, including swales, cleared weep holes, and properly angled downspouts, stop that water from finding its way into the basement while the garden sleeps. When spring returns, the stored bulbs come out of the crates ready to plant and the house comes out of winter with no surprises.