Though your favorite blooms have probably faded by now, fall is still an important time to care for flowers, namely bulbs. You should either plant hardy spring flowering bulbs like daffodils, iris, tulips, and hyacinths, or dig up and store summer-flowering bulbs like dahlias, cannas, or gladiolus.
We’ve put together a guide to help you determine which bulbs you should store over winter and the proper way to keep them healthy and ready to plant next spring.
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Which Bulbs Should You Store Over Winter?
Though you may have some tulip bulbs you forgot to plant during the fall stashed in your garden shed over the winter, the focus for winter bulb storage is summer-blooming bulbs (or tender bulbs).
Horticulturists recommend that tender bulbs be removed from the garden in zones 7 or below, where the ground freezes solid for much of the winter. These tender bulbs need to be dug up and stored correctly to save them for the next growing season.
Plants with tender bulbs include:
Tip
Some bulbs are expensive to replace every spring, and others may be a cultivar that isn’t readily replaceable—saving bulbs ensures you don’t lose the plant.
How to Dig Up Flower Bulbs
- Wait until after the first frost. To ensure tender bulbs are dormant and storing food for the next growing season, wait until the foliage of the plant dries up or after the first frost occurs. That first light frost will not harm the bulb, but will kill the tender green growth.
- Cut back dead foliage. Once a frost occurs, cut away the wilted, burned foliage.
- Gather the proper tools. When you’re ready to dig, move about 12 inches away from the stem and use a garden fork or spade to dig up each plant’s root ball. Try to avoid cutting or bruising the bulbs.
- Dig the bulbs. Get them out of the ground within a few days to protect the bulb from organisms that can enter through the stem and cause rot.
- Rinse. Carefully clean off the excess soil with a gentle stream of water from the garden hose. Placing them on a wire mesh screen is a good way to get rid of soil and water.
Tip
Gladiolus corms are small and should not be washed. Too much moisture encourages rot, and corms should be allowed to cure for three weeks before storage.
Prepping the Bulbs for Storage
Now is the time to discard any damaged bulbs and label the rest with a tag stating the variety and color of the bloom. Many of the bulbs will look very similar.
A good tip is to use a permanent marker to write directly on the bulb so you’ll know how to group plantings next spring.
The bulbs should be placed in a sheltered, well-ventilated, dark location like a garage or tool shed (no direct sunlight) and allowed to cure and air-dry for at least a week before preparing them for winter storage. Turn the bulbs every couple of days to facilitate equal and thorough drying.
How to Store Bulbs Over Winter
The best storage method for tender bulbs is an often debated topic among gardeners. It depends on the temperature and humidity of your storage area.
The key to successful storage is to keep the tender bulbs in a dark area between 35 and 50 degrees F. Some humidity is okay (about 50 percent) but the area should not be constantly damp.
- Store with newspaper and a cardboard box. Layer newspapers and bulbs in the box. The bulbs should not be touching and have good air circulation. The box should have a lid to prevent light penetration.
- Paper bag storage. Wrap each bulb separately in newspaper and store them in a large, closed paper bag.
- Mesh bags. If you have a cool, dark storage area, hang tubers in net bags.
- Refrigeration: Individual tubers can be placed in plastic bags with vermiculate and refrigerated for the winter.
- Bury in vermiculite, sawdust, or sand. Bulbs can be layered in a cardboard or wooden box with two to three inches of dry medium like vermiculite, sawdust, or sand between each layer. Use vermiculite if the storage area is overly damp.
- Check monthly. Bulbs should be checked once a month during winter storage. Discard any bulbs that are soft and rotting. Lightly mist the bulbs with plain water to increase humidity levels if they feel overly dry.
8 Additional Tips for Winter Bulb Storage
- Bulbs should not touch one another while they are being stored to help prevent the spread of rot between bulbs.
- Never store bulbs more than two or three layers deep as they generate heat which can cause decay.
- Pack similar bulbs together. If you didn’t label each bulb, label the outside of the container with the type of bulb and colors. Add information about the previous year’s planting sites if you want to be sure to return them to the same location.
- Be sure the storage spot selected never gets below the freezing temperature. If the bulbs freeze and thaw, rotting is much more likely to occur.
- Many tubers and bulbs naturalize and form new sections that can be divided to form a new plant. To prevent damage from fresh cuts, many gardeners store the root clumps whole and delay dividing until early spring when the new plant buds have swollen and can easily be seen.
- Both container and garden-grown tender bulbs can be dug up and saved for replanting in the spring.
- Tender, summer-flowering bulbs should be planted in early spring once the danger of frost has passed.
- If you can’t wait for spring to arrive, some tender bulbs like calla lilies, caladiums, and tuberous begonias can be planted in containers and forced to grow and bloom early as a houseplant. Once the weather warms, they can be transplanted to the garden or moved outside.