Lifting bulbs is a garden practice done primarily to protect tender varieties from winter cold or to divide and relocate hardy types that have become overcrowded. Timing is the most important factor for success, as lifting at the wrong moment can severely compromise the bulb’s ability to flower the following season. The correct time to lift depends entirely on the bulb’s natural life cycle and whether it is a hardy spring-flowering or a tender summer-flowering variety. The plant’s physiological signals serve as the most reliable indicator for when to begin this process.
Timing Signals for Spring-Flowering Bulbs
Hardy spring-flowering bulbs, such as tulips, daffodils, and hyacinths, do not require annual lifting for winter protection. They are usually disturbed only to divide dense clumps or to move them to a new location. The timing is dictated by the plant’s need to store energy for the next season’s bloom.
The primary signal is the natural dieback of the foliage, which must be allowed to turn yellow and wither completely. After the flower fades, the green leaves continue photosynthesis, converting sunlight into carbohydrates drawn back into the bulb for storage. Cutting the foliage too early interrupts this process, resulting in a weak bulb that may not bloom the following spring.
Wait six to eight weeks after the plant has finished flowering before lifting the bulbs. When the leaves are completely yellow or brown and easily detach, the energy transfer is complete and the bulb is fully dormant. It is helpful to lift the bulbs before the foliage entirely disappears, as the withered stems make it easier to locate the cluster underground.
Timing Signals for Tender Summer Bulbs
Tender summer-flowering bulbs, including dahlias, gladiolus, cannas, and tuberous begonias, must be lifted annually because their structures cannot tolerate freezing temperatures. For these varieties, timing is less about energy storage and more about the immediate threat of frost. The most reliable cue is the first light frost, which causes the foliage to blacken and collapse.
Waiting for this initial frost exposure triggers the plant’s dormancy, preparing the storage organ for winter rest. However, exposure to a deep or hard freeze risks direct tissue damage, which can lead to rot in storage. Therefore, lifting should commence shortly after the foliage is killed by a light frost, but before the soil begins to freeze solid.
Specific varieties vary in their ideal lifting time; for instance, dahlia tubers benefit from the frost blackening the tops, while tuberous begonias are best lifted just before a predicted hard freeze. Once the foliage is frosted, the stems should be cut back to a few inches above the soil line, and the storage organs carefully dug up.
Immediate Care and Preparation After Lifting
After lifting the bulbs, corms, or tubers, immediate care is necessary for successful storage. First, gently remove the bulk of the soil clinging to the bulb, taking care not to damage the outer skin or roots. Any bulbs showing signs of rot, mold, or mechanical damage should be discarded to prevent the spread of disease to healthy stock.
The next process is curing, which involves drying the bulbs in a warm, dry, and well-ventilated area away from direct sunlight. Curing allows the outer layers to harden and surface wounds to seal, reducing the chance of decay during storage. This drying period can last from a few days to several weeks until the surface is dry and feels papery to the touch.
After curing, a final inspection is performed before the bulbs are placed into storage. They should be stored in a breathable container, such as a mesh bag, cardboard box, or paper bag. These containers are often surrounded by a dry material like peat moss or vermiculite to absorb ambient moisture. Optimal storage involves a cool, dark location with temperatures maintained between 40 to 50 degrees Fahrenheit, though specific requirements vary by bulb type.