Lily bulbs require a period of cold dormancy to prepare for the following season’s growth, which is accomplished by lifting and storing them indoors in colder climates. This process protects the fleshy bulbs from freezing temperatures and excessive moisture in the soil, both of which can cause irreparable damage. Storing lily bulbs allows the gardener to control the environmental conditions necessary for successful overwintering and robust flowering.
Pre-Storage Preparation of Bulbs
The ideal time to lift lily bulbs is in the autumn, waiting until the foliage has naturally yellowed and died back, but before the ground freezes solid. This ensures the plant has transferred all available energy back into the bulb for storage. Once the leaves have withered, cut the stem back to about an inch or two above the soil line before carefully digging.
Use a garden fork to gently loosen the soil several inches away from the stem to avoid puncturing the delicate bulb scales. After lifting, gently brush away the bulk of the remaining soil and trim any excessively long or damaged roots. Immediately inspect each bulb carefully for any signs of disease, such as mushy spots, mold, or an unpleasant odor, and discard any compromised ones to prevent the spread of pathogens.
The next step is curing, which involves drying the outer layer of the bulb to create a protective barrier against rot. Spread the bulbs in a single layer on a piece of cardboard or newspaper, ensuring none are touching. Allow them to air-dry in a cool, dark location, ideally between 60 to 70°F, for approximately three to seven days. This brief drying period removes surface moisture without causing the bulb to shrivel.
Creating the Storage Environment
The chosen storage container must allow for air exchange to prevent the buildup of moisture that encourages fungal growth. Cardboard boxes, mesh bags, or plastic bins with numerous ventilation holes are suitable options. The packing medium serves to insulate the bulbs and maintain a stable microclimate around them.
Effective packing materials include peat moss, coconut coir, sawdust, or vermiculite, all of which offer good aeration and moisture retention. The medium should be slightly damp—not wet—as lily bulbs are fleshy and need a small amount of moisture to keep from desiccating. To achieve the correct humidity, lightly mist the medium before placing the bulbs.
Place the bulbs within the container in a way that minimizes contact between them, which prevents the transmission of rot. Achieve this by creating thin layers of the damp packing material both beneath and above the bulbs. Separating the bulbs ensures that if one begins to rot, the issue is less likely to spread to its neighbors during storage.
Maintaining Dormancy and Monitoring
Maintaining a consistent, cool temperature is the most important factor for successful lily bulb dormancy. The ideal storage temperature range is between 35°F and 55°F (2°C and 13°C), as temperatures above this range can trigger premature sprouting. Suitable locations include a cool, dark basement, an unheated garage, or a root cellar, provided they remain above freezing.
If using a refrigerator, keep the bulbs away from ripening fruits, such as apples, which release ethylene gas that can be detrimental. Ensure the storage area has adequate air circulation to prevent stagnant air, which can contribute to the development of mold and mildew. The goal is to simulate the cold, stable conditions the bulbs would experience naturally underground.
During the storage period, check the bulbs and their packing medium every three to four weeks to assess their condition. Look for any signs of trouble, such as white or green fuzzy mold on the surface of the scales, which indicates excessive moisture. If mold is present, remove the affected bulbs and replace the packing medium with a drier material to reduce humidity.
Bulbs that appear shriveled are too dry and require a slight increase in moisture, which can be achieved by lightly misting the packing medium. If you notice premature sprouting, the storage temperature is likely too warm and needs to be lowered immediately to maintain dormancy. Consistent monitoring and corrective action will ensure the bulbs remain healthy until it is time for spring planting.