Elephant ear plants (Colocasia and Alocasia) are beloved for their massive, tropical foliage. They grow from underground storage organs, often called corms or bulbs, which are native to warm regions. In climates with freezing temperatures, these tender storage organs must be harvested annually to protect them from frost damage and ensure survival through winter dormancy.
Determining the Ideal Time for Harvest
The correct timing for harvest is signaled by the plant’s natural response to cooling autumn weather. Begin the process only after the first light frost has caused the foliage to collapse and die back. This natural wilting allows the plant to draw nutrients from the leaves back into the storage organ, maximizing stored energy reserves for the following season.
The time to act is typically once night temperatures consistently drop into the low 40s Fahrenheit. While a light frost is helpful, you must complete the excavation before a hard, deep freeze occurs. A hard freeze can penetrate the soil and damage the corm, rendering it non-viable for replanting. Observing both the plant’s appearance and the local forecast indicates the proper window for lifting the bulbs.
Proper Excavation Techniques
Digging up the corm requires careful attention to avoid piercing or slicing the storage organ, which can invite rot during storage. Use a garden fork or a shovel, not a spade, and begin digging a wide circle around the plant’s main stem. Start at least 8 to 12 inches away from the base to clear the entire root system and the corm beneath the surface. This wide perimeter prevents accidental damage to the substantial corms.
Once the soil is loosened around the circumference, gently work the fork underneath the root ball. Slowly lift the entire plant mass out of the ground, minimizing disturbance to the corm. For clumping varieties, you may find smaller offsets or “pups” attached to the main corm. Place the lifted plant on a tarp or newspaper to prepare for the next step.
The goal is to keep the corm intact and undamaged, as any open wound makes the bulb susceptible to fungal pathogens. Some soil will naturally cling to the root ball, which is acceptable at this stage. It is safer to leave a small amount of soil than to risk scraping or damaging the storage organ during excavation.
Curing and Preparation
Once removed, the corms require curing to prepare them for long-term storage. Curing involves drying the exterior of the bulb for several days to two weeks in a dry, protected area. This process allows the outer skin to harden and heal minor abrasions, sealing the corm against moisture and potential disease.
A well-ventilated space, such as a garage or porch, with temperatures between 60°F and 75°F, is ideal for this initial drying period. Trim the remaining foliage, cutting the stalks down to four to six inches above the corm. Use clean, sharp pruners to create a clean cut that heals quickly.
Gently brush off any large clumps of excess soil clinging to the corm and fine roots. Avoid washing the corms with water, as introducing moisture dramatically increases the risk of fungal or bacterial rot during storage. The corms must feel dry and firm to the touch before moving to their final storage location.
Winter Storage Requirements
Successful winter storage requires maintaining a consistent environment that prevents both freezing and excessive drying. The ideal storage temperature is cool but frost-free, typically ranging from 45°F to 55°F. Storing them in a basement, insulated garage, or root cellar provides this stability. If the temperature is too warm, the corms may sprout prematurely, wasting stored energy.
The storage medium cushions the corms and regulates humidity. Pack the dried corms loosely in a breathable material such as peat moss, vermiculite, wood shavings, or shredded newspaper. Place the corms in a cardboard box, paper bag, or a mesh onion sack, ensuring the container allows for air circulation. Avoid sealed plastic bags or airtight containers, as they trap moisture and promote rot.
Throughout the winter, check the stored bulbs periodically, such as once a month, for signs of distress. If you observe shriveling or wrinkling, the environment may be too dry; lightly mist the packing material to add minimal moisture. If you notice mold or soft, rotten spots, immediately remove the affected corm to prevent the spread of disease.