Alocasia plants, known for their striking foliage, form corms. These specialized underground structures allow the plant to survive unfavorable conditions and propagate new growth. Understanding corms helps enthusiasts expand their Alocasia collection and ensure plant longevity. This guide explores Alocasia corms, how to find and harvest them, and steps for successful propagation and storage.
Understanding Alocasia Corms
Alocasia corms are swollen, bulb-like underground stems that store nutrients and energy, acting as a reservoir for the plant’s survival. These structures are distinct from true bulbs, which have fleshy scales, and tubers, which are thickened rhizomes. Corms are solid, compact stems with a basal plate from which roots grow and a growing point where new shoots emerge. Their primary function is to enable the Alocasia to endure periods of dormancy, such as during cooler temperatures or reduced light, by providing stored resources. When conditions become favorable, the corm utilizes these stored reserves to initiate new growth, allowing the plant to re-emerge and thrive. They also serve as the sole source for asexual reproduction in Alocasia, creating new plants identical to the parent.
Finding and Harvesting Corms
Alocasia corms develop among the roots within the soil, appearing as small, round, brown structures. The best time to harvest corms is during repotting, allowing easy access to the plant’s root ball. While some corms are visible at the soil surface, larger ones are usually deeper within the substrate.
Gently remove the Alocasia from its pot, avoiding damage to stems or leaves. Once out, carefully inspect the root system. Gently break apart the soil and root ball to expose the corms, which resemble small, spherical structures. Many corms detach by hand; if firmly attached, use clean, disinfected scissors or snips to cut them at their base. Collect healthy, firm corms for successful propagation.
Propagating New Plants from Corms
After harvesting, prepare the corms for successful propagation. Gently peel away the outer brown, fibrous layer, also known as the tunic, from each corm to encourage faster sprouting. If the outer shell is difficult to remove, soaking the corms in room-temperature water overnight can help soften it. Once cleaned, identify the “eye” or growth point, which is typically the more pointed end of the corm, as this is where new leaves will emerge.
For sprouting, various effective growing mediums include sphagnum moss, perlite, or Fluval Stratum. Water propagation is also an option, ensuring the corm is only partially submerged with the growth point facing upward. Maintaining warm temperatures and high humidity is important for optimal sprouting. Placing corms in a propagation box, a clear container with a lid, or covering them with a plastic bag creates a humid environment. Keep the medium consistently moist but not waterlogged to prevent rot, misting regularly if needed.
New growth, including roots and initial leaves, typically appears within a few weeks to a couple of months. Once the corm has developed a robust root system and at least two to three leaves, it is ready for transplanting into a more permanent growing medium. A well-draining potting mix, often composed of a blend of potting soil, perlite, and orchid bark, provides an ideal environment for the young Alocasia. Plant the corm just below the soil surface, ensuring the newly formed roots are covered. After transplanting, water thoroughly and place the new plant in a warm, brightly lit location with indirect light to minimize shock and encourage continued growth.
Corm Storage and Common Issues
If you do not plan to plant Alocasia corms immediately, proper storage is necessary to maintain their viability. After harvesting, allow the corms to air dry for one to two weeks in a warm, well-ventilated area to prevent rot before storage. Store them in a cool, dark, and dry location, ideally with temperatures ranging from 40-50°F (4-10°C). Wrapping individual corms in newspaper or placing them in mesh bags within a cardboard box with air vents helps ensure good air circulation and prevents moisture buildup, which can lead to spoilage. Avoid storing corms in plastic bags, as these can trap humidity and encourage rot.
Common issues with Alocasia corms include rotting, failure to sprout, or pest problems during storage. Rot often occurs due to excessive moisture, insufficient airflow, or damaged corms. If a corm shows signs of rot, such as soft or mushy spots, the affected area should be carefully removed, and the corm can be sanitized with a diluted hydrogen peroxide solution before drying and re-storing or attempting propagation. Failure to sprout can result from corms drying out excessively, inadequate warmth or humidity during propagation, or non-viable corms. Ensuring consistent moisture, warmth, and high humidity during the sprouting phase can improve success rates. While less common, pests like spider mites can affect corms, particularly if stored in humid conditions. Good airflow and periodic inspection during storage mitigate pest issues.