Alocasia plants, known for their striking foliage, can be propagated through small, round structures called corms, found at the base of their root system. These corms contain the energy and genetic material to develop into new, independent plants. Cultivating Alocasia from corms offers a cost-effective way to expand a plant collection, providing a rewarding experience and allowing growers to create new plants from existing ones.
Preparing Alocasia Corms
If harvesting corms from a mother plant, gently remove the plant from its pot and sift through the soil around the root ball. Corms typically appear as small, firm, dark brown nodules, ranging from pea-sized to small grape-sized. After detaching them, gently rinse them under lukewarm water to remove soil. Some growers carefully peel the papery outer husk, which may expose the growing point and speed up sprouting, but this risks damaging the corm. Soaking stubborn shells in room-temperature water overnight can soften them for easier removal.
After cleaning, inspect each corm for signs of rot, such as mushiness or a hollow feel, discarding any compromised ones. Allow healthy corms to air dry completely for several hours to a day to prevent fungal issues. For an optional pre-sprouting phase, place corms in a sealed container with a damp medium like sphagnum moss or perlite, or in a shallow tray of water. If using sphagnum moss, ensure it is damp like a wrung-out sponge. If using water, submerge only the bottom third to half of the corm, changing the water regularly to prevent bacterial buildup. This step encourages initial root and shoot development before planting.
Planting Alocasia Corms
For planting, select a growing medium like sphagnum moss, perlite, coco coir, or a mixture. These are more suitable than dense potting soil for initial propagation due to their aeration and moisture retention. Use small containers with drainage holes, such as 2-4 inch nursery pots or clear jars, which allow for monitoring root development.
Position the corm with its slightly more pointed end facing upwards, as this is typically where new growth emerges. If the orientation is unclear, laying the corm on its side is acceptable, as the plant will naturally adjust. Plant the corm just barely covered by the medium or with its top partially exposed. After planting, create a warm, humid environment by covering the container with a clear plastic dome, plastic wrap, or placing it within a clear plastic bin. A heat mat underneath can speed up sprouting by providing consistent warmth, ideally around 25°C (77°F).
Care for Growing Alocasia Corms
Maintain warmth, with ideal temperatures ranging between 15-27°C (59-80°F) to encourage growth. High humidity levels, ideally between 60% and 80%, benefit newly sprouted corms and young Alocasia plants, mimicking their native tropical habitats. Keeping the humidity dome in place helps maintain this enclosed environment.
As sprouts emerge, provide bright, indirect light; avoid direct sunlight, which can be too intense for tender young foliage. Water to maintain the medium consistently moist but never waterlogged, allowing the top layer to dry slightly between applications to prevent rot. If using a humidity dome, less frequent watering may be needed as moisture is retained. Ensure proper airflow to prevent mold or fungal issues by periodically opening the dome or plastic cover for short durations. Patience is necessary, as corms can take weeks or even months to sprout. Once the sprouted corm develops a few leaves and a healthy root system (typically when roots are 1-2 inches long), gradually transition it to a more traditional, well-draining potting mix. This acclimation should slowly introduce the plant to lower humidity levels to avoid shock.
Troubleshooting Growing Alocasia Corms
One common concern is when corms fail to sprout. This can stem from dormancy, improper environmental conditions (insufficient warmth or humidity), or a lack of corm viability. Not all corms sprout, and some take significantly longer.
Corm rot, indicated by a mushy or discolored texture, often results from overwatering, poor drainage, or inadequate airflow, creating an overly saturated environment conducive to fungal growth. To prevent this, ensure the planting medium is moist but not soggy, allow some drying between waterings, and provide good ventilation. Slow growth in sprouted corms might indicate insufficient light or a need for warmer temperatures. While young plants in high-humidity environments are generally less susceptible to common houseplant pests, fungus gnats can sometimes appear due to consistently moist conditions. Allowing the top layer of the medium to dry slightly can help deter these pests.