Calathea plants are cherished houseplants, recognized for their striking foliage and unique leaf movements. While their beauty is widely appreciated, a lesser-known aspect of these plants lies beneath the soil: their corms. These underground structures are fascinating and play a significant role in the plant’s life cycle and potential for propagation. This article aims to clarify the nature of Calathea corms and guide you through their discovery, propagation, and initial care.
Understanding Calathea Corms
Calathea corms are specialized underground stems, distinct from bulbs or tubers, serving as solid, swollen storage organs for nutrients and water. They enable the plant to store energy, supporting its growth and allowing it to survive periods of stress or dormancy.
Corms are found at the base of the plant, often attached to the rhizomes or root system. Their presence indicates a mature plant with reserves. They are important for the plant’s ability to regenerate and produce new shoots, making them key to its propagation potential.
Locating and Extracting Calathea Corms
Corms are discovered during the process of repotting or dividing a mature Calathea. Spring or early summer, when the plant is actively growing, is an opportune time for this activity. Begin by gently removing the Calathea from its pot, being careful to minimize stress on the plant.
Once unpotted, carefully shake away excess soil to expose the root ball. You will then be able to identify the small, rounded, or irregular corms nestled among the roots. Using clean, sharp tools, carefully separate the corms from the parent plant, ensuring each corm has at least one viable growth point or “eye.” Sterilizing your tools with alcohol before and after use helps prevent the spread of diseases.
Propagating Calathea From Corms
Propagating Calathea from corms involves several steps to encourage new growth. After separating the corms, allow any cut surfaces to air dry and form a callus for a few hours; this can help prevent rot. Prepare a suitable planting medium, which should be light, well-draining, and moisture-retentive. A good mix includes components like orchid bark, perlite, and coconut coir for aeration, drainage, and moisture retention. A pH between 6.5 and 7 is suitable for Calatheas.
When planting, bury the corm just below the surface of the potting mix, ensuring the growth point faces upwards. After planting, water the medium lightly to settle the corm, but avoid overwatering, which can lead to rot. Calathea corms thrive in warm and humid conditions. Maintain temperatures between 18-29°C (65-85°F) and humidity levels around 60% or higher.
Place the planted corms in a location that receives bright, indirect light. Direct sunlight can harm the delicate new growth, while insufficient light may hinder development. Germination can take two to four weeks. Consistent moisture in the soil, without being waterlogged, is important for successful sprouting.
Corm Storage and Initial Care
If you are unable to plant Calathea corms immediately after extraction, proper storage is important to maintain their viability. Store them in a cool, dark, and dry environment. A breathable medium like peat moss or vermiculite can prevent desiccation and rot while allowing air circulation. Ensure there is no excess moisture in the storage container.
Once the corms have been planted and new shoots begin to emerge, they require specific initial care to establish successfully. Continue to provide consistent humidity (above 60%), using a humidifier or a pebble tray. Maintain bright, indirect light exposure. Water cautiously, keeping the soil consistently moist but never soggy, as young roots are particularly susceptible to rot.