Colocasia (Elephant Ear/Taro) is a tropical plant prized for its large, dramatic foliage. Because it is often associated with wet environments, many wonder if it can be grown directly in water. Colocasia can thrive in fully aquatic or semi-aquatic conditions, making it an excellent choice for water features or indoor hydroponic setups. Successful water cultivation requires understanding the plant’s natural history and specific care requirements.
The Aquatic Nature of Colocasia
Colocasia esculenta is inherently adapted to highly saturated environments. Originating in tropical and subtropical regions, it is often found naturally growing along riverbanks, in marshes, and within boggy areas where the soil is constantly wet. This native habitat explains why the root system is tolerant of low-oxygen conditions that would cause root rot in most other terrestrial plants.
The plant is frequently utilized in water gardens and ponds because it naturally absorbs excess nutrients from the water. This function helps reduce algae growth and contributes to a healthier aquatic ecosystem. Colocasia is typically considered a marsh plant, preferring its roots to be submerged in shallow water or consistently saturated soil, allowing it to transition easily into a water-only cultivation system.
Methods for Water Cultivation
To successfully transition an established Colocasia from soil to water, the roots must first be thoroughly cleaned. Carefully remove the plant from its container and wash away all traces of soil, as organic matter left in the water can lead to stagnation and bacterial issues. Trim away old, thick, or damaged soil roots, as the plant needs to generate new, fuzzy roots specifically adapted to absorb nutrients from water.
For starting a new plant, a tuber or corm can be sprouted directly in water. Position the tuber so only the very bottom section touches the water surface, often by suspending it in a net pot or a container with a narrow neck. This encourages water root development without submerging the entire tuber, which reduces the risk of decay before growth begins.
Various containers are suitable for water culture, ranging from simple glass vases and jars to specialized pond baskets or hydroponic systems. For aesthetic display, a clear glass container allows monitoring of water levels and root health. In advanced setups, an inert medium like expanded clay aggregate (leca) can be used within a net pot to provide physical stability, with the roots extending into the nutrient-rich water reservoir below.
Essential Care Requirements in Water
The long-term success of growing Colocasia in water requires consistent maintenance of the aquatic environment. Since plain water lacks the necessary minerals for sustained growth, a diluted liquid hydroponic nutrient solution must be added. Colocasia plants are heavy feeders, requiring regular fertilization during the growing season, often with a balanced formula high in nitrogen to support their large leaves.
Water quality is a continuous concern, requiring regular replenishment and complete changes to prevent stagnation and the depletion of dissolved oxygen. Changing the water every one to two weeks helps remove metabolic waste products and maintain a healthy environment for the roots. Algae growth on the roots and container walls is a common issue, which can be managed by using opaque containers or by gently wiping the surfaces during water changes.
Colocasia prefers bright, indirect light when grown indoors, though it can tolerate partial shade outdoors. The water temperature should be kept warm, ideally within the range of 70°F to 85°F (21°C to 29°C), reflecting its tropical origin. Maintaining these warm conditions and a consistent feeding schedule is essential for keeping the plant healthy.