Nelumbo nucifera, commonly known as the lotus, is a striking aquatic perennial prized for its large, elegant flowers and unique foliage. While often mistaken for a root, the edible part of the plant is actually a rhizome, a modified underground stem that stores starches and nutrients. Growing this impressive plant requires a specialized, contained aquatic environment to thrive and produce rhizomes. Success hinges on creating the right conditions and adhering to a consistent maintenance schedule throughout the warm growing season.
Setting Up the Aquatic Environment
Growing lotus successfully starts with selecting a wide, watertight container with no drainage holes, as rhizomes spread horizontally. Containers should be at least 20 inches wide for small varieties, while larger cultivars need 3 to 5 feet in diameter. Black containers absorb solar radiation, warming the water and soil to stimulate earlier growth.
The soil composition must be heavy to anchor the plant and prevent it from floating. Use a mix of heavy clay or loam, avoiding standard potting mixes that contain light organic materials like peat moss. A layer of four to five inches of this dense soil is sufficient. The lotus requires full sun, demanding a minimum of six hours of direct sunlight each day to develop leaves, flowers, and rhizomes properly.
Planting Techniques and Timing
Lotus is propagated by planting a section of the rhizome, often called a tuber, rather than starting from seed. Planting should occur in late spring or early summer, after the final frost and when water temperature consistently reaches at least 70°F. Handle the rhizome with caution, as the delicate growing tips, or “eyes,” are easily damaged and can prevent sprouting.
To plant, gently press the rhizome horizontally into the surface of the heavy soil. The body of the rhizome should be covered with soil, but the growing tips must be left exposed or pointed slightly upward. After planting, fill the container with water, maintaining a shallow depth of two to three inches above the soil line to encourage initial sprouting.
Seasonal Maintenance and Management
Once the lotus has established aerial leaves above the water, a fertilization schedule must begin. Lotus plants are heavy feeders and require specialized, slow-release aquatic fertilizer tabs. Push these tabs deep into the soil every two to four weeks throughout the growing season, ensuring they are not placed directly against the rhizome, which can cause burning.
Water management requires maintaining the level three to six inches above the soil. Frequent refilling is necessary due to evaporation, especially during warmer months. Water temperatures around 75°F or higher are optimal for rapid growth. While algae can be a concern, it is often managed by a healthy plant shading the water; pests like aphids are usually resolved by spraying them off with a jet of water.
Harvesting and Winterizing
The rhizomes are ready for harvest once the lotus enters its dormant phase in the fall. Dormancy is signaled when the foliage has completely died back and turned brown. Avoid cutting the stems while they are still green, as this allows water to enter the hollow stems and can cause the rhizome to rot.
Harvesting involves carefully tipping the container and gently washing away the soil to reveal the newly formed rhizomes coiled around the bottom of the pot. For winter in colder climates, the container can be moved to a cool, dark, and frost-free location, such as a basement or garage. If the container is in a pond, it must be lowered below the frost line to prevent freezing. The soil should be kept moist but not fully submerged during dormancy, protecting the rhizome until spring.