The water lily, known botanically as Nymphaea, is an aquatic perennial celebrated for its striking pads and flowers. While commonly associated with outdoor ponds, cultivating a lily pad plant indoors offers a unique way to introduce an exotic, miniature water garden into a home environment. Successfully growing this plant requires careful attention to the specialized conditions it needs, transforming a standard container into a thriving aquatic habitat. This project depends on selecting the right small varieties and managing the light, temperature, and nutrient delivery.
Selecting Varieties and Preparing the Indoor Habitat
Successful indoor cultivation begins with selecting miniature or dwarf varieties suited to the size constraints of an indoor container. Dwarf tropical water lilies, such as Nymphaea ‘Dauben’ or ‘Colorata’, are excellent choices because they produce smaller pads and flowers proportionate to a tub or aquarium.
Once the variety is chosen, establish the planting container, which must be a watertight vessel without drainage holes. The lily pad plant should be potted in a separate, sturdy container, such as a plastic pot 10 to 12 inches in diameter. Water lilies require a dense growing medium; standard potting soil must be avoided because its light organic material will float and cloud the water.
The ideal substrate is heavy clay garden soil or a specialized aquatic planting mix. Plant the water lily rhizome near the edge of the pot, ensuring the growing tip, or crown, remains exposed just above the soil line. Cover the soil surface with a one-inch layer of pea gravel or coarse sand. This protective layer anchors the soil, preventing it from escaping into the water and maintaining a clear aquatic environment.
Optimizing Light, Temperature, and Water Quality
Providing sufficient light is the greatest challenge when growing a water lily indoors, as these plants are accustomed to full, direct sunlight. To encourage flowering and healthy pad growth, the plant needs a minimum of six hours of intense, direct sun daily. Since this level of natural light is usually impossible to achieve indoors, even in a south-facing window, supplemental lighting is necessary.
A high-output LED grow light, positioned directly over the water surface, should be used for 12 to 18 hours per day to simulate a long summer growing season. The fixture must be powerful enough to deliver adequate light intensity all the way to the water surface, replicating the intensity and duration of natural sunlight required by Nymphaea species.
Tropical water lilies thrive in consistently warm water, requiring temperatures above 70°F (21°C) for sustained growth and blooming. Fluctuations can slow growth or prevent flowering, so place the container away from cold drafts or air conditioning vents. If the ambient room temperature is too low, a submersible aquarium heater can be used to maintain a steady water temperature.
Water quality impacts plant health and the aesthetic appeal of the feature. Use distilled water or tap water that has sat for 24 to 48 hours to allow chlorine to dissipate. Regular evaporation concentrates minerals and salts, so periodically remove a portion of the old water and replace it with fresh, dechlorinated water to prevent the buildup of undesirable compounds.
Routine Feeding and Upkeep
Water lilies are heavy feeders, requiring regular fertilization to support rapid growth and continuous blooming. Since the plant draws nutrients exclusively from the soil, liquid fertilizers poured into the water are ineffective and only fuel algae growth. Use slow-release aquatic fertilizer tablets specifically formulated for pond plants instead.
These tablets must be inserted deep into the clay soil, several inches away from the plant’s rhizome to prevent chemical burn. Apply new fertilizer tablets every four to six weeks throughout the spring and summer growing months. Producing smaller pads or flowers often signals a need for a fresh dose of nutrients.
Routine maintenance involves pruning and deadheading to keep the habitat clean. Immediately remove spent flowers and any pads that have turned yellow, brown, or mushy by cutting the stem near the base of the plant. This prevents decaying organic matter from fouling the water, which can lead to bacterial or fungal issues.
Algae growth, appearing as green water or slimy film, usually indicates excess light or nutrients. Manage algae with controlled partial water changes and by ensuring fertilization is properly contained in the soil. Common aquatic pests like aphids can be controlled by gently submerging the affected pads for a day or two, which drowns the insects without harming the plant.