The Calathea concinna ‘Freddie’ is a popular houseplant known for its striking, patterned foliage. As a member of the Marantaceae family (prayer plants), it exhibits nyctinasty, a rhythmic movement where leaves lift at night. When the plant is stressed, however, this movement becomes a defensive mechanism. The leaves tightly roll inward to reduce their exposed surface area, signaling that the environment or care routine needs immediate adjustment.
Moisture Stress: Underwatering and Low Humidity
Leaf curling in the Calathea Freddie is most frequently a direct response to a lack of water, whether in the soil or the surrounding air. When soil moisture is insufficient, the plant initiates the curling action to minimize water loss through transpiration. This is why leaves often curl inward when the plant is significantly underwatered.
The Calathea Freddie requires a consistently moist, but not waterlogged, substrate to mimic its natural rainforest floor environment. Check the top inch or two of soil, and if it feels dry, water thoroughly until the excess liquid drains from the bottom. Allowing the soil to dry out completely between waterings starves the roots and is a common cause of this protective leaf curling.
The plant is highly sensitive to the humidity of the air around it, preferring levels above 50% to 60%. In a typical dry indoor environment, the plant will curl its leaves and develop crispy, brown edges. To increase localized humidity, group the plant with other houseplants or place the pot on a pebble tray filled with water, ensuring the pot base does not touch the water. A small room humidifier is the most effective way to maintain the stable humidity levels this plant needs.
Light Exposure and Temperature Shock
The Calathea Freddie evolved in the understory of tropical forests, thriving in consistently bright, filtered light. Excessive direct sunlight triggers leaf curling as the plant attempts to shield its leaf tissue from scorching. Intense solar energy rapidly dries out the foliage, leading to the same water conservation response seen with underwatering.
The ideal placement is near an east-facing window or a few feet away from a bright south or west-facing window where light is diffused. While the plant can tolerate lower light levels, too little light can still stress the plant. Any visible leaf damage from sun scorch, such as faded patches or crispy spots, will not reverse, but the new growth will be healthy once the plant is moved.
The plant is also susceptible to sudden changes in temperature, which immediately induce curling as a form of thermal shock protection. The Calathea Freddie prefers a stable temperature range between 65°F and 80°F. Exposure to cold drafts can be particularly damaging. Placing the plant near air conditioning vents, drafty windows, or exterior doors during winter will cause the leaves to curl and droop.
Checking for Pests and Mineral Buildup
An inspection of the foliage is necessary to rule out biological and chemical irritants that can also cause the leaves to curl. Spider mites are the most common pest to infest Calatheas, as they thrive in the same dry, low-humidity conditions that stress the plant. These tiny pests feed on the cell contents of the leaves, causing stippling, discoloration, and a general weakening that forces the leaf to curl.
To identify an infestation, look for fine, silky webbing, particularly where the leaves meet the stems or on the leaf undersides. Initial treatment involves washing the leaves thoroughly with lukewarm water to dislodge the mites. Follow this by treating both sides of the foliage with a horticultural oil like neem oil or insecticidal soap. Isolation is necessary to prevent the pests from spreading.
The Calathea Freddie is sensitive to the dissolved solids and chemicals found in standard tap water, such as chlorine, fluoride, and mineral salts. Over time, these compounds accumulate in the soil, leading to a condition that mimics water stress, causing leaf edges to brown and leaves to curl. Switching to distilled, rainwater, or allowing tap water to sit uncovered overnight before use can prevent this buildup.
Long-Term Health: Routine Care and Prevention
Preventing future leaf curling requires establishing a consistent care routine that matches the plant’s native habitat. The Calathea Freddie needs a well-draining, airy potting mix that still retains moisture, such as a blend containing potting soil, perlite, and orchid bark. Repotting every one to two years refreshes the substrate and prevents soil compaction, which impedes water and nutrient uptake.
Fertilization should occur only during the active growing season, typically spring through summer. Apply a balanced, diluted liquid fertilizer every four to six weeks to provide necessary nutrients. Stop feeding entirely during the fall and winter months when the plant’s growth naturally slows down.
The most effective long-term strategy involves frequent, proactive monitoring before the leaves begin to curl. Regularly check the soil moisture level, inspect the undersides of the leaves for early signs of pests, and ensure the ambient humidity remains high. Maintaining a stable environment is easier than correcting the stress response of a fully curled Calathea Freddie.