Calathea plants are a popular choice for indoor gardeners, celebrated for their striking foliage and unique daily movement. Their leaves, often adorned with vibrant patterns and colors, exhibit a fascinating characteristic known as nyctinasty. This rhythmic movement, where leaves fold upwards at night and unfurl with the morning light, adds a dynamic element to their visual appeal, making them captivating additions to any plant collection.
Understanding Your Calathea
Calatheas belong to the Marantaceae family, encompassing over 600 species. These tropical plants originate from the understory of rainforests in Central and South America. Their natural habitat, characterized by dappled light and high humidity, provides important clues for their care in a home environment.
The distinctive “prayer plant” movement, or nyctinasty, is a response to changes in light. Calathea leaves possess specialized joints called pulvini at their base, which regulate water pressure. This mechanism allows the leaves to maximize light absorption during the day and conserve moisture at night by reducing the exposed surface area.
Essential Calathea Care Guide
Light Requirements
Calatheas thrive in bright, indirect light, mimicking their natural environment beneath a forest canopy. Direct sunlight can scorch their delicate leaves, causing patterns to fade and potentially leading to browning or curling. An east- or west-facing window is often suitable, providing limited direct light during the gentler parts of the day. If placed near a very sunny window, sheer curtains can help diffuse intense light.
Insufficient light can also cause problems, resulting in dull or washed-out foliage and stunted growth. Observing the plant’s leaves for signs of fading colors or lack of vibrancy can indicate a need to adjust its position. Rotating the plant periodically ensures all sides receive adequate light exposure.
Watering Best Practices
Calatheas prefer consistently moist soil but are prone to root rot if overwatered. A good practice is to water when the top one to two inches of soil feel dry to the touch. Using filtered, distilled, or rainwater is highly recommended, as tap water often contains chemicals like chlorine, fluoride, and salts that can accumulate and harm the plant, leading to brown leaf edges.
When watering, ensure proper drainage from the pot to prevent waterlogging. Watering frequency varies based on environmental factors like temperature and humidity, but typically ranges from every 4-5 days in summer to once a week or every 8-9 days in winter. Using room temperature water helps avoid shocking the plant’s roots.
Humidity Needs
High humidity is crucial for Calatheas, ideally above 50% and preferably 60-80%. Their tropical origin means they are accustomed to moist air, and insufficient humidity is a common cause of leaf browning and crisping. Methods to increase humidity include placing a humidifier nearby, grouping plants together, or using a pebble tray filled with water beneath the pot, ensuring the pot does not sit directly in the water. Bathrooms can also offer naturally higher humidity levels.
Soil and Potting
Calatheas thrive in a well-draining, aerated potting mix that also retains moisture. A suitable mix often includes ingredients like peat moss or coco coir for moisture retention, combined with perlite or pumice for aeration and drainage. Components such as orchid bark or activated charcoal can further enhance drainage and prevent compaction. This blend mimics the rich, loose substrate found on the rainforest floor.
When repotting, select a pot with drainage holes that is only slightly larger than the current root ball, typically one to two inches wider in diameter. Overly large pots can retain too much moisture, increasing the risk of root rot. Repotting is best done every few years or when the plant becomes root-bound.
Feeding Your Calathea
Calatheas are not heavy feeders, but they benefit from regular fertilization during their active growing season, which spans spring and summer. A diluted liquid fertilizer, balanced in nutrients (e.g., 10-10-10 or 20-20-20 NPK ratio), is generally recommended. Fertilize every 2-4 weeks or monthly during this period.
Diluting the fertilizer to half or even a quarter of the recommended strength helps prevent root burn and nutrient buildup. Reduce or cease fertilization entirely during fall and winter when the plant’s growth naturally slows. Always water the plant lightly before applying fertilizer to minimize shock.
Temperature Considerations
Calatheas prefer consistent warm temperatures, ideally between 65°F and 80°F (18°C to 27°C). They are sensitive to cold and should not be exposed to temperatures below 60°F (15°C). Sudden temperature fluctuations, such as those near cold drafts from windows or heating/cooling vents, can stress the plant.
Maintaining a stable environment helps prevent stress and promotes healthy growth. Placing them in rooms with consistent temperatures and away from external doors or appliances that emit heat or cold air is beneficial. High humidity can also help Calatheas tolerate minor temperature shifts more effectively.
Addressing Common Calathea Issues
Leaf Browning and Crisping
Browning or crisping leaf edges are common indicators of environmental stress for Calatheas. This often points to insufficient humidity, as these plants require consistently moist air to prevent their delicate foliage from drying out. Inconsistent watering, where the soil is allowed to dry out excessively between waterings, can also contribute to this issue.
Tap water containing high levels of chlorine, fluoride, or mineral salts can accumulate in the soil and cause leaf burn, manifesting as brown tips or edges. Using filtered or distilled water can mitigate this problem. Ensuring the plant receives adequate, but not direct, light also helps prevent leaf scorching.
Yellowing Leaves
Yellowing leaves on a Calathea can signal several underlying problems. Overwatering is a frequent cause, leading to soggy soil and root rot, which impedes the plant’s ability to absorb nutrients and water. Conversely, underwatering can also result in yellowing leaves, especially if the plant is left dry for extended periods. The leaves may also yellow due to natural aging, particularly older lower leaves.
Nutrient deficiencies or over-fertilization can also contribute to yellowing foliage. Excessive fertilizer can cause salt buildup in the soil, damaging roots. Inadequate or excessive light exposure can similarly stress the plant, causing leaves to lose their vibrant color.
Pest Management
Calatheas can be susceptible to common houseplant pests, particularly in dry conditions. Spider mites, tiny arachnids that feed on plant sap, are often identified by fine webbing and stippling on leaves. Mealybugs appear as small, white, cottony masses, typically on leaf undersides and stem joints. Other potential pests include aphids and thrips.
Early detection and isolation of affected plants are important to prevent spread. Organic treatment methods include gently wiping leaves with a damp cloth or a cotton swab dipped in rubbing alcohol for mealybugs. Applying insecticidal soap or neem oil to all leaf surfaces, including the undersides, can effectively control infestations. Increasing humidity can also deter spider mites.
Popular Calathea Varieties
The diversity within the Calathea genus offers a wide array of visual appeal. Calathea Orbifolia is admired for its large, round leaves with prominent silver-green stripes. Calathea Medallion features broad, dark green leaves with a vibrant reddish-purple underside and intricate patterns. Calathea Makoyana, often called the Peacock Plant, displays feather-like patterns in shades of green on its upper surface and purple on the lower. Calathea Rattlesnake (Goeppertia insignis) has elongated, wavy-edged leaves with dark green blotches resembling snake markings.
Propagating Calathea Plants
The most effective method for propagating Calathea plants is by division, typically performed during repotting in early spring or early summer. This timing allows the plant to establish new roots before its active growth phase.
Begin by gently removing the mother plant from its pot and carefully shaking away loose soil to expose the root ball. Look for natural divisions or clumps of stems within the root system. Gently separate these sections by hand, ensuring each new division has a healthy amount of roots and at least one stem. If roots are tangled, a clean, sharp knife can be used to make a precise cut.
Pot each new division into a small pot with fresh, well-draining soil, ensuring the plant is at the same depth as before. Water thoroughly and place the newly potted plants in a warm location with bright, indirect light to encourage establishment.