Why Are My Calathea Leaves Turning Yellow?

Seeing yellow leaves on a Calathea can be disheartening. These plants, known for their ornate foliage, are expressive about their environmental conditions. When their leaves lose their vibrant color, it is a signal that their care routine needs adjustment. This guide will help you understand the reasons for yellowing and how to restore your plant’s health.

Common Causes for Yellowing Calathea Leaves

Watering Issues

The most frequent reason for yellowing leaves on a Calathea is related to moisture. Overwatering is a common misstep, leading to constantly soggy soil. This condition suffocates the roots, preventing them from absorbing oxygen and nutrients, which manifests as yellowing on the lower leaves first. This can lead to root rot, which accelerates the yellowing process.

Conversely, underwatering also causes stress. When the soil becomes too dry, the plant cannot draw up enough water, causing leaves to wilt and their edges to become brown and crispy. If dehydration continues, the plant sheds older leaves, which turn yellow before they drop. The soil should be consistently moist but never waterlogged.

Low Humidity

Originating from tropical rainforests, Calatheas are adapted to high humidity. Most household air is far drier than what these plants prefer, needing humidity levels between 50% and 60%. When the air is too dry, the plant loses moisture through its leaves faster than its roots can absorb it. This moisture stress first appears as browning or yellowing along the leaf margins, which can spread if the arid conditions are not corrected.

Improper Lighting

Lighting plays a role in the health of a Calathea’s foliage. These plants thrive in bright, indirect light, mimicking the dappled sunlight of a tropical canopy. Direct sunlight will scorch their sensitive leaves, causing them to appear faded and yellow. Insufficient light also presents problems. In a low-light environment, the plant cannot photosynthesize effectively, leading to weak growth and pale yellow leaves as it struggles to produce chlorophyll.

Water Quality

Calatheas are sensitive to the minerals and chemicals in tap water. Fluoride, chlorine, and salts can accumulate in the soil, leading to chemical burns on the plant’s root system. This damage inhibits the plant’s ability to absorb water and nutrients. The initial symptom is often brown, crispy leaf tips, a condition known as leaf tip burn, which can cause the entire leaf to turn yellow.

Pest Infestations

Pest infestations are another source of yellowing leaves. Spider mites are a common pest for Calatheas, thriving in warm, dry conditions. These tiny arachnids use piercing mouthparts to suck the contents out of leaf cells, leaving behind a pattern of tiny yellow or white dots, known as stippling. As an infestation grows, the damage can cause entire leaves to turn yellow and develop a fine, silky webbing on their undersides.

Natural Aging

Not all yellow leaves are a sign of a problem. As a Calathea matures, it is natural to shed its oldest leaves, which are located at the base of the plant. The plant redirects energy from these older leaves toward new growth. This natural process involves the leaf slowly turning yellow before it withers and falls off. This is not a cause for alarm if it only affects one or two of the lowest leaves occasionally.

How to Fix Yellow Leaves on Your Calathea

Pruning Damaged Foliage

Once a Calathea leaf has turned yellow, it will not revert to green. It is best to remove this foliage to help the plant conserve energy for new growth. Use clean, sharp scissors or pruning shears to make a clean cut. Follow its stem down to the base of the plant and snip it off as close to the soil line as possible. Removing this dying foliage improves the plant’s appearance and prevents it from expending resources.

Correcting the Environment

After pruning, address the underlying cause of the yellowing. For watering issues, allow the top soil to dry before watering again or give the plant a thorough soaking if it was too dry. Ensure the pot has proper drainage and establish a consistent schedule. To combat low humidity, use a humidifier, group it with other plants, or place it on a pebble tray.

If lighting is the problem, relocate your plant to a spot that receives bright, indirect light. For water quality issues, switch to using filtered, distilled, or rainwater. If pests are present, treat the plant by wiping down the leaves and applying an insecticidal soap or neem oil.

Preventative Care for Healthy Foliage

Maintaining the vibrant foliage of a Calathea revolves around a consistent care routine that mimics its native habitat. Proactive care starts with a regular watering schedule using filtered or distilled water to avoid mineral buildup. Check the soil every few days and water thoroughly when the top inch or two has become dry. Ensure high humidity through methods like a humidifier or regular misting, and place your plant in steady, bright, indirect sunlight. Finally, inspect the leaves regularly for any early signs of pests to intervene before an infestation can take hold.