Is Calathea Hard to Grow Indoors?

Potting and Soil

• Calathea thrives in well-draining, organic soil. Plant experts at the University of Washington recommend soil with two parts peat moss to one part loam to two parts sand or perlite. Clay pots also prevent soggy soil, because they allow air to circulate through the growing medium. With poor draining, Calathea stops growing and leaf colors fade. Also, Calathea becomes root-bound quickly. Transplant Calathea into a larger pot each spring.

Growing Environment

• Calathea grows best at 60 to 70 degrees Fahrenheit, and prefers bright but indirect light. Direct sun washes out the leaf colors. The leaves of Calathea plants will turn brown if the air is too dry, so the plant needs high humidity. Mist your Calathea plants daily during dry winter months. A nearby humidifier also keeps the air moist. A tray of pebbles filled with water and set under the Calathea’s pot provides humidity as well.

Water and Fertilizer

• Calathea plants need damp soil for their growing season in spring, summer and fall. However, soggy soil causes root rot. Let the top of the plant’s soil dry between waterings. Never let the soil dry completely, or the leaves will turn brown and the Calathea will stop growing. Remove browned leaves to encourage new growth. Plant experts at the University of Washington advise fertilizing Calathea once every two weeks in spring, summer and fall, and once a month in winter. Feed with houseplant food.

Pests and Problems

• Mealybugs, mites and scales feast on Calathea plants. Mealybugs leave cotton-like clumps underneath leaves and on stems. Mites are small and difficult to see, but their webs are visible underneath the leaves. Scales are light brown and hard to spot because they blend with the plants. All three pests cause yellowed leaves and stem die-offs. Treat infested plants with insecticidal soaps, horticultural oil or pesticides containing carbaryl. Calathea plants are also vulnerable to bacterial and fungal leaf spots. Leaf spots are tough to control once they infect a plant. Prevent outbreaks by watering from below. Water sitting on leaves encourages leaf spots.