Calathea adds bold graphics in striking combinations to the tropical houseplant collection. From rich greens to dark purple and silvery spots and stripes, the visual interest is impressive. Handsome leaves arch gracefully over the sides of a pedestal, shelf, or suspended pot. And, calatheas are nontoxic, making them safe for homes with kids and pets.

Several species (C. zebrina, C. roseopicta) are Royal Horticultural Society Award of Garden Merit recipients for their performance and showmanship. When in prime health, they look good year-round. But the tropicals aren’t without their sensitivities when they move to our home environments, and may succumb to cultural stressors.

Calathea can live for decades, bouncing back from cultural missteps. To save a dying calathea, we’ll explore fixes to common problems. With a few cultural adjustments, new leaves may unfurl to continue the show.

Provide Optimal Lighting

Too little or too much light will damage your calathea.

Medium, indirect light is ideal for calatheas. Too much direct sun, especially in the afternoon, can cause leaf scorch. Leaf edges dry and curl, and brown and white patches appear. Calathea tolerate low light conditions, but insufficient light can result in stunted growth and an overall lack of vigor.

To save your dying calathea, move it to a location with bright, indirect light. Nearer an east or west-facing window may save it with conditions that mirror the open shade of the forest. Place pots a few feet from the window to avoid direct sun.

Increase Humidity

These tropical plants love high humidity.

Calatheas thrive in humid environments. In their native temperate rainforests, relative humidity is high. If the leaves show crispy edges and curling, low humidity may be the culprit. 

To raise the ambient humidity, use a humidifier. Or, try grouping houseplants to increase the immediate moisture, especially helpful in a humid room with adequate lighting.

You can also try the pebbled tray method. Place the pot on a tray or saucer of pebbles filled with water. This helps increase moisture, with the soil and roots near the pebbles to avoid oversaturation. Clean the tray weekly to avoid mold, mildew, and attracting pests.

Fluctuations in air moisture and dry conditions cause stress. Keep pots out of hot and cold drafts like fireplaces, heaters, and open doors on winter days to save a dying calathea.

Adjust the Watering Regimen

Overwatering is harder to fix than underwatering.

Proper watering, both in frequency and type of water, is a key to success for the tropicals. First, calatheas are sensitive to hard water and fluoride-treated tap water. Distilled, filtered, or captured rainwater is best.

To save a dying calathea, consistent moisture can help. Like those in too much light or with low humidity, crispy leaves can indicate a lack of moisture. Rehydrate dry soils with a thorough watering session, allowing water to run freely through the pot’s drainage holes. 

Calatheas prefer evenly moist (not wet) soils. They often rebound from dry spells but do best with watering when the soil is dry to an inch or two deep. Water deeply at each session. Remove catchment saucers after the containers drain to prevent excess absorption.

When to water depends on plant size, container type, potting media, and environment. With all these variables, it’s best to do a soil touch test and observe the leaves. When the soil is dry a knuckle or two deep, or leaves are wilted, it’s time to water.

Overwatering can also show limp leaves, so be sure to feel the soil surface. About once a week is average during the active growing season, with reduced sessions in the cool season as growth naturally slows.

Root Rot

To save a dying calathea in this case, replace the soil and repot.

Too much water leads to root rot, a common fungal disease that causes root decay. Overwatering creates soggy conditions that are prime for fungal problems to develop. Plants in overly saturated media with poor airflow may show yellowing and wilting leaves.

If you suspect rot or prolonged saturation, unpot the specimen and inspect the roots. Healthy roots are plump and white. Prune away any brown, mushy, or damaged ones. Repot in fresh soil and water. Regulate the watering cycle based on soil moisture. If caught early, you may see rebounding growth post-rot. 

Know When to Fertilize

Stop feeding in fall and winter to give the roots a break.

For houseplants, a low-grade fertilizer during the growing season gives a boost for healthy, leafy growth. Hold off on fertilizing a stressed plant to avoid excess production. If the plant is in survival mode, it’s not ready to produce new growth until other conditions moderate.

To save a dying calathea, only resume fertilizing when healthy new leaves emerge. Opt for a balanced houseplant fertilizer and use it at ½ strength.

Apply fertilizer about once a month in the warmer months, from spring through late summer. Stop fertilizing when the active growing season ends and as temperatures cool.

Repot

Lack of root space leads to stress.

Compacted soils from inconsistent watering or aging potting mix can cause leaves to decline. After a few years, it may be time to repot a mature specimen to save your dying calathea.

Opt for a pot one or two sizes larger if roots poke through drainage holes or above the surface. If new shoots are at the edge, trailing over, or breaking off, it’s time to upsize. Water that immediately runs through the pot is a sign of degraded media and crowded roots.

The best potting media for calathea is a blend of half potting soil and the remainder a mix of coir, perlite, and a peat-alternative. The combination aids in moisture retention, aeration, and drainage (all essential to calathea root health).

Scout and Treat Pests

Pest problems are less common indoors, but can still damage your plants.

With early scouting and treatment, calatheas may recover from common pest damage. Aphids and mealybugs feed on leaf and floral tissues and, in severe cases, cause reduced health, failed buds, and distorted blooms. Fungus gnats visit saturated conditions from overwatering, too large a pot, or poor soil/drainage.

Aphids are sap-sucking insects with a nondiscriminating palette. In addition to feeding on cellular tissues, they leave behind sticky honeydew that leads to black, sooty mold. They also spread fungal spores and are vectors for viruses. Impacted houseplants may show curled, yellowing leaves and stunted growth.

Mealybugs are also soft-bodied and look like tiny tufts of white cotton on leaves and stems. Infestations are visible by the insects themselves and by yellowing, wilting, or stunted leaves.

Aphids, mealybugs, and other sap-suckers like spider mites gravitate toward selections stressed by under- or overwatering. For small populations, run plants under a stream of water to displace the pests. Dab them with a Q-tip or cotton ball soaked in isopropyl alcohol. Insecticidal soaps and horticultural oils are effective as more potent treatments.

Fungus gnats are small, winged flies and a nuisance pest. The adult flies don’t damage plants except to lay eggs, which produce root-feeding larvae. Larvae feed on decomposing organic matter in soils and then on roots, causing an inability to absorb moisture or nutrients to support upper growth.

Signs of fungus gnat stress include yellowing, dropping leaves, weak stems, and overall lack of vigor. These indicators are easy to mistake for other problems until the adult flies are visible. You’ll see movement on the soil surface as the flies crawl and flutter with disturbance.

If you spot the gnats, add a mosquito dunk with Bacillus thuringiensis at watering to save a dying calathea. The organic bacteria target the larvae and are non-toxic.

Manage Temperatures

Avoid sudden changes in temperature indoors to protect leaves.

These tropicals like warm, moderate conditions, and average room temperatures are usually fine as they adapt to our indoor environments. Keep the range within 65 to 75°F (18 to 24°C) for the best growth.

Avoid sudden temperature changes, aiming for consistent conditions. In areas with cold winters, keep them away from cold glass windowpanes to prevent damage.