Calatheas are native to the rainforests of Central America; thus, they require a warm, moist environment.
TEMPERATURE
Best growth comes with temperatures between 70 and 85. Avoid temperatures above 90 or below 65. Allow for good ventilation at higher temperatures. Keep humidity at a minimum of 60%.
LIGHT
Light levels should be kept around 1500 to 1800 foot-candles.
FERTILIZATION
Calatheas are sensitive to high salts. You will need good quality, low salt water. When incorporating dry fertilizer, use moderate rates. When using liquid fertilizers overhead, rinse plants briefly with plain water before and after the fertigation. An EC of 1.2 to 1.4 is sufficient. A ratio of
N/P2O5/K2O of 1/0.4/1.8 is recommended. Insufficient nutrient levels will cause loss of color in the leaves.
MEDIUM
As Calatheas should be kept moist at all times, it is important to have a well-drained mix with good quality peat or coir. The pH for roseo-picta types should be at 5.0. Others prefer 5.5 to 6.0. Fluorides can burn the tips and margins of older leaves. As these low pH levels make Fluorides readily available, use low-fluoride Phosphorus and water sources.
DISEASES
If kept too wet, Calatheas can get Pythium and Fusarium. High salts also cause root-rot symptoms. Leaf spot diseases such as Helminthosporium will proliferate when the foliage remains wet for extended periods. In cooler periods, botrytis can be a problem.
PESTS
Watch for spider mites, thrips and mealybugs. Microscopic mites can cause necrotic lesions near the margins similar to disease or Fluoride injury. Watch for occasional outbreaks of caterpillars and snails. Horticultural oils will burn the foliage of
Calatheas.
