Calathea plants are rainforest plants. They love humidity and bright light.
Sunlight - No direct sunlight
Watering - Spray RO water (not hard water) frequently on leaves
Soil - Mix a little mud in cocopeat, sand and vermicompost mixture
Fertilizer- Too much fertilizer is not needed. Once in two months liquid fertilizer can be given.
Other tips -
- Curling leaves shows problem with the plants.
- Donot place near AC or any heating applicances
- It grows well in summer and monsoon but not in winter
- Too much watering or direct sunlight can damage the plant
Propagation - Is by root division
P.S - These are excerpts from my beloved mother's diaries and journals. Hope you find them useful. Please leave your thoughts in the comment section below.