Calathea's love bright, indirect sunlight, and avoid placing it in any direct sunlight when it's at its strongest to prevent leaf burn. As they are a type of 'prayer plant' their leaves gently fold up-right when it goes dark. If this doesn't happen, it's a sign they're not getting the light they need, so move them to a brighter position.They also like high humidity, making it an ideal choice for a bright, humid bathroom or kitchen.
Make sure to keep the soil consistently moist but not soggy, always allowing the top couple of inches to dry out in between waterings.
When watering, thoroughly soak the soil until water drains out of the bottom of the pot. Discard any excess water in the saucer or decorative pot to prevent waterlogged roots.
Browning along the leaf edges is usually linked to watering rather than humidity. These plants don't like chlorine found in tap water, so use rainwater, filtered water or allow tap water to sit overnight before using. Brown tips on the leaves are a common occurrence.
It's important to adjust your watering routine based on the time of year and specific environmental conditions like humidity and temperature.
