Calathea Leaves Not Opening . This is often the most common reason a calathea plant’s leaves will start to curl. Your calathea plant isn’t closing at night because it is either not dark enough in your home or your plant is being overwatered. How to Care For The Lush Calathea Orbifolia Garden Lively from www.gardenlively.com Like all houseplants, calatheas need a very specific amount of water to stay healthy. Calatheas need a perfect balance of water in the soil they are growing. Of course, excess heat does not only mean that the plant is experiencing heat stress it also means that moisture is drying up faster.