Leaves curling and spots: The most likely cause here is underwatering. Check the soil for dryness and provide water - following the above instructions. Leaf tips brown: Your plant is most likely needing more humidity because the current air quality is dry.

The plant must be kept well watered in summer. It also needs to be kept in a warm place. It loves humidity and compost can be kept moist during the summer. Spraying it with cooled, previously boiled water is to be recommended, as this boosts the humidity and keeps the leaves dust free. In order to keep humidity levels high, the plant can also be placed in a shallow outer pot, or alternatively, a large saucer filled with moist pebbles. Grouping it with other plants also helps to provide the humidity it craves.