There are a number of reasons why an indoor plant might develop leaves with brown spots. The underlying cause might not be immediately obvious, but there are multiple ways to treat plants with browning leaves.
If an indoor plant is receiving too much direct sunlight, relocate the plant and find an area that is still bright but not exposed to direct sunlight. Gardeners may position their plants by the east and west-facing windows of their house or apartment so their plants only receive indirect sunlight.
Browning leaves may also indicate that a plant may be suffering from low humidity. To counteract this, gardeners may spray tiny droplets of water on the leaves of their plants. Another solution is to group indoor plants to create a mini-climate of their own.
Gardeners may also improvise a pebble tray. Use a tray or shallow dish and fill it with pebbles and water. The water should not exceed the level of the pebbles as the pebbles are supposed to prevent the plant from getting its soil too wet. This setup helps increase air moisture as water on the tray evaporates.
Overwatering can also result in plants developing brown spots. To avoid this issue, make sure that at least the top two inches of their soil feel dry to the touch before watering a plant. This does not apply to all plants so it is better to familiarize oneself with their needs. Some plants prefer to dry out completely before they ever need to be watered again.
Once browning occurs, gardeners may trim brown spots using scissors to save the remaining green portion of the leaf. If more than two-thirds of the leaf is affected by brown spots, it is better to just remove the entire leaf.