Brown leaves are fairly common on many house plants. Keep in mind that it might be perfectly natural for lower leaves on your plant to first turn pale yellow, then brown and then drop off. This happens on many kinds of tropical plants as they grow. Over time, the plant will form a bare stem.
However, in some cases, brown leaves are a sign of cultural problems. If it seems like a lot of leaves are falling off—or if many leaves turn brown at once, or the upper leaves start browning—you may have one of the following problems:
- Not enough light. If lower leaves start turning brown or yellow, the plant might not be receiving enough light. If the discoloration is isolated to the side of the plant away from your light source, it's probably too little light.
- Too much heat. This often occurs in conjunction with too little water, but too much heat will cause leaves to curl, become crinkly and then fall off. If the plant is also wilting, try increasing water. If the rest of the leaves are healthy, introduce some air flow to cool the plant off.
- Too little water. Underwatered plants will first wilt, and then the leaves will brown and fall off. This most often happens from the bottom up, but it might also start on outer leaves on more bushy plants.
- Too little humidity. If the browning is confined to the leaf tip, and the leaf margin is still green, it's possible the plant isn't receiving enough humidity. If it's a tropical plant with a high humidity requirement, try increasing misting. Too little humidity may also cause black spots to form on leaves.