Leaves dropping: The most frequent cause of defoliation is gas poisoning. The gas leak affecting the plant may be so small you won’t detect it, but it can still be enough to kill your plants. Occasionally plants will lose their leaves as the result of the shock of being moved from one environment to another, from bright sun to heavy shade, for instance.
Browning of leaf tips: Over or under-watering, sun scorch, or insect attacks are to be suspected, in the order given.
Yellowing foliage: Over-watering or soil exhaustion. Check the ball of earth to determine whether repotting is necessary. Also check for gas, lack of humidity and drafts. Occasionally yellowing leaves are a sign of red spider, scale insects or mealy bugs.
Spindly: Lack of sun and hot dry air are the growth most common causes of this failure to flourish.
Rot on leaves: Fungus growth is the cause here. Treat as noted earlier in this chapter.
Wilting spotted foliage: Under-watering or soil exhaustion. Too much sun with those plants that like shade, or over-watering can cause spots on the leaves.