Symptom 1:Leaves curl under; new leaves are undersized; leaves grow vertically when normally flat.

Cause: Too much light.
What to Do: Give plant more shade or move it farther away from plant-growing lights.

Symptom 2: Leaves turn yellow or curl and wilt.

Cause: Too much heat.
What to Do: Move the plant to a cooler spot in the house. Be sure plants are not close to a hot-air outlet.

Symptom 3: White crust appears on soil surface or on sides and rims of clay pots; leaves touching the rim wilt, rot and fall off.

Cause: Build-up of salts from fertilizer.
What to Do: Water the plant thoroughly to dissolve the salts; after half an hour, water again generously to carry the dissolved salts off through the pot’s drainage hole. Wash salts off the pot rim and sides.

Symptom 4: Yellow or brown spots appear on leaves.

Cause: Sun scorch.
What to Do: Give the plant more shade by filtering sunlight through blinds or curtains or moving the plant to a window that does not receive full midday or afternoon sun.

Symptom 5: Stems become mushy, dark in color and rotten; lower leaves curl and wilt; soil at top of pot is constantly wet; roots are black without white tips and hairs.

Cause: Too much water.
What to Do: Do not water so much or so frequently; water only when soil at the top is dry to the touch. Make sure the pot’s drainage hole is not clogged and do not let plant stand in water in its saucer for more than half an hour.

Symptom 6: Plant bears few or no flowers and an excessive amount of foliage. Stems may be elongated. Green scum may be present on the sides of clay pots.

Cause: Too much fertilizer, especially nitrogen.
What to Do: Fertilize less often, or at half the suggested rate. Do not use high-nitrogen fertilizers during the blooming season. Do not fertilize dormant plants.

Information taken from www.exoticangel.com