Overwatering
Too much water, or water that cannot drain away, starves roots of air and is the most common cause of houseplant death.
Also known as: Waterlogging, Soggy soil
Symptoms and identification
Leaves turn yellow and limp, often starting with the lower ones, even though the soil is wet. The plant may wilt in moist soil, stems turn soft at the base, the soil smells sour, and fungus gnats appear.
Causes
Watering on a fixed schedule rather than by need, pots without drainage holes, heavy soil that stays wet, decorative outer pots that collect water, and large pots for small plants.
Organic treatment
Stop watering and move the plant to a bright spot to dry out. If the soil stays soggy, remove the plant, trim any brown, mushy roots and repot in fresh, dry mix in a pot with drainage.
Prevention
Water only when the top few centimetres of soil are dry, using a finger to check. Use pots with drainage holes and a free-draining mix, and empty saucers after watering.
Chemical treatment (use with care)
Not needed. If root rot has set in, see the root rot guide.