Houseplant Problems & Solutions

Wilting or Leaf Drop

• Wilting or leaf drop result from various causes, including improper watering. As a general rule, water houseplants when the top 1/2 inch of soil feels dry to the touch. Water deeply, and then let the pot drain thoroughly to prevent rot and other diseases. Too much or too little fertilizer may also cause wilting. For most plants, regular feeding once every month during spring and summer is adequate. Use an all-purpose, water-soluble fertilizer mixed at a rate of 1/2 teaspoon per 1 gallon of water. Withhold fertilizer during fall and winter when most houseplants enter a period of dormancy. Sometimes, wilting indicates that the plant is rootbound and ready to be moved into a pot one size larger, as water may run straight through the pot without benefiting the plant. Other signs that a plant is rootbound include roots growing through the drainage hole or on the surface of the soil.

Poor Growth

• Poor growth sometimes indicates lack of nutrients, remedied by a regular fertilization routine. Lack of sunlight is a common reason for slow or spindly growth. If there isn't enough light for you to read a newspaper, the plant probably needs more sunlight. Lack of light is especially problematic during the winter months. Move the plant to a sunnier window, but for most plants, avoid direct, intense sunlight, which may cause yellowing of the leaves or brown, scorched leaf tips.

Leaf Discoloration

• Some leaf drop and discoloration of the lower leaves is normal, especially in older plants. Some plants, including spider plants (Chlorophytum comosum) and dracaena (Dracaena spp.), display leaf discoloration as a result of high fluoride levels in tap water. If possible, use bottled water. Alternatively, let the water sit out overnight to allow chemicals to dissipate. Insufficient light is a common cause of pale, yellow leaves. Inspect the plant for signs of disease or pests, as both are reasons for leaf discoloration. Similarly, too much light often causes pale green leaves or leaves with brown tips.

Diseases

• Yellow, brown or black spots on the leaves are signs of bacterial or fungal disease, often caused by humid conditions or improper watering. Similarly, leaves with a powdery, grayish-white covering most likely have powdery mildew. Remove affected leaves immediately and never place diseased plants near healthy plants. Thin overcrowded plants to improve air circulation. Water carefully and avoid wetting the leaves. Water needs vary widely depending on the plant. But most plants are healthier if the soil dries out between watering. Always use pots with drainage holes, and never let pots stand in water.

Pests

• A number of pests often affect the long-term health of indoor plants. Mites -- dust-sized pests that suck the sap from the leaves -- leave telltale webs and tiny spots on the leaves. Treat spider mites with a commercial insecticidal soap spray mixed at a rate of 5 tablespoons per gallon of water. Repeat every seven to 10 days, up to a total of three applications. Insecticidal soap spray is also effective for other indoor plant pests, including aphids, whiteflies, thrips, mealybugs and scale. But don't use insecticidal soap spray on succulents, palms (Arecaceae), dumb cane (Dieffenbachia), dracaena or delicate ferns without testing a small area first. If necessary, you can dilute the solution to half-strength for tender plants.