Diagnosis of Common Houseplant Problems
PP015 (5/03R)
By Dr. Sharon M. Douglas
Department of Plant Pathology and Ecology
The Connecticut Agricultural Experiment Station
123 Huntington Street
New Haven, CT 06511
Telephone: (203) 974-8601 Fax: (203) 974-8502
Email: Sharon.Douglas@ct.gov
Rapid Defoliation: extremes in temperature, changes in light (plant taken from bright light to relatively low light), changes in location or other cultural practices, overwatering, underwatering, or cold exposure.
Gradual Defoliation (lower leaves yellow and fall): overwatering (root damage), underwatering (not enough water to support full foliage), lack of sufficient light, or lack of fertilizer.
New Growth Wilted, Burned, or Blackened: too much fertilizer (leaching needed), cold drafts, hot drafts, too dry, sunburn, too warm, or freeze damage.
Wilting of Entire Plant: too little water, too much water (root rot), too much fertilizer (roots burned), or overexposed to cold temperatures.
Spotted Foliage: overwatering (check roots), burn from direct sun, cold water on foliage, bacterial or fungal infection (especially if plants are in very humid, wet conditions), or pollutants in the air (fumes from cleaning agents, gases, etc.).
Torn Foliage: animal damage (cats, dogs, rodents, etc.), children or adults (toys, maintenance equipment, carts, jewelry, chairs, doors, curtains, drapes).
Overall Light-Green Color of Foliage: low light conditions, too dry (soil or air), excess light (direct sun), or lack of fertilizer.
Browning of Leaf Tips or Leaf Margins: low humidity, excess fertilizer, poor water quality, excess of damaging ions in the water supply or soil (chlorine, fluoride, sodium, boron, soluble salts, etc.), deficiency of fertilizer, spray damage (insecticides, oil, leaf-glossing materials), unfavorable soil pH (too high or too low), or pollutants in the atmosphere.
Stunted Plants: excess fertilizer (root damage), too dry (lack of water), or overwatered (root damage).
New Foliage Small, Light-Green, and Spindly: too little light, lack of fertilizer, or soil too dry.
Leaves Yellowing between Veins (veins remain green): pH either too high or too low, iron deficiency (when pH is too high or alkaline), or magnesium deficiency (when pH is too low or acidic).
Cupped Leaves, Numerous Small Leaves at Growing Tip, Leaves Curled, Leaves Drop Continuously: unburned gas injury, spray or vapor damage from cleaning fluids, industrial pollution, or general pollutants in the atmosphere, aphid or mite damage.
Tiny, White Spots on Leaves, Cottony Masses on Stems, Round or Oval-Shaped Bumps on Leaves or Stems, Sticky Spots on Lower Foliage or Plant Stand: usually caused by insects (primarily spider mites, mealy bugs, scale, and aphids). Look on undersides of leaves as well as top of foliage. Many times a hand lens is needed since the pests are small.
Summary
Houseplants can develop a variety of problems that lessen their value to the indoor landscape. This fact sheet describes the most common symptoms that can develop on houseplants and outlines possible causes for these problems.