Common Symptoms of Poor Health of Indoor Plants
Living plants are being used in great numbers and variety in all types of indoor environments. Although most indoor environments are satisfactory for the maintenance of the health of plants for relatively long periods, problems do occasionally occur. Most of the problems are not due to infectious diseases, caused by fungi, bacteria, etc., but result instead from imbalances in the environment or from care practices that give rise to plant stress. Inability to recognize symptoms, determine the causes of stress and promptly initiate corrective care techniques can result in unhealthy plants.
Determining the cause of indoor plant problems can sometimes require skilled laboratory diagnosis or site consultations. However, most problems are relatively simple to diagnose if one will remember that various stress-producing elements of an environment often affect the plant simultaneously. Detecting all of the imbalanced elements of the environment is the key to proper diagnosis and initiation of corrective measures. Many of the “symptoms” of problems on indoor plants are not specific. In other words, a certain symptom may be distinct and striking, but it may result from any number of imbalanced environmental elements. As you attempt to improve your diagnostic skills, do not be misled into thinking a distinct symptom should always have a specific cause.
Use the following diagnostic checklist as a guide to begin your analysis and plan for corrections.
Symptoms & Possible Causes
Brown or Scorched Leaf Tips
A) Poor root health from over watering, excessive soil dryness (especially between watering), excessive fertilizer or other soluble salts in the soil.
B) Specific nutrient toxicities (such as fluoride, copper or boron).
C) Low humidity.
D) Pesticide or mechanical injury.
Leaf spots, blotches, blemishes, blisters, or scabby spots
A) Intense light (sunburn) associated with a recent move of the plant or excessive soil dryness and wilting.
B) Chilling injury (below 50 degrees F).
C) Chemical sprays injury.
D) Over watering.
E) Fungal or bacterial infections (rare unless plants have recently come from a field or greenhouse)
Foliage yellow-green; older leaves
A) Insufficient fertilizer, especially nitrogen.
B) Poor root health due to pot-bound growth, compacted soil, or poor drainage.
C) Insufficient light.
Foliage yellow-green; newer leaves
A) Soil pH (acidity) imbalance.
B) Minor nutrient imbalance.
Foliage yellow-green; general
A) Too much light.
B) Insufficient fertilization.
C) High temperatures, especially when associated with dryness.
D) Insect infestation or root rot disease.
A) Poor root health from over watering, excessive dryness, excessive fertilizer or other soluble salts in the soil, compacted soil or pot bound roots.
B) Sudden change in light, temperature, or relative humidity.
C) Root rot disease.
Wilting or drooping of foliage
A) Poor root health from over watering, excessive dryness, excessive fertilizer or other soluble salts in the soil, compacted soil, or a poorly drained container.
B) A toxic chemical poured into soil.
Roots brown in color, soft or rotted; roots with tissue that can easily be “slipped off” leaving behind the stringlike center tissues; roots massed at top or bottom of pot. Associated with one or more of the symptoms noted above.
C) Over-or under watering.
Yellowed leaves with tiny speckling; leaves later bronzed and drying; webbing noted near growing points.
A) Spider-mite infestation.
Leaves covered with a sticky substance; dark mold growing on leaves; tiny brown or white objects seen on leaves or in crotches of branches; leaf drop or branch dieback; leaf or growing point distortion.
A) Scale or mealy bug infestation.
Adapted from Nancy J. Taylor, Stephen Nameth and Jim Chatfield, Ohio State University Extension, 2000