Purdue University
Department of Botany and Plant Pathology
Lilly Hall of Life Sciences

Plant Disease Control

BP-1-12

Houseplant Problems
Paul C. Pecknold, Extension Plant Pathologist

Houseplant problems can often be avoided
by knowing the proper environment in which
a plant should be grown and placing the plant
in that environment -- as best you can.
Houseplants are often plagued, however, with
certain disease and disorder problems which
are not so easily avoided and which require
specific cultural and/or chemical controls.
The most effective way to Control indoor
plant diseases or disorders is to prevent
them before they get started. Prevention be-
gins before the plant is purchased, Inspect
the plant before you buy it! Look for indica-
tions that the plant has a good root system.
Newly formed leaves (which are pale green
in contrast to the dark green of older leaves)
and new shoots or buds indicate the plant is
indeed growing, not just surviving.
"Clean" soil or planting media will/help
prevent problems caused by various disease
or insect pests. The use of prepared plant-
ing media pre-packaged for purchase is the
most certain way of getting clean soil. If
you use a home-made mix containing garden
soil, pasteurize it prior to use. Put the mix
in a shallow baking dish in a two-inch deep
layer; be sure the soil is moist but not wet.
Raise the temperature to 180 degrees F for 20
minutes. Also sterilize old pots, utensils,
etc. by boiling in water for 30 minutes or
rinsing in a Chlorox bleach solution diluted
1:10 in water.
To help in determining the cause(s) of
plant problems the list at the top of page 2
describes problem symptoms and their most
probable causes. Remember that more than
one factor may be the cause of a problem
and that symptoms may often overlap in
their appearance.

Causes and Controls
A. Root rot: The most common prob-
lem with houseplants is root rot. Several
factors may cause the roots of a plant to rot;
but, without doubt, the number one reason
is overwatering. Excessive watering causes
an oxygen deficiency in the soil resulting in
root death and subsequent rot. Often certain
soil-borne fungi and bacteria will invade
root systems which are weakened by an oxy-
gen deficiency. Heavy soils (containing too
much clay) and containers that lack adequate
drainage water holes will often be associated
with overwatering and aggravate the problem.

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Agriculture Cooperating. H. G. Diesslin, Director, West Lafayette, Ind. Issued in furtherance of the Acts of May 8 and June 30,
1914. It is the policy of the Cooperative Extension Service of Purdue University that all persons shall have equal opportunity
and access to its programs and facilities without regard to race, religion, color, sex or national origin.