University of Vermont Extension
Department of Plant and Soil Science
Dr. Leonard Perry, Extension
University of Vermont
Whether you bought new houseplants
recently, or have some several years old, if they aren’t looking
be able to figure out the problem yourself by a simple diagnosis.
There are several symptoms to watch for
relating to leaves, growth, and flowers if appropriate. Unless
one of the main pests—aphids,
scales, spider mites, or mealybugs—the problems likely are caused
culture (often called “physiological”).
Diseases, such as leaf spots and root rots, often come about as a
of poor culture.
Probably the number one cause of
problems is overwatering. This can lead
to most problems, except bending or curling leaves, or leaf
Even if a plant wilts, this may be a sign of
overwatering. Roots may be waterlogged
and rotting, so unable to take up water even if the soil is wet.
doubt about whether to water, don’t,
and wait a day or two.
If a plant is wilted, and the soil
is dry, it likely needs water. Other
causes of wilt may be too much light or too high temperature, too much
fertilizer (burning the roots so they don’t function), compacted
isn’t absorbed well), and drafts (this is especially a problem on
such as poinsettias).
Yellowish green (often called
“chlorotic”) leaves are most often a sign of low
causes though might be too much or too
low light or temperature, too much water or fertilizer, compacted soil,
pollution (as from gas leaks or incomplete burning in stoves).
If leaves are starting to drop, are
all dropping or just older ones? If the
latter, this may be natural
as the plant grows. Too little light,
too high temperature, or root problems from improper watering
and fertilizer also may be to blame. Too
much or too little water, too much fertilizer, or air pollution may be
cause if suddenly all leaves begin dropping off, not just the older
Often indoors growth may become weak
and thin, and new leaves small. If this
is the case, examine whether plants are getting too little light, too
temperatures, or both. Lack of
fertilizer, or compacted soil, also may cause weak growth. If
new leaves are small, make sure
you don’t have air pollution.
If growth has stopped, or in the
worse case the plant died, this could be from low temperatures (as
tender plants to freezing between a store and your car, or in an
or garage). Symptoms from cold
temperatures are usually sudden. Slower
causes of no growth or death include overwatering, too little water, or
If your plant is supposed to flower
and has buds, but they don’t develop and drop off, most any cause
much light may be to blame. If flowers
don’t last as long as they have in the past, or come and go
the temperature isn’t too high, the plants aren’t too dry,
affecting them, or there isn’t air pollution.
If there aren’t any blooms, and there should be, plants may have
light, too much heat, or both. Some
plants form flowers only when the day (actually night) is a certain
length. Poinsettias, in general, need at
least 14 hours of uninterrupted darkness during a 10-week period in the
order to flower.
Plants often tell you what is wrong
by their symptoms. If you want to make
sure of your diagnosis, or can’t figure it out, check with your
greenhouse or garden center professionals.