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Copyright 2005, Board of Trustees, University
GETTING THE MOST FROM FOLIAGE PLANTS IN THE RETAIL SHOP
Charles A. Conover i
Agricultural Research Center Apopka
Mimeo No. 72-6 U 4G 27
Retail shop managers are faced with the same problem .ewrienced
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by consumers when they maintain foliage plants under interior conriTtieona
Those most frequently encountered are foliar yellowing, abscission (leaf
drop), tip burn and size reduction. Although these problems can be
discouraging to everyone they can be prevented or controlled in the
retail shop. In addition, when proper information is supplied at point-
of-sale, the consumer also remains satisfied and becomes a repeat
To get the most from any foliage plant.- especially for the short
term period in the shop there are three main factors to consider.
The first two factors, proper light and watering, are equally important
and are the keys to successful plant maintenance. The third factor,
proper nutrition is less important in the retail shop because it is a
long-term factor and of more concern Lo the consumer. Other important
factors include temperature, humidity, growing medium, disease and
insect pests and residues on foliage. Considering the three main
factors mentioned, the way to get the most from any foliage plant in a
retail shop is (1) give adequate light, (2) always keep soil moist,
but not saturated and (3) do not fertilize for the first 3 months. On
the other hand, to obtain the least from a foliage plant in a retail
shop; (1) provide inadequate light, (2) water only when soil is dry or
keep saturated, and (3) apply excessive fertilizer. Since these
recommendations probably differ from those practices used by retail
shop managers, further clarification is provided under the separate
headings of light, watering and fertilization. Comments on some
aspects of other, but less controllable factors influencing longevity
are also discussed.
Light Unless a greenhouse is part of the retail shop, the quantity of
light available in the shop will probably be much lower than the
location in which the foliage plant was grown. However, foliage plants
will not deterioriate rapidly unless light levels are below 50 foot-
candles. Desirable lighting for foliage plants in retail shops may
vary, but should be in the range of 150 to 200 foot-candles for ten
hours a day including weekends. Less total light may be supplied
for longer periods, as long as the equivalent amount received remains
the same (200 foot-candles x 10 hours = 2000 foot-candles or 100 foot-
candles x 20 hours = 2000 foot-candles). Light quality is less
important for foliage plants than those grown primarily for their
flowers. Light sources in retail shops may be fluorescent, incandescent
or a combination of the two types. Foliage plants look best under
fluorescent lighting and usually sell best from such displays. Excess-
ively low light levels cause chlorophyll degradation (foliar yellowing),
utilization of carbohydrate (food) reserves and formation of hormones
which cause leaf abscission; any of which reduce quality of foliage
plants in the retail shop and those obtained by the consumer.
Watering Proper soil moisture is absolutely necessary for plant and
root growth and prevention of root damage from soluble salts present
in the soil medium. A soluble salt level in moist soil of up to 2000
parts per million (ppm) will not cause injury to most foliage plants
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if soil is moist, but if soil is allowed to become dry plants may be
severely injured because the salt level may double or triple the
original figure. This occurs because the level of soluble salts
depend on the amount of free water present in a soil medium, and salt
levels double each time there is a 50% reduction in soil moisture.
Resulting higher soluble salts levels often severely damage root systems
which prevents absorption of nutrients and water and may predispose
them to disease organisms. Symptoms of injury from high soluble salts
on foliage plants may appear as marginal leaf chlorosis or necrosis
of newer leaves and yellowing and dropping of older leaves.
Application of excessive water to foliage plants also creates
problems, because saturated soils exclude oxygen and often cause root
death. Saturated soil conditions may be prevented by allowing excessive
water to drain from containers with provision for drainage, tipping
small containers without drainage on their side until excessive water
is removed and using a dipstick technique on large planters and
containers without drainage. Two rules to remember for proper
watering techniques are (1) never allow the entire soil medium to
become dry (top to inch is acceptable) and (2) never allow plants
to stand in water.
Nutrition Additions of fertilizer to foliage plants for the first few
months after moving to interior locations are unnecessary. Nutritional
levels supplied by growers are adequate under reduced interior light
levels fgr up to three months, and fertilizer added by the retail shop
manager increase the probability of soluble salts damage to roots.
Therefore, retail shop managers should not only resist the temptation
to add fertilizer, but should caution consumers about the practice.
Retail shop managers sometimes add fertilizer because the plant
is not of the desired dark-green color. However, in most cases this is
unnecessary, as foliage plants will develop a darker green color under
reduced light intensities found inside retail shops.
Factors of no lesser importance, but those where the retail shop
manager often has less control include temperature, humidity, original
soil medium, pests and foliar residue.
Comfortable temperature levels for humans will also be adequate
for most foliage plants. Humidity, unfortunately, is lower in modern
building interiors than optimum for foliage plants, however, proper
watering and maintenance of adequate light levels will aid in obtaining
the most from foliage plants when low humidity exists, unless levels
are less than 20 percent.
Foliage growers use many soil mixtures, but they generally have
in common the ability to retain water and fertilizer and still provide
proper aeration. When repotting is.necessary or desired in the retail
shop, a mixture of three parts sphagnum peat and one part perlite is
suggested. One ounce of Perk and four ounces Dolomite per cubic
foot should be incorporated into this soil medium before potting to
control pH and supply needed micronutrients. Addition of six ounces
of 13-6-12 Osmocote per cubic foot is also suggested where fertilization
for a year is desired.
Unfortunately plants are sometimes received that have insect or
disease causing organisms present. Foliar diseases are usually
controlled most easily by keeping foliage dry, although this nor any
method will have an effect on already damaged areas.
Soil borne diseases (root and lower stem rots) can usually be
controlled with a soil drench of Dexon and Terraclor. Use one ounce
of Dexon and 3/4 ounce Terraclor to 6 gallons of water and apply the
equivalent of 1 pint to a 6 inch pot, 2 pints to an 8 inch and 5 pints
to a 12 inch. Terraclor may cause slight growth reductions, but this
will not be unacceptable under interior conditions. Insect pests may
be controlled systemically with Temik, but plants cannot be sold for
10 days after treatment because of possible human toxicity.
Foliar residues are undesirable, but usually present to some
degree because of pesticide sprays and use of overhead irrigation.
Two methods presently used to combat this problem are use of shine or
cleaning compounds and hand cleaning with a soft moist cloth and a
small amount of hand soap.
In summary, remember that to get the most from foliage plants in
a retail shop (1) provide adequate light, (2) always keep soil moist,
but not saturated and (3) do not fertilize for the first 3 months
unless the plant is obviously nutritionally deficient.